The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production ...The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min<sup>-1</sup>, 5358.1461 J·mol<sup>-1</sup>, 1383.03691 min<sup>-1</sup>, 51577.6100 J·mol<sup>-1</sup> respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. Organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.展开更多
Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily h...Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily hydrolyzed to release cyanide salt compounds which is toxic to the nervous system especially the optic nerve, sometimes leading to optic neuropathy and visual impairment. Aim: The aim of this study is to find out the impact of selected processing methods of high-level cyanide in cassava on optic neuropathy in Wistar albino rats. Methodology: Twenty-four Wistar albino rats were fed with different concentration and duration of predetermined high-cyanide content cassava root cultivar which was processed using different processing methods adopted by various communities in Rivers State, Nigeria (for human consumption). A control group of 3 Wistar albino rats was fed with normal “Growth Mesh” meals. The pre and post weights of the animals and the fundoscopic optic nerve status of the rats were evaluated after 30 and 60 days. SPSS Version 25 was employed for descriptive and inferential statistical analyses. A p-value of ≤0.05 was considered statistically significant. Results: The Cassava species available in Rivers State have high cyanide content (2336.79 mg CN<sup>-</sup>/kg dry weight of cassava). There was statistically significant reduction in the cyanide content (p = 0.000) depending on the various common processing methods (into garri for human consumption): 24 hours, 48 hours, fermentation;with and without red palm oil additive. The individual weights as well as the mean weight of the 24 rats in the experimental group increased gradually from the first week to the 9<sup>th</sup> week with a slight weight reduction on the third and fourth weeks which was not statistically significant (p = 0.092). However, there was a steady increase in the weights of the animals in the control group throughout the 9 weeks. Varying degrees of optic neuropathy occurred, worse with the rats that had 24-hour fermented cassava twice daily for 60 days. The intra and inter group differences in the optic disc changes was statistically significant (p = 0.000). Conclusion: Longer duration of processing cassava roots into garri for human consumption reduces its cyanide content and minimizes the adverse impact on the optic nerve.展开更多
Soy protein isolate and egg white protein were added to cassava-banana gluten-free pasta and the effects on the nutritional quality,digestibility properties,protein digestibility corrected amino acid(PDCAA),and sensor...Soy protein isolate and egg white protein were added to cassava-banana gluten-free pasta and the effects on the nutritional quality,digestibility properties,protein digestibility corrected amino acid(PDCAA),and sensory acceptance of the pasta was observed.Banana-cassava composite flour(75:25)was blended with soy protein isolate or egg white protein at the following rates:0,5,10,and 15 g/100 g flour.Cooked pasta samples were analysed for total phenolic content(TPC),antioxidant activity,amino acid profiles,protein content,starch digestibility,protein digestibility and protein digestibility corrected amino acid score(PDCAAS).Addition of both proteins decreased starch digestibility,increased protein digestibility,improved the balance of the amino acid profile,and PDCAAS whereas only soy protein isolate enhanced the TPC and antioxidant capacity of the banana-cassava pasta.An egg white protein-fortified banana-cassava pasta had better customer acceptance and purchase intent than soy protein isolate inclusion.展开更多
Soil salinity affects the expression of serine/arginine-rich(SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.We previously identified the cassava spliceosomal...Soil salinity affects the expression of serine/arginine-rich(SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.We previously identified the cassava spliceosomal component 35 like(SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses.However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich(RS) subfamily in response to salt stress remains to be explored.In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions.Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses.Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes.However,overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA.Moreover, the MeRS40 protein interacted with MeU1-70Ks(MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively.Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants.展开更多
Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomainleucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars.However, the role ...Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomainleucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars.However, the role of MeHDZ14 in cassava growth regulation has remained unclear. Here we report that MeHDZ14 affected plant height, such that a dwarf phenotype and altered internode elongation were observed in transgenic cassava lines. MeHDZ14 was found to negatively regulate the biosynthesis of lignin. Its overexpression resulted in abaxially rolled leaves. The morphogenesis of leaf epidermal cells was inhibited by overexpression of MeHDZ14, with decreased auxin and gibberellin and increased cytokinin contents. MeHDZ14 was found to regulate many drought-responsive genes, including genes involved in cell wall synthesis and expansion. MeHDZ14 bound to the promoter of caffeic acid 3-Omethyltransferase 1(MeCOMT1), acting as a transcriptional repressor of genes involved in cell wall development. MeHDZ14 appears to act as a negative regulator of internode elongation and epidermal cell morphogenesis during cassava leaf development.展开更多
Chilling-induced accumulation of reactive oxygen species(ROS) is harmful to plants,which usually produce anthocyanins to scavenge ROS as protection from chilling stress.As a tropical crop,cassava is hypersensitive to ...Chilling-induced accumulation of reactive oxygen species(ROS) is harmful to plants,which usually produce anthocyanins to scavenge ROS as protection from chilling stress.As a tropical crop,cassava is hypersensitive to chilling,but the biochemical basis of this hypersensitivity remains unclear.We previously generated Me MYB2-RNAi transgenic cassava with increased chilling tolerance.Here we report that Me MYB2-RNAi transgenic cassava accumulated less ROS but more cyanidin-3-O-glucoside than the wild type under early chilling stress.Under this stress,the anthocyanin biosynthesis pathway was more active in Me MYB2-RNAi lines than in the wild type,and several genes involved in the pathway,including Me TT8,were up-regulated by Me MYB2-RNAi in the transgenic cassava.Me MYB2 bound to the Me TT8 promoter and blocked its expression under both normal and chilling conditions,thereby inhibiting anthocyanin accumulation.Me TT8 was shown to bind to the promoter of Dihydroflavonol 4-reductase(Me DFR-2)and increased Me DFR-2 expression.Me MYB2 appears to act as an inhibitor of chilling-induced anthocyanin accumulation during the rapid response of cassava to chilling stress.展开更多
The present study evaluated the stabilizing effect of starch produced from corns and cassava on the stability of cow milk yogurt. A sample of both corn and cassava starch was selected and used in the yogurt making as ...The present study evaluated the stabilizing effect of starch produced from corns and cassava on the stability of cow milk yogurt. A sample of both corn and cassava starch was selected and used in the yogurt making as stabilizers. The yogurt samples have been analyzed for their WHC, syneresis and protein content. The yogurt with no added starch has found to have very low WHC and high syneresis compared to other samples. The yogurt made with the addition of corn starch as a stabilizer was highly accepted than the yogurt with cassava starch and the yogurt without starch. The findings from this study provide an alternative to add the value of local corns and cassava.展开更多
A better understanding of population structure and genetic diversity among cassava germplasm for African cassava mosaic disease and fresh root yield traits is useful for cassava improvement programme. Phenotype-based ...A better understanding of population structure and genetic diversity among cassava germplasm for African cassava mosaic disease and fresh root yield traits is useful for cassava improvement programme. Phenotype-based selection for these traits is cumbersome due to phenotypic plasticity and difficulty in screening of phenotypic-induced variations. This study assessed quantitative trait loci (QTL) regions associated with African cassava mosaic disease (ACMD) and fresh storage root yield (FSRY) in 131 cassava (Manihot esculenta) genotypes using a genome-wide association study (GWAS). The single nucleotide polymorphism (SNP) loci and associated candidate genes, when validated, would be a valuable resource for marker-assisted selection in the breeding process for development of new cassava genotypes with improved resistance to ACMD and desirable high root yield. Population structure analysis using 12,500 SNPs differentiated the 131 genotypes into five distinct sub-groups (K = 5). Marker-trait association (MTA) analysis using the generalized linear model identified two QTL regions significant for ACMD and three for FSRY. This study demonstrated that DArTseq markers are useful genomic resources for genome-wide association studies of ACMD and FSRY traits in cassava for the acceleration of varietal development and release.展开更多
It has been observed that farmers adopt only a small number of the “improved” cultivars. A nationwide germplasm collection exercise in February 2018 provided the opportunity to collect indigenous technical knowledge...It has been observed that farmers adopt only a small number of the “improved” cultivars. A nationwide germplasm collection exercise in February 2018 provided the opportunity to collect indigenous technical knowledge (ITK) of the diversity of cassava varieties in terms of: their morphology, growth characteristics, uses (of tubers and leaves) and desirable characteristics. The objective is to see to what extent the objectives of the plant breeders are consistent with what farmers’ value. We performed 405 structured and semi-structured interviews with informants who were selected based on “purposive household sampling”. We found a considerable turn-over in cassava varieties, just over a third (45) have been in cultivation for at least 40 years, however, since the end of the civil war an additional 25 varieties are cultivated, while others varieties seem to have disappeared. One major issue with estimating turnover of varieties is whether the same variety might have several local names, and conversely the same name may be applied to different cultivars. Farmers overwhelmingly use ITK to select and preserve cassava germplasm for future use. Farmers have a clear preference for: sweet taste, high yield, early maturity and easy cooking and preferentially adopt cultivars that have those qualities. Cassava is primarily a human food eaten boiled or fried, some are processed into fufu and gari, and uses as livestock feed and medicine are reported but at low levels. The information produced during this study could help plant breeders choose selection criteria that will ensure their efforts are adopted and sustainable, the importance of preserving the genetic resources of local cultivars is also highlighted.展开更多
Cassava mosaic disease (CMD) caused by Cassava Mosaic Begomoviruses (CMBs) is one of the most devastating crop diseases and a major constraint for cassava production. In order to ensure surveillance for epidemic preve...Cassava mosaic disease (CMD) caused by Cassava Mosaic Begomoviruses (CMBs) is one of the most devastating crop diseases and a major constraint for cassava production. In order to ensure surveillance for epidemic prevention, low-cost diagnostic tools are appropriate for large-scale testing of cassava viruses. Multiplex PCR diagnosis is one approach that can reduce diagnostic costs and delays. A multiplex PCR approach was developed for simultaneous detection of African cassava mosaic virus (ACMV), East African Cassava Mosaic Virus and East African cassava mosaic Cameroon virus (EACMV/CM) in Togo CMD-infected cassava leaves. Three primers pairs were used to target their respective viruses in a single tube PCR. Multiplex PCR detected ACMV, EACMV and EACMV/CM in plant DNA extracts prepared from cassava leaves infected with CMB. The primers amplified 783 bp specific to ACMV, 650 bp specific to EACMV and 560 bp specific to EACMCV/CM in both uniplex and multiplex formats. Multiplex PCR is an excellent tool for the effective control of cassava diseases. .展开更多
The current study deals Swith thermo-mechanical properties of stabilized soil small bricks with the help of organic binders of sugar cane molasses and cassava starch. Different formulations of soil concrete have been ...The current study deals Swith thermo-mechanical properties of stabilized soil small bricks with the help of organic binders of sugar cane molasses and cassava starch. Different formulations of soil concrete have been suggested after the geotechnical characterization of samples of soil was taken. From these, it arises that the studied soil is the most plastically clay (of type A<sub>3</sub>) according to GTR classification. Samples made of small bricks and measured out at 4%, 6% and 8% of binders (molasses, starch or molasses + starch) have been warmed up to different temperatures (100°C, 150°C, 200°C and 250°C) for the rising of the thermic behavior under different conditions and submitted to crushing testings for the estimation of characteristic resistances to the compression. According to the mechanical behavior, we note an improvement of resistances for small bricks measured 4%, 6% and 8%, of molasses respectively of 32.44%, 32.06% and 23.43% against the value of reference for small bricks without molasses. In the same way, the binder (molasses + starch) also reveals an improvement of resistance to the compression of 13.27%, 26.17% and 26.17%. On the contrary, the stabilization with the starch binder did not bring a significative improvement. According to the thermic influence, the heating at 100°C of stabilized small bricks at 4%, 6% and 8% of molasses, reveals a significative improvement of resistances. Moreover, the stabilization with the starch reveals on the contrary a good behavior for heatings at 150°C and 250°C. In short, for the binder (molasses + starch), it is the heating at 200°C that shows some improvements of remarkable resistances. Different analyses of realized statistics also show the effectivity of obtained results. For all realized formulations, the measuring out at 6% of binders (molasses, or molasses + starch) seems as optimal in front of the best thermo-mechanical revealed properties.展开更多
Cassava-groundnut intercropping is not a common practice among smallholder farmers in Sierra Leone even though both crops are well suited for intercropping. On-farm trials were conducted in three locations (Bai Largor...Cassava-groundnut intercropping is not a common practice among smallholder farmers in Sierra Leone even though both crops are well suited for intercropping. On-farm trials were conducted in three locations (Bai Largor, Bassah, and Njala Kanima) in the Moyamba district during the 2021 cropping season to investigate the efficacy of cassava-groundnut intercropping for increasing crop productivity and soil organic carbon stock on smallholder farms in the Moyamba district, Southern Sierra Leone. The experimental design was a randomized complete block design in three replications with treatments of sole groundnut, sole cassava and cassava-groundnut intercropping. Data on the yield and yield components of cassava and groundnut were analysed using the PROC MIXED procedure of SAS 9.4 and means were compared using the standard error of difference (SED). The above-ground biomass, number of roots per plant, and fresh root yield of cassava were not significantly (p > 0.05) affected by the cassava-based cropping system. Averaged across locations, intercropping cassava with groundnut decreased the above-ground biomass, the number of roots per plant, and fresh root yield of cassava by 17%, 11%, and 17%, respectively. The above-ground biomass, number of pods per plant and fresh pod yield of groundnut were significantly (p 1), the highest net revenue and benefit-cost ratio. The benefit-cost ratio was also favourable for the sole cassava (BCR > 1) but not favourable for the sole groundnut (BCR < 1). Averaged across locations, intercropping cassava with groundnut increased the benefit-cost ratio by 121% and 13% when compared to the sole groundnut and sole cassava. In the event of a 40% yield loss for the cassava and groundnut, the benefit-cost ratio was favourable (1.12) only for the cassava groundnut intercropping system. The net soil organic carbon stock was favourable only for the cassava-groundnut intercrop. Averaged across locations, the net soil organic carbon for the cassava-groundnut intercropping increased by 3.4% when compared to the baseline within one cropping cycle of the cassava (12 months). The results confirm that cassava-groundnut intercropping is a sustainable land management practice that could enhance crop productivity and soil organic carbon stock on smallholder farms.展开更多
Cassava productivity is hampered by pests and diseases including cassava<span style="font-family:;" "=""><span style="font-family:Verdana;"> mosaic disease (CMD) and cass...Cassava productivity is hampered by pests and diseases including cassava<span style="font-family:;" "=""><span style="font-family:Verdana;"> mosaic disease (CMD) and cassava brown streak disease (CBSD).</span><b> </b><span style="font-family:Verdana;">The main ob</span><span style="font-family:Verdana;">jective of this study was to identify stable superior genotypes that combine</span><span style="font-family:Verdana;"> dis</span><span style="font-family:Verdana;">ease resistance and high yield. Sixteen cassava genotypes were planted in a</span> <span style="font-family:Verdana;">randomized complete block design with three replications for six planting </span><span style="font-family:Verdana;">seasons (years) at five sites in Tanzania. The genotypes were assessed using the additive main effect and multiplicative interaction (AMMI) analysis, and highly significant (</span></span><span style="font-family:Verdana;">P </span><span style="font-family:Verdana;">< 0.001) effects of genotype, environment, and genotype-</span><span style="font-family:;" "=""><span style="font-family:Verdana;">by-environment (</span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;">) interactions were observed for all traits studied. Per</span><span style="font-family:Verdana;">cent sum of squares (SS) due to environment (12.66% - 85.23%) was the</span><span style="font-family:Verdana;"> highest followed by </span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;"> (14.12% - 39.56%) for CMD foliar symptoms, root weight and dry matter. On the other hand, % SS due to genotype (52.14% - 69.14%) </span><span><span style="font-family:Verdana;">was highest followed by </span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;"> (26.14% - 35.91%) for CBSD foliar and root</span></span><span style="font-family:Verdana;"> symptoms indicating that the environment and </span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;"> greatly influenced trait expression. The most stable genotypes which combined disease resistance and high yield were NDL 2003/31 and NDL 2003/111. The findings of this study will give impetus for the release of new cassava varieties that are not only high yielding but are also dually resistant to both CMD and CBSD in different locations and sites.</span></span>展开更多
One-pot achievement of ethyl levulinate from cassava was conducted in ethanol-water system over several simple sulfate salt catalysts.Al_2(SO_4)_3 catalyst had the best performance in synthesizing ethyl levulinate com...One-pot achievement of ethyl levulinate from cassava was conducted in ethanol-water system over several simple sulfate salt catalysts.Al_2(SO_4)_3 catalyst had the best performance in synthesizing ethyl levulinate comparing with those of a series of sulfate salts.The highest yields of ethyl levulinate was up to39.27%as well as 7.78%levulinate acid when cassava was catalyzed in ethanol medium by adding 10 wt%water.^(13)C and ~1H NMR spectroscopic investigations confirmed that isomerization of glucose to fructose over Al_2(SO_4)_3 catalyst is an important step in producing ethyl levulinate and levulinate acid.Due to aggregations of Al^(3+) under hydrothermal conditions,tiny amount of Al^(3+) were detected in filtrate at the percentage of 0.32%even if in absolute water.Bronsted and Lewis acids could improve the yield of ethyl levulinate and levulinate acid by synergistic effect.All results suggested that A1_2(SO_4)_3 was a simple and efficient catalyst for ethyl levulinate and levulinate acid production.展开更多
Cassava(Manihot esculenta Crantz) is an important root crop worldwide. It exhibits substantial differential genotypic responses to varying environmental conditions, a phenomenon termed genotype × environment inte...Cassava(Manihot esculenta Crantz) is an important root crop worldwide. It exhibits substantial differential genotypic responses to varying environmental conditions, a phenomenon termed genotype × environment interaction(GEI). A significant GEI presents challenges in the selection of superior genotypes. The objective of this study was to examine the effect of genotype,environment and GEI on early fresh storage root yield(FSRY) and related traits in cassava.Accordingly, 12 cassava genotypes were evaluated in a randomised complete block design at three contrasting locations(Jinja, Nakasongola and Namulonge) in Uganda. Trials were harvested nine months after planting and the data collected were analysed using the additive main effects and multiplicative interaction(AMMI) model. The AMMI analysis of variance showed significant variation among genotypes for early FSRY and all other traits assessed.Locations were significantly different for all traits except for cassava brown streak disease root necrosis. The GEI effect was non-significant for early FSRY, but significant for other traits. For early FSRY, 48.5% of the treatment sum of squares was attributable to genotypes, 27.3% to environments, and 24.1% to GEI, indicating a predominance of genotypic variation for this trait.Predominance of genotypic variation was also observed for all the other traits. A majority of the genotypes(67%) had low interaction effects with locations for early FSRY, with Akena, CT2, CT4 and NASE14 being the most stable genotypes for the trait. Significant negative correlation was observed between cassava mosaic disease severity and early FSRY and storage root number,indicating significant negative effects of cassava mosaic disease on early FSRY and stability in cassava. The information generated will inform future selection initiatives for superior early-yielding cassava genotypes combining resistance to cassava mosaic and brown streak diseases in Uganda.展开更多
A new cleaner production process for cassava ethanol has been developed, in which the thin stillage by-product was treated initially by anaerobic digestion, and the digestate further processed by hydrogen-form cation ...A new cleaner production process for cassava ethanol has been developed, in which the thin stillage by-product was treated initially by anaerobic digestion, and the digestate further processed by hydrogen-form cation exchange resin before being recycled as process water to make mash for the next ethanol fermentation batch.Thus wastewater was eliminated and freshwater and energy consumption was significantly reduced. To evaluate the new process, ten consecutive batches of ethanol fermentation and anaerobic digestion at lab scale were carried out. Average ethanol production in the recycling batches was 11.43%(v/v) which was similar to the first batch, where deionized(DI) water was used as process water. The chemical oxygen demand(COD) removal rate reached 98% and the methane yield was 322 ml per gram of COD removed, suggesting an efficient and stable operation of the anaerobic digestion. In conclusion, the application of the new process can contribute to sustainable development of the cassava ethanol industry.展开更多
The globally invasive cassava mealybug Phenacoccus manihoti Matile-Ferrero is a pernicious pest of cassava,and its recent introduction into Asia has raised considerable alarm.To slow or prevent further invasion,an acc...The globally invasive cassava mealybug Phenacoccus manihoti Matile-Ferrero is a pernicious pest of cassava,and its recent introduction into Asia has raised considerable alarm.To slow or prevent further invasion,an accurate,simple,and developmental-stage-independent detection method for P.manihoti is required.In the present study,a PCR method based on a species-specific mitochondrial DNA cytochrome oxidase I(SS-COI)marker was developed for rapid identification of P.manihoti.One pair of SS-COI primers(PMSSZW-1F and PMSSZW-1R)was designed based on sequence variations in the COI gene among P.manihoti and related mealybug species.Specificity of the primer pair was validated on 21 closely related species.Sensitivity tests were performed on four immature developmental stages and female adults.Efficacy tests demonstrated that at the relatively low concentration of(135.2±14.7)pgresuspended DNA,the specific fragment was detected in all replicates.Furthermore,the SS-COI primer pair was assayed on three populations of P.manihoti from major exporting countries of cassava.The PCR assay was proved to be a rapid,simple,and reliable molecular measure for the identification of P.manihoti.This tool will be useful for quarantine,monitoring,and management of this invasive pest.展开更多
Cassava is an important tropical cash crop. Severe drought stresses affect cassava productivity and quality, and cause great economic losses in agricultural production. Enhancing the drought tolerance of cassava can e...Cassava is an important tropical cash crop. Severe drought stresses affect cassava productivity and quality, and cause great economic losses in agricultural production. Enhancing the drought tolerance of cassava can effectively improve its yield. Long non-coding RNAs(lncRNAs) are present in a wide variety of eukaryotes. Recently, increasing evidence has shown that lncRNAs play a critical role in the responses to abiotic stresses. However, the function of cassava lncRNAs in the drought response remains largely unknown. In this study, we identified a novel lncRNA, DROUGHT-INDUCED INTERGENIC lncRNA(DIR). Gene expression analysis showed that DIR was significantly induced by drought stress treatment, but did not respond to abscisic acid(ABA) or jasmonic acid(JA) treatments. In addition, overexpression of the DIR gene enhanced proline accumulation and drought tolerance in transgenic cassava. RNA-seq analysis revealed that DIR preferentially affected drought-related genes that were linked to transcription and metabolism. Moreover, RNA pull-down mass spectrometry analysis showed that DIR interacted with 325 proteins. A protein–protein interaction(PPI)analysis found a marked enrichment in proteins associated with the mRNA export and protein quality control pathways.Collectively, these results suggest that DIR and its interacting proteins that regulate mRNA or protein metabolism are involved in mediating the drought stress response. Thus, regulating DIR expression has potential for improving cassava yield under drought conditions.展开更多
Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 1...Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.展开更多
As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is us...As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is usually cultivated on hilly areas that are nutrient-poor. Nitrogen(N) is one of the significant factors affecting cassava yield. A double factorial(N level×genotypes) split-plot field experiment was conducted to analyze differences in yield and N accumulation of 25 cassava genotypes under low-N conditions to screen for cassava genotypes with high-N efficiency. The two-year field experiment showed that cassava yield and N accumulation are determined by specific genotypes, soil N levels, and year. Among these factors, soil N levels are the main factors that are responsible for differences in cassava yield. When yield and relative N accumulation under low-N conditions were used as screening markers, we identified an efficient and responsive genotype(SC10), and two inefficient and non-responsive genotypes(SC205 and GR5). The efficient and responsive genotype and the inefficient and non-responsive genotype can be used as study materials to further reveal the mechanisms for high-N efficiency in cassava.展开更多
文摘The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min<sup>-1</sup>, 5358.1461 J·mol<sup>-1</sup>, 1383.03691 min<sup>-1</sup>, 51577.6100 J·mol<sup>-1</sup> respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. Organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.
文摘Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily hydrolyzed to release cyanide salt compounds which is toxic to the nervous system especially the optic nerve, sometimes leading to optic neuropathy and visual impairment. Aim: The aim of this study is to find out the impact of selected processing methods of high-level cyanide in cassava on optic neuropathy in Wistar albino rats. Methodology: Twenty-four Wistar albino rats were fed with different concentration and duration of predetermined high-cyanide content cassava root cultivar which was processed using different processing methods adopted by various communities in Rivers State, Nigeria (for human consumption). A control group of 3 Wistar albino rats was fed with normal “Growth Mesh” meals. The pre and post weights of the animals and the fundoscopic optic nerve status of the rats were evaluated after 30 and 60 days. SPSS Version 25 was employed for descriptive and inferential statistical analyses. A p-value of ≤0.05 was considered statistically significant. Results: The Cassava species available in Rivers State have high cyanide content (2336.79 mg CN<sup>-</sup>/kg dry weight of cassava). There was statistically significant reduction in the cyanide content (p = 0.000) depending on the various common processing methods (into garri for human consumption): 24 hours, 48 hours, fermentation;with and without red palm oil additive. The individual weights as well as the mean weight of the 24 rats in the experimental group increased gradually from the first week to the 9<sup>th</sup> week with a slight weight reduction on the third and fourth weeks which was not statistically significant (p = 0.092). However, there was a steady increase in the weights of the animals in the control group throughout the 9 weeks. Varying degrees of optic neuropathy occurred, worse with the rats that had 24-hour fermented cassava twice daily for 60 days. The intra and inter group differences in the optic disc changes was statistically significant (p = 0.000). Conclusion: Longer duration of processing cassava roots into garri for human consumption reduces its cyanide content and minimizes the adverse impact on the optic nerve.
文摘Soy protein isolate and egg white protein were added to cassava-banana gluten-free pasta and the effects on the nutritional quality,digestibility properties,protein digestibility corrected amino acid(PDCAA),and sensory acceptance of the pasta was observed.Banana-cassava composite flour(75:25)was blended with soy protein isolate or egg white protein at the following rates:0,5,10,and 15 g/100 g flour.Cooked pasta samples were analysed for total phenolic content(TPC),antioxidant activity,amino acid profiles,protein content,starch digestibility,protein digestibility and protein digestibility corrected amino acid score(PDCAAS).Addition of both proteins decreased starch digestibility,increased protein digestibility,improved the balance of the amino acid profile,and PDCAAS whereas only soy protein isolate enhanced the TPC and antioxidant capacity of the banana-cassava pasta.An egg white protein-fortified banana-cassava pasta had better customer acceptance and purchase intent than soy protein isolate inclusion.
基金supported by grants from the Talent Program of Guangdong Academy of Sciences, China(2021GDASYL-20210103038, 2020GDASYL-2020102011,and 2021GDASYL-20210103036)the National Natural Science Foundation of China(32171292 and 32100294)+2 种基金the Guangdong Pearl River Talents Program, China(2021CX02N173)the China Postdoctoral Science Foundation(2020M682629)the Zhanjiang Plan for Navigation, China(211207157080997)。
文摘Soil salinity affects the expression of serine/arginine-rich(SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.We previously identified the cassava spliceosomal component 35 like(SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses.However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich(RS) subfamily in response to salt stress remains to be explored.In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions.Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses.Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes.However,overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA.Moreover, the MeRS40 protein interacted with MeU1-70Ks(MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively.Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants.
基金supported by the China Agriculture Research System (CARS11-HNCX)the Major Science and Technology Plan of Hainan Province (ZDKJ2021012)+3 种基金the Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (1630052022008)the National Key Research and Development Program of China (2018YFD1000501)the National Natural Science Foundation of China (31501378)the Hainan Yazhou Bay Seed Lab (B21HJ0303)。
文摘Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomainleucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars.However, the role of MeHDZ14 in cassava growth regulation has remained unclear. Here we report that MeHDZ14 affected plant height, such that a dwarf phenotype and altered internode elongation were observed in transgenic cassava lines. MeHDZ14 was found to negatively regulate the biosynthesis of lignin. Its overexpression resulted in abaxially rolled leaves. The morphogenesis of leaf epidermal cells was inhibited by overexpression of MeHDZ14, with decreased auxin and gibberellin and increased cytokinin contents. MeHDZ14 was found to regulate many drought-responsive genes, including genes involved in cell wall synthesis and expansion. MeHDZ14 bound to the promoter of caffeic acid 3-Omethyltransferase 1(MeCOMT1), acting as a transcriptional repressor of genes involved in cell wall development. MeHDZ14 appears to act as a negative regulator of internode elongation and epidermal cell morphogenesis during cassava leaf development.
基金supported by the Hainan Provincial Natural Science Foundation of China (322RC798)the National Key Research and Development Program of China (2018YFD1000501)+1 种基金the Major Science and Technology Plan of Hainan Province (ZDKJ2021012)the China Agriculture Research System (CARS11-HNCX)。
文摘Chilling-induced accumulation of reactive oxygen species(ROS) is harmful to plants,which usually produce anthocyanins to scavenge ROS as protection from chilling stress.As a tropical crop,cassava is hypersensitive to chilling,but the biochemical basis of this hypersensitivity remains unclear.We previously generated Me MYB2-RNAi transgenic cassava with increased chilling tolerance.Here we report that Me MYB2-RNAi transgenic cassava accumulated less ROS but more cyanidin-3-O-glucoside than the wild type under early chilling stress.Under this stress,the anthocyanin biosynthesis pathway was more active in Me MYB2-RNAi lines than in the wild type,and several genes involved in the pathway,including Me TT8,were up-regulated by Me MYB2-RNAi in the transgenic cassava.Me MYB2 bound to the Me TT8 promoter and blocked its expression under both normal and chilling conditions,thereby inhibiting anthocyanin accumulation.Me TT8 was shown to bind to the promoter of Dihydroflavonol 4-reductase(Me DFR-2)and increased Me DFR-2 expression.Me MYB2 appears to act as an inhibitor of chilling-induced anthocyanin accumulation during the rapid response of cassava to chilling stress.
文摘The present study evaluated the stabilizing effect of starch produced from corns and cassava on the stability of cow milk yogurt. A sample of both corn and cassava starch was selected and used in the yogurt making as stabilizers. The yogurt samples have been analyzed for their WHC, syneresis and protein content. The yogurt with no added starch has found to have very low WHC and high syneresis compared to other samples. The yogurt made with the addition of corn starch as a stabilizer was highly accepted than the yogurt with cassava starch and the yogurt without starch. The findings from this study provide an alternative to add the value of local corns and cassava.
文摘A better understanding of population structure and genetic diversity among cassava germplasm for African cassava mosaic disease and fresh root yield traits is useful for cassava improvement programme. Phenotype-based selection for these traits is cumbersome due to phenotypic plasticity and difficulty in screening of phenotypic-induced variations. This study assessed quantitative trait loci (QTL) regions associated with African cassava mosaic disease (ACMD) and fresh storage root yield (FSRY) in 131 cassava (Manihot esculenta) genotypes using a genome-wide association study (GWAS). The single nucleotide polymorphism (SNP) loci and associated candidate genes, when validated, would be a valuable resource for marker-assisted selection in the breeding process for development of new cassava genotypes with improved resistance to ACMD and desirable high root yield. Population structure analysis using 12,500 SNPs differentiated the 131 genotypes into five distinct sub-groups (K = 5). Marker-trait association (MTA) analysis using the generalized linear model identified two QTL regions significant for ACMD and three for FSRY. This study demonstrated that DArTseq markers are useful genomic resources for genome-wide association studies of ACMD and FSRY traits in cassava for the acceleration of varietal development and release.
文摘It has been observed that farmers adopt only a small number of the “improved” cultivars. A nationwide germplasm collection exercise in February 2018 provided the opportunity to collect indigenous technical knowledge (ITK) of the diversity of cassava varieties in terms of: their morphology, growth characteristics, uses (of tubers and leaves) and desirable characteristics. The objective is to see to what extent the objectives of the plant breeders are consistent with what farmers’ value. We performed 405 structured and semi-structured interviews with informants who were selected based on “purposive household sampling”. We found a considerable turn-over in cassava varieties, just over a third (45) have been in cultivation for at least 40 years, however, since the end of the civil war an additional 25 varieties are cultivated, while others varieties seem to have disappeared. One major issue with estimating turnover of varieties is whether the same variety might have several local names, and conversely the same name may be applied to different cultivars. Farmers overwhelmingly use ITK to select and preserve cassava germplasm for future use. Farmers have a clear preference for: sweet taste, high yield, early maturity and easy cooking and preferentially adopt cultivars that have those qualities. Cassava is primarily a human food eaten boiled or fried, some are processed into fufu and gari, and uses as livestock feed and medicine are reported but at low levels. The information produced during this study could help plant breeders choose selection criteria that will ensure their efforts are adopted and sustainable, the importance of preserving the genetic resources of local cultivars is also highlighted.
文摘Cassava mosaic disease (CMD) caused by Cassava Mosaic Begomoviruses (CMBs) is one of the most devastating crop diseases and a major constraint for cassava production. In order to ensure surveillance for epidemic prevention, low-cost diagnostic tools are appropriate for large-scale testing of cassava viruses. Multiplex PCR diagnosis is one approach that can reduce diagnostic costs and delays. A multiplex PCR approach was developed for simultaneous detection of African cassava mosaic virus (ACMV), East African Cassava Mosaic Virus and East African cassava mosaic Cameroon virus (EACMV/CM) in Togo CMD-infected cassava leaves. Three primers pairs were used to target their respective viruses in a single tube PCR. Multiplex PCR detected ACMV, EACMV and EACMV/CM in plant DNA extracts prepared from cassava leaves infected with CMB. The primers amplified 783 bp specific to ACMV, 650 bp specific to EACMV and 560 bp specific to EACMCV/CM in both uniplex and multiplex formats. Multiplex PCR is an excellent tool for the effective control of cassava diseases. .
文摘The current study deals Swith thermo-mechanical properties of stabilized soil small bricks with the help of organic binders of sugar cane molasses and cassava starch. Different formulations of soil concrete have been suggested after the geotechnical characterization of samples of soil was taken. From these, it arises that the studied soil is the most plastically clay (of type A<sub>3</sub>) according to GTR classification. Samples made of small bricks and measured out at 4%, 6% and 8% of binders (molasses, starch or molasses + starch) have been warmed up to different temperatures (100°C, 150°C, 200°C and 250°C) for the rising of the thermic behavior under different conditions and submitted to crushing testings for the estimation of characteristic resistances to the compression. According to the mechanical behavior, we note an improvement of resistances for small bricks measured 4%, 6% and 8%, of molasses respectively of 32.44%, 32.06% and 23.43% against the value of reference for small bricks without molasses. In the same way, the binder (molasses + starch) also reveals an improvement of resistance to the compression of 13.27%, 26.17% and 26.17%. On the contrary, the stabilization with the starch binder did not bring a significative improvement. According to the thermic influence, the heating at 100°C of stabilized small bricks at 4%, 6% and 8% of molasses, reveals a significative improvement of resistances. Moreover, the stabilization with the starch reveals on the contrary a good behavior for heatings at 150°C and 250°C. In short, for the binder (molasses + starch), it is the heating at 200°C that shows some improvements of remarkable resistances. Different analyses of realized statistics also show the effectivity of obtained results. For all realized formulations, the measuring out at 6% of binders (molasses, or molasses + starch) seems as optimal in front of the best thermo-mechanical revealed properties.
文摘Cassava-groundnut intercropping is not a common practice among smallholder farmers in Sierra Leone even though both crops are well suited for intercropping. On-farm trials were conducted in three locations (Bai Largor, Bassah, and Njala Kanima) in the Moyamba district during the 2021 cropping season to investigate the efficacy of cassava-groundnut intercropping for increasing crop productivity and soil organic carbon stock on smallholder farms in the Moyamba district, Southern Sierra Leone. The experimental design was a randomized complete block design in three replications with treatments of sole groundnut, sole cassava and cassava-groundnut intercropping. Data on the yield and yield components of cassava and groundnut were analysed using the PROC MIXED procedure of SAS 9.4 and means were compared using the standard error of difference (SED). The above-ground biomass, number of roots per plant, and fresh root yield of cassava were not significantly (p > 0.05) affected by the cassava-based cropping system. Averaged across locations, intercropping cassava with groundnut decreased the above-ground biomass, the number of roots per plant, and fresh root yield of cassava by 17%, 11%, and 17%, respectively. The above-ground biomass, number of pods per plant and fresh pod yield of groundnut were significantly (p 1), the highest net revenue and benefit-cost ratio. The benefit-cost ratio was also favourable for the sole cassava (BCR > 1) but not favourable for the sole groundnut (BCR < 1). Averaged across locations, intercropping cassava with groundnut increased the benefit-cost ratio by 121% and 13% when compared to the sole groundnut and sole cassava. In the event of a 40% yield loss for the cassava and groundnut, the benefit-cost ratio was favourable (1.12) only for the cassava groundnut intercropping system. The net soil organic carbon stock was favourable only for the cassava-groundnut intercrop. Averaged across locations, the net soil organic carbon for the cassava-groundnut intercropping increased by 3.4% when compared to the baseline within one cropping cycle of the cassava (12 months). The results confirm that cassava-groundnut intercropping is a sustainable land management practice that could enhance crop productivity and soil organic carbon stock on smallholder farms.
文摘Cassava productivity is hampered by pests and diseases including cassava<span style="font-family:;" "=""><span style="font-family:Verdana;"> mosaic disease (CMD) and cassava brown streak disease (CBSD).</span><b> </b><span style="font-family:Verdana;">The main ob</span><span style="font-family:Verdana;">jective of this study was to identify stable superior genotypes that combine</span><span style="font-family:Verdana;"> dis</span><span style="font-family:Verdana;">ease resistance and high yield. Sixteen cassava genotypes were planted in a</span> <span style="font-family:Verdana;">randomized complete block design with three replications for six planting </span><span style="font-family:Verdana;">seasons (years) at five sites in Tanzania. The genotypes were assessed using the additive main effect and multiplicative interaction (AMMI) analysis, and highly significant (</span></span><span style="font-family:Verdana;">P </span><span style="font-family:Verdana;">< 0.001) effects of genotype, environment, and genotype-</span><span style="font-family:;" "=""><span style="font-family:Verdana;">by-environment (</span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;">) interactions were observed for all traits studied. Per</span><span style="font-family:Verdana;">cent sum of squares (SS) due to environment (12.66% - 85.23%) was the</span><span style="font-family:Verdana;"> highest followed by </span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;"> (14.12% - 39.56%) for CMD foliar symptoms, root weight and dry matter. On the other hand, % SS due to genotype (52.14% - 69.14%) </span><span><span style="font-family:Verdana;">was highest followed by </span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;"> (26.14% - 35.91%) for CBSD foliar and root</span></span><span style="font-family:Verdana;"> symptoms indicating that the environment and </span><i><span style="font-family:Verdana;">G</span><sup><span style="font-family:Verdana;">*</span></sup><span style="font-family:Verdana;">E</span></i><span style="font-family:Verdana;"> greatly influenced trait expression. The most stable genotypes which combined disease resistance and high yield were NDL 2003/31 and NDL 2003/111. The findings of this study will give impetus for the release of new cassava varieties that are not only high yielding but are also dually resistant to both CMD and CBSD in different locations and sites.</span></span>
基金supported by the National Natural Science Foundation of China(51536009 and 51576199)
文摘One-pot achievement of ethyl levulinate from cassava was conducted in ethanol-water system over several simple sulfate salt catalysts.Al_2(SO_4)_3 catalyst had the best performance in synthesizing ethyl levulinate comparing with those of a series of sulfate salts.The highest yields of ethyl levulinate was up to39.27%as well as 7.78%levulinate acid when cassava was catalyzed in ethanol medium by adding 10 wt%water.^(13)C and ~1H NMR spectroscopic investigations confirmed that isomerization of glucose to fructose over Al_2(SO_4)_3 catalyst is an important step in producing ethyl levulinate and levulinate acid.Due to aggregations of Al^(3+) under hydrothermal conditions,tiny amount of Al^(3+) were detected in filtrate at the percentage of 0.32%even if in absolute water.Bronsted and Lewis acids could improve the yield of ethyl levulinate and levulinate acid by synergistic effect.All results suggested that A1_2(SO_4)_3 was a simple and efficient catalyst for ethyl levulinate and levulinate acid production.
基金funds from the Alliance for a Green Revolution in Africa through the African Centre for Crop Improvement
文摘Cassava(Manihot esculenta Crantz) is an important root crop worldwide. It exhibits substantial differential genotypic responses to varying environmental conditions, a phenomenon termed genotype × environment interaction(GEI). A significant GEI presents challenges in the selection of superior genotypes. The objective of this study was to examine the effect of genotype,environment and GEI on early fresh storage root yield(FSRY) and related traits in cassava.Accordingly, 12 cassava genotypes were evaluated in a randomised complete block design at three contrasting locations(Jinja, Nakasongola and Namulonge) in Uganda. Trials were harvested nine months after planting and the data collected were analysed using the additive main effects and multiplicative interaction(AMMI) model. The AMMI analysis of variance showed significant variation among genotypes for early FSRY and all other traits assessed.Locations were significantly different for all traits except for cassava brown streak disease root necrosis. The GEI effect was non-significant for early FSRY, but significant for other traits. For early FSRY, 48.5% of the treatment sum of squares was attributable to genotypes, 27.3% to environments, and 24.1% to GEI, indicating a predominance of genotypic variation for this trait.Predominance of genotypic variation was also observed for all the other traits. A majority of the genotypes(67%) had low interaction effects with locations for early FSRY, with Akena, CT2, CT4 and NASE14 being the most stable genotypes for the trait. Significant negative correlation was observed between cassava mosaic disease severity and early FSRY and storage root number,indicating significant negative effects of cassava mosaic disease on early FSRY and stability in cassava. The information generated will inform future selection initiatives for superior early-yielding cassava genotypes combining resistance to cassava mosaic and brown streak diseases in Uganda.
基金Supported by the National Natural Science Foundation of China(21506075)the Natural Science Foundation of Jiangsu Province(BK20150131)the Fundamental Research Funds for the Central Universities(JUSRP51504)
文摘A new cleaner production process for cassava ethanol has been developed, in which the thin stillage by-product was treated initially by anaerobic digestion, and the digestate further processed by hydrogen-form cation exchange resin before being recycled as process water to make mash for the next ethanol fermentation batch.Thus wastewater was eliminated and freshwater and energy consumption was significantly reduced. To evaluate the new process, ten consecutive batches of ethanol fermentation and anaerobic digestion at lab scale were carried out. Average ethanol production in the recycling batches was 11.43%(v/v) which was similar to the first batch, where deionized(DI) water was used as process water. The chemical oxygen demand(COD) removal rate reached 98% and the methane yield was 322 ml per gram of COD removed, suggesting an efficient and stable operation of the anaerobic digestion. In conclusion, the application of the new process can contribute to sustainable development of the cassava ethanol industry.
基金supported by the National Key R&D Program of China(2017YFC1200600,2016YFC1201200 and 2015BAD08A16)the Science and Technology Innovation Program of CAAS(caascx-2013-2018-IAS)
文摘The globally invasive cassava mealybug Phenacoccus manihoti Matile-Ferrero is a pernicious pest of cassava,and its recent introduction into Asia has raised considerable alarm.To slow or prevent further invasion,an accurate,simple,and developmental-stage-independent detection method for P.manihoti is required.In the present study,a PCR method based on a species-specific mitochondrial DNA cytochrome oxidase I(SS-COI)marker was developed for rapid identification of P.manihoti.One pair of SS-COI primers(PMSSZW-1F and PMSSZW-1R)was designed based on sequence variations in the COI gene among P.manihoti and related mealybug species.Specificity of the primer pair was validated on 21 closely related species.Sensitivity tests were performed on four immature developmental stages and female adults.Efficacy tests demonstrated that at the relatively low concentration of(135.2±14.7)pgresuspended DNA,the specific fragment was detected in all replicates.Furthermore,the SS-COI primer pair was assayed on three populations of P.manihoti from major exporting countries of cassava.The PCR assay was proved to be a rapid,simple,and reliable molecular measure for the identification of P.manihoti.This tool will be useful for quarantine,monitoring,and management of this invasive pest.
基金supported by the National Key Research and Development Program of China(2018YFD1000500,2019YFD1000500,and 2019YFD1001105)the Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences(1630052021026 and 1630052022008)+2 种基金the National Natural Science Foundation of China(31960440)the Hainan Provincial Natural Science Foundation of China(320MS097)the Natural Science Foundation of China(31701484)。
文摘Cassava is an important tropical cash crop. Severe drought stresses affect cassava productivity and quality, and cause great economic losses in agricultural production. Enhancing the drought tolerance of cassava can effectively improve its yield. Long non-coding RNAs(lncRNAs) are present in a wide variety of eukaryotes. Recently, increasing evidence has shown that lncRNAs play a critical role in the responses to abiotic stresses. However, the function of cassava lncRNAs in the drought response remains largely unknown. In this study, we identified a novel lncRNA, DROUGHT-INDUCED INTERGENIC lncRNA(DIR). Gene expression analysis showed that DIR was significantly induced by drought stress treatment, but did not respond to abscisic acid(ABA) or jasmonic acid(JA) treatments. In addition, overexpression of the DIR gene enhanced proline accumulation and drought tolerance in transgenic cassava. RNA-seq analysis revealed that DIR preferentially affected drought-related genes that were linked to transcription and metabolism. Moreover, RNA pull-down mass spectrometry analysis showed that DIR interacted with 325 proteins. A protein–protein interaction(PPI)analysis found a marked enrichment in proteins associated with the mRNA export and protein quality control pathways.Collectively, these results suggest that DIR and its interacting proteins that regulate mRNA or protein metabolism are involved in mediating the drought stress response. Thus, regulating DIR expression has potential for improving cassava yield under drought conditions.
基金Funded by the National Natural Science Foundation of China(No.51503041)the Natural Science Foundation of Fujian Province,China(No.2018J01752)
文摘Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.
基金provided by the Guangxi Natural Science Foundation,China(2014GXNSFAA118077 and 2018GXNSFDA281056)the Guangxi Postgraduate Innovative Education Research Program,China(YCBZ2017013 and YCSW2018039)。
文摘As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is usually cultivated on hilly areas that are nutrient-poor. Nitrogen(N) is one of the significant factors affecting cassava yield. A double factorial(N level×genotypes) split-plot field experiment was conducted to analyze differences in yield and N accumulation of 25 cassava genotypes under low-N conditions to screen for cassava genotypes with high-N efficiency. The two-year field experiment showed that cassava yield and N accumulation are determined by specific genotypes, soil N levels, and year. Among these factors, soil N levels are the main factors that are responsible for differences in cassava yield. When yield and relative N accumulation under low-N conditions were used as screening markers, we identified an efficient and responsive genotype(SC10), and two inefficient and non-responsive genotypes(SC205 and GR5). The efficient and responsive genotype and the inefficient and non-responsive genotype can be used as study materials to further reveal the mechanisms for high-N efficiency in cassava.
