Sweetpotato, Ipomoea batatas(L.) Lam., is an important food crop worldwide. Large scale evaluation of sweetpotato germplasm for genetic diversity is necessary to determine the genetic relationships between them and ef...Sweetpotato, Ipomoea batatas(L.) Lam., is an important food crop worldwide. Large scale evaluation of sweetpotato germplasm for genetic diversity is necessary to determine the genetic relationships between them and effectively use them in the genetic improvement. In this study, the genetic diversity of 617 sweetpotato accessions, including 376landraces and 162 bred varieties from China and 79 introduced varieties from 11 other countries, was assessed using 30 simple sequence repeat(SSR) primer pairs with high polymorphism. Based on the population structure analysis,these sweetpotato accessions were divided into three groups, Group 1, Group 2 and Group 3, which included 228, 136and 253 accessions, respectively. Consistent results were obtained by phylogenic analysis and principal coordinate analysis(PCoA). Of the three groups, Group 2 showed the highest level of genetic diversity and its accessions were mainly distributed in low-latitude regions. The accessions from South China exhibited the highest level of genetic diversity, which supports the hypothesis that Fujian and Guangdong were the first regions where sweetpotato was introduced to China. Analysis of molecular variance(AMOVA) indicated significant genetic differentiations between the different groups, but low levels of genetic differentiation existed between the different origins and accession types.These results provide valuable information for the better utilization of these accessions in sweetpotato breeding.展开更多
Sweetpotato(Ipomoea batatas(L.)Lam.)is a widely grown food crop especially in developing countries.Increasing storage-root yield and dry-matter content has been the main breeding objective of the crop,and DNA marker-a...Sweetpotato(Ipomoea batatas(L.)Lam.)is a widely grown food crop especially in developing countries.Increasing storage-root yield and dry-matter content has been the main breeding objective of the crop,and DNA marker-assisted breeding is needed for this purpose.In this study,using a mapping population of 500 F1 individuals from a cross between Xushu 18(female)and Xu 781(male),we constructed a highdensity genetic linkage map of sweetpotato using 601 simple-sequence repeat(SSR)primer pairs.The Xushu 18 map contained 90 linkage groups with 5547 SSR markers and spanned 18,263.5 cM,and the Xu 781 map contained 90 linkage groups with 4599 SSR markers and spanned 18,043.7 cM,representing the highest genome coverage yet reported for sweetpotato.We identified 33 QTL for storage-root yield and 16 QTL for dry-matter content,explaining respectively 6.5%–47.5%and 3.2%–18.9%of variation.These results provide a foundation for fine-mapping and cloning of QTL and for marker-assisted breeding in sweetpotato.展开更多
Sweetpotato is an important crop for food security in many developing countries which is cultivated using vine cuttings. Studies have revealed that there are at least fifteen well characterized viruses known to infect...Sweetpotato is an important crop for food security in many developing countries which is cultivated using vine cuttings. Studies have revealed that there are at least fifteen well characterized viruses known to infect sweetpotato of which 10 are economically important that contribute to yield reduction. Planting materials use by farmers are often infected by one or more of these viruses. The aim of this study was to evaluate three different sources of planting materials of different health status for their field performance and virus presence. The sources of planting materials were in vitro generated platelets, symptomless Field materials and Farmer’s materials. Four sweetpotato varieties Apomuden, Bohye, Ligri and Dadanyuie were selected from each source of planting material. The trial was laid in a split plot design with the sources of planting material allocated to main plots and the varieties to sub-plots. The plantlets of the four varieties were planted at Botanga Irrigation Scheme in Northern region of Ghana. Viral symptom scores were taken twice, score 1 being the average from 4 - 7 weeks after planting (WAP) and score 2 being the average from 8 - 11 WAP. Nitrocellulose Membranes Enzyme Linked Immunosorbent Assay (NCM-ELISA) kits were employed for the detection of sweetpotato viruses on the field. The source of planting materials significantly influenced (P In vitro generated material showed the least symptoms of virus followed by Field materials. Apomuden and Bohye varieties recorded the highest virus score in the first and second virus symptom observational score respectively. NCM-ELISA revealed that the viruses SPFMV, SPMMV, SPMSV, SPCFV, SPCSV, and CMV were significantly present among the different sources of planting materials. In vitro, Field and Farmer materials recorded NCM-ELISA score of 0.225, 1.075 and 1.500 respectively. Apomuden variety recorded the highest virus score in the assay. Vine and root yield was higher among the in vitro generated material. Farmers should use laboratory cleaned material however, in the absence of such material they should select field material showing no symptom of virus.展开更多
Simple sequence repeat(SSR) markers have been shown to be a powerful tool for varieties identification in plants.However,SSR fingerprinting of sweetpotato varieties has been a little reported.In this study,a total of ...Simple sequence repeat(SSR) markers have been shown to be a powerful tool for varieties identification in plants.However,SSR fingerprinting of sweetpotato varieties has been a little reported.In this study,a total of 1 294 SSR primer pairs,including 1 215 genomic-SSR and 79 expressed sequence tag(EST)-SSR primer pairs,were screened with sweetpotato varieties Zhengshu 20 and Luoxushu 8 and their 2 F1 individuals randomly sampled,and 273 and 38 of them generated polymorphic bands,respectively.Four genomic-SSR and 3 EST-SSR primer pairs,which showed good polymorphism,were selected to amplify 203 sweetpotato varieties and gave a total of 172 bands,85(49.42%) of which were polymorphic.All of the 203 sweetpotato varieties showed unique fingerprint patterns,indicating the utility of SSR markers in variety identification of this crop.Polymorphism information content(PIC) ranged from 0.5824 to 0.9322 with an average of 0.8176.SSR-based genetic distances varied from 0.0118 to 0.6353 with an average of 0.3100 among these varieties.Thus,these sweetpotato varieties exhibited high levels of genetic similarity and had distinct fingerprint profiles.The SSR fingerprints of the 203 sweetpotato varieties have been successfully constructed.The highly polymorphic SSR primer pairs developed in this study have the potential to be used as core primer pairs for variety identification,genetic diversity assessment and linkage map construction in sweetpotato and other plants.展开更多
Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research.The results ...Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research.The results showed that after virus-elimination, all varieties had a yield increase ranging from 14.95% -91.61% and marketable quality improvement, despite the changes in location and season. The changes of dry matter content and disease resistance were not significant. Virus-free sweetpotato performed vigorous vine growth and strong dry matter assimilation ability. Virus-free parents had a slightly high seed setting percentage, but its flowering ability and performance of off-springs were similar to that of its check plants.展开更多
Sweetpotato,Ipomoea batatas(L.) Lam.,is a globally important food crop and usually grown on arid-and semi-arid lands.Therefore,investigating the molecular mechanism of drought tolerance will provide important informat...Sweetpotato,Ipomoea batatas(L.) Lam.,is a globally important food crop and usually grown on arid-and semi-arid lands.Therefore,investigating the molecular mechanism of drought tolerance will provide important information for the improvement of drought tolerance in this crop.In this study,transcriptome analysis of the drought-tolerant sweetpotato line Xushu 55-2 was conducted on Illumina HiSeq 2500 platform.A total of 86.69 Gb clean data were generated and assembled into 2 671 693 contigs,222 073 transcripts,and 73 636 unigenes.In total,11 359 differentially expressed genes(DEGs) were identified after PEG6000 treatment,in which 7 666 were up-regulated and 3 693 were down-regulated.Of the 11 359 DEGs,10 192 DEGs were annotated in at least one database,and the remaining 1 167 DEGs were unknown.Abscisic acid(ABA),ethylene(ETH),and jasmonic acid(JA) signalling pathways play a major role in drought tolerance of sweetpotato.Drought-inducible transcription factors were identified,some of which have been reported to be associated with drought tolerance and others are unknown in plants.In addition,7 643 SSRs were detected.This study not only reveals insights into the molecular mechanism of drought tolerance in sweetpotato but also provides the candidate genes involved in drought tolerance of this crop.展开更多
Sweetpotato[Ipomoea batatas(L.)Lam.],a food crop with both nutritional and medicinal uses,plays essential roles in food security and health-promoting.Chlorogenic acid(CGA),a polyphenol displaying several bioactivities...Sweetpotato[Ipomoea batatas(L.)Lam.],a food crop with both nutritional and medicinal uses,plays essential roles in food security and health-promoting.Chlorogenic acid(CGA),a polyphenol displaying several bioactivities,is distributed in all edible parts of sweetpotato.However,little is known about the specific metabolism of CGA in sweetpotato.In this study,IbPAL1,which encodes an endoplasmic reticulum-localized phenylalanine ammonia lyase(PAL),was isolated and characterized in sweetpotato.CGA accumulation was positively associated with the expression pattern of IbPAL1 in a tissue-specific manner,as further demonstrated by overexpression of IbPAL1.Overexpression of IbPAL1 promoted CGA accumulation and biosynthetic pathway genes expression in leaves,stimulated secondary xylem cell expansion in stems,and inhibited storage root formation.Our results support a potential role for IbPAL1 in sweetpotato CGA biosynthesis and establish a theoretical foundation for detailed mechanism research and nutrient improvement in sweetpotato breeding programs.展开更多
Geranylgeranyl pyrophosphate synthase(GGPS) plays an important role in the biosynthesis of carotenoids. In a previous study, the IbGGPS gene was isolated from a sweetpotato, Ipomoea batatas(L.) Lam., line Nongdafu 14 ...Geranylgeranyl pyrophosphate synthase(GGPS) plays an important role in the biosynthesis of carotenoids. In a previous study, the IbGGPS gene was isolated from a sweetpotato, Ipomoea batatas(L.) Lam., line Nongdafu 14 with high carotenoid contents, but its role and underlying mechanisms in carotenoid biosynthesis in sweetpotato were not investigated. In the present study, the IbGGPS gene was introduced into a sweetpotato cv. Lizixiang and the contents of β-carotene, β-cryptoxanthin, zeaxanthin and lutein were significantly increased in the storage roots of the IbGGPSoverexpressing sweetpotato plants. Further analysis showed that IbGGPS gene overexpression systematically upregulated the genes involved in the glycolytic, 2-C-methyl-D-erythritol-4-phosphate(MEP) and carotenoid pathways,which increased the carotenoid contents in the transgenic plants. These results indicate that the IbGGPS gene has the potential for use in improving the carotenoid contents in sweetpotato and other plants.展开更多
Four sweetpotato (Ipomoea batatas (L.) Lam.) cultivars grown in Alexandria, Egypt, including Monofya 6, Monofya 66, Abeeis, and Beauregard were cooked using four different home-cooking methods (boiling, baking, microw...Four sweetpotato (Ipomoea batatas (L.) Lam.) cultivars grown in Alexandria, Egypt, including Monofya 6, Monofya 66, Abeeis, and Beauregard were cooked using four different home-cooking methods (boiling, baking, microwaving, and deep-frying). The antioxidant contents (total phenolics by Folin-Denis, and individual phenolic acids by HPLC) as well as the antioxidant activity determined by reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) were measured in this study. Results indicated that total phenolic contents of raw flesh tissue by Folin-Denis ranged from 0.53 to 0.87 mg chlorogenic acid equivalent (mg ChAE)/g dry weight basis (dw). The RP ranged between 0.1 and 0.25 mg ChAE/g dw, DPPH and ABTS radical scavenging activities varied from 1.10 to 1.72 and 0.85 to 1.51 μmol trolox equivalent (TE)/g dw, respectively. Thermal processing significantly (P ≤ 0.05) increased the total phenolic content, as well as individual phenolic acids and antioxidant capacity of all the cultivars under study. In this respect, deep-frying exhibited the highest increment among the four processing methods. The most abundant individual phenolic acids in processed flesh roots tissues were chlorogenic acid followed by 3,5-dicaffeoylquinic acid. Total phenolic contents were highly correlated with RP, DPPH, and ABTS, also the correlation between the DPPH and ABTS values were significantly high.展开更多
Chemical and functional properties of ten sweetpotato varieties were investigated. The sweetpotato were of various flesh colours which included orange, yellow, cream and white with dry matter content ranging from 30.2...Chemical and functional properties of ten sweetpotato varieties were investigated. The sweetpotato were of various flesh colours which included orange, yellow, cream and white with dry matter content ranging from 30.2% - 39.2%. The sweetpotato varieties varied significantly (p < 0.05) in total amylase activity, total starch and amylose content whose value ranges were 0.256 - 0.570 mg/ml/min 68.4% - 73.6%, 16.2% - 23.4% respectively. The pH of flours from the different sweetpotato varieties ranged from 6.01 - 6.64. The pasting behaviours of the sweetpotato flours also showed significant differences (p < 0.05) in the individual parameters (peak time, pasting temperature, peak viscosity, trough viscosity, final viscosity, breakdown and setback) among the different varieties. The results revealed the influence of variety on the chemical composition of sweetpotato and their pasting properties. Correlations were also revealed among different components of the sweetpotatoes which would be a basis in selection of the varieties for processing into different products.展开更多
Sweetpotato is a major staple food in the world. It is a good source of carbohydrates, vitamin A, vitamin C and protein. The maximum production potential of the crop is being hampered by severe drought which ravages m...Sweetpotato is a major staple food in the world. It is a good source of carbohydrates, vitamin A, vitamin C and protein. The maximum production potential of the crop is being hampered by severe drought which ravages most parts of Africa. The main aim of this study therefore was to screen accessions of sweetpotato for drought tolerance in a quick screening method, followed by field screening with a view to identify accessions that can perform well under water stress conditions. Fifty sweetpotato accessions consisting of cultivars and breeding lines collected from the ARC-VOPI gene bank were planted for drought screening in the glass house for six weeks during which water was withheld to induce stress. Observations were made on number of dead plants and days to wilting point. The results were analyzed and 12 best performing accessions were selected for field trials. The field trial was carried out in Lwamondo, Limpopo province, a drought prone area in South Africa, under rain-fed conditions. The best performing accessions were Zapallo, Tacna, Ejumula, 2004-9-2 and Ndou.展开更多
Sweetpotato varieties (five) were investigated for changes in α- and β-amylase activities during root development and on subjection of harvested roots to different postharvest handling and storage conditions. Change...Sweetpotato varieties (five) were investigated for changes in α- and β-amylase activities during root development and on subjection of harvested roots to different postharvest handling and storage conditions. Changes in α- and β-amylase activities in development were monitored from 10 weeks after planting. At physiological maturity, sweetpotato roots were harvested and subjected to various conditions: freshly harvested roots and cured roots (spread under the sun for four days at 29℃ - 31℃ and 63% - 65% relative humidity), stored at ambient conditions (23℃ - 26℃ and 70% - 80% relative humidity) and in a semi-underground pit (19℃ - 21℃ and 90% - 95% relative humidity). Generally α- and β-amylase activities increased during development with NASPOT 9 and 10 consistently registering the highest activities and NASPOT 1 the lowest activity. Generally, maximum α-amylase activities were achieved at week 3 in ambient stores for NASPOT 9 and NASPOT 10 at 0.930 and 0.897 CU/g, respectively. Maximum β-amylase activity was achieved in ambient stores at week 3 and 4 for fresh and cured NASPOT 9 at 806 and 782 BU/g, respectively. Generally, curing and storing sweetpotatoes in ambient conditions registered the highest amylase activity. Maximum α- and β-amylase activities were registered at 67℃ - 68℃ and 58℃ - 60℃, respectively. These findings provide information for controlled modification of amylase activities of these sweetpotato varieties for product development efforts and monitoring the shelf life of the roots during storage.展开更多
As a critical food crop,sweetpotato(Ipomoea batatas(L.)Lam.)is widely planted all over the world,but it is deeply affected by Sweetpotato Virus Disease(SPVD).The present study utilized short tandem target mimic(STTM)t...As a critical food crop,sweetpotato(Ipomoea batatas(L.)Lam.)is widely planted all over the world,but it is deeply affected by Sweetpotato Virus Disease(SPVD).The present study utilized short tandem target mimic(STTM)technology to effectively up-regulate the expression of laccase(Ib LACs)by successfully inhibiting the expression of mi R397.The upstream genes in the lignin synthesis pathway were widely up-regulated by feedback regulation,including phenylalanine ammonialyase(PAL),4-coumarate-Co Aligase(4 CL),hydroxycinnamoyl Co A:shikimatetransferase(HTC),caffeicacid O-methyltransferase(COMT),and cinnamyl alcohol dehydrogenase(CAD).Meanwhile,the activities of PAL and LAC increased significantly,finally leading to increased lignin content.Lignin deposition in the cell wall increased the physical defence ability of transgenic sweetpotato plants,reduced the accumulation of SPVD transmitted by Bemisia tabaci(Gennadius),and promoted healthy sweetpotato growth.The results provide new insights for disease resistance breeding and green production of sweetpotato.展开更多
S-metolachlor is used to control/suppress yellow nutsedge, annual grasses and several broadleaf weeds in sweetpotato. However, a decline in storage root quality is suspected when excessive rainfall occurs within 24-h ...S-metolachlor is used to control/suppress yellow nutsedge, annual grasses and several broadleaf weeds in sweetpotato. However, a decline in storage root quality is suspected when excessive rainfall occurs within 24-h after application. A greenhouse study was conducted to determine the effect of S-metolachlor application timing on sweetpotato growth and development. S-metolachlor treatments (0 and 1 kg·ha-1) were applied over-the-top at 0, 5 and ten days after transplanting (DAT) and a simulated rainfall treatment delivered 25 mm of rain, 51 mm·h-1 intensity, immediately after herbicide application. Plants were harvested at 5, 10, 15, 20 and 80 DAT. During the first four harvests, roots were scanned and analyzed with WinRHIZO-Pro image analysis system to estimate root number, length, volume, and surface area along with aboveground growth parameters. At the final harvest, plant growth and biomass components, and quality of storage roots were recorded. Plants treated with S-metolachlor on day 0 and 5 DAT were significantly less than those of 10 DAT and untreated control for all measured parameters for the initial 20 days of plant growth. Even though vine length, leaf number, stem biomass, and total storage roots were not different among the treatments at 80 DAT, all other plant components and total biomass production and leaf area development for plants treated at 0 and 5 DAT were significantly (P < 0.05) less than from those of 10 DAT and the untreated control. Marketable storage root conversion efficiency declined by 18% and 16% for plants treated at 0 and 5 DAT, respectively, relative to the untreated check. These results indicate that delaying S-metolachlor application to 10 DAT will be less damaging to sweetpotato growth and development, particularly marketable storage roots and yield.展开更多
The S-metolachlor is used to control/suppress yellow nutsedge, annual grasses, and several broadleaf weeds in sweetpotato. However, when used under adverse environmental conditions, it may lead to crop injury. Informa...The S-metolachlor is used to control/suppress yellow nutsedge, annual grasses, and several broadleaf weeds in sweetpotato. However, when used under adverse environmental conditions, it may lead to crop injury. Information is limited on the effect of S-metolachlor application followed immediately by rainfall on sweetpotato growth and development under different temperature regimes. The objective of this study was to determine sweetpotato response to S-metolachlor under low, optimum, and high temperatures with no rainfall and rainfall immediately after application. Sweetpotato slips were transplanted to sandy loam soil-filled pots. Half of the pots were subjected to 38 mm rainfall at 50.8 mm·h-1 intensity within the first 24 h after POST-transplant S-metolachlor application at 0, 0.86, 1.72, 2.58 and 3.44 kg·ha-1. The pots were moved into sunlit, computer-controlled plant growth chambers that were maintained at their respective temperatures for 61 days. Plant growth, development and plant-component dry weights and quantity of storage roots were recorded at harvest. Storage root yield was highest at the optimum temperature and declined at low and high temperature conditions. Shoot, root, and total plant biomass yield declined with increasing concentration of S-metolachlor across temperature conditions. In addition, storage root yield decline was S-metolachlor rate-dependent and aggravated by a rainfall event immediately after herbicide treatment across temperatures tested. These results can be used to weigh the risk of potential crop injury against the benefits of S-metolachlor when making management decisions as well as considering weather forecast information to avoid herbicide application coinciding with adverse weather conditions such as excessive rainfall event.展开更多
The study was carried out to determine the effect of salt on the sensory, nutritive and keeping quality of OFSP crisps. Crisps were made by deep frying slices of approximately 3.5 mm thickness treated with, 2% and 4% ...The study was carried out to determine the effect of salt on the sensory, nutritive and keeping quality of OFSP crisps. Crisps were made by deep frying slices of approximately 3.5 mm thickness treated with, 2% and 4% table salt. A control with no salt treatment was prepared alongside the treated ones. Two varieties of OFSP;Ejumula and Kakamega were used in the study. After deep frying, the crisps were cooled to room temperature, packed in paper-lined high density polythene pouches and stored in a dark cupboard at room temperature for three months. During the storage period, the crisps were analyzed for proteins, fat and carotenoid content. Changes in sensory attributes were analyzed using a semi-trained panel. Results indicated that freshly prepared crisps treated with 2% salt had the highest acceptability mean scores for all attributes while there was no significant difference (p > 0.05) between crisps made from either Ejumula or Kakamega variety. Carotenoid content decreased with increase in salt concentration in both OFSP varieties. Shelf-life studies showed that the decline in sensory attributes started after 2 months of storage. The study shows that OFSP crisps treated with 2% salt are more acceptable and reasonably stable during storage.展开更多
Vitamin A Deficiency (VAD) is a major concern in the world today and is a risk for children in developing countries. Trends have shown that food based interventions are the preferred long-term solution in controlling ...Vitamin A Deficiency (VAD) is a major concern in the world today and is a risk for children in developing countries. Trends have shown that food based interventions are the preferred long-term solution in controlling VAD as opposed to supplements. The orange-fleshed sweetpotato and mangoes are rich in beta-carotene, yet they are not fully utilized. A processed product from these raw materials will make use of surplus produce, promote year round utilization, increase the economic value of the crops and provide variety and convenience of uses. The roots were obtained from the field station, University of Nairobi, while the mangoes were purchased from the local market. The roots were washed, peeled and sliced. They were boiled to softness and mashed. The mangoes were washed, peeled, sliced and pureed in a blender. The two raw materials were mixed using six different formulations. Each formula was pasteurized at 80°C for 5 min in a batch pasteurizer, packaged by hot filling, cooled immediately and stored. The cooking time for the sweetpotatoes was 19.5 min. Losses of beta-carotene and ascorbic acid ranged from 17% - 21% and 18% - 28% respectively after pasteurization. The total solids increased by 3% on average. Changes due to storage of the product at 25°C could be detected by sensory analysis only after six months of storage. After storage, beta-carotene and ascorbic acid decreased by 18% and by 45% respectively. The final stored product could provide 73.7% and 64.5% of retinol equivalent for infants and 1 - 10 year-olds respectively. It could also provide 48.9% of ascorbic acid for children 1 - 10 years old, when consumed in amounts of 100 g per day.展开更多
The stability of β-carotene in cream-fleshed sweetpotato-based complementary food stored in three different containers under simulated tropical temperature of 32°C and 85% relative humidity in an environmental c...The stability of β-carotene in cream-fleshed sweetpotato-based complementary food stored in three different containers under simulated tropical temperature of 32°C and 85% relative humidity in an environmental chamber for 24 weeks was investigated. The formulation stored in a metallised polyester film in a refrigerator (approximately 3.0°C and 95% relative humidity) retained about 81% of β-carotene at 24 weeks, with no significant change in the moisture content. The formulation stored in either a metallised polyester film or a translucent polypropylene container placed in the environmental chamber retained approximately half of the β-carotene at 24 weeks, with a slight increase in moisture content. However, the formulation held in a transparent low-density polyethylene bag had the lowest β-carotene retention (37%) and the highest moisture content at week 24. Within the limits of this study, it has been demonstrated that β-carotene in cream-fleshed sweetpotato-based complementary food was well retained when moisture uptake was minimised.展开更多
Characterization of genes related to sweetpotato viral disease resistance is critical for understanding plant-pathogen interactions, especially with feathery mottle virus infection. For example, genes encoding eukaryo...Characterization of genes related to sweetpotato viral disease resistance is critical for understanding plant-pathogen interactions, especially with feathery mottle virus infection. For example, genes encoding eukaryotic translation initiation factor (eIF)4E, its isoforms, eIF(iso)4E, and the cap-binding protein (CBP) in plants, have been implicated in viral infections aside from their importance in protein synthesis. Full-length cDNA encoding these putative eIF targets from susceptible/resistant and unknown hexaploid sweetpotato (Ipomoea batatas L. Lam) were amplified based on primers designed from the diploid wild-type relative Ipomoea trifida consensus sequences, and designated IbeIF4E, IbeIF(iso)4E and IbCBP. Comparative analyses following direct-sequencing of PCR-amplified cDNAs versus the cloned cDNA sequences identified multiple homeoalleles: one to four IbeIF4E, two to three IbeIF(iso)4E, and two IbCBP within all cultivars tested. Open reading frames were in the length of 696 bp IbeIF4E, 606 bp IbeIF(iso)4E, and 675 bp IbCBP. The encoded single polypeptide lengths were 232, 202, and 225 amino acids for IbeIF4E, IbeIF(iso)4E, and IbCBP, with a calculated protein molecular mass of 26 kDa, 22.8 kDa, and 25.8 kDa, while their theoretical isoelectric points were 5.1, 5.57, and 6.6, respectively. Although the homeoalleles had similar sequence lengths, single nucleotide polymorphisms and multi-allelic variations were detected within the coding sequences. The multi-sequence alignment performed revealed a 66.9% - 96.7% sequence similarity between the predicted amino acid sequences obtained from the homeoalleles and closely related species. Furthermore, phylogenetic analysis revealed ancestral relationships between the eIF4E homeoalleles and other species. The outcome herein on the eIF4E superfamily and its correlation in sequence variations suggest opportunities to decipher the role of eIF4E in hexaploid sweetpotato feathery mottle virus infection.展开更多
The sweetpotato production in Tanzania has been increasing due to the changing status of the crop from famine relief to a commercial crop particularly in the central zone of Tanzania.Production of the crop is affected...The sweetpotato production in Tanzania has been increasing due to the changing status of the crop from famine relief to a commercial crop particularly in the central zone of Tanzania.Production of the crop is affected by environmental and biotic stresses.Apart from prolonged drought which affects timely availability of planting materials,sweetpotato weevils were recently reported by growers as a major setback to the productivity of the crop.The study was conducted between December 2016 and July 2017 in Gairo and Ikungi Districts of Morogoro and Singida regions respectively.The aim was to identify sweetpotato weevil species existing in the area,determine the seasonal abundance of the pests and test the response of popular and farmers’preferred sweetpotato varieties to the pest.The effect of planting time on the abundance of sweetpotato weevils was also studied.It was established that Cylas puncticollis is the lone weevil species infesting the crop in the study area.Time of planting significantly(p<0.05)influenced weevils’abundance with early planted crop sustaining least number of pests compared to the late planted.Sweetpotato variety,Gudugudu was least damaged by C.puncticollis.Locational influence suggested that Gairo District sustained greater weevil abundance and associated damages compared to Ikungi District.It was concluded that planting dates had influence on seasonal abundance of sweetpotato weevil with early planted crop sustaining least infestation with C.puncticollis compared to late planted crop.展开更多
基金National Key R&D Program of China (2019YFD1001301 and 2019YFD1001300)the earmarked fund for CARS-10Sweetpotato and the Hebei Key R&D Program, China (20326320D)。
文摘Sweetpotato, Ipomoea batatas(L.) Lam., is an important food crop worldwide. Large scale evaluation of sweetpotato germplasm for genetic diversity is necessary to determine the genetic relationships between them and effectively use them in the genetic improvement. In this study, the genetic diversity of 617 sweetpotato accessions, including 376landraces and 162 bred varieties from China and 79 introduced varieties from 11 other countries, was assessed using 30 simple sequence repeat(SSR) primer pairs with high polymorphism. Based on the population structure analysis,these sweetpotato accessions were divided into three groups, Group 1, Group 2 and Group 3, which included 228, 136and 253 accessions, respectively. Consistent results were obtained by phylogenic analysis and principal coordinate analysis(PCoA). Of the three groups, Group 2 showed the highest level of genetic diversity and its accessions were mainly distributed in low-latitude regions. The accessions from South China exhibited the highest level of genetic diversity, which supports the hypothesis that Fujian and Guangdong were the first regions where sweetpotato was introduced to China. Analysis of molecular variance(AMOVA) indicated significant genetic differentiations between the different groups, but low levels of genetic differentiation existed between the different origins and accession types.These results provide valuable information for the better utilization of these accessions in sweetpotato breeding.
基金supported by the National Key Research and Development Program of China(2019YFD1001300,2019YFD1001301)the Earmarked Fund for CARS-10-Sweetpotato(CARS-10)+1 种基金the Beijing Food Crops Innovation Consortium Program(BAIC02-2022)Hebei Key R&D Program(20326320D,22322911D)。
文摘Sweetpotato(Ipomoea batatas(L.)Lam.)is a widely grown food crop especially in developing countries.Increasing storage-root yield and dry-matter content has been the main breeding objective of the crop,and DNA marker-assisted breeding is needed for this purpose.In this study,using a mapping population of 500 F1 individuals from a cross between Xushu 18(female)and Xu 781(male),we constructed a highdensity genetic linkage map of sweetpotato using 601 simple-sequence repeat(SSR)primer pairs.The Xushu 18 map contained 90 linkage groups with 5547 SSR markers and spanned 18,263.5 cM,and the Xu 781 map contained 90 linkage groups with 4599 SSR markers and spanned 18,043.7 cM,representing the highest genome coverage yet reported for sweetpotato.We identified 33 QTL for storage-root yield and 16 QTL for dry-matter content,explaining respectively 6.5%–47.5%and 3.2%–18.9%of variation.These results provide a foundation for fine-mapping and cloning of QTL and for marker-assisted breeding in sweetpotato.
文摘Sweetpotato is an important crop for food security in many developing countries which is cultivated using vine cuttings. Studies have revealed that there are at least fifteen well characterized viruses known to infect sweetpotato of which 10 are economically important that contribute to yield reduction. Planting materials use by farmers are often infected by one or more of these viruses. The aim of this study was to evaluate three different sources of planting materials of different health status for their field performance and virus presence. The sources of planting materials were in vitro generated platelets, symptomless Field materials and Farmer’s materials. Four sweetpotato varieties Apomuden, Bohye, Ligri and Dadanyuie were selected from each source of planting material. The trial was laid in a split plot design with the sources of planting material allocated to main plots and the varieties to sub-plots. The plantlets of the four varieties were planted at Botanga Irrigation Scheme in Northern region of Ghana. Viral symptom scores were taken twice, score 1 being the average from 4 - 7 weeks after planting (WAP) and score 2 being the average from 8 - 11 WAP. Nitrocellulose Membranes Enzyme Linked Immunosorbent Assay (NCM-ELISA) kits were employed for the detection of sweetpotato viruses on the field. The source of planting materials significantly influenced (P In vitro generated material showed the least symptoms of virus followed by Field materials. Apomuden and Bohye varieties recorded the highest virus score in the first and second virus symptom observational score respectively. NCM-ELISA revealed that the viruses SPFMV, SPMMV, SPMSV, SPCFV, SPCSV, and CMV were significantly present among the different sources of planting materials. In vitro, Field and Farmer materials recorded NCM-ELISA score of 0.225, 1.075 and 1.500 respectively. Apomuden variety recorded the highest virus score in the assay. Vine and root yield was higher among the in vitro generated material. Farmers should use laboratory cleaned material however, in the absence of such material they should select field material showing no symptom of virus.
基金supported by the earmarked fund for the China Agriculture Research System (CARS-11)the National Natural Science Foundation of China (31461143017)the Science andTechnology Planning Project of Guangdong Province,China (2015B020202008)
文摘Simple sequence repeat(SSR) markers have been shown to be a powerful tool for varieties identification in plants.However,SSR fingerprinting of sweetpotato varieties has been a little reported.In this study,a total of 1 294 SSR primer pairs,including 1 215 genomic-SSR and 79 expressed sequence tag(EST)-SSR primer pairs,were screened with sweetpotato varieties Zhengshu 20 and Luoxushu 8 and their 2 F1 individuals randomly sampled,and 273 and 38 of them generated polymorphic bands,respectively.Four genomic-SSR and 3 EST-SSR primer pairs,which showed good polymorphism,were selected to amplify 203 sweetpotato varieties and gave a total of 172 bands,85(49.42%) of which were polymorphic.All of the 203 sweetpotato varieties showed unique fingerprint patterns,indicating the utility of SSR markers in variety identification of this crop.Polymorphism information content(PIC) ranged from 0.5824 to 0.9322 with an average of 0.8176.SSR-based genetic distances varied from 0.0118 to 0.6353 with an average of 0.3100 among these varieties.Thus,these sweetpotato varieties exhibited high levels of genetic similarity and had distinct fingerprint profiles.The SSR fingerprints of the 203 sweetpotato varieties have been successfully constructed.The highly polymorphic SSR primer pairs developed in this study have the potential to be used as core primer pairs for variety identification,genetic diversity assessment and linkage map construction in sweetpotato and other plants.
文摘Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research.The results showed that after virus-elimination, all varieties had a yield increase ranging from 14.95% -91.61% and marketable quality improvement, despite the changes in location and season. The changes of dry matter content and disease resistance were not significant. Virus-free sweetpotato performed vigorous vine growth and strong dry matter assimilation ability. Virus-free parents had a slightly high seed setting percentage, but its flowering ability and performance of off-springs were similar to that of its check plants.
基金supported by the earmarked fund for China Agriculture Research System (CARS-10,Sweetpotato)
文摘Sweetpotato,Ipomoea batatas(L.) Lam.,is a globally important food crop and usually grown on arid-and semi-arid lands.Therefore,investigating the molecular mechanism of drought tolerance will provide important information for the improvement of drought tolerance in this crop.In this study,transcriptome analysis of the drought-tolerant sweetpotato line Xushu 55-2 was conducted on Illumina HiSeq 2500 platform.A total of 86.69 Gb clean data were generated and assembled into 2 671 693 contigs,222 073 transcripts,and 73 636 unigenes.In total,11 359 differentially expressed genes(DEGs) were identified after PEG6000 treatment,in which 7 666 were up-regulated and 3 693 were down-regulated.Of the 11 359 DEGs,10 192 DEGs were annotated in at least one database,and the remaining 1 167 DEGs were unknown.Abscisic acid(ABA),ethylene(ETH),and jasmonic acid(JA) signalling pathways play a major role in drought tolerance of sweetpotato.Drought-inducible transcription factors were identified,some of which have been reported to be associated with drought tolerance and others are unknown in plants.In addition,7 643 SSRs were detected.This study not only reveals insights into the molecular mechanism of drought tolerance in sweetpotato but also provides the candidate genes involved in drought tolerance of this crop.
基金supported by the National Key Research and Development Program of China(2019YFD1001302 and 2019YFD1001300)National Natural Science Foundation of China(31701483 and 31601382)+2 种基金Jiangsu Agricultural Science and Technology Independent Innovation Fund[CX(19)3063]the National Technical System of Sweetpotato Industry(CARS-10-C3)Jiangsu Province Science and Technology Support Program(BK20171325)。
文摘Sweetpotato[Ipomoea batatas(L.)Lam.],a food crop with both nutritional and medicinal uses,plays essential roles in food security and health-promoting.Chlorogenic acid(CGA),a polyphenol displaying several bioactivities,is distributed in all edible parts of sweetpotato.However,little is known about the specific metabolism of CGA in sweetpotato.In this study,IbPAL1,which encodes an endoplasmic reticulum-localized phenylalanine ammonia lyase(PAL),was isolated and characterized in sweetpotato.CGA accumulation was positively associated with the expression pattern of IbPAL1 in a tissue-specific manner,as further demonstrated by overexpression of IbPAL1.Overexpression of IbPAL1 promoted CGA accumulation and biosynthetic pathway genes expression in leaves,stimulated secondary xylem cell expansion in stems,and inhibited storage root formation.Our results support a potential role for IbPAL1 in sweetpotato CGA biosynthesis and establish a theoretical foundation for detailed mechanism research and nutrient improvement in sweetpotato breeding programs.
基金supported by the National Key Research and Development Program of China(2019YFD1001302 and 2019YFD1001300)the China Agriculture Research System of MOF and MARA(CARS-10-Sweetpotato)。
文摘Geranylgeranyl pyrophosphate synthase(GGPS) plays an important role in the biosynthesis of carotenoids. In a previous study, the IbGGPS gene was isolated from a sweetpotato, Ipomoea batatas(L.) Lam., line Nongdafu 14 with high carotenoid contents, but its role and underlying mechanisms in carotenoid biosynthesis in sweetpotato were not investigated. In the present study, the IbGGPS gene was introduced into a sweetpotato cv. Lizixiang and the contents of β-carotene, β-cryptoxanthin, zeaxanthin and lutein were significantly increased in the storage roots of the IbGGPSoverexpressing sweetpotato plants. Further analysis showed that IbGGPS gene overexpression systematically upregulated the genes involved in the glycolytic, 2-C-methyl-D-erythritol-4-phosphate(MEP) and carotenoid pathways,which increased the carotenoid contents in the transgenic plants. These results indicate that the IbGGPS gene has the potential for use in improving the carotenoid contents in sweetpotato and other plants.
文摘Four sweetpotato (Ipomoea batatas (L.) Lam.) cultivars grown in Alexandria, Egypt, including Monofya 6, Monofya 66, Abeeis, and Beauregard were cooked using four different home-cooking methods (boiling, baking, microwaving, and deep-frying). The antioxidant contents (total phenolics by Folin-Denis, and individual phenolic acids by HPLC) as well as the antioxidant activity determined by reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) were measured in this study. Results indicated that total phenolic contents of raw flesh tissue by Folin-Denis ranged from 0.53 to 0.87 mg chlorogenic acid equivalent (mg ChAE)/g dry weight basis (dw). The RP ranged between 0.1 and 0.25 mg ChAE/g dw, DPPH and ABTS radical scavenging activities varied from 1.10 to 1.72 and 0.85 to 1.51 μmol trolox equivalent (TE)/g dw, respectively. Thermal processing significantly (P ≤ 0.05) increased the total phenolic content, as well as individual phenolic acids and antioxidant capacity of all the cultivars under study. In this respect, deep-frying exhibited the highest increment among the four processing methods. The most abundant individual phenolic acids in processed flesh roots tissues were chlorogenic acid followed by 3,5-dicaffeoylquinic acid. Total phenolic contents were highly correlated with RP, DPPH, and ABTS, also the correlation between the DPPH and ABTS values were significantly high.
文摘Chemical and functional properties of ten sweetpotato varieties were investigated. The sweetpotato were of various flesh colours which included orange, yellow, cream and white with dry matter content ranging from 30.2% - 39.2%. The sweetpotato varieties varied significantly (p < 0.05) in total amylase activity, total starch and amylose content whose value ranges were 0.256 - 0.570 mg/ml/min 68.4% - 73.6%, 16.2% - 23.4% respectively. The pH of flours from the different sweetpotato varieties ranged from 6.01 - 6.64. The pasting behaviours of the sweetpotato flours also showed significant differences (p < 0.05) in the individual parameters (peak time, pasting temperature, peak viscosity, trough viscosity, final viscosity, breakdown and setback) among the different varieties. The results revealed the influence of variety on the chemical composition of sweetpotato and their pasting properties. Correlations were also revealed among different components of the sweetpotatoes which would be a basis in selection of the varieties for processing into different products.
文摘Sweetpotato is a major staple food in the world. It is a good source of carbohydrates, vitamin A, vitamin C and protein. The maximum production potential of the crop is being hampered by severe drought which ravages most parts of Africa. The main aim of this study therefore was to screen accessions of sweetpotato for drought tolerance in a quick screening method, followed by field screening with a view to identify accessions that can perform well under water stress conditions. Fifty sweetpotato accessions consisting of cultivars and breeding lines collected from the ARC-VOPI gene bank were planted for drought screening in the glass house for six weeks during which water was withheld to induce stress. Observations were made on number of dead plants and days to wilting point. The results were analyzed and 12 best performing accessions were selected for field trials. The field trial was carried out in Lwamondo, Limpopo province, a drought prone area in South Africa, under rain-fed conditions. The best performing accessions were Zapallo, Tacna, Ejumula, 2004-9-2 and Ndou.
基金The authors wish to express their sincere thanks to the Norwegian Programme for Development,Research and Education(NUFU)for facilitating this research by pro-viding financial support through the Norwegian Univer-sity of Life Sciences(UMB)in Norway and Makerere University(MAK)in Uganda.
文摘Sweetpotato varieties (five) were investigated for changes in α- and β-amylase activities during root development and on subjection of harvested roots to different postharvest handling and storage conditions. Changes in α- and β-amylase activities in development were monitored from 10 weeks after planting. At physiological maturity, sweetpotato roots were harvested and subjected to various conditions: freshly harvested roots and cured roots (spread under the sun for four days at 29℃ - 31℃ and 63% - 65% relative humidity), stored at ambient conditions (23℃ - 26℃ and 70% - 80% relative humidity) and in a semi-underground pit (19℃ - 21℃ and 90% - 95% relative humidity). Generally α- and β-amylase activities increased during development with NASPOT 9 and 10 consistently registering the highest activities and NASPOT 1 the lowest activity. Generally, maximum α-amylase activities were achieved at week 3 in ambient stores for NASPOT 9 and NASPOT 10 at 0.930 and 0.897 CU/g, respectively. Maximum β-amylase activity was achieved in ambient stores at week 3 and 4 for fresh and cured NASPOT 9 at 806 and 782 BU/g, respectively. Generally, curing and storing sweetpotatoes in ambient conditions registered the highest amylase activity. Maximum α- and β-amylase activities were registered at 67℃ - 68℃ and 58℃ - 60℃, respectively. These findings provide information for controlled modification of amylase activities of these sweetpotato varieties for product development efforts and monitoring the shelf life of the roots during storage.
基金financially supported by the National Key R&D Program of China (2019YFD1001300 and 2019YFD1001305)the earmarked fund for CARS-10-Sweetpotatothe Jiangsu Postgraduate Scientific Research and Practical Innovation Program Project, China (KYCX19-2207)
文摘As a critical food crop,sweetpotato(Ipomoea batatas(L.)Lam.)is widely planted all over the world,but it is deeply affected by Sweetpotato Virus Disease(SPVD).The present study utilized short tandem target mimic(STTM)technology to effectively up-regulate the expression of laccase(Ib LACs)by successfully inhibiting the expression of mi R397.The upstream genes in the lignin synthesis pathway were widely up-regulated by feedback regulation,including phenylalanine ammonialyase(PAL),4-coumarate-Co Aligase(4 CL),hydroxycinnamoyl Co A:shikimatetransferase(HTC),caffeicacid O-methyltransferase(COMT),and cinnamyl alcohol dehydrogenase(CAD).Meanwhile,the activities of PAL and LAC increased significantly,finally leading to increased lignin content.Lignin deposition in the cell wall increased the physical defence ability of transgenic sweetpotato plants,reduced the accumulation of SPVD transmitted by Bemisia tabaci(Gennadius),and promoted healthy sweetpotato growth.The results provide new insights for disease resistance breeding and green production of sweetpotato.
文摘S-metolachlor is used to control/suppress yellow nutsedge, annual grasses and several broadleaf weeds in sweetpotato. However, a decline in storage root quality is suspected when excessive rainfall occurs within 24-h after application. A greenhouse study was conducted to determine the effect of S-metolachlor application timing on sweetpotato growth and development. S-metolachlor treatments (0 and 1 kg·ha-1) were applied over-the-top at 0, 5 and ten days after transplanting (DAT) and a simulated rainfall treatment delivered 25 mm of rain, 51 mm·h-1 intensity, immediately after herbicide application. Plants were harvested at 5, 10, 15, 20 and 80 DAT. During the first four harvests, roots were scanned and analyzed with WinRHIZO-Pro image analysis system to estimate root number, length, volume, and surface area along with aboveground growth parameters. At the final harvest, plant growth and biomass components, and quality of storage roots were recorded. Plants treated with S-metolachlor on day 0 and 5 DAT were significantly less than those of 10 DAT and untreated control for all measured parameters for the initial 20 days of plant growth. Even though vine length, leaf number, stem biomass, and total storage roots were not different among the treatments at 80 DAT, all other plant components and total biomass production and leaf area development for plants treated at 0 and 5 DAT were significantly (P < 0.05) less than from those of 10 DAT and the untreated control. Marketable storage root conversion efficiency declined by 18% and 16% for plants treated at 0 and 5 DAT, respectively, relative to the untreated check. These results indicate that delaying S-metolachlor application to 10 DAT will be less damaging to sweetpotato growth and development, particularly marketable storage roots and yield.
文摘The S-metolachlor is used to control/suppress yellow nutsedge, annual grasses, and several broadleaf weeds in sweetpotato. However, when used under adverse environmental conditions, it may lead to crop injury. Information is limited on the effect of S-metolachlor application followed immediately by rainfall on sweetpotato growth and development under different temperature regimes. The objective of this study was to determine sweetpotato response to S-metolachlor under low, optimum, and high temperatures with no rainfall and rainfall immediately after application. Sweetpotato slips were transplanted to sandy loam soil-filled pots. Half of the pots were subjected to 38 mm rainfall at 50.8 mm·h-1 intensity within the first 24 h after POST-transplant S-metolachlor application at 0, 0.86, 1.72, 2.58 and 3.44 kg·ha-1. The pots were moved into sunlit, computer-controlled plant growth chambers that were maintained at their respective temperatures for 61 days. Plant growth, development and plant-component dry weights and quantity of storage roots were recorded at harvest. Storage root yield was highest at the optimum temperature and declined at low and high temperature conditions. Shoot, root, and total plant biomass yield declined with increasing concentration of S-metolachlor across temperature conditions. In addition, storage root yield decline was S-metolachlor rate-dependent and aggravated by a rainfall event immediately after herbicide treatment across temperatures tested. These results can be used to weigh the risk of potential crop injury against the benefits of S-metolachlor when making management decisions as well as considering weather forecast information to avoid herbicide application coinciding with adverse weather conditions such as excessive rainfall event.
文摘The study was carried out to determine the effect of salt on the sensory, nutritive and keeping quality of OFSP crisps. Crisps were made by deep frying slices of approximately 3.5 mm thickness treated with, 2% and 4% table salt. A control with no salt treatment was prepared alongside the treated ones. Two varieties of OFSP;Ejumula and Kakamega were used in the study. After deep frying, the crisps were cooled to room temperature, packed in paper-lined high density polythene pouches and stored in a dark cupboard at room temperature for three months. During the storage period, the crisps were analyzed for proteins, fat and carotenoid content. Changes in sensory attributes were analyzed using a semi-trained panel. Results indicated that freshly prepared crisps treated with 2% salt had the highest acceptability mean scores for all attributes while there was no significant difference (p > 0.05) between crisps made from either Ejumula or Kakamega variety. Carotenoid content decreased with increase in salt concentration in both OFSP varieties. Shelf-life studies showed that the decline in sensory attributes started after 2 months of storage. The study shows that OFSP crisps treated with 2% salt are more acceptable and reasonably stable during storage.
文摘Vitamin A Deficiency (VAD) is a major concern in the world today and is a risk for children in developing countries. Trends have shown that food based interventions are the preferred long-term solution in controlling VAD as opposed to supplements. The orange-fleshed sweetpotato and mangoes are rich in beta-carotene, yet they are not fully utilized. A processed product from these raw materials will make use of surplus produce, promote year round utilization, increase the economic value of the crops and provide variety and convenience of uses. The roots were obtained from the field station, University of Nairobi, while the mangoes were purchased from the local market. The roots were washed, peeled and sliced. They were boiled to softness and mashed. The mangoes were washed, peeled, sliced and pureed in a blender. The two raw materials were mixed using six different formulations. Each formula was pasteurized at 80°C for 5 min in a batch pasteurizer, packaged by hot filling, cooled immediately and stored. The cooking time for the sweetpotatoes was 19.5 min. Losses of beta-carotene and ascorbic acid ranged from 17% - 21% and 18% - 28% respectively after pasteurization. The total solids increased by 3% on average. Changes due to storage of the product at 25°C could be detected by sensory analysis only after six months of storage. After storage, beta-carotene and ascorbic acid decreased by 18% and by 45% respectively. The final stored product could provide 73.7% and 64.5% of retinol equivalent for infants and 1 - 10 year-olds respectively. It could also provide 48.9% of ascorbic acid for children 1 - 10 years old, when consumed in amounts of 100 g per day.
文摘The stability of β-carotene in cream-fleshed sweetpotato-based complementary food stored in three different containers under simulated tropical temperature of 32°C and 85% relative humidity in an environmental chamber for 24 weeks was investigated. The formulation stored in a metallised polyester film in a refrigerator (approximately 3.0°C and 95% relative humidity) retained about 81% of β-carotene at 24 weeks, with no significant change in the moisture content. The formulation stored in either a metallised polyester film or a translucent polypropylene container placed in the environmental chamber retained approximately half of the β-carotene at 24 weeks, with a slight increase in moisture content. However, the formulation held in a transparent low-density polyethylene bag had the lowest β-carotene retention (37%) and the highest moisture content at week 24. Within the limits of this study, it has been demonstrated that β-carotene in cream-fleshed sweetpotato-based complementary food was well retained when moisture uptake was minimised.
文摘Characterization of genes related to sweetpotato viral disease resistance is critical for understanding plant-pathogen interactions, especially with feathery mottle virus infection. For example, genes encoding eukaryotic translation initiation factor (eIF)4E, its isoforms, eIF(iso)4E, and the cap-binding protein (CBP) in plants, have been implicated in viral infections aside from their importance in protein synthesis. Full-length cDNA encoding these putative eIF targets from susceptible/resistant and unknown hexaploid sweetpotato (Ipomoea batatas L. Lam) were amplified based on primers designed from the diploid wild-type relative Ipomoea trifida consensus sequences, and designated IbeIF4E, IbeIF(iso)4E and IbCBP. Comparative analyses following direct-sequencing of PCR-amplified cDNAs versus the cloned cDNA sequences identified multiple homeoalleles: one to four IbeIF4E, two to three IbeIF(iso)4E, and two IbCBP within all cultivars tested. Open reading frames were in the length of 696 bp IbeIF4E, 606 bp IbeIF(iso)4E, and 675 bp IbCBP. The encoded single polypeptide lengths were 232, 202, and 225 amino acids for IbeIF4E, IbeIF(iso)4E, and IbCBP, with a calculated protein molecular mass of 26 kDa, 22.8 kDa, and 25.8 kDa, while their theoretical isoelectric points were 5.1, 5.57, and 6.6, respectively. Although the homeoalleles had similar sequence lengths, single nucleotide polymorphisms and multi-allelic variations were detected within the coding sequences. The multi-sequence alignment performed revealed a 66.9% - 96.7% sequence similarity between the predicted amino acid sequences obtained from the homeoalleles and closely related species. Furthermore, phylogenetic analysis revealed ancestral relationships between the eIF4E homeoalleles and other species. The outcome herein on the eIF4E superfamily and its correlation in sequence variations suggest opportunities to decipher the role of eIF4E in hexaploid sweetpotato feathery mottle virus infection.
文摘The sweetpotato production in Tanzania has been increasing due to the changing status of the crop from famine relief to a commercial crop particularly in the central zone of Tanzania.Production of the crop is affected by environmental and biotic stresses.Apart from prolonged drought which affects timely availability of planting materials,sweetpotato weevils were recently reported by growers as a major setback to the productivity of the crop.The study was conducted between December 2016 and July 2017 in Gairo and Ikungi Districts of Morogoro and Singida regions respectively.The aim was to identify sweetpotato weevil species existing in the area,determine the seasonal abundance of the pests and test the response of popular and farmers’preferred sweetpotato varieties to the pest.The effect of planting time on the abundance of sweetpotato weevils was also studied.It was established that Cylas puncticollis is the lone weevil species infesting the crop in the study area.Time of planting significantly(p<0.05)influenced weevils’abundance with early planted crop sustaining least number of pests compared to the late planted.Sweetpotato variety,Gudugudu was least damaged by C.puncticollis.Locational influence suggested that Gairo District sustained greater weevil abundance and associated damages compared to Ikungi District.It was concluded that planting dates had influence on seasonal abundance of sweetpotato weevil with early planted crop sustaining least infestation with C.puncticollis compared to late planted crop.
