Acid soils occupy approximately 50% of potentially arable lands.Improving crop productivity in acid soils,therefore,will be crucial for ensuring food security and agricultural sustainability.High soil acidity often co...Acid soils occupy approximately 50% of potentially arable lands.Improving crop productivity in acid soils,therefore,will be crucial for ensuring food security and agricultural sustainability.High soil acidity often coexists with phosphorus(P) deficiency and aluminum(Al) toxicity,a combination that severely impedes crop growth and yield across wide areas.As roots explore soil for the nutrients and water required for plant growth and development,they also sense and respond to below-ground stresses.Within the terrestrial context of widespread P deficiency and Al toxicity pressures,plants,particularly roots,have evolved a variety of mechanisms for adapting to these stresses.As legumes,soybean(Glycine max) plants may acquire nitrogen(N) through symbiotic nitrogen fixation(SNF),an adaptation that can be useful for mitigating excessive N fertilizer use,either directly as leguminous crop participants in rotation and intercropping systems,or secondarily as green manure cover crops.In this review,we investigate legumes,especially soybean,for recent advances in our understanding of root-based mechanisms linked with root architecture modification,exudation and symbiosis,together with associated genetic and molecular strategies in adaptation to individual and/or interacting P and Al conditions in acid soils.We propose that breeding legume cultivars with superior nutrient efficiency and/or Al tolerance traits through genetic selection might become a potentially powerful strategy for producing crop varieties capable of maintaining or improving yields in more stressful soil conditions subjected to increasingly challenging environmental conditions.展开更多
Bacteria play critical roles in regulating soil phosphorus(P) cycling. The effects of interactions between crops and soil P-availability on bacterial communities and the feedback regulation of soil P cycling by the ba...Bacteria play critical roles in regulating soil phosphorus(P) cycling. The effects of interactions between crops and soil P-availability on bacterial communities and the feedback regulation of soil P cycling by the bacterial community modifications are poorly understood. Here, six soybean(Glycine max) genotypes with differences in P efficiency were cultivated in acidic soils with long-term sufficient or deficient P-fertilizer treatments. The acid phosphatase(AcP) activities, organic-P concentrations and associated bacterial community compositions were determined in bulk and rhizosphere soils. The results showed that both soybean plant P content and the soil AcP activity were negatively correlated with soil organic-P concentration in P-deficient acidic soils. Soil P-availability affected the ɑ-diversity of bacteria in both bulk and rhizosphere soils. However, soybean had a stronger effect on the bacterial community composition, as reflected by the similar biomarker bacteria in the rhizosphere soils in both P-treatments. The relative abundance of biomarker bacteria Proteobacteria was strongly correlated with soil organic-P concentration and AcP activity in low-P treatments. Further high-throughput sequencing of the phoC gene revealed an obvious shift in Proteobacteria groups between bulk soils and rhizosphere soils, which was emphasized by the higher relative abundances of Cupriavidus and Klebsiella, and lower relative abundance of Xanthomonas in rhizosphere soils. Among them, Cupriavidus was the dominant phoC bacterial genus, and it was negatively correlated with the soil organic-P concentration. These findings suggest that soybean growth relies on organic-P mineralization in P-deficient acidic soils, which might be partially achieved by recruiting specific phoCharboring bacteria, such as Cupriavidus.展开更多
Nitrogen(N) and phosphorus(P) are two essential mineral nutrients for plant growth,which are required in relative high amount in plants.Plants have evolved a series of strategies for coordinately acquiring and utilizi...Nitrogen(N) and phosphorus(P) are two essential mineral nutrients for plant growth,which are required in relative high amount in plants.Plants have evolved a series of strategies for coordinately acquiring and utilizing N and P.However,physiological and molecular mechanisms underlying of N and P interactions remain largely unclear in soybean(Glycine max).In this study,interactions of N and P were demonstrated in soybean as reflected by significant increases of phosphate(Pi) concentration in both leaves and roots by N deficiency under Pi sufficient conditions.A total of four nitrogen limitation adaptation(NLA),encoding RING-type E3 ubiquitin ligase were subsequently identified in soybean genome.Among them,transcription of Gm NLA1-1 and Gm NLA1-3 was decreased in soybean by N starvation under Pi sufficient conditions,not for Gm NLA1-2.Suppression of all three Gm NLA1 members was able to increase Pi concentration regardless of the P and N availability in the growth medium,but decrease fresh weight under normal conditions in soybean hairy roots.However,comparted to changes in control lines at two N levels,N deficiency only resulted in a relatively higher increase of Pi concentration in Gm NLA1-1 or Gm NLA1-3 suppression lines,strongly indicating that Gm NLA1-1 and Gm NLA1-3 might regulate P homeostasis in soybean response to N starvation.Taken together,our result suggest that redundant and diverse functions present in Gm NLA1 members for soybean coordinate responses to P and N availability,which mediate P homeostasis.展开更多
Increasing global demand for food presents a significant challenge to maintaining soil health and sustainable production of agricultural crops. As plant root-associated microbial fitness is greatly impacted by communi...Increasing global demand for food presents a significant challenge to maintaining soil health and sustainable production of agricultural crops. As plant root-associated microbial fitness is greatly impacted by community growth, development, and nutrient acquisition, the cultivation of functional assembly of root-associated microbes may provide solutions for achieving food security while maintaining healthy soils. Here, we propose a four-part strategy to promote soil health and agricultural productivity by partnering crops with root-associated microbes.展开更多
Beany flavor induced by three lipoxygenases(LOXs, including LOX1, LOX2, and LOX3)restricts human consumption of soybean. It is desirable to generate lipoxygenase-free new mutant lines to improve the eating quality of ...Beany flavor induced by three lipoxygenases(LOXs, including LOX1, LOX2, and LOX3)restricts human consumption of soybean. It is desirable to generate lipoxygenase-free new mutant lines to improve the eating quality of soybean oil and protein products. In this study, a pooled clustered regularly interspaced short palindromic repeats(CRISPR)-CRISPRassociated protein 9(Cas9) strategy targeting three GmLox genes(GmLox1, GmLox2, and GmLox3) was applied and 60 T_0 positive transgenic plants were generated, carrying combinations of sg RNAs and mutations. Among them, GmLox-28 and GmLox-60 were gmlox1 gmlox2 gmlox3 triple mutants and GmLox-40 was a gmlox1 gmlox2 double mutant.Sequencing of T_1 mutant plants derived from GmLox-28, GmLox-60, and GmLox-40 showed that mutation in the GmLox gene was inherited by the next generation. Colorimetric assay revealed that plants carrying different combinations of mutations lost the corresponding lipoxygenase activities. Transgene-free mutants were obtained by screening the T_2 generation of lipoxygenase-free mutant lines(GmLox-28 and GmLox-60). These transgeneand lipoxygenase-free mutants could be used for soybean beany flavor reduction without restriction by regulatory frameworks governing transgenic organisms.展开更多
Sugarcane mosaic virus (SCMV;genus Potyvirus, family Potyviridae) is a causal pathogen of sugarcane mosaic disease, and it is widespread in regions where sugarcane (Saccharum spp. hybrids) is grown. It is difficult to...Sugarcane mosaic virus (SCMV;genus Potyvirus, family Potyviridae) is a causal pathogen of sugarcane mosaic disease, and it is widespread in regions where sugarcane (Saccharum spp. hybrids) is grown. It is difficult to investigate the molecular mechanism of pathogen infection in sugarcane because of limited genomic information. Here, we demonstrated that SCMV strain FZ1 can systemically infect Brachypodium distachyon inbred line Bd21 and Nicotiana benthamiana through inoculation, double antibody sandwich enzyme-linked immunosorbent, transmission electron microscopy, and reverse transcription PCR assays. The leaves of Bd21 developed mosaic symptoms, while the leaves of N. benthamiana showed no obvious symptoms under the challenge of SCMV-FZ1. We concluded that B. distachyon inbred line Bd21 is a promising experimental model plant compared with N. benthamiana for study on the infectivity of SCMV. This is the first report on the SCMV infection of model plants B. distachyon inbred line Bd21 and N. benthamiana, which will shed light on the mechanism of SCMV infection of sugarcane and benefit sugarcane breeding against sugarcane mosaic disease.展开更多
Cytoplasmic male sterility(CMS)-restorer system is a useful tool to exploit heterosis in soybean.The major restorer gene for the M-type CMS is known as Rf-m,located in the 162.4-kb region on chromosome 16.Sequence ana...Cytoplasmic male sterility(CMS)-restorer system is a useful tool to exploit heterosis in soybean.The major restorer gene for the M-type CMS is known as Rf-m,located in the 162.4-kb region on chromosome 16.Sequence analysis has revealed that the Rf-m locus in Glycine max consists of seven penta tricopeptide repeat(GmPPR)genes.The deduced amino acid sequences contain 8 to 14 PPR motifs,and a phylogenetic analysis grouped these GmPPR proteins into two PPR subfamilies:Glyma.16G161800 belongs to the PLS subfamily,and the P subfamily consists.of Glyma.16G161900,Glyma 16G162000,Glyma.16G162100,Glyma.16G162700,Glyma.16G162800,and Gly-ma 16G163100.The phylogenetic analysis of seven GmPPR proteins and 27 other plant PPR proteins also showed that proteins in the same subfamilies cluster together.Comparative sequence analysis was conducted using the seven Rf-m candidate GmPPR genes from the sterile line W931A,the maintainer line W931B,and the restorer line WR016,the result showed that Glyma 16G161900 had higher polymorphism than the other candidate genes.Based on real-time quantitative RT-PCR data,all seven GmPPR genes were differentially expressed but showed constitutive expression in roots,stems,leaves,and pollen grains.Additionally,the expression level of Gly-ma 16G161900 in the sterile line W931 A was significantly higher in all tissues than in the restorer line WR016.Taken together,these results suggest that Glyma 16G161900 is the most likely candidate for the restorer gene Rf-m.This study is the first report and analysis of candidate fertility restorer(Rf)genes encoding PPR proteins in soybean.展开更多
Cadmium(Cd)is a non-essential toxic metal that is harmful to plants.To investigate the genetic mechanism of Cd tolerance in rice,quantitative trait loci(QTLs)associated with Cd tolerance at the seedling stage were ana...Cadmium(Cd)is a non-essential toxic metal that is harmful to plants.To investigate the genetic mechanism of Cd tolerance in rice,quantitative trait loci(QTLs)associated with Cd tolerance at the seedling stage were analyzed using a recombinant inbred line(RIL)population derived from a cross between PA64s and 93-11.A total of 36 QTLs associated with shoot length,root length,shoot dry weight,root dry weight and total dry weight were detected in Hangzhou and Lingshui of China.Among them,15 QTLs were identified under the control condition and 15 QTLs were identified under the Cd stress condition,and 6 QTLs for Cd tolerant coefficient were detected on chromosomes 1,3,7 and 9.The qCDSL1.1 and qCDSL1.2 were identified in Hangzhou and Lingshui,respectively,and had overlapping intervals on chromosome 1.To further confirm the effects of qCDSL1.1 and qCDSL1.2,we developed a chromosome segment substitution line(CSSL),CSSLqCDSL1,in 93-11 background harboring qCDSL1.1/qCDSL1.2 from PA64s.Compared to 93-11,CSSLqCDSL1 had increased shoot length under the Cd stress condition.These results pave the way for further isolation of those genes controlling Cd tolerance in rice and marker-assistant selection of rice elite varieties with Cd tolerance.展开更多
Under water and phosphorus (P) coupled stresses, root architecture may be related to P acquisition efficiency of plants. Understanding the relationship between root architecture and P acquisition efficiency may provid...Under water and phosphorus (P) coupled stresses, root architecture may be related to P acquisition efficiency of plants. Understanding the relationship between root architecture and P acquisition efficiency may provide basic information for improving P acquisition efficiency of plants. In the present study, we quantitatively described the effects of root architecture on P acquisition efficiency by computer simulation together with controlled biological experiments so as to determine an ideal root architecture for efficient P acquisition under water and P coupled stresses. Our results indicate that under given soil water conditions, the ideal root architecture for P acquisition efficiency of a tap root plant (as represented by common bean) is an 搖mbrella-shape?root system whose basal roots tend to be shallow in the P-rich topsoil and tap roots tend to be deep for water in the subsoil. Meanwhile, the ideal root architecture for a fibrous root plant (as represented by upland rice) is a beard-shape?root system with the moderately dispersed yet uniformly distributed adventitious and lateral roots so as to keep most roots in the topsoil for P and a few roots in the subsoil for water.展开更多
Root-associated microbes are critical for plant growth and nutrient acquisition. However, scant information exists on optimizing communities of beneficial root-associated microbes or the mechanisms underlying their in...Root-associated microbes are critical for plant growth and nutrient acquisition. However, scant information exists on optimizing communities of beneficial root-associated microbes or the mechanisms underlying their interactions with host plants. In this report, we demonstrate that rootassociated microbes are critical influencers of host plant growth and nutrient acquisition. Three synthetic communities(SynComs) were constructed based on functional screening of 1,893 microbial strains isolated from root-associated compartments of soybean plants. Functional assemblage of SynComs promoted significant plant growth and nutrient acquisition under both N/P nutrient deficiency and sufficiency conditions.Field trials further revealed that application of SynComs stably and significantly promoted plant growth, facilitated N and P acquisition, and subsequently increased soybean yield. Among the tested communities, SynCom1 exhibited the greatest promotion effect, with yield increases of up to 36.1% observed in two field sites. Further RNA-seq implied that SynCom application systemically regulates N and P signaling networks at the transcriptional level, which leads to increased representation of important growth pathways, especially those related to auxin responses. Overall,this study details a promising strategy for constructing SynComs based on functional screening,which are capable of enhancing nutrient acquisition and crop yield through the activities of beneficial root-associated microbes.展开更多
On acid soils,the trivalent aluminium ion(Al3+)predominates and is very rhizotoxic to most plant species.For some native plant species adapted to acid soils including tea(Camellia sinensis),Al3+has been regarded as a ...On acid soils,the trivalent aluminium ion(Al3+)predominates and is very rhizotoxic to most plant species.For some native plant species adapted to acid soils including tea(Camellia sinensis),Al3+has been regarded as a beneficial mineral element.In this study,we discovered that Al3+is actually essential for tea root growth and development in all the tested varieties.Aluminum ion promoted new root growth in five representative tea varieties with dose-dependent responses to Al3+availability.In the absence of Al3+,the tea plants failed to generate new roots,and the root tips were damaged within 1 d of Al deprivation.Struc-tural analysis of root tips demonstrated that Al was required for root meristem development and activity.In situ morin@staining of Al3+in roots revealed that Al mainly localized to nuclei in root meristem cells,but then gradually moved to the cytosol when Al3+was subsequently withdrawn.This movement of Al3+from nuclei to cytosols was accompanied by exacerbated DNA damage,which suggests that the nuclear-targeted Al primarily acts to maintain DNA integrity.Taken together,these results provide novel evidence that Al3+is essential for root growth in tea plants through maintenance of DNA integrity in meristematic cells.展开更多
Improving crop nutrient ef ficiency becomes an essential consideration for environmentally friendly and sustainable agriculture. Plant growth and development is dependent on 17 essential nutrient elements,among them,n...Improving crop nutrient ef ficiency becomes an essential consideration for environmentally friendly and sustainable agriculture. Plant growth and development is dependent on 17 essential nutrient elements,among them,nitrogen（N） and phosphorus（P） are the two most important mineral nutrients. Hence it is not surprising that low N and/or low P availability in soils severely constrains crop growth and productivity,and thereby have become high priority targets for improving nutrient ef ficiency in crops. Root exploration largely determines the ability of plants to acquire mineral nutrients from soils. Therefore,root architecture,the 3-dimensional con figuration of the plant＇s root system in the soil,is of great importance for improving crop nutrient ef ficiency. Furthermore,the symbiotic associations between host plants and arbuscular mycorrhiza fungi/rhizobial bacteria,are additional important strategies to enhance nutrient acquisition. In this review,we summarize the recent advances in the current understanding of crop species control of root architecture alterations in response to nutrient availability and root/microbe symbioses,through gene or QTL regulation,which results in enhanced nutrient acquisition.展开更多
Quantification of 3-dimensional (3-D) plant root architecture is one of the most important approaches to investigating plant root growth and its function in nutrient acquisition and utilization. However, no effective ...Quantification of 3-dimensional (3-D) plant root architecture is one of the most important approaches to investigating plant root growth and its function in nutrient acquisition and utilization. However, no effective methods have been reported hitherto to quantify 3-D root architecture parameters, making it difficult to further study the 3-D characteris- tics of the root system and its function. In the present study, we created a rapid algorithm to reconstruct 3-D root system images based on the basic structural features of such linear objects as roots, using 2-D root images taken by digital CCD cameras at multi- viewing angles. This method is very effective in the reconstruction of plant root system images, thus enabling us to obtain the digital model of 3-D root architecture and its 3-D skeleton, based on which some major root architecture parameters can be calculated. Using this method, we were able to ac- quire 3-D parameters of soybean root architecture whose root diameter was more than 0.3 mm, includ- ing tap root length, total root length, average basal root angle, ratio of root width to root depth, percent- age distribution of root length in different layers and root distribution in different 3-D regions of the growth medium. We also quantitatively analyzed the rela- tionship between different root architecture parame-ters and such plant nutrition parameters as soybean biomass and phosphorus (P) uptake. Our study may provide a new tool in studying the growth and nutri- tional functions of plant root systems.展开更多
As an essential plant macronutrient, the low availability of phosphorus （P） in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition...As an essential plant macronutrient, the low availability of phosphorus （P） in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition, remobilization and recycling of phosphate （Pi） to maintain P homeostasis. Spatio-temporal molecular, physiological, and biochemical Pi deficiency responses developed by plants are the consequence of local and systemic sensing and signaling pathways. Pi deficiency is sensed locally by the root system where hormones serve as important signaling components in terms of developmental reprogramming, leading to changes in root system architecture. Root-to-shoot and shoot-to-root signals, delivered through the xylem and phloem, respectively, involving Pi itself, hormones, miRNAs, mRNAs, and sucrose, serve to coordinate Pi deficiency responses at the whole-plant level. A combination of chromatin remodeling, transcriptional and posttranslational events contribute to globally regulating a wide range of Pi deficiency responses. In this review, recent advances are evaluated in terms of progress toward developing a comprehen- sive understanding of the molecular events underlying control over P homeostasis. Application of this knowledge, in terms of developing crop plants having enhanced attributes for P use efficiency, is discussed from the perspective of agricultural sustainability in the face of diminishing global P supplies.展开更多
Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively st...Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions （OAs; mainly malate, citrate and oxalate） to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3＋ and mobilize phosphate （Pi）, while OAs synthesized in the cell can internally sequester Al^3＋ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.展开更多
A potential mechanism to enhance utilization of sparingly soluble forms of phosphorus （P） is the root secretion of malate, which is mainly mediated by the ALMT gene family in plants. In this study, a total of 34 GmA...A potential mechanism to enhance utilization of sparingly soluble forms of phosphorus （P） is the root secretion of malate, which is mainly mediated by the ALMT gene family in plants. In this study, a total of 34 GmALMT genes were identified in the soybean genome. Expression patterns diverged considerably among GmALMTs in response to phosphate （Pi） starvation in leaves, roots and flowers, with expression altered by P availability in 26 of the ：34 GmALMTs. One root-specific GmALMT whose expression was significantly enhanced by Pi-starvation, GmALMTS, was studied in more detail to determine its possible role in soybean P nutrition. Analysis of GmALMT5 tissue expression patterns, subcellular localization, and malate exudation from transgenic soybean hairy rootsoverexpressing GmALMT5, demonstrated that GmALMT5 is a plasma membrane protein that mediates malate efflux from roots. Furthermore, both growth and P content of transgenic Arabidopsis overexpressing GmALMT5 were significantly increased when sparingly soluble Ca-P was used as the external P source. Taken together, these results indicate that members of the soybean GmALMT gene family exhibit diverse responses to Pi starvation. One member of this family, GmALMT5, might contribute to soybean P efficiency by enhancing utilization of sparingly soluble P sources under P limited conditions.展开更多
Hybrid sterility is a major hindrance to utiliz-ing the heterosis in indica-japonica hybrids. To isolate a gene Sc conferring the hybrid sterility, the locus was mapped us-ing molecular markers and an F2 population de...Hybrid sterility is a major hindrance to utiliz-ing the heterosis in indica-japonica hybrids. To isolate a gene Sc conferring the hybrid sterility, the locus was mapped us-ing molecular markers and an F2 population derived from a cross between near isogenic lines. A primary linkage analysis showed that Sc was linked closely with 4 markers on chro-mosome 3, on which the genetic distance between a marker RG227 and Sc was 0.07 cM. Chromosome walking with a rice TAC genomic library was carried out using RG227 as a starting probe, and a contig of ca. 320 kb covering the Sc locus was constructed. Two TAC clones, M45E14 and M90J01 that might cover the Sc locus, were partially se-quenced. By searching the rice sequence databases with se-quences of the TACs and RG227 a japonica rice BAC se-quence, OSJNBb0078P24 was identified. By comparing the TAC and BAC sequences, six new PCR-based markers were developed. With these markers the Sc locus was further mapped to a region of 46 kb. The results suggest that the BAC OSJNBb0078P24 and TAC M45E14 contain the Sc gene. Six ORFs were predicted in the focused 46-kb region.展开更多
Rice tiller angle is a key agronomic trait that contributes to ideal plant architecture and grain production.LAZY1 (LA1) was previously shown to control tiller angle via affecting shoot gravitropism,but the underlying...Rice tiller angle is a key agronomic trait that contributes to ideal plant architecture and grain production.LAZY1 (LA1) was previously shown to control tiller angle via affecting shoot gravitropism,but the underlying molecular mechanism remains largely unknown.In this study,we identified an LA1-interacting protein named Brevis Radix Like 4 (OsBRXL4).We showed that the interaction between OsBRXL4 and LA1 occurs at the plasma membrane and that their interaction determines nuclear localization of LA1.We found that nuclear localization of LA1 is essential for its function,which is different from AtLA1,its Arabidopsis ortho.log.Overexpression of OsBRXL4 leads to a prostrate growth phenotype,whereas OsBRXLs RNAi plants,in which the expression levels of OsBRXLI,OsBRXL4,and OsBRXL5 were decreased,display a compact phenotype.Further genetic analysis also supported that OsBRXL4 controls rice tiller angle by affecting nuclear localization of LA1.Consistently,we demonstrated that OsBRXL4 regulates the shoot gravitropism through affecting polar auxin transport as did LA1.Taken together,our study not only identifies OsBRXL4 as a regulatory component of rice tiller angle but also provides new insights into genetic regulation of rice plant architecture.展开更多
Rice is one of the most important cereal crops in the world, and a substantial increase in grain yield is necessary for food security. However, high yields of semidwarf modern rice varieties are heavily dependent on t...Rice is one of the most important cereal crops in the world, and a substantial increase in grain yield is necessary for food security. However, high yields of semidwarf modern rice varieties are heavily dependent on the application of mineral nitrogenous fertilizer (Tilman et al., 2002;Sun et al., 2014). Nitrogen (N)-insensitive sponses associated with reduced N-use efficiency (NUE) is a major characteristic of the green revolution varieties (GRVs), in which the growth-inhibiting protein SLENDER RICE1 (SLR1) accumulates (Li et al., 2018). Unfortunately, increasing the level of N fertilizer use to reach the full yield potential of GRVs is subject to diminishing returns, quite apart from its deleterious effect on the environments (Rahn et al., 2009;Liu et al., 2015). Therefore, there is an urgent need to develop new rice GRVs that increase NUE while maintaining their high yields. Recently, several genes (e.g., DEP1, OsNRTl.lB, OsNRT2.3b, ARE1 and GRF4) responsible for improved NUE have been identified in rice (Sun et al.. 2014;Hu et al., 2015;Fan et al., 2016;Wang et al., 2018;Li et al., 2018). More importantly, boosting the activity of the transcription factor GRF4 overcomes the ability of SLR1 to prevent the GRF4-GIF1 interaction, which in turn promotes the coordinated expression of the genes involved in N assimilation and carbon fixation and consequently enhances the NUE of rice GRVs, thereby improving our ability to grow crops sustainably (Li et al., 2018). However, current understanding of the genetic basis for improving NUE remains at the level of identification of a number of quantitative trait loci (QTLs), without any understanding of the nature of the gene products.展开更多
Soybean (Glycine max L.) is a very important food and oil crop in China. Legume-rhizobium symbiotic nitrogen (N) fixation is an important biological character and also the base of improving soil fertility of soybean. ...Soybean (Glycine max L.) is a very important food and oil crop in China. Legume-rhizobium symbiotic nitrogen (N) fixation is an important biological character and also the base of improving soil fertility of soybean. However, soybean production and development is severely limited in tropical and subtropical areas in China due to a lack of effective rhizobial inoculants adapting to low-phosphorus (P) acid soils. In the present study, 12 soybean rhizobial strains were isolated and purified from the nodules of two soybean genotypes contrasting in P efficiency, which were grown on different low-P acid soils with different soybean cultivation histories. Results from 16S rDNA sequence analysis showed that these 12 rhizobial strains belonged to the genus of Bradyrhizobium, which had higher nitrogenase activities compared to the control strain, Bradyrhizboium japonicum USDA110. A field experiment was carried out by applying rhizobial inoculants, a mixture of three rhizobial strains that showed the highest ni- trogenase activity, on a typical low-P acid soil in South China. The results showed that, without inocu- lation, no nodules were formed in the three soybean genotypes tested; with inoculation, the nodulation rates in all were 100%. Inoculation with rhizobial inoculants not only made many nodules formed, but also increased soybean shoot biomass and yield, and improved nitrogen (N) and P nutrient status. Among which, shoot dry weight, N and P content of a soybean genotype, Huachun 3, inoculated with rhizobium were increased 154.3%, 152.4% and 163.2% compared to that without inoculation, respec- tively. We concluded that: (i) The effective indigenous rhizobial strains isolated in this study from soybeans on low-P acid soils in South China have the characters of broad host range, high nodulation efficiency, efficient N fixation, great low pH and low P tolerance. (ii) Soil environment and host types are the key factors to screen the effective rhizobial strains. Considering soil pH values and P efficiency of the host genotypes might increase the screening efficiency. (iii) Improving N status and facilitating root growth might be the mechanisms of increasing the P uptake in soybean plants inoculated with the ef- fective rhizobial strains on low-P acid soils. (iv) Inoculation with the effective rhizobial inoculants could significantly improve growth, N and P content of soybean on low-P acid soils, which might be an effec- tive approach to enhance soybean cultivation and development in these areas. Therefore, application and extension of inoculation techniques with effective rhizobial inoculants in legumes would result in great economical, environmental and ecological benefits.展开更多
基金financially supported by the National Natural Science Foundation of China (32072661)the National Key Research and Development Program of China(2021YFF1000500)。
文摘Acid soils occupy approximately 50% of potentially arable lands.Improving crop productivity in acid soils,therefore,will be crucial for ensuring food security and agricultural sustainability.High soil acidity often coexists with phosphorus(P) deficiency and aluminum(Al) toxicity,a combination that severely impedes crop growth and yield across wide areas.As roots explore soil for the nutrients and water required for plant growth and development,they also sense and respond to below-ground stresses.Within the terrestrial context of widespread P deficiency and Al toxicity pressures,plants,particularly roots,have evolved a variety of mechanisms for adapting to these stresses.As legumes,soybean(Glycine max) plants may acquire nitrogen(N) through symbiotic nitrogen fixation(SNF),an adaptation that can be useful for mitigating excessive N fertilizer use,either directly as leguminous crop participants in rotation and intercropping systems,or secondarily as green manure cover crops.In this review,we investigate legumes,especially soybean,for recent advances in our understanding of root-based mechanisms linked with root architecture modification,exudation and symbiosis,together with associated genetic and molecular strategies in adaptation to individual and/or interacting P and Al conditions in acid soils.We propose that breeding legume cultivars with superior nutrient efficiency and/or Al tolerance traits through genetic selection might become a potentially powerful strategy for producing crop varieties capable of maintaining or improving yields in more stressful soil conditions subjected to increasingly challenging environmental conditions.
基金This work was supported by grants from the National Key Research and Development Program of China(2021YFF1000500)the Open Competition Program of Ten Major Directions of Agricultural Science and Technology Innovation for the 14th Five-Year Plan of Guangdong Province,China(2022SDZG07)+3 种基金the Key Areas Research and Development Programs of Guangdong Province,China(2022B0202060005)the STICGrantof China(SGDX20210823103535007)the Major Program of Guangdong Basic and Applied Research,China(2019B030302006)the Natural Science Foundation of Guangdong Province,China(2021A1515010826and 2020A1515110261).
文摘Bacteria play critical roles in regulating soil phosphorus(P) cycling. The effects of interactions between crops and soil P-availability on bacterial communities and the feedback regulation of soil P cycling by the bacterial community modifications are poorly understood. Here, six soybean(Glycine max) genotypes with differences in P efficiency were cultivated in acidic soils with long-term sufficient or deficient P-fertilizer treatments. The acid phosphatase(AcP) activities, organic-P concentrations and associated bacterial community compositions were determined in bulk and rhizosphere soils. The results showed that both soybean plant P content and the soil AcP activity were negatively correlated with soil organic-P concentration in P-deficient acidic soils. Soil P-availability affected the ɑ-diversity of bacteria in both bulk and rhizosphere soils. However, soybean had a stronger effect on the bacterial community composition, as reflected by the similar biomarker bacteria in the rhizosphere soils in both P-treatments. The relative abundance of biomarker bacteria Proteobacteria was strongly correlated with soil organic-P concentration and AcP activity in low-P treatments. Further high-throughput sequencing of the phoC gene revealed an obvious shift in Proteobacteria groups between bulk soils and rhizosphere soils, which was emphasized by the higher relative abundances of Cupriavidus and Klebsiella, and lower relative abundance of Xanthomonas in rhizosphere soils. Among them, Cupriavidus was the dominant phoC bacterial genus, and it was negatively correlated with the soil organic-P concentration. These findings suggest that soybean growth relies on organic-P mineralization in P-deficient acidic soils, which might be partially achieved by recruiting specific phoCharboring bacteria, such as Cupriavidus.
基金supported by the National Key Research and Development Program of China (2021YFF1000500)Major Program of Guangdong Basic and Applied Research (2019B030302006)+2 种基金the National Natural Science Foundation of China (32172659,32172658, 31872164)the STIC Grant (SGDX20210823103535007)the Natural Science Foundation of Guangdong Province of China(2021A1515010826, 2020A1515110261)。
文摘Nitrogen(N) and phosphorus(P) are two essential mineral nutrients for plant growth,which are required in relative high amount in plants.Plants have evolved a series of strategies for coordinately acquiring and utilizing N and P.However,physiological and molecular mechanisms underlying of N and P interactions remain largely unclear in soybean(Glycine max).In this study,interactions of N and P were demonstrated in soybean as reflected by significant increases of phosphate(Pi) concentration in both leaves and roots by N deficiency under Pi sufficient conditions.A total of four nitrogen limitation adaptation(NLA),encoding RING-type E3 ubiquitin ligase were subsequently identified in soybean genome.Among them,transcription of Gm NLA1-1 and Gm NLA1-3 was decreased in soybean by N starvation under Pi sufficient conditions,not for Gm NLA1-2.Suppression of all three Gm NLA1 members was able to increase Pi concentration regardless of the P and N availability in the growth medium,but decrease fresh weight under normal conditions in soybean hairy roots.However,comparted to changes in control lines at two N levels,N deficiency only resulted in a relatively higher increase of Pi concentration in Gm NLA1-1 or Gm NLA1-3 suppression lines,strongly indicating that Gm NLA1-1 and Gm NLA1-3 might regulate P homeostasis in soybean response to N starvation.Taken together,our result suggest that redundant and diverse functions present in Gm NLA1 members for soybean coordinate responses to P and N availability,which mediate P homeostasis.
基金support from the National Key Research and Development Program of China(No.2021YFF1000500)。
文摘Increasing global demand for food presents a significant challenge to maintaining soil health and sustainable production of agricultural crops. As plant root-associated microbial fitness is greatly impacted by community growth, development, and nutrient acquisition, the cultivation of functional assembly of root-associated microbes may provide solutions for achieving food security while maintaining healthy soils. Here, we propose a four-part strategy to promote soil health and agricultural productivity by partnering crops with root-associated microbes.
基金supported by funds from the National Key Research and Development Program of China(2016YFD0100700)to Y.G。
文摘Beany flavor induced by three lipoxygenases(LOXs, including LOX1, LOX2, and LOX3)restricts human consumption of soybean. It is desirable to generate lipoxygenase-free new mutant lines to improve the eating quality of soybean oil and protein products. In this study, a pooled clustered regularly interspaced short palindromic repeats(CRISPR)-CRISPRassociated protein 9(Cas9) strategy targeting three GmLox genes(GmLox1, GmLox2, and GmLox3) was applied and 60 T_0 positive transgenic plants were generated, carrying combinations of sg RNAs and mutations. Among them, GmLox-28 and GmLox-60 were gmlox1 gmlox2 gmlox3 triple mutants and GmLox-40 was a gmlox1 gmlox2 double mutant.Sequencing of T_1 mutant plants derived from GmLox-28, GmLox-60, and GmLox-40 showed that mutation in the GmLox gene was inherited by the next generation. Colorimetric assay revealed that plants carrying different combinations of mutations lost the corresponding lipoxygenase activities. Transgene-free mutants were obtained by screening the T_2 generation of lipoxygenase-free mutant lines(GmLox-28 and GmLox-60). These transgeneand lipoxygenase-free mutants could be used for soybean beany flavor reduction without restriction by regulatory frameworks governing transgenic organisms.
基金Financial support was provided by the National Natural Science Foundation of China (31371688)
文摘Sugarcane mosaic virus (SCMV;genus Potyvirus, family Potyviridae) is a causal pathogen of sugarcane mosaic disease, and it is widespread in regions where sugarcane (Saccharum spp. hybrids) is grown. It is difficult to investigate the molecular mechanism of pathogen infection in sugarcane because of limited genomic information. Here, we demonstrated that SCMV strain FZ1 can systemically infect Brachypodium distachyon inbred line Bd21 and Nicotiana benthamiana through inoculation, double antibody sandwich enzyme-linked immunosorbent, transmission electron microscopy, and reverse transcription PCR assays. The leaves of Bd21 developed mosaic symptoms, while the leaves of N. benthamiana showed no obvious symptoms under the challenge of SCMV-FZ1. We concluded that B. distachyon inbred line Bd21 is a promising experimental model plant compared with N. benthamiana for study on the infectivity of SCMV. This is the first report on the SCMV infection of model plants B. distachyon inbred line Bd21 and N. benthamiana, which will shed light on the mechanism of SCMV infection of sugarcane and benefit sugarcane breeding against sugarcane mosaic disease.
基金the National Key Research and Development Program of China(Grant No.2016YFD0101503)the Key Research and Development Program of Anhui Province(Grant No.202004a06020034)+1 种基金the Major Science and Technology Project of Anhui Province(Grant No.18030701178)the Program on Industrial Technology System of National Soybean(Grant No.CARS-04-PS07)。
文摘Cytoplasmic male sterility(CMS)-restorer system is a useful tool to exploit heterosis in soybean.The major restorer gene for the M-type CMS is known as Rf-m,located in the 162.4-kb region on chromosome 16.Sequence analysis has revealed that the Rf-m locus in Glycine max consists of seven penta tricopeptide repeat(GmPPR)genes.The deduced amino acid sequences contain 8 to 14 PPR motifs,and a phylogenetic analysis grouped these GmPPR proteins into two PPR subfamilies:Glyma.16G161800 belongs to the PLS subfamily,and the P subfamily consists.of Glyma.16G161900,Glyma 16G162000,Glyma.16G162100,Glyma.16G162700,Glyma.16G162800,and Gly-ma 16G163100.The phylogenetic analysis of seven GmPPR proteins and 27 other plant PPR proteins also showed that proteins in the same subfamilies cluster together.Comparative sequence analysis was conducted using the seven Rf-m candidate GmPPR genes from the sterile line W931A,the maintainer line W931B,and the restorer line WR016,the result showed that Glyma 16G161900 had higher polymorphism than the other candidate genes.Based on real-time quantitative RT-PCR data,all seven GmPPR genes were differentially expressed but showed constitutive expression in roots,stems,leaves,and pollen grains.Additionally,the expression level of Gly-ma 16G161900 in the sterile line W931 A was significantly higher in all tissues than in the restorer line WR016.Taken together,these results suggest that Glyma 16G161900 is the most likely candidate for the restorer gene Rf-m.This study is the first report and analysis of candidate fertility restorer(Rf)genes encoding PPR proteins in soybean.
基金the National Natural Science Foundation of China(Grant No.31671761)the Agricultural Science and Technology Innovation Program,Shenzhen Science and Technology Program(Grant No.2017050414212249).
文摘Cadmium(Cd)is a non-essential toxic metal that is harmful to plants.To investigate the genetic mechanism of Cd tolerance in rice,quantitative trait loci(QTLs)associated with Cd tolerance at the seedling stage were analyzed using a recombinant inbred line(RIL)population derived from a cross between PA64s and 93-11.A total of 36 QTLs associated with shoot length,root length,shoot dry weight,root dry weight and total dry weight were detected in Hangzhou and Lingshui of China.Among them,15 QTLs were identified under the control condition and 15 QTLs were identified under the Cd stress condition,and 6 QTLs for Cd tolerant coefficient were detected on chromosomes 1,3,7 and 9.The qCDSL1.1 and qCDSL1.2 were identified in Hangzhou and Lingshui,respectively,and had overlapping intervals on chromosome 1.To further confirm the effects of qCDSL1.1 and qCDSL1.2,we developed a chromosome segment substitution line(CSSL),CSSLqCDSL1,in 93-11 background harboring qCDSL1.1/qCDSL1.2 from PA64s.Compared to 93-11,CSSLqCDSL1 had increased shoot length under the Cd stress condition.These results pave the way for further isolation of those genes controlling Cd tolerance in rice and marker-assistant selection of rice elite varieties with Cd tolerance.
基金This work wassupported by the National Key Basic Research Special Funds of China (Grant No. G1999011700) the National Outstanding Youth Foundation (Grant No. 39925025) the National Natural Science Foundation of China (Grant No. 30070441).
文摘Under water and phosphorus (P) coupled stresses, root architecture may be related to P acquisition efficiency of plants. Understanding the relationship between root architecture and P acquisition efficiency may provide basic information for improving P acquisition efficiency of plants. In the present study, we quantitatively described the effects of root architecture on P acquisition efficiency by computer simulation together with controlled biological experiments so as to determine an ideal root architecture for efficient P acquisition under water and P coupled stresses. Our results indicate that under given soil water conditions, the ideal root architecture for P acquisition efficiency of a tap root plant (as represented by common bean) is an 搖mbrella-shape?root system whose basal roots tend to be shallow in the P-rich topsoil and tap roots tend to be deep for water in the subsoil. Meanwhile, the ideal root architecture for a fibrous root plant (as represented by upland rice) is a beard-shape?root system with the moderately dispersed yet uniformly distributed adventitious and lateral roots so as to keep most roots in the topsoil for P and a few roots in the subsoil for water.
基金supported by the by National Natural Science Foundation of China(No.31830083)China National Key Program for Research and Development(No.2016YFD0100700)。
文摘Root-associated microbes are critical for plant growth and nutrient acquisition. However, scant information exists on optimizing communities of beneficial root-associated microbes or the mechanisms underlying their interactions with host plants. In this report, we demonstrate that rootassociated microbes are critical influencers of host plant growth and nutrient acquisition. Three synthetic communities(SynComs) were constructed based on functional screening of 1,893 microbial strains isolated from root-associated compartments of soybean plants. Functional assemblage of SynComs promoted significant plant growth and nutrient acquisition under both N/P nutrient deficiency and sufficiency conditions.Field trials further revealed that application of SynComs stably and significantly promoted plant growth, facilitated N and P acquisition, and subsequently increased soybean yield. Among the tested communities, SynCom1 exhibited the greatest promotion effect, with yield increases of up to 36.1% observed in two field sites. Further RNA-seq implied that SynCom application systemically regulates N and P signaling networks at the transcriptional level, which leads to increased representation of important growth pathways, especially those related to auxin responses. Overall,this study details a promising strategy for constructing SynComs based on functional screening,which are capable of enhancing nutrient acquisition and crop yield through the activities of beneficial root-associated microbes.
基金This research was financially supported by the National Natural Science Foundation of China(31701989)MOA Modern Agricultural Talents Support Project and the Natural Science Foundation of Fujian Province in China(2017J01602).
文摘On acid soils,the trivalent aluminium ion(Al3+)predominates and is very rhizotoxic to most plant species.For some native plant species adapted to acid soils including tea(Camellia sinensis),Al3+has been regarded as a beneficial mineral element.In this study,we discovered that Al3+is actually essential for tea root growth and development in all the tested varieties.Aluminum ion promoted new root growth in five representative tea varieties with dose-dependent responses to Al3+availability.In the absence of Al3+,the tea plants failed to generate new roots,and the root tips were damaged within 1 d of Al deprivation.Struc-tural analysis of root tips demonstrated that Al was required for root meristem development and activity.In situ morin@staining of Al3+in roots revealed that Al mainly localized to nuclei in root meristem cells,but then gradually moved to the cytosol when Al3+was subsequently withdrawn.This movement of Al3+from nuclei to cytosols was accompanied by exacerbated DNA damage,which suggests that the nuclear-targeted Al primarily acts to maintain DNA integrity.Taken together,these results provide novel evidence that Al3+is essential for root growth in tea plants through maintenance of DNA integrity in meristematic cells.
基金the National Natural Science Foundation of China (U1301212)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB15030202)
文摘Improving crop nutrient ef ficiency becomes an essential consideration for environmentally friendly and sustainable agriculture. Plant growth and development is dependent on 17 essential nutrient elements,among them,nitrogen（N） and phosphorus（P） are the two most important mineral nutrients. Hence it is not surprising that low N and/or low P availability in soils severely constrains crop growth and productivity,and thereby have become high priority targets for improving nutrient ef ficiency in crops. Root exploration largely determines the ability of plants to acquire mineral nutrients from soils. Therefore,root architecture,the 3-dimensional con figuration of the plant＇s root system in the soil,is of great importance for improving crop nutrient ef ficiency. Furthermore,the symbiotic associations between host plants and arbuscular mycorrhiza fungi/rhizobial bacteria,are additional important strategies to enhance nutrient acquisition. In this review,we summarize the recent advances in the current understanding of crop species control of root architecture alterations in response to nutrient availability and root/microbe symbioses,through gene or QTL regulation,which results in enhanced nutrient acquisition.
基金This work was jointly supported by the National Key Basic Research Funds of China(Grant No.2005CB120902)the National Natural Science Foundation of China(Grant No.30230220)the McKnight Foundation Collaborative Crop Research Program(Grant No.05-780).
文摘Quantification of 3-dimensional (3-D) plant root architecture is one of the most important approaches to investigating plant root growth and its function in nutrient acquisition and utilization. However, no effective methods have been reported hitherto to quantify 3-D root architecture parameters, making it difficult to further study the 3-D characteris- tics of the root system and its function. In the present study, we created a rapid algorithm to reconstruct 3-D root system images based on the basic structural features of such linear objects as roots, using 2-D root images taken by digital CCD cameras at multi- viewing angles. This method is very effective in the reconstruction of plant root system images, thus enabling us to obtain the digital model of 3-D root architecture and its 3-D skeleton, based on which some major root architecture parameters can be calculated. Using this method, we were able to ac- quire 3-D parameters of soybean root architecture whose root diameter was more than 0.3 mm, includ- ing tap root length, total root length, average basal root angle, ratio of root width to root depth, percent- age distribution of root length in different layers and root distribution in different 3-D regions of the growth medium. We also quantitatively analyzed the rela- tionship between different root architecture parame-ters and such plant nutrition parameters as soybean biomass and phosphorus (P) uptake. Our study may provide a new tool in studying the growth and nutri- tional functions of plant root systems.
基金supported by grants from the United States Department of AgricultureNational Institute of Food and Agriculture (NIFA 201015479+2 种基金 W.J.L.)the National Natural Science Foundation of China (31025022 H.L.)
文摘As an essential plant macronutrient, the low availability of phosphorus （P） in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition, remobilization and recycling of phosphate （Pi） to maintain P homeostasis. Spatio-temporal molecular, physiological, and biochemical Pi deficiency responses developed by plants are the consequence of local and systemic sensing and signaling pathways. Pi deficiency is sensed locally by the root system where hormones serve as important signaling components in terms of developmental reprogramming, leading to changes in root system architecture. Root-to-shoot and shoot-to-root signals, delivered through the xylem and phloem, respectively, involving Pi itself, hormones, miRNAs, mRNAs, and sucrose, serve to coordinate Pi deficiency responses at the whole-plant level. A combination of chromatin remodeling, transcriptional and posttranslational events contribute to globally regulating a wide range of Pi deficiency responses. In this review, recent advances are evaluated in terms of progress toward developing a comprehen- sive understanding of the molecular events underlying control over P homeostasis. Application of this knowledge, in terms of developing crop plants having enhanced attributes for P use efficiency, is discussed from the perspective of agricultural sustainability in the face of diminishing global P supplies.
基金financially supported by the National Natural Science Foundation of China(No.U1301212)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB15030202)
文摘Aluminum （AI） toxicity and phosphorous （P） deficiency are two major limiting factors for plant growth on acidic soils. Thus, the physiological mechanisms for AJ tolerance and P acquisition have been intensively studied. A commonly observed trait is that plants have developed the ability to utilize organic acid anions （OAs; mainly malate, citrate and oxalate） to combat AI toxicity and P deficiency. OAs secreted by roots into the rhizosphere can externally chelate Al^3＋ and mobilize phosphate （Pi）, while OAs synthesized in the cell can internally sequester Al^3＋ into the vacuole and release free Pi for metabolism. Molecular mechanisms involved in OA synthesis and transport have been described in detail. Ensuing genetic improvement for AI tolerance and P efficiency through increased OA exudation and/or synthesis in crops has been achieved by transgenic and marker-assisted breeding. This review mainly elucidates the crucial roles of OAs in plant Al tolerance and P efficiency through summarizing associated physiological mechanisms, molecular traits and genetic manipulation of crops.
基金supported by grants from the National Natural Science Foundation of China (31672220, 31422046 and U1301212) the National Key Research and Development Program (2016YFD0100700)+2 种基金the Guangdong Natural Science Funds for Distinguished Young Scholars (2015A030306034)the Guangdong High-level Personnel of Special Support Program (2015TQ01N078 and 2015TX01N042) the Research Team Project of the Natural Science Foundation of Guangdong Province (2016A030312009). D D F
文摘A potential mechanism to enhance utilization of sparingly soluble forms of phosphorus （P） is the root secretion of malate, which is mainly mediated by the ALMT gene family in plants. In this study, a total of 34 GmALMT genes were identified in the soybean genome. Expression patterns diverged considerably among GmALMTs in response to phosphate （Pi） starvation in leaves, roots and flowers, with expression altered by P availability in 26 of the ：34 GmALMTs. One root-specific GmALMT whose expression was significantly enhanced by Pi-starvation, GmALMTS, was studied in more detail to determine its possible role in soybean P nutrition. Analysis of GmALMT5 tissue expression patterns, subcellular localization, and malate exudation from transgenic soybean hairy rootsoverexpressing GmALMT5, demonstrated that GmALMT5 is a plasma membrane protein that mediates malate efflux from roots. Furthermore, both growth and P content of transgenic Arabidopsis overexpressing GmALMT5 were significantly increased when sparingly soluble Ca-P was used as the external P source. Taken together, these results indicate that members of the soybean GmALMT gene family exhibit diverse responses to Pi starvation. One member of this family, GmALMT5, might contribute to soybean P efficiency by enhancing utilization of sparingly soluble P sources under P limited conditions.
文摘Hybrid sterility is a major hindrance to utiliz-ing the heterosis in indica-japonica hybrids. To isolate a gene Sc conferring the hybrid sterility, the locus was mapped us-ing molecular markers and an F2 population derived from a cross between near isogenic lines. A primary linkage analysis showed that Sc was linked closely with 4 markers on chro-mosome 3, on which the genetic distance between a marker RG227 and Sc was 0.07 cM. Chromosome walking with a rice TAC genomic library was carried out using RG227 as a starting probe, and a contig of ca. 320 kb covering the Sc locus was constructed. Two TAC clones, M45E14 and M90J01 that might cover the Sc locus, were partially se-quenced. By searching the rice sequence databases with se-quences of the TACs and RG227 a japonica rice BAC se-quence, OSJNBb0078P24 was identified. By comparing the TAC and BAC sequences, six new PCR-based markers were developed. With these markers the Sc locus was further mapped to a region of 46 kb. The results suggest that the BAC OSJNBb0078P24 and TAC M45E14 contain the Sc gene. Six ORFs were predicted in the focused 46-kb region.
基金supported by grants from the National Natural Science Foundation of China (9163530191535204+2 种基金31601276)the Ministry of Agriculture of China (2016ZX08009-003)the Strategic Priority Research Program "Molecular Mechanism of Plant Growth and Development" of CAS (XDPB0401).
文摘Rice tiller angle is a key agronomic trait that contributes to ideal plant architecture and grain production.LAZY1 (LA1) was previously shown to control tiller angle via affecting shoot gravitropism,but the underlying molecular mechanism remains largely unknown.In this study,we identified an LA1-interacting protein named Brevis Radix Like 4 (OsBRXL4).We showed that the interaction between OsBRXL4 and LA1 occurs at the plasma membrane and that their interaction determines nuclear localization of LA1.We found that nuclear localization of LA1 is essential for its function,which is different from AtLA1,its Arabidopsis ortho.log.Overexpression of OsBRXL4 leads to a prostrate growth phenotype,whereas OsBRXLs RNAi plants,in which the expression levels of OsBRXLI,OsBRXL4,and OsBRXL5 were decreased,display a compact phenotype.Further genetic analysis also supported that OsBRXL4 controls rice tiller angle by affecting nuclear localization of LA1.Consistently,we demonstrated that OsBRXL4 regulates the shoot gravitropism through affecting polar auxin transport as did LA1.Taken together,our study not only identifies OsBRXL4 as a regulatory component of rice tiller angle but also provides new insights into genetic regulation of rice plant architecture.
基金supported by grants from the National Natural Science Foundation of China (31830082)the National Key Research and Development Program of China (2016YFD0100401)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB27010000)
文摘Rice is one of the most important cereal crops in the world, and a substantial increase in grain yield is necessary for food security. However, high yields of semidwarf modern rice varieties are heavily dependent on the application of mineral nitrogenous fertilizer (Tilman et al., 2002;Sun et al., 2014). Nitrogen (N)-insensitive sponses associated with reduced N-use efficiency (NUE) is a major characteristic of the green revolution varieties (GRVs), in which the growth-inhibiting protein SLENDER RICE1 (SLR1) accumulates (Li et al., 2018). Unfortunately, increasing the level of N fertilizer use to reach the full yield potential of GRVs is subject to diminishing returns, quite apart from its deleterious effect on the environments (Rahn et al., 2009;Liu et al., 2015). Therefore, there is an urgent need to develop new rice GRVs that increase NUE while maintaining their high yields. Recently, several genes (e.g., DEP1, OsNRTl.lB, OsNRT2.3b, ARE1 and GRF4) responsible for improved NUE have been identified in rice (Sun et al.. 2014;Hu et al., 2015;Fan et al., 2016;Wang et al., 2018;Li et al., 2018). More importantly, boosting the activity of the transcription factor GRF4 overcomes the ability of SLR1 to prevent the GRF4-GIF1 interaction, which in turn promotes the coordinated expression of the genes involved in N assimilation and carbon fixation and consequently enhances the NUE of rice GRVs, thereby improving our ability to grow crops sustainably (Li et al., 2018). However, current understanding of the genetic basis for improving NUE remains at the level of identification of a number of quantitative trait loci (QTLs), without any understanding of the nature of the gene products.
基金Supported by National Key Basic Research and Development of China (Grant No. 2005CB120902)McKnight Foundation Collaborative Crop Research Program (USA) (Grant No. 05-780)National Natural Science Foundation of China (Grant No. 30571111)
文摘Soybean (Glycine max L.) is a very important food and oil crop in China. Legume-rhizobium symbiotic nitrogen (N) fixation is an important biological character and also the base of improving soil fertility of soybean. However, soybean production and development is severely limited in tropical and subtropical areas in China due to a lack of effective rhizobial inoculants adapting to low-phosphorus (P) acid soils. In the present study, 12 soybean rhizobial strains were isolated and purified from the nodules of two soybean genotypes contrasting in P efficiency, which were grown on different low-P acid soils with different soybean cultivation histories. Results from 16S rDNA sequence analysis showed that these 12 rhizobial strains belonged to the genus of Bradyrhizobium, which had higher nitrogenase activities compared to the control strain, Bradyrhizboium japonicum USDA110. A field experiment was carried out by applying rhizobial inoculants, a mixture of three rhizobial strains that showed the highest ni- trogenase activity, on a typical low-P acid soil in South China. The results showed that, without inocu- lation, no nodules were formed in the three soybean genotypes tested; with inoculation, the nodulation rates in all were 100%. Inoculation with rhizobial inoculants not only made many nodules formed, but also increased soybean shoot biomass and yield, and improved nitrogen (N) and P nutrient status. Among which, shoot dry weight, N and P content of a soybean genotype, Huachun 3, inoculated with rhizobium were increased 154.3%, 152.4% and 163.2% compared to that without inoculation, respec- tively. We concluded that: (i) The effective indigenous rhizobial strains isolated in this study from soybeans on low-P acid soils in South China have the characters of broad host range, high nodulation efficiency, efficient N fixation, great low pH and low P tolerance. (ii) Soil environment and host types are the key factors to screen the effective rhizobial strains. Considering soil pH values and P efficiency of the host genotypes might increase the screening efficiency. (iii) Improving N status and facilitating root growth might be the mechanisms of increasing the P uptake in soybean plants inoculated with the ef- fective rhizobial strains on low-P acid soils. (iv) Inoculation with the effective rhizobial inoculants could significantly improve growth, N and P content of soybean on low-P acid soils, which might be an effec- tive approach to enhance soybean cultivation and development in these areas. Therefore, application and extension of inoculation techniques with effective rhizobial inoculants in legumes would result in great economical, environmental and ecological benefits.
