Natural variations and geographical distributions of seed carotenoids and chlorophylls in 1167 Chinese soybean accessions

Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces.Genotype,planting year,accession type,seed cotyledon color,and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls.The mean total carotenoid content was in the range of 8.15–14.72μg g–1 across the ecoregions.The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars.Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons.Remarkably,lutein was the most abundant carotenoid in all the germplasms,ranging from 1.35–37.44μg g–1.Carotenoids and chlorophylls showed significant correlations with other quality traits,which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components.Collectively,our results demonstrate that carotenoids are adequately accumulated in soybean seeds,however,they are strongly influenced by genetic factors,accession type,and germplasm origin.We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs,and thereby as the raw materials for food sectors,pharmaceuticals,and the cosmetic industry.

Profiling of seed fatty acid composition in 1025 Chinese soybean accessions from diverse ecoregions

The stability of soybean(Glycine max L.Merrill)oil is determined mainly by its fatty acid(FA)composition.We evaluated the FA composition of 1025 Chinese soybean accessions collected from diverse ecoregions and grown in multiple locations and years.We observed highly significant differences(P<0.001)between accessions in palmitic acid(PA),stearic acid(SA),oleic acid(OA),linoleic acid(LA),and linolenic acid(LNA)contents.Growth year affected(P<0.001)the abundance of all FAs except PA.The mean PA,SA,OA,LA,and LNA contents were 12.2%,3.8%,21.5%,54.2%,and 8.3%,respectively.The geographical origin of the accession influenced seed FA composition,indicating that accessions originating in each ecoregion tend to have distinct FA composition.We observed significant positive correlations among the three locations and between the two years,suggesting the high heritability and stability of individual accessions across contrasting environments.We also observed a relatively high negative correlation between the contents of OA and both LA and LNA(r=-0.90 and-0.59,respectively,each significant at P<0.001),providing a potential entry point for developing strains producing oil with higher OA and lower LA and LNA levels.These would be appropriate for specialized use in the food industry.Our results will be useful in breeding soybean with improved quality to meet human nutritional and industrial needs.

Genomic dissection of widely planted soybean cultivars leads to a new breeding strategy of crops in the post-genomic era

Soybeans specially the widely planted cultivars have been dramatically improved in agronomic performance and is well adapted to local planting environments after long-time domestication and breeding.Uncovering the unique genomic features of popular cultivars will help to understand how soybean genomes have been modified through breeding.We re-sequenced 134 soybean cultivars that were released and most widely planted over the last century in China.Phylogenetic analyses established that these cultivars comprise two geographically distinct sub-populations:Northeast China (NE) versus the HuangHuai-Hai River Valley and South China (HS).A total of 309 selective regions were identified as being impacted by geographical origins.The HS sub-population exhibited higher genetic diversity and linkage disequilibrium decayed more rapidly compared to the NE sub-population.To study the association between phenotypic differences and geographical origins,we recorded the vegetative period under different growing conditions for two years,and found that clustering based on the phenotypic data was closely correlated with cultivar geographical origin.By iteratively calculating accumulated genetic diversity,we established a platform panel of cultivars and have proposed a novel breeding strategy named "Potalaization"for selecting and utilizing the platform cultivars that represent the most genetically diversity and the highest available agronomic performance as the "plateau"for accumulating elite loci and traits,breeding novel widely adapted cultivars,and upgrading breeding technology.In addition to providing new genomic information for the soybean research community,the "Potalaization"strategy that we devised will also be practical for integrating the conventional and molecular breeding programs of crops in the post-genomic era.

Profiling seed soluble sugar compositions in 1164 Chinese soybean accessions from major growing ecoregions

Soluble sugar is a key quality trait of soybean seeds.We developed rapid and economic extraction and quantification methods for seed soluble sugars using an ultra-high performance liquid chromatography system with a refractive index detector.We evaluated the soluble sugar compositions of 1164 soybean accessions collected from diverse ecoregions and grown in multiple locations and years.Total soluble sugar(TSS)content was influenced by accession type,year of cultivation,and ecoregion.The mean contents of fructose,glucose,sucrose,raffinose,stachyose and TSS were 3.31,5.21,55.60,6.60,35.47,and 106.19 mg g^(-1),respectively.The highest mean TSS content(108.71 mg g^(-1)) was observed in accessions from Northern Region of China.Cultivars contained higher contents of sucrose,raffinose,and TSS,whereas landraces had a higher content of stachyose.Fourteen accessions with mean TSS contents>130 mg g^(-1) were identified as elite soybean resources.TSS was correlated with sucrose,raffinose,stachyose,protein,oil and total tocopherol.The main soluble sugar components were correlated with latitude and longitude,indicating that the geographical origin of the accessions affected their seed soluble sugar compositions.The developed methods and elite identified accessions can be used in the food and feed industry and in soybean breeding programs aimed at improving soybean seed nutrition.

GmNMHC5 may promote nodulation via interaction with GmGAI in soybean

Soybean(Glycine max[L.]Merr.)is a food and oil crop whose growth and yield are influenced by root and nodule development.In the present study,Gm NMHC5 was found to promote the formation of nodules in overexpressing mutants.In contrast,the number of nodules in Gmnmhc5 edited with CRISPR/Cas9 decreased sharply.In 35 S:Gm NMHC5 mutants,expression levels of genes involved in nodulation were significantly up-regulated.Both in vitro and in vivo biochemical analyses showed that Gm NMHC5 directly interacted with Gm GAI(a DELLA protein),and the content of gibberellin 3(GA_(3))in overexpressing mutants was lower than that in the wild type.These results revealed that Gm NMHC5 participates in the classical GA signaling pathway,and may regulate the content of GA_3 to match the optimal concentration required for nodule formation,thereby promoting nodulation by directly interacting with Gm GAI.A model illustrating the mechanism by which Gm NMHC5 promotes soybean nodulation is presented.

Assessment of Castor Plant (Ricinus communis L.) Tolerance to Heavy Metal Stress-A Review

Increased urbanization and industrialization have greatly contributed to the emission of higher amount of heavy metals such as cadmium,nickel,and lead into the environment.These metals are non-biodegradable and toxic,causing much effects on plants and by extension to animals and humans,which have become a major global concern.The inherent ability of plants to resist heavy metal toxicity seems to be the most sustainable and cost-effective strategy.Castor plant is widely studied due to its tolerance to the effects of heavy metal contaminated soils,owing to its large biomass content and high accumulating capacity.Castor plants to some extent can tolerate elevated levels of heavy metals through several developed mechanisms,such as activation of antioxidant enzymes,exclusion,accumulation of proline,compartmentalization,organic acid exudation,and phytochelatins.Molecular studies have identified some stress-responsive to aid the tolerance of heavy metals in castor.Stress caused by heavy metal toxicity affects seedling growth,biomass,photosynthetic pigments,protein level,and nutrient uptake of castor plant.The response of castor,however,to these stresses differs among cultivars,metal type and concentration,and time of metal applied.This review aims to summarize the physiological responses and various defense mechanisms of castor to tolerate and eradicate heavy metal toxicity and some stress-responsive genes identified at transcriptional and posttranscriptional levels that confer metal tolerance in this plant.