Hsp90 is one of the most conserved and abundant molecular chaperones and is an essential component of the protective stress response; however, its roles in abiotic stress responses in soybean (Glycine max) remain obscure. Here, 12 GmHsp90 genes from soybean were identified and found to be expressed and to function differentially under abiotic stresses. The 12 GmHsp90 genes were isolated and named GmHsp90A1–GmHsp90A6, GmHsp90B1, GmHsp90B2, GmHsp90C1.1, GmHsp90C1.2, GmHsp90C2.1 and GmHsp90C2.2 based on their characteristics and high homology to other Hsp90s according to a new nomenclature system. Quantitative real-time PCR expression data revealed that all the genes exhibited higher transcript levels in leaves and could be strongly induced under heat, osmotic and salt stress but not cold stress. Overexpression of five typical genes (GmHsp90A2, GmHsp90A4, GmHsp90B1, GmHsp90C1.1 and GmHsp90C2.1) in Arabidopsis thaliana provided useful evidences that GmHsp90 genes can decrease damage of abiotic stresses. In addition, an abnormal accumulation of proline was detected in some transgenic Arabidopsis plants suggested overexpressing GmHsp90s may affect the synthesis and response system of proline. Our work represents a systematic determination of soybean genes encoding Hsp90s, and provides useful evidence that GmHsp90 genes function differently in response to abiotic stresses and may affect the synthesis and response system of proline.

No abstract

Association mapping is a useful alternative to linkage mapping for the detection of marker-phenotype associations. The main objective of this study is to identify simple sequence repeat (SSR) markers associated with the vegetable soybean quality traits of 100-pod weight, 100-seed weight, sucrose content and free amino acid content. The four quality traits were evaluated in 323 soybean cultivar accessions from China, and the 323 accessions were genotyped with 101 SSR markers. Analysis of population structure revealed two subgroups in the population. The mean linkage disequilibrium (LD) value (D¢) for all statistically significant loci pairs was 0.258. The decay of the LD based on the D¢ value showed little change with the increasing genetic distance between pairs. A total of 79 markertrait associations related to the four traits were identified, involving 44 different SSR markers. According to the results, the association analysis approach in this study can be an effective method for quantitative trait loci mapping and can help breeders to develop new strategies for improving vegetable soybean quality.

This study aimed to investigate the proximate and phytochemicals present in seeds of 24 mung bean (Vigna radiate L.) genotypes from four provinces of China for estimating their nutritional and antioxidant properties. Proximate analysis of mung bean genotypes revealed that starch, protein, fat, ash and water-soluble polysaccharide ranged from 39.54–60.66, 17.36–24.89, 4.24–12.18, 2.78–3.53 and 1.99–2.96 g/100 g respectively. The five principal fatty acids detected in mung beans were stearic acid, palmitic acid, linoleic acid, oleic acid, and linolenic acid. The contents of insoluble-bound phenolic compounds, soluble phenolic compounds, and flavonoids ranged from 0.78 to 1.5 mg GAE g− 1, 1.78 to 4.10 mg GAE g− 1, and 1.25 to 3.52 mg RE g− 1, respectively. The black seed coat mung bean genotype M13 (Suheilv 1) exhibited highest flavonoid and phenolic contents which showed strong antioxidant activity. Two flavonoids (vitexin and isovitexin) and four phenolic acids (caffeic, syringic acid, p-coumaric, and ferulic acids) were identified by HPLC. Vitexin and isovitexin were the major phenolic compounds in all mung bean genotypes. The content of soluble phenolic compounds had positive correlation with DPPH (r2 = 0.713) and ABTS (r2 = 0.665) radical scavenging activities. Principal component analysis indicated that the first two principal components could reflect most details on mung bean with a cumulative contribution rate of 66.1%. Twenty-four mung bean genotypes were classified into four groups based on their phenolic compounds contents and antioxidant activities. The present study highlights the importance of these mung bean genotypes as a source of nature antioxidant ingredient for the development of functional foods or a source of health promoting food. Graphical Abstract

Mungbean (Vigna radiata [L.]) is an important economic crop grown in South, and East Asia. The low contiguity of the current assembly of V. radiata genome has limited its application. Here, we report a high-quality chromosome-scale assembled genome of V. radiata to facilitate the investigation of its genome characteristics and evolution. By combination of Nanopore long reads, Illumina short reads and Hi-C data, we generated a high-quality genome assembly of V. radiata, with 473.67 megabases assembled into 11 chromosomes with contig N50 and scaffold N50 of 11.3 and 42.4 megabases, respectively. A total of 52.8% of the genome was annotated as repetitive sequences, among which LTRs (long terminal repeats) were predominant (33.9%). The genome of V. radiata was predicted to contain 33,924 genes, 32,470 (95.7%) of which could be functionally annotated. Evolutionary analysis revealed an estimated divergence time of V. radiata from its close relative V. angularis of ~11.66 million years ago. In addition, 277 V. radiata specific gene families, 18 positively selected genes were detected and functionally annotated. This high-quality mungbean genome will provide valuable resources for further genetic analysis and crop improvement of mungbean and other legume species.