SOYBEAN (GLYCINE MAX L.) GERMPLASM SCREENING AND GEOGRAPHICAL DETERMINATION BASED ON TARGETED ISOFLAVONE METABOLOMICS

In this study, the combination of high-performance liquid chromatography (HPLC) based isoflavone profiling with multivariate analysis was used to screen specific soybean germplasms from Southwestern China, and simultaneously to investigate the influence of genotype, the geographical environment and the germplasm community size on isoflavone biosynthesis. A total of 144 soybean germplasms were evaluated for 12 isoflavones, which varied markedly due to genotypes and locations. Partial least squares analysis (PLS) results exhibited little variability among the 144 samples of four different locations. Five samples were separated from other genotypes based on the first PLS principal component that had high isoflavones. Daidzin, genistin, malonyldaidzin, malonylgenistin and acetylgenistin were the discriminating metabolites. Later the bidirectional orthogonal projection to latent structures-discriminant analysis (O2PLS-DA) was applied for geographical determination of five specific germplasms samples. Geographical environment influenced mainly acetylgenistin, acetyldaidzin, glycitein and malonylglycitin. Our results suggest that genetic factors play a vital role in the isoflavones biosynthesis of a major community, whereas the environmental factors can effectively regulate the isoflavones accumulation especially in the evaluation of small groups of soybean germplasms. These results demonstrate the use of the HPLC based metabolite profiling combined with multivariate analysis (PLS and O2PLS-DA) as a tool for the determination of specific germplasm, biomarker metabolite and geographical origin.