Combined analysis of transcriptome and metabolite data reveals extensive differences between black and brown nearly-isogenic soybean (Glycine max) seed coats enabling the identification of pigment isogenes

摘要

BackgroundThe R locus controls the color of pigmented soybean (Glycine max) seeds. However information about its control over seed coat biochemistry and gene expressions remains limited. The seed coats of nearly-isogenic black (iRT) and brown (irT) soybean (Glycine max) were known to differ by the presence or absence of anthocyanins, respectively, with genes for only a single enzyme (anthocyanidin synthase) found to be differentially expressed between isolines. We recently identified and characterized a UDP-glycose:flavonoid-3-O-glycosyltransferase (UGT78K1) from the seed coat of black (iRT) soybean with the aim to engineer seed coat color by suppression of an anthocyanin-specific gene. However, it remained to be investigated whether UGT78K1 was overexpressed with anthocyanin biosynthesis in the black (iRT) seed coat compared to the nearly-isogenic brown (irT) tissue.In this study, we performed a combined analysis of transcriptome and metabolite data to elucidate the control of the R locus over seed coat biochemistry and to identify pigment biosynthesis genes. Two differentially expressed late-stage anthocyanin biosynthesis isogenes were further characterized, as they may serve as useful targets for the manipulation of soybean grain color while minimizing the potential for unintended effects on the plant system.