Transcriptomic dissections of the 1 drought resistance traits of a soya bean landrace

With diverse genetic backgrounds, soybean landraces are valuable resource forbreeding programs. Herein, we apply multi-omic approaches to extensivelycharacterise the molecular basis of drought tolerance in the soybean landrace LX. LXgerminated better than landrace William82 under drought stress conditions andaccumulated more anthocyanin, flavonoids. Untargeted mass spectrometry incombination with transcriptomic analyses revealed the chemical diversity and geneticbasis underlying the overall performance of LX landrace. Under control and droughtconditions, significant differences in the expression of a suite of secondary metabolismgenes, particularly those involved in the general phenylpropanoid pathway andflavonoid but not lignin biosynthesis, were seen in LX compared to William82. Theexpression of these genes correlated with the corresponding secondary metabolites inLX plants. Further correlation analysis between metabolites and transcripts targetedpathway structural genes and transcription factors likely are responsible for the LXagronomic traits. The activities of some key biosynthetic genes were confirmed throughheterologous expression in in transgenic Arabidopsis. We propose a regulatorymechanism based on flavonoid secondary metabolism and adaptive traits of thislandrace which could be of relevance to cultivated soybean.