Abstract

Starch is the final product of photosynthesis and the main storage form in plants. Studies have shown that there is a close synergistic regulatory relationship between ABA signal transduction and starch biosynthesis. In this study, we employed RNA sequencing (RNA-Seq) to investigate transcriptomic changes of theEuryale feroxseeds treated by exogenous ABA. The differentially expressed genes engaged in the “Starch and sucrose” and “TCA cycle” pathway. Furthermore, the key transcription factor EfABI4 in ABA signaling pathway and the key genes of starch biosynthesis (EfDBE1,EfSBE2,EfSS1,EfSS2,EfSS3,EfSS4andEfGBSS1) were significantly up-regulated. Further, theEuryale feroxplant was treated with ABA, it was found that the total starch content ofEuryale feroxseeds at different development stages was significantly higher than that of the control, and the key genes of starch synthesis inEuryale feroxseeds were also significantly up-regulated. Finally, yeast one-hybrid and dual luciferase assay proved that EfABI4 can promote the expression ofEfSS1by directly binding to its promoter. Subcellular localization results showed that EfABI4 protein was located at the nucleus and EfSS1 protein was located in the cytomembrane. These findings revealed that ABA promotes starch synthesis and accumulation by mediating EfABI4 to directly promoteEfSS1gene expression, which is helpful for understanding starch synthesis in seeds.Keywords:ABA;starch;E. ferox(Euryale feroxSalisb.);transcriptome;EfABI4 transcription factor;EfSS1