The SPATULA transcription factor regulates seed oil content by controlling seed specific genes in Arabidopsis thaliana

Seed oil content, as a key economical trait, is influenced by multiple factors during seed development. Recent studies have established that control of seed development and seed oil content are interrelated process, controlled by transcription factors. Previously, a bHLH transcription factor SPATULA was reported to have pleiotropic effect on various organ development including root, leaf, and siliques but not seed development. Here, our results demonstrated a novel function of SPATULA to regulate seed size and seed fatty acids (FAs) content in Arabidopsis . The loss function of SPATULA significantly increased seed size, reduced seed FAs content. On the contrary, overexpression of SPATULA significantly increased the fatty acid contents without changing seed size. Ultrastructure analysis revealed that modification of seed FAs content by SPATULA was mainly through alteration of aleurone grain in seed embryo cells. Gene expression analyses provide a brief overview on the effects of SPATULA on key genes implicated in seed FAs content. These results demonstrated the SPATULA promotes fatty acid accumulation through inhibition of seed storage protein associate gene and induction of fatty acid associate genes during seed development in Arabidopsis . Our study had further extended the knowledge of SPATULA function, and it can provide new genetic resource for oil crop modification in Brassicaceae .