B-box containing proteins mediate seed oil accumulation in Arabidopsis

Abstract

WRINKLED1 (WRI1) transcription factor plays a pivotal role in governing plant oil biosynthesis. However, the regulatory mechanism of WRI1 remains unclear. Here, we identify a member from the B-box (BBX) family as a novel interacting partner of Arabidopsis WRI1 (AtWRI1). Currently, there is no evidence showing the involvement of BBX in plant oil metabolism. This project aims to investigate the role of WRI1-BBX module in mediating plant oil biosynthesis. AtWRI1 and BBX physically interacted in the yeast-two-hybrid and the bimolecular fluorescence complementation assays. Seeds of bbx null mutants displayed reduced oil content. In contrary, transgenic lines overexpressing BBX showed increased seed oil content. Co-expression of BBX and AtWRI1 resulted in enhanced transcriptional activity of AtWRI1. Taken together, our preliminary data suggest that BBX might function as a positive regulator of AtWRI1-mediated seed oil accumulation and potentially bridge environmental signals with lipid metabolism.