Quantitative proteomic analysis to understand the role of Arabidopsis thaliana LEAFY COTYLEDON 2 in promoting lipid accumulation in Chlorella sorokiniana by upregulating photosynthetic proteins and G3PDH.

Microalgae have attracted significant attention for biofuel production and transcription factors that can effectively regulate lipid accumulation in higher plants. In this study we expressed the transcription factor LEAFY COTYLEDON 2 from Arabidopsis thaliana in Chlorella sorokiniana. The relative electron transport rate (rel.ETR) of C. sorokiniana-AtLEC2 improved significantly under high-intensity light. As a result, the total lipid content and main fatty acid composition (C16, C18) increased by more than onefold. Differentially expressed proteins were analyzed using a label-free strategy to elucidate the regulation mechanism of AtLEC2. The results showed upregulation of TAG biosynthesis (G3PDH) and photosynthesis-related proteins (e.g., ATP synthase F0, Photosystem II, Photosystem I P700, cytochrome b6, cytochrome b6f, chlorophyll a-b binding protein, Photosystem I assembly protein). Furthermore, AtLEC2 expression in C. sorokiniana led to fixed carbon flow in photosynthesis to TAG through G3PDH upregulation. The current study will provide a new direction for the cultivation of high-yield oil algae and will reveal the mechanism of regulation of AtLEC2 on TAG accumulation in C. sorokiniana. [ABSTRACT FROM AUTHOR]