Regulation of autophagy and lipid accumulation under phosphate limitation in Rhodotorula toruloides

• Published in: Frontiers in microbiology Vol. 13; p. 1046114
• Main Authors: Wang, Ya-nan, Liu, Fang-jie, Liu, Hong-di, Zhang, Yue, Jiao, Xiang, Ye, Ming-liang, Zhao, Zong-bao Kent, Zhang, Su-fang
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 26.01.2023
• Subjects: Atg9; autophagy; lipid accumulation; Microbiology; phosphate limitation; Rhodotorula toruloides; Atg9; autophagy; Rhodotorula toruloides; phosphate limitation; lipid accumulation
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2022.1046114

It is known that autophagy is essential for cell survival under stress conditions. Inorganic phosphate (Pi) is an essential nutrient for cell growth and Pi-limitation can trigger autophagy and lipid accumulation in oleaginous yeasts, yet protein (de)-phosphorylation and related signaling events in response to Pi limitation and the molecular basis linking Pi-limitation to autophagy and lipid accumulation remain elusive. Here, we compared the proteome and phosphoproteome of CGMCC 2.1389 under Pi-limitation and Pi-repletion. In total, proteome analysis identified 3,556 proteins and the phosphoproteome analysis identified 1,649 phosphoproteins contained 5,659 phosphosites including 4,499 pSer, 978 pThr, and 182 pTyr. We found Pi-starvation-induced autophagy was regulated by autophagy-related proteins, but not the pathway. When 9 was knocked down, the engineered strains produced significantly less lipids under Pi-limitation, suggesting that autophagy required Atg9 in . and that was conducive to lipid accumulation. Our results provide new insights into autophagy regulation under Pi-limitation and lipid accumulation in oleaginous yeast, which should be valuable to guide further mechanistic study of oleaginicity and genetic engineering for advanced lipid producing cell factory.