Enhancement of lipid synthesis by the transcription factor Asg1 in Saitozyma podzolica zwy-2-3 under dissolved oxygen stress.

Microbial oils have been of considerable interest as food additives and biofuel resources due to high lipid contents, but lipid accumulation of oleaginous microorganisms can be induced by environmental stresses, such as dissolved oxygen (DO), which limit large-scale lipid production. Here, DO stress gave rise to the endogenous nitric oxide (NO) level to mediate S-nitrosylation of SpAsg1, regulating the lipid accumulation in Saitozyma podzolica zwy-2-3. Notably, qRT-PCR, yeast one-hybrid, dual-luciferase reporter assays, and metabolomics analysis exhibited that overexpression of SpAsg1 promoted lipid synthesis by directly regulation of glucose metabolism, enhancing glucose uptake, ATP and NADPH contents under DO stress. Meanwhile, SpAsg1 improved the antioxidant capacity to reduce the intracellular reactive oxygen species (ROS) and NO levels. Overall, we systematically investigated the regulation of SpAsg1 on lipid metabolism of S. podzolica zwy-2-3 under DO stress, which sheds light on further studies for alleviating oxygen limitation of lipid production in microbial industry.