Transcriptomic and lipidomic analysis reveal the mechanism of phosphorus-induced lipid class remodeling in Nannochloropsis sp. PJ12

Phytoplankton lipids, such as microalgae lipids, are important compounds of increasing interest in bioenergy, food, pharmacy, aquaculture and ecology for their high molecular diversity. There is a taxonomically diverse lipid response under P stress with unresolved questions related to the diversified mechanism behind the lipid responses. A marine microalgae with high EPA content was isolated, named Nannochloropsis sp. PJ12. We reveal a mechanism of phosphorus-induced lipid class remodeling in Nannochloropsis sp. PJ12 based on highly corresponding transcriptome and lipidome data. Phosphorus- deprivation leads to the rapid reduction of phospholipids (PL) and synthesis of the betaine lipids (BL). Phosphorus-complement recovers the content of PL and BL to the original level. The changes are mediated mainly by a glycerophosphoryldiester phosphodiesterases on the transcriptome level. To adapt to low phospholipids, the transcription levels of gene encoding P transporter were upregulated. When Nannochloropsis sp. PJ12 was once again under phosphorus-complement, some of gene encoding P transporter continue to increase on the transcription levels. The novel phospholipid-remodeling scheme opens new avenues for metabolic engineering of lipid composition in algae. Examination of transcriptional profiling of PJ12 cells in response to phosphorus replete, phosphorus deprivation and phosphorus replenishment