Transcriptomic Characterizations of the Molecular Mechanisms Regulating Lipid Production and Composition in Mortierella alpina in Response to Cold Stress

Cold stress causes changes in the lipid composition of Mortierella alpina. In order to investigate the molecular mechanisms of M. alpina in response to cold stress, transcriptome analyses were performed on three groups of M. alpina cultured at (1) 25 degrees C, (2) 15 degrees C, and (3) first at 25 degrees C for 2 days and then 15 degrees C for 7 days, respectively. The results of a gas chromatography-mass spectrometry (GC-MS) analysis suggested that, compared with 25 degrees C conditions, dry weight and lipid production were significantly decreased in M. alpina grown at 15 degrees C, with a total of 1552 differentially expressed genes (DEGs) identified in response to cold stress. The quantitative real-time PCR (qRT-PCR) analysis was conducted to verify the expression patterns of six DEGs involved in lipid metabolism. Results of the enrichment analyses of the DEGs based on the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases showed that fatty acid compositions were regulated by genes involved in the glycolysis pathway, fatty acid synthesis, the pentose phosphate pathway, the glycerolipid pathway, the tricarboxylic acid (TCA) cycle, and the glycerophospholipid pathway. Our study provided solid experimental evidence and novel insights into the metabolic engineering and the molecular mechanisms regulating the response to cold stress in M. alpina.

Automated summary

Cold stress leads to changes in lipid composition in Mortierella alpina. Transcriptome analysis revealed decreased lipid production and identified 1552 differentially expressed genes in response to cold stress. qRT-PCR analysis confirmed the expression patterns of six differentially expressed genes involved in lipid metabolism. Enrichment analysis based on the GO and KEGG databases showed that fatty acid composition is regulated by genes in multiple metabolic pathways.