Structural, expression and evolutionary analysis of the non-specific phospholipase C gene family in Gossypium...

Nonspecific phospholipase C (NPC), which belongs to a phospholipase C subtype, is a class of phospholipases that hydrolyzes the primary membrane phospholipids, such as phosphatidylcholine, to yield sn-1, 2-diacylglycerol and a phosphorylated head-group. NPC plays multiple physiological roles in lipid metabolism and signaling in plants. To fully understand the putative roles of NPC genes in upland cotton, we cloned NPC genes from Gossypium hirsutum and carried out structural, expression and evolutionary analysis.

Eleven NPC genes were cloned from G. hirsutum, which were found on chromosomes scaffold269.1, D03, A07, D07, A08, D11, and scaffold3511_A13. All GhNPCs had typical phosphoesterase domains and have hydrolase activity that acts on ester bonds. GhNPCs were annotated as phospholipase C, which was involved in glycerophospholipid metabolism, ether lipid metabolism, and biosynthesis of secondary metabolites. These GhNPCs showed differential expression patterns in distinct plant tissues and in response to various types of stress (low-phosphate, salt, drought, and abscisic acid). They also had different types and numbers of cis-element. GhNPCs could be classified into four subfamilies. Four pairs of GhNPCs were generated by whole-genome duplication and they underwent purifying selection.

Our results suggested that GhNPCs are involved in regulating key abiotic stress responses and ABA signaling transduction, and they may have various functional roles for different members under complex abiotic stress conditions. Functional divergence may be the evolutionary driving force for the retention of four pairs of duplicate NPCs. Our analysis provides a solid foundation for the further functional characterization of the GhNPC gene family, and leads to potential applications in the genetic improvement of cotton cultivars.