Working group session:
Functional Genomics
Presentation type:
oral
Authors:
Qin, Yongmei ; Liu, Gaojun
Presenter:
Qin, Yongmei ; Liu, Gaojun
Correspondent:
Qin, Yongmei
Abstract:
Glycerophospholipids (GPLs) severed as the major components of plasma membranes and signaling molecules are classified according to their head groups, backbones and fatty acyl chains. Previous transcriptome studies showed that lipid biosynthesis pathway was preferentially expressed during the rapid and vigorous cotton fiber elongation. To examine GPL composition changes during fiber elongation, here, by application of ultra-performance liquid chromatography coupled to electrospray ionization and tandem mass spectrometry, we find that lipid biogenesis is activated in the same growth stage. Membrane lipids targeted on phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol (PtdIns), phosphatidic acid (PA), phosphatidylserine and phosphatidylglycerol were extracted and separated from 10 day post-anthesis, fast-elongating wild-type cotton (G. hirsutum) fibers, wild-type ovules with fibers removed and ovules from the fuzzless-lintless (fl) mutant harvested at the same age. A total of 1566 GPL species were identified and further quantified. Fiber cells contained significantly higher amount of PtdIns and PA than that extracted from ovule samples of both genotypes, with 34:3 (16:0, 18:3) being the most predominant molecular species of PtdIns. Exogenously applied soybean L-α-PtdIns or C18:3 per se rather than other phospholipids in ovule culture medium significantly promoted fiber cell elongation. Genes encoding fatty acid desaturases, PtdIns synthase and phosphatidylinositol-specific phospholipase C were activated during this growth stage with substantial increases in endogenous levels of phosphatidylinositol monophosphate, 1,4,5-triphosphate and inositol hexaphosphate. Our data thus lay a basis for future investigation of how PtdIns and its phosphorylated derivates are involved in regulation of cotton fiber cell growth.