Mechanism Analysis Of NPCL Regulation Pollen Germination And Development In Arabidopsis

The germination and growth of pollen is one of the most important physiological process of sexual reproductive development, and it is an important system for research of polarized growth, differentiation, intracellular and extracellular signal transduction in plant cell. Our laboratory obtained a T-DNA insertion mutation in preparatory work. The mutant gene is the NPC-like gene(Nonspecific Phospholipase C like gene,same as NPCL)which is expressed specifically in pollen,and has role in pollen germination and tube growth, which had been evidenced further by transgenic line. This research provided the further experimental evidence that this gene participated in this physiological process, and analyzed the mechanism of this gene. The results showed that AtNPCL is located in plasma membrane and endomembrane system by YFP fusion expression, when null mutant of AtNPCL obtained the genes of non-signal AtNPCL by transgenic, it's phenotypes of pollen germination and tube growth were similar with null mutant of AtNPCL. These demonstrated that AtNPCL has the role in the membrane system and it can't work without signal peptide. Further, the lipoid components of AtNPCL mutant flower were analyzed by ESI-MS /MS. It showed that total phospholipids decreased 19% compared with wild type. All of the evidence above confirmed that AtNPCL participated in physiological process of the germination and growth of pollen as an enzyme in lipid synthesis.In addition, the fertilization of AtNPCL mutant were detected and be found that the gene just interference the rate of pollen germination and growth, but not the fertilization. It demonstrated that this gene mainly reacted in the competitive growth of pollen tube.AtNPCL has another homorganic, be named AtPLC15. The rate of pollen germination and tube growth in vivo and in vitro of AtPLC15 T-DNA insertion null mutant were similar with wild type Arabidopsis. The phenotype of double- mutation mutant of AtNPCL and AtPLC15 were similar with At NPCL mutant. These results show that AtNPCL played a major role in the AtNPCL homorganic family.