Function Analysis Of AtPLC1 And AtPLC6 Regulates Pollen Development And Pollen Tube Tip Growth In Arabidopsis Thaliana

Pollen development involves complex developmental control of gene expression by the haploid genome. Phosphoinositide-specific phospholipase C is a key role in the phosphoinositide signaling transduction pathway.It results in the generation of two intracellular messengers, diacylglycerol(DAG) and inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] by hydrolyzing phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]. These two messenger substance play crucial role in extracelluar stimuli and mediating various physiological processes.Here, we adopted a reverse genetics approach to investigate the function of AtPLC1 and AtPLC6 the Arabidopsis thaliana encoding AtPLC gene.In this study,P1 and P6,two mutants from SALK library were characterized. P1 was the AtPLC1 heterozygous line and P6 was AtPLC6 knock-out line. We attempted to isolate Arabidopsis plants that do not express the AtPLC1 gene, but could not recover homozygous mutant plants. Expression patterns of two genes in different organs by GUS stining.The progeny of P1 heterozygous plants,harboring a T-DNA insertion, showed a segregation ratio of 1:0.38:0 for Wild-type,heterozygous and homozygous mutant plants,indicating a gametophytic defect. Genetic transmission analysis showed that the abnormal segregation ratio was due to failure to transmit the mutant allele through the male gametophyte. Microscopic observation revealed that higher proportions of pollen grains in heterozygous plants than wild type were lack, or showed reduced number of nuclei.Indicating that AtPLC1 is essential for the pollen development. Pollen polarity were impaired in homozygous mutant plants lacking AtPLC6 transcript, pollen of P6 was triggered tip branching events. These results demonstrated that AtPLC6 may modulated polar tip growth of pollen tubes.The phosphoinositide pathway and inositol-1,4,5-trisphosphate (InsP3) are implicated in plant responses to stress,we also treated the overexpress mutant P1-1,P1-2,P6-1 and P6-2 by ABA, NaCl,glucose and sugar. The results demonstrated that the germination rate of P1-1 and P1-2 in ABA treatment was significantly depressed. However the germination rate P6-1 and P6-2 was nearly Col. The germination rate of P1-1 and P1-2 in glucose and sugar treatment was faster then Col,but the results was not significant. The germination rate of P1-1 and P1-2 in NaCl treatment was near Col. These results demonstrate that AtPLC1 may involved in the response of ABA and the osmosis response.