Functional Analysis Of AtPLC3 And AtPLC4 In Salt Stress Response Of Arabidopsis Thaliana

Response to salt stress signal transduction in plant is a huge and complex network, there are many key signal components to be deeply understood. Phosphatidylinositol-4,5-bisphosphate-specific-phospholipase C (PIP2-PLC) is a lipid-associated enzyme which employs PIP2 to produce inositol-l,4,5-trisphosphate (IP3) and diacylglycerol (DAG). These two messenger substances play crucial roles in amplifying extracellular stimuli and mediating various physiological processes caused by different abiotic stresses.In this study, P3 and P4, two mutants from the SALK library were characterized. P3 was the AtPLC3 knock-out line and P4 was AtPLC4 overexpression line. The result showed that the germination rate of P3 and P4 in NaCl treatment was significantly faster than Col. In 100 mM NaCl concentration, the survival rate of P3 and P4 mutant was about 30 percent higher than Col. Further investigation into the contents of praline and the activity of SOD and POD of the two mutants under salt stress conditions revealed that Proline increasing range of the two mutant was less than Col and the activity of SOD and POD was above Col. These results demonstrated that AtPLC3 and AtPLC4 gene isoforms were involved in the regulation of salt stress response.We constructed several transgenic expression vectors used for tissue localization and subcellular localization of AtPLC3 and AtPLC4 genes. We have got some positive transgenic plants. The roots and leaves espressed a higher level of AtPLC3 and AtPLC4 by GUS staining and confocal microscopy. These results also provided collateral evidence for the phenotypes of the main root and lateral roots. The two isoforms were located in the membrane by confocal microscopy. These localizational informations provide a basis for further studying the regulational mechanisms of two isoforms in salt stress response.