Overexpression of a Phosphatidylinositol-Specific Phospholipase C Gene from Populus simonii x P. nigra Improves Salt Tolerance in Transgenic Tobacco

Phosphatidylinositol-specific phospholipase C (PI-PLC) catalyzes the hydrolysis of phosphatidylinositol-4,5-bisphosphate into diacylglycerol and inositol 1,4,5-trisphosphate. It can play an essential role in plant stress response and signaling. However, the functions of PLCs remain unclear in wooden plants. This study carried out the bioinformatics analysis of the PLC gene family in poplar. The expression pattern analysis suggested the transient up-regulation of PsnPLC in salt stress conditions. The transgenic tobacco plants overexpressing PsnPLC were generated by the Agrobacterium-mediated leaf disc method. The transgenic lines showed a significant increase in plant height, SOD and POD activity, and proline content under salt stress. By contrast, transgenic lines showed a decreased malondialdehyde content under salt stress. Comparative transcriptome analysis indicated that the overexpression of PsnPLC mainly affects membrane-associated GO terms and signaling pathways, and the differential expression of salt-responsive genes may contribute to the enhanced salt tolerance. Overall, the results indicated that PsnPLC plays an essential role in modulating salt tolerance in transgenic tobacco.