Research On Improving Plant Persistence Disease Resistance By Inducible Signal Pathways

Using the SAR (Systemic acquired resistance) to improve the disease resistance of crops has aroused more attention. In this study, we have cloned the key gene-NPR1 of the systemic acquired resistance (SAR) genes by RT-PCR methods from Arabidpsis thaliana. We has used the downstream gene PR-la promoter to drive the NPR1 gene and the SAR8.2b promoter to drive the HRP gene. Finally we successfully constructed a bivalent plant expression vector-pCambia 2300-PRla-NPR1-SAR-harpin. Under two positive feedback signals, we use a promoter which is induced by pathogen to improve the resistance against the pathogenic bacteria by the crop themselves.We have transfered the recombined vector into Agrobacterium tumefaciens GV3101 with the method of freeze-diffluence. Mean while, we use Tubulin gene as a contral gene and the Pr-la, PDF1.2, ETR1 genes as the key genes of the salicylic induced signal pathway,ethene induced signal pathway and Jasmonic acid induced signal pathway. By the analysis of semi-quantitative RT-PCR the results indicate that under induced conditions, the expression of the key genes in transgenic plants is higher than the common plants.We transformed the vector into cotton by using the method of pollun tube.After the preliminary screening of kanamycin and PCR,we have gained the transgenic plants.