| Rubber Powdery mildew is one of the most important diseases in Hevea brasiliensiso It affects seriously the growth and yield of Hevea brasiliensis. Using of inducers induce plant resistance and stimulate plant immunity to achieve the effects of disease Prevention. Cloning of Resistance Gene Analogues in Hevea brasiliensis The Hevea brasiliensis RGAs sequence can be combined with molecular markers, library screening, may further to get the R gene.In this study, choices no phytotoxicity concentration of the period of the rubber tree bronze to greenish-term leaves by SA inducing with the varieties RRIM600 and PR107,and to explore the mechanism of induced resistance from the activity of defense related enzymes. The effect of the induced resistance is measured to powdery mildew in Hevea brasiliensis. The Resistance Gene Analogues was cloned and Analysis of Resistance Gene Analogues in the SA-induced 2 varieties. The results are as follows:1.0.5mmol/L SA induces the bronze to greenish period of rubber leaf does not produce injury and other concentrations of SA have varying degrees of injury to leaf. Induce different periods of plant resistance POD, PPO, PAL enzyme activity was measured. Results showed flu and resistant varieties induced by SA activity of three enzymes have different degrees of improvement compared with the control, the same time as the the SA induction time of change, the enzymatic activity along with changes in susceptible varieties and disease-resistant varieties enzyme activity trends are not the same. Hevea brasiliensis Leaves by SA 0.5mmol/L treatment in different time periods inoculated with powdery mildew and the results show that the SA-induced inoculated with powdery mildew disease index has declined after treatment 48 h in resistant varieties. Best control effect induced in susceptible varieties by SA after inoculation 24 h was 35.14%.2. According to the NBS-LRR conserved domain P-loop and GLPL of known resistance genes design degenerate primers. cDNA of the SA induce four time periods as a template to amplify obtain about 500bp fragment after recycling, transformation, positive plasmid identified 80 positive clones. After sequencing analysis, of which 76 has an open reading frame, and has the known p-loop of the conserved domains of the R gene of NBS kinsae-2a, kinase-3a, and GLPL region, its also have RNBS-A, RNBS-B and RNBS-C three mold body by Meyer defined.76 RGAs by cluster analysis mainly clustered into two categories that NBS type TIR-NBS and non-the TIR-NBS. RGAs translation into amino acid sequences were compared with the known resistance genes and other plants RGAs having high homology. Polymorphism analysis showed that the nucleotide diversity in 8 processing of two varieties have some differences, while the neutral detection showed that the 2-RGAs did not reach a significant level, comply with the neutral hypothesis in the evolution of these RGAs.SA induction Hevea brasiliensis leaves improve resistance-associated enzyme activity, there is a certain amount of control effect on the rubber powdery mildew, and provide new avenues for powdery mildew. At the same time the RGAs of obtained provide research-base for positioning cloned Hevea brasiliensis disease resistance R genes and molecular marker-assisted breeding. |
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