Study On Stress Induced Resistance To Cladosporium Cucumerinum In Cucumber Seeding

Cucumber is a kind of important vegetable, while the Cladosporium cucumerinum is a kind of serious disease affected the cucumber quality and quantity. Presently, there are usually two ways to prevention and cure it: chemical fungicides; breeding for resistant species. However the chemical produces are easy to make the pathogens develop tolerance to the fungicides, at the same time the chemicals pollute the nature severity. The mono resistant species tend to "lose" the effects of resistant to the specific pathogens. For this reason, the technical innovation and recommendations for quality, health, efficacy, safety and environment-friendly are active and popular all around the world.Many research proved that plants have the huge potential of resistant to pathogens, and the potential can be expressed by induce the plant resistant. The plant induced resistant is kind of ability of nonspecific and long effective to the pathogens. In our experiment, we innovated a method to simulate the non-host resistance. A certain strengthen local stress were stimulated on the first real leave of the cucumber seeding, which can induce the cucumber resistant to the Cladosporium cucumerinum. By assay the changes of defense-related enzymes activity of non-stimulated leaves, which include phenylanine ammonia lyase (PAL), peroxidase (POD), polyphenoloxidase (PPO),superoxide dismutase (SOD) and pathogenesis-related protein (PR protein), a primary study of the biochemical mechanism of stress stimulus induced the cucumber resistant to C. cucumerinum were undertaking .By applying the peptides contained the RGD (Arg-Gly-Asp) motif,which can specific break the adhesion between cell wall and plasma membrane , we study the possible stress signal transduction system and the stress signal induced resistant in plant cell preliminary.According to the results, we found that the stress stimulus can act as a kind of elicitor which can efficiently induce the resistance of cucumber against fungal pathogen. After the treatment of the stress stimulus on leaves, the activities of resistance-related enzymes were significant increased. Such as PAL, POD , SOD and PPO ,which are strongly associated with the plant disease resistance. Also the expression of PR protein were activated by stress stimulus ,with the results that the activities of chitinase and -l,3glucanase were increased obviously. The data showed that one of the mechanism of stress stimulus induction plant resistance may act via eliciting themetabolism related disease resistance within plant, which can produce many suppressing and antimicrobial compounds to against pathogens infection efficiently.The result of RGD test suggest that, after treatment of RGD peptides previously, the stress stimulus can not induce the resistance to C. cucumerinum in cucumber seeding. The stress induced resistance is depended on the RGD specific mediated adhesion between cell wall and plasma membrane. There is a similar analysis between mammal cell and the plant cell on the stress signal transduction, which the signaling across a dynamic continuum involving the "ECM-Integrin-cytoskeleton" system.