Influence Of Environmental Stresses And Hormone On The Expression Of Pathogenesis-related Genes In Tomato

When crops grow, they would encounter all kind of biotic stresses(plant diseases and insect pests, etc) and abiotic stresses(drought, salt, cold, high and low temperature, lack of nutrition, heavy metal stress, flood, ultraviolet radiation, etc), which was the main reason for loss of production of crops. Stresses have become austere problem and badly restricted the development of agriculture.It was proved that when plants were infected by pathogen, there would be a defence response which was called systemic acquired resistance(SAR) under stimulation of pathogen. Not only pathogen(such as fungi, bacteria and viruses), but also some stresses, such as UV radiation, wounding, drought, different temperatures, chemical substances and plant hormone would induce plants to cause SAR response, which included synthesis of so-called pathogenesis-related proteins(PRP). According to SDS-PAGE electrophoresis, PR proteins, including PR-1, PR-2, PR-3, PR-4 and PR-5 family were named in turn. In addition, A plenty of experiments results have showed ethylene, one important plant hormone, was evolved in paint stress responses and could induced expression of many plant pathogenesis-related proteins.Nowadays, many PR proteins were cloned in tobacco, and their biochemical characters were studied clearly, the effect of wounding, plant diseases and insect pests and hormone on the expression of it had been reported. In contrast, the studies dealed with PR proteins in tomato, especially the effect of abiotic stresses and ethylene on it were less.We have had a series of experiments on stresses on Wild-type(WT) tomato, rin(ripening inhibitor, rin), Nr(Never-ripening, Nr) and T4B-11(ACC oxidase I co-suppression transgene tomato, T4B-11), collected correlative samples to extract total RNA,and amplified gene fragment of PR-1,PR-5 and PR-NP24. Then these genes were analyzed by Northern blot hybridisation technology in mRNA level. The Northern blot hybridization results indicated that the expression of these genes could be inhibited by drought, induced by hormone and some environmental stresses, such as wounding and flood, but under different temperatures the expression level had no distinct change.