In Vitro Selection Of Mutants Resistance To Botrytis Cinerea In Tomato Using Fungi Toxin

Grey mould, caused by Botrytis cinerea, is one of common diseases in tomato protected cultivation, and it can infect stems, leaves, flowers and fruits, caused severe economic losses. Chemicals are mainly used for preventing and controlling the disease, but if they had been used for a long time, it would induce some problems such as chemical pesticide residue, environment pollution and fungicide resistance. It is an economical and effective method to plant resistant cultivars to control the disease. By presently, it is lack of resistant cultivars in tomato, and resistant resources lie in wild accessions which are difficult to be used, so it is urgent to find an effective breeding method.Using cultivation ’No9of Su Fen’ as test material, on the basis of studying culture conditions of the crude toxin produced by Botrytis cinerea, the crude toxin was used as the selective agent to screen resistant mutants in callus of tomato in vitro, obtaining regenerated plants, and the enzyme activities of cells and regeneration plants were analysised after treated by toxin. The test following:1. The culture conditions of toxin produced by Botrytis cinerea were studied with the method of inhibition the growth of tomato root, and the biological activities of crude toxin were assayed. The crude toxin were separated by the thin layer chromatography (TLC) in the test.The results showed that the optimal conditions for producing phytotoxin were PD liquid medium at pH5.0-6.0and at20-25℃for20days with successive darkness and stationary during culturing, and the leaves appeared chlorotic spot, the seedlings wilt after treated by toxin. It also showed that four components were separated by TLC, and they were variation in biological activities.2. In the study, the toxin produced by Botrytis cinerea was used as select agent to screen resistant mutant in intro with the way of multi-step selection. The result showed that the inductions, the growths and the differentiations of callus were inhibited by toxin and the inhibition enhanced with the concentration of crude toxin increasing. Resistant callus were selected under the toxin concentration of40%as the highest selection pressure in multi-step selection, and regeneration plants were analysised by inoculation, the original plants were used as control, it showed that the index of disease of plants from resistant callus was39, while the control was80, and the effect of resistance was51.25%.3. The changes in activities of peroxidase (POD), polyphenol oxidase (PPO) and phenylalanine ammonialyase (PAL) in mutant and original callus of tomato and their regeneration plants were studied after treated by different concentrations of crude toxin in different treatment time. The results showed that the changes in enzyme activity of callus were similar with those in plants, and the enzyme activities increased rapidly at the beginning and then decreased. The peaks of enzyme activity appeared at different time segments, but the enzyme activities were higher in the resistant callus and their regeneration plants than those in original callus and their regeneration plants. The enzyme activities were higher treated by higher concentrations of crude toxin. There was positive correlation between the three enzymes activities and resistance to grey mould of tomato.