水稻基腐细菌毒素的分离纯化、性质和生物学作用

目的]水稻基腐细菌毒素迄今未见报道.毒素是病原微生物重要的致病因子之一,毒素的分离纯化是研究病菌毒素功能和作用的前提和基础.方法]通过几种层析柱的多次层析分离及对水稻 ,幼苗的生物活性跟踪测定,分离纯化水稻基腐细菌毒素;采用化学及生物化学方法,研究毒素的性质及生物学作用.结果]获得了水稻基腐细菌毒素的一个成分T<,3>,该成分为黄色固体,溶于甲醇、正丁醇、水和甲酸;不溶于三氯甲烷、乙酸乙酯;微溶于丙酮,是非糖类和非蛋白质类物质,对紫外线敏感.毒素具有抑制水稻生根、使水稻秧苗萎蔫和对烟草细胞坏死的作用.高浓度毒素抑制水稻、玉米、番茄和烟草种子萌发,低浓度毒素则具有促进根、芽生长的作用.毒素对来自5个属的10种植物病原细菌具有抑菌活性,同时具有诱导水稻PAL和POD活性,且对抗病品种128的POD和PAL诱导活性均高于感病品种特籼13.结论]首次建立了水稻基腐细菌毒素的分离纯化方法.该毒素具有抑制水稻幼根生长、导致秧苗萎蔫、引起烟草细胞坏死、抑制植物病原细菌和诱导水稻防卫酶活性等生物学作用.

Separation, characters and biological functions of Erwiniachrysanthemi pv. zeae toxin

Abstract: Objective] The toxin produced by Erwinia chrysanthemi pv. zeae has not been reported so far. Toxin is one of the important pathogenic factors for plant pathogenic bacteria. The separation and purification of toxin are the key and basal work for toxin functional study. Methods] We used several chromatography columns, chemical and biochemical methods for Erwinia chrysanthemi pv. zeae toxin separation and its characterization. Results] We obtained a pure ingre-dient T3 of Erwinia chrysanthemi pv. zeae toxin . It was a yellow solid and dissolved in methanol, N-butyl alcohol(NBA), water and formic acid. It dissolved weakly in acetone but did not dissolve in trichloromethane and ethyl acetate. The re-sults showed that T3 toxin ingredient was neither carbohydrate nor protein, and was sensitive to ultraviolet ray. Biological assays of the toxin showed that it could inhibit rice growth, cause rice seedlings to wilt and make tobacco cells necrosis. Toxin with high content could inhibit buds and roots of rice, corn, tomato and tobacco to grow, whereas toxin with low content could promote their growth. In addition, the toxin inhibited 10 plant pathogenic bacteria with 5 genera. Further-more, toxin T3 induced the activities of phenylalanine ammonia-lysae(PAL) and peroxidase(POD) in rice. Conclusions] It is the first report about the separation and purification of E.chrysanthemi pv.zeae toxin. The T3 toxin of E. chrysanthemi pv.zeae had the biological characters with inhibiting plant seeds germination, causing rice seedlings wilt, inhibiting some plant pathogenic bacteria and inducing defense enzyme activities in rice.