Elicitin诱导烟草微敏反应和防卫基因的表达  

Microscopic hypersensitive response and expression of defense response induced by the proteinaceous elicitor elicitin-parasiticein

作　　者：梁元存[1] 刘爱新[1] 王金生[2] 张天宇[1] 董汉松[2] 

机构地区：[1]山东农业大学植物病理学系,泰安271018 [2]南京农业大学农业部病虫检测与治理重点开放实验室,南京210095

出　　处：《植物病理学报》2007年第6期610-615,共6页Acta Phytopathologica Sinica

基　　金：山东省中青年科学家奖励基金资助项目(03BS131);教育部博士点基金(B200106)

摘　　要：研究了一种α型elicitin—parasiticein对烟草微敏反应（microscopic hypersensitive response，micro-HR）和防卫反应分子表征基因表达的诱导作用。用150nmol/L的parasiticein喷洒烟草叶片12h后，经曲利本蓝（trypanblue）染色，光镜下可观察到有细胞坏死，说明parasiticein引起了micro—HR，而水和低浓度的parasiticein不能引起micro—HR。用parasiticein注射叶片可引起肉眼可见的HR，注射用parasiticein浓度远比喷洒引起micro-HR的浓度低。Parasiticein还可诱导对TMV的抗性，浓度在30nmol/L时比150nmol/L的效果好。用parasiticein注射烟草30min，HR表征基因hsr203J和hin1开始表达，在9h内逐渐降低，12—16h肉眼可观察到HR。Parasiticein喷洒烟草后，病程相关蛋白（pathogenesis-related，PR）基因PR-1b易在诱导的第1d到第5d都有一定量的表达。可见，parasiticein能同步诱导过敏反应和抗病性及其分子表征基因的表达。Elicitins produced by species of plant pathogenic oomycetes constitute a unique group of small proteins that induce hypersensitive response （HR） and pathogen defense in plants. Modes and molecular bases of the responses have not been well understood. Here we studied a particular elicitin, parasiticein from Phytophthora parasitica var. nicotianae, and focused on modes of HR and pathogen defense that the protein causes. To illustrate whether parasiticein induces microscopic hypersensitive response （micro-HR）, tobacco leaves were sprayed with parasiticein, stained with trypan blue, and observed by light microscopy. Micro-HR was observed on leaves in 12 h after treatment with a moderate dose of parasiticein. Inversely, water and low concentrations of parasiticein did not cause evident micro-HR. Tobacco resistance to Tobacco mosaic virus （TMV） also was induced, as observed based on scoring leaf lesions caused by TMV inoculated to untreated leaves at 3 days after treatment. The application of 30 nmol/L parasiticein provided the optimal level of resistance, in comparison with those induced by a range of the elicitin concentrations. Consistently, HR marker genes hsr203J and hinl were expressed in leaves at extents coincident with the HR levels. The defense response gene, PR-1b, was expressed concomitantly with resistance development. Moreover, PR-1b started to express by 24 h and lasted at least 5 days after parasiticein treatment, suggesting a time course of the molecular responses initiated prior to the onset of resistance. These results suggest that the elicitin induces micro-HR and pathogen defense in consistence with activation of critical marker genes.

关 键 词：ELICITIN parasiticein 微敏反应(micro—HR) 防卫反应 

分 类 号：S432.23[农业科学—植物病理学]