Biocontrol agent Pseudomonas fluorescens 2P24,one of plant growth-promoting rhizobacteria（PGPR）,possesses a type-Ⅲ secretion system（T3SS） for association with plants.To enable 2P24 to express a harpin protein which triggers hypersensitive response（HR） in plants and to have the ability to induce resistance to plant pathogen infection,we constructed a fusion of a hap1 gene,which encodes a harpin of Xanthomonas oryzae pv.oryzicola,with a promoter of avrPto1 of Pseudomonas syringae pv.tomato DC3000 which was induced in 2P24.This recombination led 2P24 to express the harpin protein Hpa1.The protein,secreted via the T3SS of 2P24,triggered HR in tobacco via the activation of HR marker genes,HIN1 and HRS203J,and pathogenesis-related protein gene PR1a.The genetic modified 2P24 with the harpin coding gene,as the recipient strain 2P24,had antimicrobial ability against wheat scab Fusarium graminearum and cotton wilt F.oxysporum f.sp.vasinfectum.Using HR-elicitors from plant-pathogen interactions to genetically modify biocontrol antimicrobes provides a fundamental basis for plant disease control.%荧光假单胞菌Pseudomonas fluorescens 2P24是根围促生细菌（PGPR）,具有Ⅲ型分泌系统（T3SS）。为了在2P24中表达植物过敏反应激发子harpin,赋予生防菌诱导抗病性能力,本文选择可在2P24中表达的来自Pseudomonas syringae pv.tomato DC3000的avrPto1基因启动子与水稻细菌性条斑病菌Xanthomonasoryzae pv.oryzicola harpin蛋白编码基因hpa1进行融合,实现了harpin蛋白在2P24的表达。重组菌株通过T3SS分泌harpin蛋白,可激发烟草产生过敏反应（HR）,激活HR途径的HIN1基因和HRS203J基因以及病程相关蛋白PR1a基因的转录表达。harpin重组菌株与2P24一样,对小麦赤霉病菌Fusarium graminearum和棉花枯萎病菌F.oxysporum f.sp.vasinfectum具有抑制作用。这为利用植物-病原物互作中激发植物产生抗病性的激发子来遗传改良生防微生物奠定了理论和实践基础。
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