Rapid induction of a protein disulfide isomerase and defense-related genes in wheat in response to the hemibiotrophic fungal pathogen Mycosphaerella graminicola
Rapid induction of a protein disulfide isomerase and defense-related genes in wheat in response to the hemibiotrophic fungal pathogen Mycosphaerella graminicola
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DOI：
10.1023/b:plan.0000019120.74610.52
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发表时间：
2003-11-01
影响因子：
5.1
通讯作者：
Goodwin, SB
中科院分区：
文献类型：
--
作者：
Ray, S;Anderson, JM;Goodwin, SB
禾生球腔菌（Mycosphaerella graminicola）是小麦壳针孢斑病（Septoria triuminicblotch）的重要病原菌，与其它作为寄主-病原菌互作遗传模型的真菌关系不密切。小麦中的一些抗病基因已经被鉴定，但抗病的分子机制尚不清楚。为了鉴定参与抗性反应的宿主基因，研究了小麦品系Tadinia（含有Stb 4抗性基因）和感病品系Yecora Rojo在未接种和接种M.用差异显示聚合酶链反应（DD-PCR）对禾生菌属（Graminicola）和禾生菌属（Graminicola）进行比较。其中差异表达的基因是蛋白质二硫键异构酶（PDI），这是众所周知的分子伴侣和组成部分的信号转导途径在动物系统中，但没有牵连以前在植物防御反应。实时定量逆转录PCR和北方分析表明，PDI诱导接种3小时内最高的诱导病原体处理的抗性品系。PDI的这些反应与病程相关（PR）蛋白PR-1、PR-2和PR-5所显示的早期和强抗性相关反应相似。与此相反，小麦脂氧合酶下调的时间点对应的PR基因的峰值诱导的抗性线。因此，抗性机制的一部分可能涉及抑制基因，否则可能有助于真菌生长。小麦对M.禾生菌这些早期反应开始之前，主机的渗透和似乎决定了主机-病原体相互作用的结果。
Mycosphaerella graminicola, incitant of septoria tritici blotch, is a widespread and significant pathogen of wheat that is not closely related to other fungi being developed as genetic models for host-pathogen interactions. Several resistance genes in wheat have been identified, yet the molecular mechanisms of resistance are unknown. To identify host genes involved in the resistance response, expression profiles of the wheat line Tadinia (containing the Stb4 gene for resistance) and the susceptible line Yecora Rojo, non-inoculated or inoculated with M. graminicola, were compared by differential-display polymerase chain reaction (DD-PCR). Among the differentially expressed genes was a protein disulfide isomerase (PDI), which is well known as a molecular chaperone and component of signal-transduction pathways in animal systems but had not been implicated previously in plant defense response. Real-time quantitative reverse-transcription PCR and northern analysis revealed that PDI was induced within 3 h of inoculation with highest induction in the pathogen-treated resistant lines. These responses of PDI were similar to the early and strong resistance-related responses displayed by the pathogenesis-related (PR) proteins, PR-1, PR-2 and PR-5. In contrast, a wheat lipoxygenase was down-regulated in the resistant lines at time points corresponding with peak induction of the PR genes. Thus, part of the resistance mechanism may involve repression of a gene that could otherwise aid fungal growth. Wheat responds much more rapidly than believed previously to signals produced by M. graminicola. These early responses begin prior to penetration of the host and appear to determine the outcome of the host-pathogen interaction.