Genetic Studies of infection-related morphogenesis in Magnaporthe grisea

稻瘟病菌感染相关形态发生的遗传学研究

• 批准号: 9219305
• 负责人: John Hamer
• 金额: $ 29.3万
• 依托单位: Purdue Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-03-01 至 1996-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9219305&HistoricalAwards=false
• 关键词: Genetic; Studies; infection; related; morphogenesis

This research concerns the morphological and biochemical specialization demonstrated by the rice blast fungus, Magnaporthe grisea. Asexual spores of M. grisea attach to plant surfaces, initiate growth through the emergence of a germ tube, and differentiate an infection structure called an appressorium (1). The appressorium is a specialized cell capable of generating enormous turgor pressures that facilitate the direct penetration of the plant epidermis (2). Large, swollen, infectious hyphae rapidly appear within and between plant cells (3). Finally, surface borne conidiophores produce numerous asexual spores to reinitiate the disease cycle. The goal of this research is to understand the biochemical events that key disease-related morphogenesis in M. grisea. Genetic and biochemical investigations can identify components in this process that could elucidate central processes in fungal cell morphogenesis and may provide strategies for the development of novel disease control measures. Previous investigations identified a genetic locus termed SMO1 (4). Phenotypic analysis suggests that the SMO gene product plays a central role in establishing the polarity of cell growth and morphogenesis in particular disease-related cell types of M. grisea and thus Smo-mutations reduce pathogenicity towards rice. Additionally, mutations at this locus occur at a high frequency in certain genetic backgrounds of M. grisea. The SMO locus has been cloned by a novel mapped based cloning procedure developed by this laboratory for M. grisea. The studied have demonstrated that SMO is closely linked to chromosomal duplication. To advance the understanding of the SMO locus and its relationship to fungal growth and disease-related morphogenesis, three related experimental strategies will be used: (1) A fine structure analysis of the SMO locus and smo-minus. (2) Cytological and biochemical identification of the SMO protein and more refined characterization of the duplication around the SMO locus. (3) The isolation and characterization of additional mutations affecting disease-related morphogenesis in M. grisea. %%% The fungus Magnaporthe grisea is an economically significant pathogen of rice. The goal of this research is to increase our understanding of the process by which this fungus undergoes the structural changes necessary to initiate an infection. The investigator will be studying a gene which he has already shown to function in the development by the fungus of a specialized infection structure and will identify and characterize other mutations affecting morphogenesis related to the infection process.

本研究关注稻瘟病菌Magnaporthe grisea所表现出的形态和生化特化。稻瘟杆菌的无性孢子附着在植物表面，通过芽管的出现开始生长，并分化成一种称为附着胞的感染结构(1)。附着胞是一种特殊的细胞，能够产生巨大的膨胀压力，促进直接穿透植物表皮(2)。在植物细胞内部和细胞之间迅速出现大而肿胀的感染性菌丝(3)。最后，表面生的分生孢子产生大量无性孢子，重新启动疾病循环。本研究的目的是了解稻瘟杆菌关键疾病相关形态发生的生化事件。遗传和生化研究可以识别这一过程中的成分，从而阐明真菌细胞形态发生的核心过程，并可能为开发新的疾病控制措施提供策略。先前的研究发现了一个称为SMO1(4)的遗传位点。表型分析表明，SMO基因产物在稻瘟杆菌特定疾病相关细胞类型的细胞生长极性和形态发生中起核心作用，因此SMO突变降低了对水稻的致病性。此外，该位点的突变在稻瘟病菌的某些遗传背景中发生的频率很高。SMO基因座已通过本实验室为稻瘟杆菌开发的一种新的基于图谱的克隆程序克隆。研究表明，SMO与染色体重复密切相关。为了进一步了解SMO位点及其与真菌生长和疾病相关形态发生的关系，本文将采用三种相关的实验策略：(1)对SMO位点和SMO -进行精细结构分析。(2) SMO蛋白的细胞学和生化鉴定以及SMO位点周围复制的更精细表征。(3)稻瘟病菌中影响疾病相关形态发生的其他突变的分离和鉴定。稻瘟病菌（Magnaporthe grisea）是水稻的重要经济病原菌。这项研究的目的是增加我们对这种真菌经历必要的结构变化以启动感染的过程的理解。研究者将研究一个他已经证明在真菌的特殊感染结构的发展中起作用的基因，并将识别和表征影响与感染过程相关的形态发生的其他突变。