Genetic Studies of infection-related morphogenesis in Magnaporthe grisea

这项研究涉及形态学和生物化学 稻瘟病菌Magnaporthe 稻瘟病菌 M.稻瘟病菌附着在植物表面， 通过芽管的出现启动生长，以及 分化出一个被称为附着胞的感染结构（1）。 附着胞是一种特殊的细胞， 巨大的膨压促进了直接渗透 植物的表皮（2）。 大的、肿胀的、感染性菌丝 迅速出现在植物细胞内和细胞间（3）。 最后， 表面生分生孢子梗产生大量无性孢子， 重新启动疾病循环。 这项研究的目的是 了解与关键疾病相关的生化事件， 形态发生在M.稻瘟病菌 遗传和生物化学研究 可以确定这个过程中的成分， 真菌细胞形态发生的中心过程， 制定新的疾病控制措施的战略。 以前的研究确定了一个名为SMO 1的遗传位点（4）。 表型分析表明，SMO基因产物起作用， 在建立细胞生长极性中的核心作用， 形态发生，特别是疾病相关的细胞类型的M。瘟病菌 因此Smo突变降低了对水稻的致病性。 此外，该基因座的突变发生频率很高， 一定的遗传背景。稻瘟病菌 SMO基因座 克隆的一种新的映射为基础的克隆程序开发的这一点， 实验室M.稻瘟病菌 研究表明，SMO 与染色体复制密切相关 推进 了解SMO基因座及其与真菌 生长和疾病相关的形态发生，三个相关 实验策略包括：（1）精细结构分析 SMO基因座和smo-负的基因(2)细胞学和生物化学 SMO蛋白的鉴定和更精确的表征 SMO基因座周围的复制。(3)分离和 影响疾病相关性的其他突变的表征 形态发生在M.稻瘟病菌 %%% 稻瘟病菌（Magnaporthe grisea）是一种经济上重要的真菌， 水稻病原菌 这项研究的目的是增加我们的 了解这种真菌经历的过程， 引发感染所必需的结构变化。 的 研究人员将研究一种基因，他已经证明， 在真菌发育中的功能， 感染结构，并将识别和表征其他 影响与感染过程相关的形态发生的突变。

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.