Genetic and Molecular Dissection of Hyphal Anastomosis

智力优势 丝状真菌是环境中植物纤维素物质的主要降解者。 不同种类的丝状真菌与几乎所有植物物种的根部都有共生关系，使植物能够从土壤中获得微量营养素。 此外，其他物种是植物中的致病因子，或引起重要的人类疾病。 所有这些丝状真菌，无论是有益的还是致病的，都通过顶端延伸、分支和菌丝融合来生长以形成菌丝网络。 菌丝网络的形成被认为是根伴生真菌和腐殖真菌在整个生态系统中转移营养物质以及病原真菌的菌落建立和资源开发所必需的。 虽然丝状真菌的顶端生长和分支已经被广泛研究，但对菌丝融合的机制或菌丝网络的功能知之甚少。 模式丝状真菌粗糙脉孢菌中菌丝融合的活细胞成像和遗传分析揭示了菌丝融合过程是一个复杂且精心调节的生物学过程。 在N. crassa中的信号转导途径组分、极化组分、丝状真菌特异蛋白和跨膜蛋白。 菌丝融合突变体显示发育缺陷，除了较慢的生长速率和/或滞后期，以达到最大的生长速率。 这些观察结果表明，在丝状真菌的相互连接的网络的形成是必不可少的环境生态位的开发和发展过程。 本研究的目的是通过活细胞成像、遗传分析和生物化学手段相结合的方法来剖析芽/菌丝融合的过程，阐明自我信号、极化和膜融合的机制，最终目的是了解菌丝网络在生态系统、共生和致病中的作用。更广泛的影响：丝状真菌中的菌丝融合与其他生物体中遗传上相同的细胞之间的细胞融合事件相当，例如导致合胞体的细胞-细胞融合，例如肌肉分化期间的成肌细胞融合，胎盘发育期间的滋养层融合以及骨形成期间破骨细胞之间的融合。因此，研究N. crassa为理解更复杂的真核生物中细胞融合事件的分子机制提供了有用的模型。 该项目为本科生、研究生和博士后提供了优秀的培训项目。 一些本科生加州机会学者已被招募到这个项目;这些学生来自弱势背景和湾区表现不佳的学校。

Intellectual Merit Filamentous fungi are the primary degraders of plant cellulosic material in the environment. Different species of filamentous fungi are associated with the roots of almost all plant species in a symbiotic relationship that allows plants to gain micronutrients from soil. In addition, other species are disease causing agents in plants, or cause important human diseases. All of these filamentous fungi, both beneficial and pathogenic species, grow by tip extension, branching and hyphal fusion to form a hyphal network. The formation of the hyphal network is believed to be essential for transfer of nutrients throughout ecosystems by root associated and saprophytic fungi and for colony establishment and exploitation of resources in pathogenic fungi. Although tip growth and branching have been extensively studied in filamentous fungi, little is known about the mechanism of hyphal fusion or the function of the hyphal network. Live cell imaging and genetic analysis of hyphal fusion in the model filamentous fungus, Neurospora crassa have revealed that the process of hyphal fusion is a complex and carefully regulated biological process. A large number of components essential for hyphal fusion have been identified in N. crassa, including components of signal transduction pathways, polarization components, filamentous fungal specific proteins and transmembrane proteins. Hyphal fusion mutants show developmental defects, in addition to slower growth rates and/or lag phase to reach maximal growth rate. These observations indicate that the formation of an interconnected network in filamentous fungi is essential for both exploitation of an environmental niche and for developmental processes. The objectives of this research are to dissect the process of germling/hyphal fusion using a combination of live cell imaging, genetic analysis and biochemical tools to elucidate the mechanisms of self-signaling, polarization and membrane merger with the ultimate goal of understanding the role of hyphal networks in ecosystems, symbiosis and pathogenesis. Broader Impact:Hyphal fusion in filamentous fungi is comparable to cell fusion events between genetically identical cells in other organisms, such as cell-cell fusion resulting in syncytia, such as myoblast fusion during muscle differentiation, trophoblast fusion during placental development and between osteoclasts during bone formation. Thus, studying cell-cell fusion in N. crassa provides a useful model for understanding molecular mechanisms of cell fusion events in more complex eukaryotic species. This project provides excellent training projects for undergraduate, graduate students and post-doctoral associates. A number of undergraduate California Opportunity Scholars have been recruited to this project; these students come from disadvantaged backgrounds and low performing schools in the Bay Area.