极性生长被认为是关系丝状真菌生长、发育及侵染寄主的关键。研究显示，cAMP途径及其关键酶PKA可通过影响F-actin形成和几丁质合成酶（CHSs）极性定位调控丝状真菌的极性生长。但相关研究多集中于致病微生物和工业微生物，且缺乏PKA对actin、CHSs磷酸化作用的直接证据。作为我国第二大水生蔬菜茭白的内生真菌-茭白黑粉菌，其极性生长对于茭白的形成至关重要，但未见这方面的研究报道。项目组前期研究发现cAMP途径参与茭白黑粉菌极性生长，PKA调节亚基缺失的菌株无法形成菌丝。本研究结合基因敲除、结构域敲除、磷酸化位点突变及植物组织互作等试验方法，及质谱鉴定、FRAP等技术，深入了解PKA调控茭白黑粉菌极性生长的可能机制，及对寄主植物防御反应的影响。所得结果不仅可阐明茭白黑粉菌极性生长的内在机制，且有助于了解茭白黑粉菌与其寄主植物的互作关系。

Polarized growth was fundamental to growth, infection of filamentous fungi. Previous studies showed that cAMP pathway and its key kinase PKA regulated polarity of cell growth by modulation of F-actin rearrangement and polar localizing chitin synthases. Unfortunately, most studies focused on pathogenicity and industrial fungi. Regarding the ability of PKA phosphorylate actin and CHSs, conclusive evidence has still been lacking. As the endophyte of Zizania latifolia, which was the second largest planted aquicolous vegetable in China, polarized growth of Ustilago esculenta was essential to gall formation. But fewer related research reports were found in Ustilago esculenta until now. In the present study, we will employ gene knock-out mutants, funtional domain knock-out mutant, point mutation of phosphorylating site, and interaction with plant tissue, to investigate the mechanisms involved in PKA regulating polarity of cell growth in Ustilago esculenta, and the defensive response of the plant tissue of polarized growth of fungi. Our expected findings will uncover the underlying mechanisms involved in PKA regulating polarized growth, and advance our understanding of the interaction between Ustilago esculenta and host plant.