细胞凋亡在假禾谷镰刀菌侵染过程中的功能分析

Apoptosis is known to regulate the growth, development and pathogenicity of various pathogenic fungi, but the occurrence and regulation mechanism are still not clear in Fusarium. In previous studies, we found that the number of TUNEL-positive cells was increased after hydrogen peroxide treatment of Fusarium pseudograminearum conidia, which indicated apoptosis occurrence of F. pseudograminearum. Expression levels of fourteen apoptosis-related genes were analyzed, and several genes might be involved in pathogen infection process. Here, apoptosis regularity will be investigated by analyses of F. pseudograminearum TUNEL positive cells at different stages, and the regulation mechanism of F. pseudograminearum infection processes by apoptosis will be elucidated by functional analysis of apoptosis-related genes. The signal pathway of apoptosis in F. pseudograminearum will be analyzed through interactional proteins identification. These results will aid the understanding of apoptosis regulation mechanisms of F. pseudograminearum pathogenicity, and provide scientific basis for development of novel control strategies against F. pseudograminearum by regulating cell apoptosis.

细胞凋亡调控多种病原真菌的生长、发育及致病过程，但在镰刀菌中的发生和调控机制尚不清楚。我们前期利用TUNEL法检测到过氧化氢可以诱导假禾谷镰刀菌分生孢子细胞凋亡的发生，并发现多个细胞凋亡相关基因可能参与调控病原菌的侵染过程。本研究拟通过检测细胞凋亡在假禾谷镰刀菌生长、发育及侵染等阶段的发生规律，明确其细胞凋亡的发生特点；通过对细胞凋亡信号通路上关键基因的功能分析，揭示细胞凋亡对假禾谷镰刀菌侵染过程的调控机制；鉴定细胞凋亡蛋白的互作蛋白，解析其信号通路。研究结果为进一步深入探索假禾谷镰刀菌的致病机制以及以调控细胞凋亡为途径的病害防治提供理论依据。

假禾谷镰孢菌引起的小麦茎基腐病在中国黄淮麦区呈现不断蔓延和加重的趋势，但是目前对于假禾谷镰孢菌的致病分子机制研究非常少。本研究解析了细胞凋亡在假禾谷镰孢菌生长、产孢和侵染过程中的作用。在假禾谷镰孢菌中鉴定到18个细胞凋亡相关基因，多个基因在侵染阶段诱导表达；利用遗传转化方法，明确FpBir1负调控假禾谷镰孢菌细胞凋亡，而细胞凋亡正调控基因核酸酶FpNUC1参与病原菌的细胞周期过程；揭示了细胞凋亡负调控假禾谷镰孢菌分生孢子的萌发和致病性，且对病原菌生长和产孢过程是必须的。在此基础上，进一步研究了热激蛋白和转录因子等可能参与细胞凋亡过程的基因，解析了内质网定位的Hsp70蛋白FpLhs1通过调控蛋白的分泌影响假禾谷镰孢菌的致病过程；发现了多个转录因子参与假禾谷镰孢菌的致病性。通过解析细胞凋亡在假禾谷镰孢菌致病过程中的作用，明确了病原菌在侵染过程中抑制自身细胞凋亡的发生，这将为进一步制定针对假禾谷镰孢菌引起的病害防治措施奠定基础。