水稻纹枯病菌不致病菌株基因组重测序以及致病力相关基因分析

水稻纹枯病是水稻世界三大病害之一,严重影响水稻的产量与质量,揭示水稻纹枯病菌的致病机理对于防治水稻纹枯病具有重要意义。为此,本研究对立枯丝核菌AG1 IA的自然突变不致病菌株Rs3的形态和组织病理学研究以及基因组重测序分析其关键致病基因的突变,探寻其致病力丧失的原因。研究结果显示,与野生型AG1 IA相比,不致病菌株Rs3具有生长慢、接种水稻叶片不产生侵染附着结构,以及不导致水稻产生坏死病斑等生物学特点。而重测序结果分析显示,与野生型AG1 IA相比,不致病菌株Rs3的基因组范围内存在大量的突变,包括SNP和Indel,其中涉及与菌丝生长相关的actin基因,致病相关的cAMP通路、MAPK通路和钙离子信号等通路基因,以及效应因子相关基因。本研究通过对水稻纹枯病菌不致病菌株的组织病理学差异以及基因组层面上的基因突变分析,从菌株对寄主的识别、侵染生长和致病信号通路方面揭示了Rs3致病力丧失的可能原因,为后续纹枯病菌关键致病因子的发病机理研究奠定基础。

The genome re sequencing and pathogenicity associated genes analyzing in a non pathogenic strain of rice sheath blight fungus Rhizoctonia solani

Rice sheath blight is one of three most important diseases worldwide on rice, which has significantly impacts on the yield and quality of rice. Revealing the pathogenicity mechanism of rice sheath blight fungus plays an important role in control of this devastating rice disease. Therefore, a non pathogenic mutant Rs3 of Rhizoctonia solani AG1IA was selected to perform the morphological and histopathological study as well as the genome resequencing for revealing the reason of the lost in pathogenicity. Biological study showed that, compared to wild type AG1IA, the Rs3 mutant was significantly slow in growth rate, not forming typical infection structures during infection and non pathogenicity to rice. Re sequenced genome analysis exhibited lots of mutations in genome of Rs3, including massive SNP and Indel mutations which located in hyphae growth related actin gene, pathogenicity related genes in the cAMP MAPK and Ca²⁺ pathways, and the candidate effector genes. In this study, the histopathology and gene mutation analysises on the genomic scale for the non pathogenic strain Rs3 lay the foundation for the subsequent pathogenesis researches of Rhizoctonia solani.