豌豆镰孢根腐病菌的鉴定及其致病基因多样性

Identification of the Pathogen Causing Fusarium Root Rot of Pea and Diversity of Pathogenicity Genes

【目的】明确中国不同地区豌豆镰孢根腐病菌的种类及其致病基因多样性,为病害防治及抗病育种提供依据。【方法】通过形态学观察、致病性测定和特异性分子标记检测对病原菌分离物进行鉴定,通过茄镰孢豌豆专化型(Fusarium solani f.sp.pisi)致病基因特异性PCR引物对病原菌分离物致病基因进行检测。【结果】96个病原菌分离物鉴定为茄镰孢豌豆专化型。致病性测定表明所有分离物对豌豆品种"草原27"致病,其中81.3%的分离物致病力强,10.4%的分离物致病力中等,只有8.3%的分离物具弱致病力。用4个致病基因PDA、PEP1、PEP3和PEP5特异性引物对分离物基因组DNA进行PCR扩增,在96个分离物中共检测到10种基因组合(基因型),其中含有4个基因组合和3个基因组合的分离物约占91%,这些分离物绝大多数具有强致病力(87.4%)或中等致病力(9.2%),而检测不到PDA的分离物基本上都是弱致病力类型,表明致病基因的种类和数量与茄镰孢豌豆专化型的致病力水平有关。【结论】茄镰孢豌豆专化型是引起中国豌豆根腐病的主要病原菌,豌豆主产区大多数分离物致病力强。

【Objective】The objective of this study is to determine the pathogen causing Fusarium root rot on pea and diversity of pathogenicity genes.【Method】The Fusarium isolates were identified by PCR detection using specific primers for F.solani,morphological characteristics,and pathogenicity test.Pea pathogenicity genes PDA,PEP1,PEP3,and PEP5 in the isolates identified as F.solani f.sp.pisi were detected using the gene-specific primers.【Result】Ninety-six isolates were identified as F.solani f.sp.pisi.Pathogenicity tests showed that all isolates were pathogenic to pea variety ＂Caoyuan 27＂.There was a great difference in virulence among the isolates with 8.3%,10.4% and 81.3% being weakly virulent,moderately virulent and highly virulent to pea,respectively.Results of the PCR detection of the pathogenicity genes indicated that there were 10 combinations of pathogenicity genes（genotypes） in the 96 isolates and about 91% isolates possessed three or 4 pathogenicity genes.Most of the isolates containing four or three pathogenicity genes were highly virulent（87.4%） or moderately virulent（9.2%）.The isolates without the PDA generally possessed weak virulence.These results suggest that virulence of F.solani f.sp.pisi isolates were determined by the type,the number,and/or the combination of the pathogenicity genes.【Conclusion】F.solani f.sp.pisi is the major pathogen causing pea root rot,and the highly virulent pathogen type appears to be prevalent in main pea production areas in China.