渝产多花黄精根腐病病原菌的分离与鉴定

为了明确重庆地区多花黄精根腐病的病原菌,并进一步为该病害的防治提供理论依据。采集典型根腐病症状的多花黄精样品,通过切片和组织分离法对病原菌进行分离和纯化。按柯赫氏法则对其致病性测定,并对其中毒性最强的菌株L1和L6进行形态学、分子生物学鉴定。结果表明:分离的致病菌经形态学初步鉴定分别为尖孢镰刀菌(Fusarium oxysporum)和腐皮镰刀菌(F.solani);柯赫氏法则表明两种病原菌都能使多花黄精发病,发病症状与田间症状一致,且存在复合侵染现象;PCR技术扩增病菌rDNA-ITS基因,获得长度为600 bp、570 bp的DNA片段,菌株序列与尖孢镰刀菌和腐皮镰刀菌的序列同源性分别达到99%;ITS系统发育树上,L1与尖孢镰刀菌和L6与腐皮镰刀菌聚在同一分支上。结合形态特征、序列分析和系统进化分析,确定尖孢镰刀菌和腐皮镰刀菌是引起多花黄精根腐病的病原菌。本研究可为根腐病拮抗菌的筛选和多花黄精--根腐病互作机理研究提供帮助。

Isolation and Identification of Pathogen of Polygonatum cyrtonema Hua Root Rot Disease in Chongqing

In order to identify the pathogen causing root rot of Polygonatum cyrtonema Hua in Chongqing area,and provide a theoretical basis for the control of root rot disease.Samples with typical symptoms of root rot were collected.The pathogen of P.cyrtonema root rot was isolated and purified by sectioning and tissue separation.According to Koch’s rule,the most toxic strains L1 and L6 were identified by morphology and phylogenetic analysis.The results showed that the isolated pathogens were Fusarium oxysporum and F.solani.Koch’s rule showed the complex infection of F.oxysporum and F.solani,and the symptoms were the same as those in the field.The rDNA-ITS gene was amplified by PCR to obtain DNA fragments with a length of 600 bp and 570 bp.The sequence homology with F.oxysporum and F.solani sapropelis was 99%.Combined with morphological characteristics,sequence analysis and systematic evolution analysis,it was confirmed that F.oxysporum and F.solani were the pathogens of root rot of P.cyrtonema.This study can provide help for the screening of antagonistic bacteria and molecular mechanism of interaction between P.cyrtonema and the pathogen.