云南金铁锁根腐病病原菌的分离及鉴定

Isolation and identification of pathogens causing root rot disease of Psammosilene tunicoides in Yunnan Province

金铁锁(Psammosilene tunicoides)是西南地区重要的民族民间药物、云南白药等中成药的主要原料药。为分离并鉴定云南金铁锁根腐病病原菌,该研究采用微生物纯培养方法,分离纯化金铁锁根腐病植株根部的病健交接处组织,获得金铁锁根腐病病原微生物。按照Koch’s法则验证分离得到的病原菌的致病性。结合形态学观察、真菌rDNA-ITS和TEF-1α序列分析以及系统发育树的构建鉴定获得的病原菌的种类。结果表明:(1)从金铁锁根腐病植株组织中分离纯化得到85株真菌,其中PSD-1、PSD-2、PSD-3菌株均能引起金铁锁的根腐病。(2)金铁锁健康植株接种PSD-1、PSD-2、PSD-3菌株后,产生与大田植株根腐病相似的症状,并且发病率分别为60%、61.7%、71.7%。(3)结合形态学观察及基因序列分析,鉴定该三株菌株均为尖孢镰刀菌(Fusarium oxysporum)。该文首次报道了尖孢镰刀菌是引起金铁锁根腐病的主要病原菌之一,为深入探究具有根腐病生物防治功能的内生菌群及其作用机制奠定了基础,也为后续金铁锁病害的防治工作提供了理论依据。

Psammosilene tunicoides is an important ethnic medicine in Southwest China and the main raw material for Chinese patent medicines like Yunnan Baiyao.The purpose of this study was to isolate and identify the pathogenic fungus of root rot of Psammosilene tunicoides in Yunnan.In this study,the disease-health junction of the root tissue of diseased plant was isolated and purified by pure culture method to obtain the main pathogenic microorganisms of P.tunicoides.Pathogenicity of isolated pathogenic microorganisms was analyzed the according to Koch’s Postulates,and then were identified by morphological observation,rDNA-ITS and TEF-1αsequence analysis and phylogenetic tree construction.The results were as follows:(1)A total of 85 strains of fungi were obtained,among which PSD-1,PSD-2 and PSD-3 of Fusarium fungi caused root rot of Psammosilene tunicoides.(2)These three strains were re-inoculated into the P.tunicoides,which produced similar disease symptoms occurred with field plants,and the disease incidences after inoculation with pathogenic fungi were 60%,61.7% and 71.7%,respectively.(3)Combined with morphological observation and gene sequence analysis,the three strains were identified as Fusarium oxysporum.This study firstly found that the F.oxysporum was one of the main pathogenic fungi causing root rot of Psammosilene tunicoides.The results of this study lay a foundation for the in-depth exploration of the endophytic flora with biological control of root rot and its mechanism,and serve as a theoretical basis for the follow-up prevention and control of the disease.