三七根腐病病原菌尖孢镰刀菌的生物学特性分析

Biological Characteristics of Fusarium oxysporum,A Pathogen of Panax notoginseng Root Rot

目的:旨在分离鉴定三七苗期根腐病病原菌,并对其生物学特性进行研究,从而了解该病原菌的发病条件,为该病原菌引起的三七病害的监测和防治提供理论参考。方法:采集三七根腐病幼苗,用PDA培养基对病原菌进行分离纯化,得到了2株真菌。通过对菌落、菌丝和孢子形态观察及ITS序列的比对,对其中1株病原菌进行了鉴定。并研究了温度、pH、光照、碳源及氮源等对菌丝生长和孢子萌发的影响。结果:该病原菌鉴定为尖孢镰刀菌(Fusarium oxysporum)。将病原菌回接一年生三七植株,发现其有很强的致病性。该病原菌在30℃、pH 5的培养条件下生长最快,可有效利用多种碳和氮源,其中以淀粉、乳糖为最佳碳源,硝酸铵为最适氮源。孢子在30℃、pH 6~7的条件下萌发率最高,孢子的致死温度为50℃。结论:明确了三七苗期根腐病病原菌(尖孢镰刀菌)的生物学特性,确定了该病原菌生长和孢子萌发的最适培养条件。

Objective:To isolate and identify the pathogenic bacteria of Panax notoginseng root rot at seedling stage and to study its biological characteristics,so as to understand the pathogenic conditions of the pathogenic bacteria and provide theoretical reference for the monitoring and control of Panax notoginseng disease caused by this pathogen.Methods:The seedlings of Panax notoginseng root rot were collected and two strains of fungi were isolated and purified by PDA medium.Through the observation of colony,mycelium and spore morphology and ITS sequence comparison,one pathogen was identified.And the effects of temperature,pH,light,carbon and nitrogen sources on mycelia growth and spore germination were studied.Results:The pathogen was identified as Fusarium oxysporum.When this strain was inoculated back to annual Panax notoginseng,the strain led to serious pathogenicity.The pathogen grown fastest under the culture condition of 30℃and pH 5,and could effectively use a variety of carbon and nitrogen sources,among which starch and lactose were the best carbon sources and ammonium nitrate was the most suitable nitrogen source.The germination rate of spores was highest at 30℃and pH 6~7 and its lethal temperature was 50℃.Conclusion:This study can clarify the biological characteristics of the root rot pathogen(Fusarium oxysporum)in seedling stage of Panax notoginseng,and determine the optimum culture conditions for its growth and spore germination.