烟草叶斑病新病原分离鉴定及其生物学特性测定

Isolation,identification and biological characteristics of a new pathogen of tobacco leaf spot

  • 摘要: 【目的】明确广西贺州烟区一种烟草真菌性叶斑病害的病原菌种类和生物学特性,为病害的及时防控和后续研究提供理论参考。【方法】采用组织分离法对从广西贺州烟区采集的具明显叶斑病症状的烟草叶片组织进行病原菌分离纯化,利用柯赫氏法则验证其致病性;通过形态学结合多基因(ITS、LSU、TUB2RPB2)序列联合分析对病原菌进行种类鉴定;应用十字交叉法测定病原菌的生物学特性。【结果】经分离纯化共获得7株菌株,通过柯赫氏法则证明7株菌株均为烟草品种K326的叶斑病病原菌,7株菌株间的致病力无明显差异。基于ITS、LSU、RPB2TUB2构建的系统发育进化树显示,7株菌株均与菌株Stagonosporopsis vannaccii LFN0148和S.vannaccii YTH-12聚为一支,且支持率为100%。生物学特性测定结果表明,7株菌株菌丝生长的最适温度为25~28℃,最适碳源为可溶性淀粉,最适氮源为蛋白胨和牛肉浸粉,最适pH为6~9;适宜培养基为马铃薯葡萄糖培养基(PDA)、燕麦培养基(OA)和南瓜汁琼脂培养基(PA),在全光照条件下菌丝生长最快,最低致死温度为50℃水浴10 min。【结论】引起广西贺州烟区烟草叶斑病的病原菌为S.vannaccii,该病原菌喜好在弱酸性至弱碱性、光照充足且营养丰富的环境条件下生长。在烟草生产过程中可通过控制烟草种植密度、加强田间管理以及采取化学、生物防治等方法对由S.vannaccii引起的烟草叶斑病进行综合防控。

     

    Abstract: 【Objective】 To identify the species of a fungal totacco leaf spot disease and its biological characteristics in tobacco producing area of Hezhou,Guangxi,so as to provide theoretical reference for timely prevention and control and further research of the disease.【Method】The pathogen was isolated and purified from totacco leaf tissues with obvious symptom of tobacco leaf spot collected from the tobacco producing area of Hezhou,Guangxi by tissue separation method.And its pathogenicity was identified according to Koch’ s rule.Morphological analysis and multi-gene sequence analysis (ITS,LSU,TUB2RPB2)were used to identify the pathogen species.Biological characteristics of the pathogens were determined by cross method.【Result】 Seven strains of fungi were isolated and purified,and according to Koch’ s rule,all the 7 strains were pathogenic fungi of tobacco variety K326.No significant difference in pathogenicity among the 7 strains was found.A phylogenetic tree was constructed based on ITS,LSU,TUB2 and RPB2 genes.The results showed that all the 7 strains were clustered with Stagonosporopsis vannaccii LFNOI48 and YTH-12,and the support rate was 100%.The results of biological characteristics showed that the optimum temperature for the mycelium growth of the 7 strains was 25-28℃;the optimum carbon source was soluble starch;the optimum nitrogen source was peptone and beef extract powder;and the optimum pH was 6-9;the optimum medium was potato glucose medium(PDA),oat medium(OA)and pumpkin juice medium(PA).Mycelia grew the fastest under full light,and the lethal temperature was 50℃ for 10 min.【Conclusion】 S.vannaccii is the pathogen of tobacco leaf spot disease in Hezhou tobacco producing area of Guangxi.This pathogen grows in environment of weak acid to weak alkaline conditions,with sufficient light and rich nutrition.Tobacco leaf spot caused by S.vannaccii can be prevented and controlled by means of arranging planting density,strengthening field management,chemical and biological control,etc.

     

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