河南烟草根际短体线虫鉴定及其致病性分析

Identification and pathogenicity of a root-lesion nematode species on tobacco in Henan

【目的】明确从河南省南阳市烟草根际采集到的一种短体线虫的种类及其对烟草的致病性,为烟草根腐线虫病害的识别与有效防治提供理论依据。【方法】采用形态学与分子生物学相结合的方法,对分离自河南省南阳市烟草根际的一种短体线虫进行鉴定,并采用温室盆栽接种的方法测定其对烟草的致病性。【结果】形态学分析发现,待鉴定短体线虫与咖啡短体线虫(Pratylenchus coffeae)的形态特征较为一致。rDNA-ITS和rDNA 28S D2~D3序列分析发现,该线虫种群与NCBI数据库中的咖啡短体线虫序列具有高度相似性。基于rDNA-ITS和rDNA 28S D2~D3序列构建的贝叶斯进化树显示,该短体线虫与其他咖啡短体线虫位于同一高度支持的分支。因此,将从河南省南阳市烟草根际采集到的短体线虫鉴定为咖啡短体线虫。接种咖啡短体线虫75 d后的烟株生长缓慢,植株矮小,叶片黄化萎蔫,根部出现褐色病斑甚至坏死腐烂,咖啡短体线虫在烟草根际的繁殖率达到5.81。【结论】河南省南阳市烟草根腐线虫病病原为咖啡短体线虫,其对烟草具有较强的致病性。

【Objective】The research confirmed the species and pathogenicity of a root-lesion nematode collected from tobacco(Nicotiana tabacum)in Nanyang,Henan to provide basis for the identification and effective control of tobacco root-lesion nematode diseases.【Method】A root-lesion nematode was extracted from the rhizosphere of tobacco in Nanyang,Henan,and the nematode was identified based on morphological and molecular biological technology.The pathogenicity of the root-lesion nematode to tobacco was also tested via pot experiment in a greenhouse.【Result】Base on the morphological analysis,the root-lesion nematode collected in this study was identified as Pratylenchus coffeae.The rDNA-ITS and rDNA 28S D2-D3 sequences of the root-lesion nematode from tobacco had high identities with the sequences of P.coffeae in the GenBank database.Bayesian tree inferred from rDNA-ITS and rDNA 28S D2-D3 sequences showed that the root-lesion nematode formed a highly supported clade with other P.coffeae populations.Both morphological and molecular studies revealed that the root-lesion nematode extracted from rhizosphere of tobacco in Nanyang,Henan was P.coffeae.After inoculation with P.coffeae,the tobacco growth and height were reduced,leaves became yellow,and the roots presented brown spots and heavily rotted.The reproductive factor(R f)of P.coffeae reached 5.81 after inoculated tobacco for 75 days.【Conclusion】The species of root-lesion nematode infected tobacco in Nanyang,Henan was P.coffeae,and it has strong pathogenicity to tobacco.