山西长治玉米根腐线虫病病原鉴定及致病性测定

Identification and pathogenicity of a root-lesion nematode on corn in Changzhi,Shanxi

【目的】明确从山西长治玉米根际分离到的一种根腐线虫病的病原种类及其对玉米的致病性,为玉米根腐线虫病害的识别和有效防治提供科学依据。【方法】采用贝曼漏斗法对采集的样品进行分离,采用形态学与分子生物学相结合的方法对分离的根腐线虫进行种类鉴定,并采用室内盆栽接种的方法测定其对玉米的致病性。【结果】形态学分析发现,待鉴定的短体线虫与斯克里布纳短体线虫(Pratylenchus scribneri)的形态特征较为一致;rDNA-ITS、rDNA 28S D2~D3区和mtDNA-COI区序列分析发现,该短体线虫种群与NCBI数据库中斯克里布纳短体线虫的序列具有高度相似性;基于rDNA-ITS、rDNA 28S D2~D3区和mtDNA-COI序列构建的系统进化树显示,该短体线虫种群与其他斯克里布纳短体线虫种群位于同一高度支持的分支,据此将山西长治玉米根际分离到的短体线虫鉴定为斯克里布纳短体线虫。与对照组玉米植株相比,接种供试斯克里布纳短体线虫60 d后,玉米表现出植株矮小,生长缓慢,地上部鲜质量和根鲜质量显著减轻,根部出现明显的褐色病斑甚至坏死腐烂的发病症状,斯克里布纳短体线虫在玉米根际的繁殖系数(R_(f))达到19.44。【结论】山西长治玉米根腐线虫病的病原种类为斯克里布纳短体线虫,其对玉米具有较强的致病性。

【Objective】This study identified the pathogenic species and pathogenicity of a root-lesion nematode separated from corn in Changzhi,Shanxi to provide basis for the identification and effective control of corn root-lesion nematode disease.【Method】The collected samples were isolated by Baermann funnel method.The extracted root-lesion nematodes were identified based on morphological and molecular biological methods.The pathogenicity of the root-lesion nematodes to corn was also tested by pot experiment in a greenhouse.【Result】Based on morphological characteristics,the Pratylenchus collected in this study was identified as Pratylenchus scribneri.The rDNA-ITS,rDNA 28S D2-D3 and mtDNA-COI sequences of the root-lesion nematode from corn had highly identities with the sequence of P.scribneri in NCBI database.The Bayesian tree inferred from rDNA-ITS,rDNA 28S D2-D3 and mtDNA-COI sequences showed that the root-lesion nematode collected in this study had a highly supported clade with other P.scribneri population.Therefore,the root-lesion nematode was identified as P.scribneri.Compared with corn plants in the control group,60 days after inoculation with P.scribneri,the corn growth and height were reduced and the roots showed distinct brown spots and even heavily necrosis and rot.The reproductive factor(R_(f))of the P.scribneri in corn rhizosphere reached 19.44.【Conclusion】The pathogen of the corn root-lesion nematode disease in Shanxi was P.scribneri,and it had strong pathogenicity to corn.