水稻叶部一种植物线虫的形态和分子鉴定

Morphological and molecular identification of a plant-nematode on rice leaves

【目的】旨在明确河南省开封市祥符区部分水稻长势弱,叶尖表现灰白干枯、扭曲干尖等症状的病因,为进一步研究水稻上该病害的发生危害规律和防治提供科学依据。【方法】通过改良贝尔曼漏斗法和直接浸泡法分离采集水稻地上部的线虫,挑取单条雌虫在胡萝卜愈伤组织上进行单雌扩繁,采用形态学和分子生物学相结合的方法对纯化培养的水稻线虫KF-1群体进行了种类鉴定。【结果】形态学结果表明待鉴定线虫与水稻干尖线虫(Aphelenchoides besseyi Christie,1942)的形态特征较一致。rDNA的ITS和28S rRNA基因中D2-D3区序列比对结果表明,待鉴定线虫与GenBank中水稻干尖线虫序列具有高度相似性,最高分别达到100%和98.98%。基于rDNA-ITS和28S D2-D3区序列构建的系统进化树结果与已知鉴定结果相一致,待鉴定线虫与其他水稻干尖种群位于同一高度支持的分支。【结论】通过形态和分子鉴定,确定了造成河南开封市祥符区部分水稻叶尖干枯的病原为水稻干尖线虫,这是河南东部地区首次发现该线虫的发生危害,应采取相应措施避免该线虫病害的进一步扩散蔓延。

【Objectives】Aimed to ascertain the reasons for the symptoms of weak rice growth,dry gray and white leaf tips and twisted leaf tips in Xiangfu District,Kaifeng City of Henan Province,which could provide theoretical references for further research on the occurrence and control of this disease in rice.【Methods】Nematodes were extracted from rice leaves by modified Baermann funnel method and direct soaking method,and one individual female nematode was selected to propagate on carrot disks by parthenogenesis.The purified rice nematodes KF-1 population was identified base on morphological and molecular biological technology.【Results】Base on the morphological studies,the rice nematodes collected in this study was highly similarity with Aphelenchoides besseyi.The rDNA-ITS and rRNA 28S D2-D3 region sequences of the rice nematode had high identities with the sequences of A.besseyi in the GenBank,up to 100%and 98.98%,respectively.The phylogenetic tree inferred from rDNA-ITS and D2-D3 expansion segments of 28S rRNA gene sequences showed that the collected rice nematode KF-1 population formed a highly supported clade with another A.besseyi.【Conclusions】Both morphological and molecular studies revealed that the pathogen of rice leaf is A.besseyi,which caused typical symptom of“white tip”on the leaf tips in Xiangfu District,Kaifeng City,Henan Province.This is the first time to find the damage of A.besseyi in Kaifeng city of eastern Henan Province,and corresponding measures should be taken to prevent the further spread of the nematode disease.