海南岛象耳豆根结线虫的种类鉴定及其rDNA-ITS序列分析

Identification and analysis of rDNA-ITS of the nematode Meloidogyne enterolobii on Hainan Island,China

【背景】植物根结线虫病是世界性分布的土传病害,常造成农作物的重大经济损失。目前分布于热带亚热带区域的象耳豆根结线虫,由于其致病性和分子特征以及与植物互作关系的独特性,被认为是一种对农作物具有潜在危害性的重要病原根结线虫,因而引起国内外植物寄生线虫学者的广泛关注。【方法】用形态学、同工酶技术和分子生物学技术相结合的方法,对从海南岛农作物上采集到的10个根结线虫纯化种群进行分类鉴定。【结果】象耳豆根结线虫在海南岛大面积栽培的10种农作物和南药植物,包括黄瓜、南瓜、苦瓜、丝瓜、葫芦瓜、辣椒、番石榴、海巴戟、沈香和丁香上均有寄生,其形态学、酯酶表型和mtDNA-PCR扩增产物均有别于常见的根结线虫种类;用引物18S和28S扩增象耳豆根结线虫种群的rDNA-ITS区序列,并对其进行克隆、测序和比对分析,结果表明,象耳豆根结线虫4HBJ种群分别与南方根结线虫、爪哇根结线虫和花生根结线虫的同源性均仅为88%左右。【结论与意义】本文准确鉴定了象耳豆根结线虫,首次阐述其对海南岛多种农作物的致害性;阐释了象耳豆根结线虫的形态和分子特征,并明确了其与3种常见根结线虫的系统发育关系。本研究对今后进一步开展象耳豆根结线虫的基础研究和防治工作具有重要参考价值。

[Background]The Plant root-knot nematode disease（Meloidogyne spp.） is a soil-borne pest and may cause great economic losses.As M.enterolobii is distributed widely in the tropical and subtropical regions,and is a potentially harmful pathogenic root-knot nematode for several cultivated crops,it is the subject of intensive study around the world,based on its peculiarity of pathogenicity,molecular characteristics and interaction with plants.[Method]Ten purified populations of root-knot nematodes collected from Hainan Province,Southern China,were identified by using the morphological,isozyme and molecular biological methods.[Result]The presence of M.enterolobii was confirmed on 10 cultivated crops and herbs,including as cucumber,pumpkin,balsam pear,loofah,bottle gourd,pepper,guava,clove and the herbs Morinda citrifolia,and Excoecaria agallocha.Its morphology,esterase phenotype and mtDNA-PCR amplification products were different from the common species of root knot nematodes.Primers 18S and 28S were used to amplify the rDNA-ITS region of M.enterolobii and population 4HBJ were cloned,sequenced and compared.We found about 88% homology between M.enterolobii and M.incognita,M.javanica and M.arenaria,respectively.[Conclusion and significance]M.enterolobii was accurately identified,and its presence on crops in Hainan Island was firstly proven.The morphological and molecular characteristics of M.enterolobii were clarified,and the molecular phylogenetic relationship between M.enterolobii and three other common species of Meloidogyne was explained.The research results had important value for the future study of M.enterolobii and disease control.