福建省毛豆根结线虫种类鉴定及初侵染来源

Identification and primary inoculum sources of root-knot nematode in Glycine max in Fujian province

福建省漳州市一基地毛豆(品种:‘毛豆64’)苗期发生严重根结线虫病,发病株率为78%。为明确其病原的种类及其初侵染来源,通过形态学、分子生物学方法进行了种类鉴定。研究结果表明,该线虫雌虫、雄虫、2龄幼虫(J2)的形态学特征与测量值和拟禾本科根结线虫Meloidogyne graminicola相吻合;基于线虫rDNA-ITS序列和28S rDNA D2D3序列构建的系统发育树进一步确定其为拟禾本科根结线虫;室内接种试验确定了其致病性。这是首次在福建省毛豆上发现拟禾本科根结线虫。在毛豆基地畦地残留的前作水稻稻茬根内和根际土壤中均分离到大量J_(2)s,经特异性引物扩增确定为拟禾本科根结线虫,研究认为前作水稻根系受拟禾本科根结线虫侵染,在灌溉淹水状态下线虫2龄幼虫和卵在根内与土壤中长期存活,成为轮作毛豆根结线虫病的初侵染源。

A serious root-knot nematode disease occurring at the seedling stage of Glycine max‘maodou 64’,with a disease incidence of 78%,has been found in fields in Zhangzhou region,Fujian province.Morphological measurements of females,males and second juveniles(J_(2)s)matched the original description of Meloidogyne graminicola.Species identification was further carried out by phylogenetic analysis based on the sequences of rDNA-internal transcribed spacer(ITS)region and D2D3 region of 28S rDNA.The inoculation test in greenhouses confirmed the nematode’s pathogenicity.This is the first report of M.graminicola parasitizing soybean in Fujian province.A large number of J_(2)s had been isolated from the root of preceding rice stubbles and rhizosphere soil in ridged fields of the‘maodou 64’,and the species identification was confirmed with M.graminicola specific primers.These results indicated that the root of the preceding rice was infected by M.graminicola,and eggs and J_(2)s of the nematode survived in waterlogged soil and infected root for a long period of time in irrigated rice cultivation,and became the primary inoculum sources for the root-knot nematode disease when soybeans are planted as a rotating crop.