广东省水稻孢囊线虫病调查与鉴定

Investigation and Species Identification of Cyst Nematode Disease on Rice in Guangdong Province

【目的】明确广东省水稻上孢囊线虫发生种类、分布。【方法】从广东省的14个市采集了231份水稻根系和根际土壤样品,从水稻根系及根际土壤样品中分离孢囊线虫,采用形态学和分子生物学方法鉴定孢囊线虫种类。【结果】在广东清远、肇庆、江门等地水稻根系及根际土样中发现孢囊线虫,孢囊检出率分别为40%、23.7%、10%。形态学研究表明,孢囊柠檬形或近圆形,主要为柠檬形,阴门锥双半膜孔,膜孔近圆形,阴门桥窄,下桥中等大小;二龄幼虫唇区半球形,略缢缩;尾圆锥形,尾端尖,透明尾长占尾长的53%~66%。分子生物学研究表明,该线虫28S rDNA D2-D3区序列与NCBI数据库中旱稻孢囊线虫相似度99.73%~100%,rDNA-ITS区序列与NCBI数据库中旱稻孢囊线虫相似度96.72%~99.91%。系统进化树分析表明,该线虫与旱稻孢囊线虫处于同一分支,置信度为100%。使用旱稻孢囊线虫特异性引物He-F/He-R扩增清远、肇庆、江门采集的孢囊线虫rDNA-ITS区均得到281 bp的单一条带,与已报道结果一致。【结论】清远、肇庆、江门采集到的孢囊线虫均为旱稻孢囊线虫。这是首次在广东省发现旱稻孢囊线虫。

【Objective】To investigate the species,distribution,and occurrence of cyst nematode disease on rice in Guangdong Province.【Methods】A total of 231 rice roots and rhizosphere soil samples from 14 cities in Guangdong Province were collected and analyzed.The cyst nematode species in these samples were identified through morphological and molecular identification.【Results】Cyst nematodes were found on rice in Qingyuan,Zhaoqing,and Jiangmen in Guangdong Province,with detection rates of 40%,23.7%,and 10%,respectively.Morphological identification revealed that the cysts were lemon to spherical-shaped,predominantly lemon-shaped,with an ambifenestrate vulval cone,a nearly round fenestral,a narrow vulval bridge,and a medium-sized underbridge.The second-stage juvenile(J2)had a hemispherical and offset labial region,a conical tail with a pointed tip,and a hyaline region occupying 53%to 66%of the tail length.Molecular identification indicated that the 28S rDNA D2-D3 region of the cyst nematode was 99.73%-100%similar to Heterodera elachista in the NCBI database,and the rDNA-ITS region was 96.72%-99.91%similar to Heterodera elachista in the NCBI database.Phylogenetic analysis placed the nematode in the same branch as H.elachista with a confidence level of 100%.Using specific primers He-F/He-R of H.elachista,a 281 bp single band was amplified from the rDNA-ITS region of the cyst nematodes,consistent with previous reports.【Conclusion】The cyst nematodes collected in Qingyuan,Zhaoqing,and Jiangmen were identified as H.elachista,marking the first report of H.elachista in Guangdong Province.