小麦丛矮病病原分子生物学鉴定

Identification of the pathogen causing wheat rosette stunt disease in Hebei Province

2009年4月,从河北邯郸、邢台、保定麦田采集表现小麦丛矮病症状的植株,经室内人工饲养的无毒灰飞虱饲食传毒,可致健康小麦表现叶脉间褪绿,矮化,分蘖增多,整株黄化等典型丛矮病症状。根据已报道的小麦丛矮病毒(Wheat ro-sette stunt virus,WRSV)各基因片段和北方禾谷花叶病毒(Northern cereal mosaic virus,NCMV)基因组序列设计引物,利用反转录PCR(RT-PCR)方法,在上述3个标样中均检测到了NCMV,而未检测到WRSV。用RT-PCR扩增到NCMV全基因组序列,长度为13221nt,具有9个开放读框。核酸序列比对结果显示,该序列与日本报道的NCMV有93%的同源性;推导氨基酸序列与日本报道的NCMV有99%同源性;但核酸和氨基酸序列与WRSV无明显同源性。上述结果表明,从河北省小麦丛矮病株中检测到的病原是NCMV,首次通过分子生物学研究检测到中国小麦上感染有NCMV。

Sampling was carried out in Handan,Xingtai and Baoding,Hebei Province,China,in April,2009.Wheat plants with excessive tillers and stunt were collected and used as inoculums in artificial inoculation with vector of Laodelphax Striatellus Fallén.Typical symptom of chlorotic striping occurred first,then excessive tillers,stunted rosettes and yellowing of wheat rosette stunt disease were appeared about 10 days after inoculation.Primers were designed based on Wheat rosette stunt virus（WRSV）and Northern cereal mosaic virus（NCMV）genome sequences.The RT-PCR results showed that NCMV genomic component was detected in the samples from all three sampling districts,while WRSV detection was negative.The whole NCMV genome of Hebei isolates was successfully amplificated,which contained 13 221nt with 9 open reading frames（ORF）.Nucleotide sequence analysis showed that the genome of NCMV from Hebei had 93% identity with Japanese isolate.The encoded protein sequence analysis indicated that the genome of NCMV from Hebei had 99% identity with Japanese isolate.But there was no homology with WRSV in both nucleotide and amino acid sequences.Therefore it was concluded that wheat rosette stunt disease in Hebei Province was caused by NCMV.This is the first report of NCMV in China based on molecular biology.