旱稻孢囊线虫在广西的发生及其rDNA-ITS异质性分析

摘要

2011年，从广西龙胜梯田的水稻根系和稻田土壤中分离到一种孢囊线虫.该线虫形态特征与已报道的旱稻孢囊线虫(Heterodera elachista)相符，其 rDNA-ITS序列与 GenBank中旱稻孢囊线虫的 rDNA-ITS序列相似性为97．7％~99．3％. rDNA-ITS分子发育树表明该线虫与旱稻孢囊线虫以100％的置信度及较小的遗传距离形成一个单系，据此将该线虫鉴定为旱稻孢囊线虫.进一步对本研究获得的10条旱稻孢囊线虫 rDNA-ITS区序列及 Tanha Maafi 等报道的1条旱稻孢囊线虫 rDNA-ITS序列(AF498391)的酶切位点进行分析，结果发现AluⅠ、AvaⅠ、MvaⅠ和RsaⅠ4个内切酶的酶切位点在11条序列中完全一致，而Bsh1236Ⅰ、BsuRⅠ和CfoⅠ3种酶的酶切位点存在变异，其中Bsh1236Ⅰ和BsuRⅠ有2种变异型， CfoⅠ则有3种变异型，表明旱稻孢囊线虫的 rDNA-ITS序列存在DNA异质性.%In 2011,a cyst nematode was isolated from rice roots and soils in Longsheng Terrace of Guangxi Region, China.Morphological characteristics of the cyst nematode were consistent with previous descriptions of Heterodera ela-chista.The rDNA-ITS sequences of the cyst nematode and H.elachista in GenBank shared 97.7%-99.3% identities. The phylogenetic tree based on rDNA-ITS showed that the cyst nematode was in the same monophyletic clade as H . elachista with 100% support and short branch differences.The results indicated the cyst nematode was Heterodera elachista.The restriction enzyme cutting sites of ten rDNA-ITS sequences of H .elachista amplified and the one reported by Tanha Maafi (GenBank accession number:AF498391)were analyzed.The restriction enzyme cutting sites of AluⅠ,AvaⅠ,MvaⅠ and RsaⅠ in these 1 1 sequences were identical,however there were 2 different patterns after Bsh1236Ⅰ and BsuRⅠ digestion,respectively,and 3 different patterns after CfoⅠ digestion.The results show intra-species heterogeneity in rDNA-ITS region exists in H .elachista.