不同抗性小麦根与菲利普孢囊线虫(Heterodera filipjevi)互作的表型特征

摘要

Heterodera filipjevi is a newly identified pathogenic species of cereal cyst nematode that invades wheat (Triticum aes-tivum L.) in central China. A two-year field test (2009-2011) conducted in Xuchang County, Henan Province, China, where H. Filipjevi has severely damaged wheat for several years, demonstrated that the wheat-rye (Secale cereale L.) chromosome substitution line 6R(6D) (carrying gene CreR for resistance to Heterodera spp.) was highly resistant (HR) to the nematode. The wheat cultivar Taikong 6 was moderately resistant (MR) and its parental cultivar Yumai 49 was highly susceptible (HS). Attraction of H. Filipjevi juveniles to root tips of wheat differed in resistance to H. Filipjevi was studied using Pluronic F-127 gel as a medium. Although root tips from wheat cultivars with different resistance were able to attract juveniles of nematode alone, the number of juveniles around the root tip from line 6R(6D) was obviously less than that from Taikong 6 (MR) and Yumai 49 (HS) when they were challenged together concurrently by H. Filipjevi. The juveniles were capable to penetrate into wheat roots regardless of their resistance as revealed by acid fuschin-sodium hypochlorite staining of infected roots. However, significantly smaller number of nematodes in the roots of 6R(6D) and Taikong 6 were observed compared to those of Yumai 49 at later stage of wheat-H. Filipjevi interaction. These findings demonstrate that some of the H. Filipjevi juveniles are not able to continue to reproduce themselves although they can penetrate the roots of resistant wheat cultivars 6R(6D) and Taikong 6. The results from this study provide experimental evidence on mechanism of host resistance to H. Filipjevi.%菲利普孢囊线虫(Heterodera filipjevi)是最近在我国新发现的小麦病原线虫,在黄淮冬麦区对小麦生产构成威胁.2009-2011年2个生长季在河南省许昌市进行的田间病圃抗性鉴定中,小麦-黑麦6R(6D)染色体代换系(带有抗病基因CreR)对H.filipjevi Hfc-1致病型表现高抗反应型(HR),小麦品种太空6号表现中抗反应型(MR),其亲本品种豫麦49表现高感反应型(HS).利用Pluronic F-127胶体为介质,研究了不同抗性小麦品种根尖对线虫的吸引性.结果显示,无论品种的抗性水平如何,其根尖单独存在时均能够吸引线虫的二龄幼虫;当3个品种(系)的根尖同时存在时,6R(6D)根尖吸引的二龄幼虫数量显著少于太空6号和豫麦49.采用酸性品红-次氯酸钠染色法观察线虫对根系的侵染,发现不论抗性水平高低,二龄幼虫都能侵入寄主根的组织,但至侵染后期,6R(6D)和太空6号根中的线虫数量显著少于豫麦49.这些结果表明,虽然线虫能够侵入抗病品种的根组织,但是大部分二龄幼虫却不能继续发育而形成孢囊.这为了解小麦对H.filipjevi的抗性机制提供了实验证据.