摘要
从浙江各地、江苏南部和上海等地采集的西瓜枯萎病株和其他瓜类植株上,分离纯化尖孢镰孢霉(Fusarium oxysporum)菌种23个(每个菌种来自一个植株样本).接种试验表明:酉瓜植株上分离的19个菌种,有16个对长蜜、新红宝和圳宝等3个酉瓜品种表现为致病性,而其他菌种表现为非致病性.所有23个菌种均获得抗氯酸盐的硝酸盐营养突变株(nit mutant).根据来自同一菌种nit突变株的营养体亲和性与突变类型鉴定,选择3个西瓜致病菌的Nit M类型突变株(W 024～5,W 072～4和W 014～9)为营养体亲和性测试株.各菌种上获得的nit突变株分别与测试株作营养体亲和性配对反应,23个菌种可划分成8个营养体亲和群(VCG)和1个营养体自身非亲和类型.16个西瓜致病菌中,除一个为营养体自身非亲和类型外,其余均属同一亲和群(M1001),而与西瓜非致病菌不存在营养体亲和反应.由此显示:营养体亲和群与西瓜枯萎病菌存在相关性,而与地理分布无关.
Twenty-three isolates of Fusarium oxysporum were obtained from wilted plants of watermelon and other three melon crops in different areas of Zhejiang, Jiangsu and Shanghai (one isolate per plant). Based on virulence tests of the isolates on three watermelon cultivars: Xing Hongbao, Chang Mi and Zen Bao, sixteen isolates from watermelon proved to be highly virulent to the cultivars, whereas others, including three from watermelon plants, were not. The isolates virulent to the cultivars were assigned to be F. oxysporum f. sp. niveum. Nitrate nonutilizing (nit) mutants were recovered from all the isolates by transferring chlorate-resistant sectors on KPS medium to MM medium. Three Nit M mutants from the isolates of F. oxysporum f. sp. niveum were selected as vegetative compatibility testers by testing their vegetative compatibility. All the isolates were placed into eight vegetative compatibility groups(VCGs) amd one self-incompatibility by pairing one of the three testers with mutants from each of the other isolates, respectively. Except one isolate as self-incompatibility, the remaining isolates of F. oxysporum f. sp. niveum were in a unique VCG(M1001) , which were not compatible with nonvirulent isolates. The results indicated that the VCG corresponded to isolate traits in F. oxysporum f. sp. niveum,but no relation was observed between VCG and geographic origin.
基金
国家自然科学基金
关键词
致病性
西瓜
枯萎病菌
Fusarium ozysporum sp. niveum
nitrate nonutilizing mutant
vegetative compat- facforsibility group
virulence
