Characterization of Colletotrichum acutatum Causing Anthracnose of Anemone (Anemone coronaria L.)

Anthracnose, or leaf-curl disease of anemone, caused by Colletotrichum sp., has been reported to occur in Australia, western Europe, and Japan. Symptoms include tissue necrosis, corm rot, leaf crinkles, and characteristic spiral twisting of floral peduncles. Three epidemics of the disease have been recorded in Israel: in 1978, in 1990 to 1993, and in 1996 to 1998. We characterized 92 Colletotrichum isolates associated with anthracnose of anemone (Anemone coronaria L.) for vegetative compatibility (72 isolates) and for molecular genotype (92 isolates) and virulence (4 isolates). Eighty-six of the isolates represented the three epidemics in Israel, one isolate was from Australia, and five isolates originated from western Europe. We divided these isolates into three vegetative-compatibility groups (VCGs). One VCG (ANE-A) included all 10 isolates from the first and second epidemics, and 13 of 62 examined isolates from the third epidemic in Israel, along with the isolate from Australia and 4 of 5 isolates from Europe. Another VCG (ANE-F) included most of the examined isolates (49 of the 62) from the third epidemic, as well as Colletotrichum acutatum from strawberry, in Israel. Based on PCR amplification with species-specific primers, all of the anemone isolates were identified as C. acutatum. Anemone and strawberry isolates of the two VCGs were genotypically similar and indistinguishable when compared by arbitrarily primed PCR of genomic DNA. Only isolate NL-12 from The Netherlands, confirmed as C. acutatum but not compatible with either VCG, had a distinct genotype; this isolate represents a third VCG of C. acutatum. Isolates from anemone and strawberry could infect both plant species in artificial inoculations. VCG ANE-F was recovered from natural infections of both anemone and strawberry, but VCG ANE-A was recovered only from anemone. This study of C. acutatum from anemone illustrates the potential of VCG analysis to reveal distinct subspecific groups within a pathogen population which appears to be genotypically homogeneous by molecular assays.

由胶孢炭疽菌属（Colletotrichum sp.）引发的银莲花炭疽病（又称银莲花卷叶病），已在澳大利亚、西欧及日本被报道发生。其典型症状包括组织坏死、球茎腐烂、叶片皱缩，以及花葶特有的螺旋状扭曲。
以色列曾记录三次该病害的流行事件：分别为1978年、1990年至1993年，以及1996年至1998年。
本研究针对92株与银莲花（Anemone coronaria L.）炭疽病相关的胶孢炭疽菌分离株开展了系统表征：其中72株用于营养体亲和性分析，92株用于分子基因型鉴定，另有4株用于毒力测定。上述分离株的来源分布如下：86株采自以色列的三次流行事件，1株分离自澳大利亚，剩余5株源自西欧。
研究将这些分离株划分为3个营养体亲和群（vegetative-compatibility group, VCG）。其中群ANE-A包含首次及第二次流行事件的全部10株分离株，第三次流行事件中62株检测分离株里的13株，同时涵盖来自澳大利亚的分离株，以及西欧5株分离株中的4株。群ANE-F则包含第三次流行事件中绝大多数的检测分离株（62株中的49株），以及以色列境内从草莓上分离得到的尖孢炭疽菌（Colletotrichum acutatum）。
通过种特异性引物进行聚合酶链式反应（PCR）扩增鉴定，所有银莲花分离株均被鉴定为尖孢炭疽菌（C. acutatum）。对基因组DNA开展随机引物PCR分析的结果显示，两个营养体亲和群的银莲花分离株与草莓分离株在基因型上高度相似，无法通过该方法区分。仅有一株来自荷兰的分离株NL-12，经鉴定为尖孢炭疽菌，但无法与上述两个VCGs形成亲和性，其基因型具有独特性，代表了尖孢炭疽菌的第三个营养体亲和群。
人工接种试验表明，采自银莲花与草莓的分离株均可侵染这两种植物。营养体亲和群ANE-F可从银莲花与草莓的自然侵染样本中分离得到，而ANE-A仅能从银莲花样本中分离得到。本项针对银莲花来源尖孢炭疽菌的研究表明，尽管通过分子检测看似基因型均一，但营养体亲和性分析可揭示病原菌种群内存在不同的亚种类群。