Thomidis T, Exadaktylou E
Alexander Technological Education Institute of Thessaloniki, Department of Crop Production, 57400, Sindos Macedonia, Greece.
Plant Dis. 2011 Jul;95(7):872. doi: 10.1094/PDIS-04-11-0294.
Pomegranate (Punica granatum L.) is an important crop in Greece. In 2010, fruits of the pomegranate cv. Wonderful, in commercial fields located in the Prefecture of Komotini in eastern Greece, were observed to have symptoms of distinct dark brown spots. The waxy acervuli observed in infected tissue were subepidermal, typically with setae and simple, short, erect conidiophores. Conidia were hyaline, one celled, ovoid to oblong, slightly curved or dumbbell shaped, and 10 to 15 μm long and 5 to 7 μm wide. The pathogen was isolated on acidified potato dextrose agar (PDA) (2.5 ml of 85% lactic acid per liter of nutrient medium) and incubated at 23°C for 7 days. The pathogen was identified as Colletotrichum gloeosporiodes (Penz) Sacc. on the basis of morphological characteristics and internal transcribed spacer (ITS) sequence (100% identity to AJ301912, C. gloeosporioides species complex) (3) by CBS Fungal Biodiversity Centre, Identification Service, Utrecht, the Netherlands, (CG-1 isolate deposited in CBS Collection; Accession No. CBS 129372). Koch's postulates were completed in the laboratory by placing a 40-μl drop of suspension (4 × 10 conidia ml of water) on a wounded area of healthy fruits of cv. Wonderful. Fruits were surface sterilized by dipping in 0.1% chlorine solution and allowed to dry in a laminar flow hood. There were 15 inoculated and 15 control fruits (similarly sprayed with sterile distilled water) in a randomized design. Fruits were covered with perforated polythene bags to maintain a high humidity necessary for infection that were removed 48 h after inoculation and the fruits were maintained at room temperature (23 ± 2°C). Lesion development was recorded daily for each fruit. Koch's postulates were satisfied after reisolating the fungus from inoculated fruit that developed symptoms similar to those observed on fruits collected from fields. To our knowledge, this is the first report of the occurrence of C. gloeosporioides as a causal agent of fruit spot of pomegranates in Greece. Fruit spots caused by C. gloeosporioides have been reported in pomegranate fields of other countries around the world (1,2). References: (1) B. K. M. Lakshmi et al. Trop. Agric. Res. 22:183, 2011. (2) D. S. Patel. Indian Phytopathol. 62:252, 2009. (3) B. S. Weir and P. R. Johnston. Mycotaxon 111:209, 2010.
石榴（Punica granatum L.）是希腊的一种重要作物。2010年，在希腊东部科莫蒂尼州的商业果园中，观察到石榴品种“奇妙”的果实出现明显的深褐色斑点症状。在受感染组织中观察到的蜡质分生孢子盘位于表皮下，通常有刚毛和简单、短小、直立的分生孢子梗。分生孢子无色透明，单细胞，卵形至长方形，稍弯曲或呈哑铃形，长10至15μm，宽5至7μm。病原菌在酸化马铃薯葡萄糖琼脂（PDA）（每升营养培养基中加入2.5 ml 85%乳酸）上分离，并在23°C下培养7天。根据形态特征和内转录间隔区（ITS）序列（与AJ301912的同源性为100%，属于炭疽菌复合种），该病原菌被鉴定为胶孢炭疽菌（Colletotrichum gloeosporiodes (Penz) Sacc.）（3），由荷兰乌得勒支的CBS真菌生物多样性中心鉴定服务部鉴定（CG - 1分离株保藏于CBS菌种保藏中心；保藏编号CBS 129372）。通过在“奇妙”品种健康果实的伤口处滴加40μl悬浮液（4×10⁶个分生孢子/ml水），在实验室中完成了柯赫氏法则验证。果实通过浸入0.1%氯溶液进行表面消毒，然后在层流罩中晾干。采用随机设计，有15个接种果实和15个对照果实（同样喷洒无菌蒸馏水）。果实用打孔的聚乙烯袋覆盖，以保持感染所需的高湿度，接种48小时后去除袋子，果实保持在室温（23±2°C）。每天记录每个果实的病斑发展情况。从出现与田间采集果实上观察到的症状相似症状的接种果实中重新分离出真菌后，柯赫氏法则得到满足。据我们所知，这是希腊首次报道胶孢炭疽菌作为石榴果实斑点病原菌的发生情况。世界其他国家的石榴园中也曾报道过由胶孢炭疽菌引起的果实斑点（1,2）。参考文献：（1）B. K. M. Lakshmi等人，《热带农业研究》22:183，2011年。（2）D. S. Patel，《印度植物病理学》62:252，2009年。（3）B. S. Weir和P. R. Johnston，《真菌分类学》111:209，2010年。
