Zhang W, Nan Z B, Liu G D
State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, P.O. Box 61, Lanzhou 730020, China.
Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Key Laboratory of Tropical Crops Germplasm Research Utilization, Ministry of Agriculture, Danzhou 571737, China.
Plant Dis. 2012 Sep;96(9):1374. doi: 10.1094/PDIS-01-12-0053-PDN.
Seashore paspalum (Paspalum vaginatum Swartz.) is a prostrate-growing, perennial, warm-season turfgrass native to tropical and coastal areas (2). Because of its good texture and natural tolerance to various environmental stresses, seashore paspalum has been introduced to golf courses in coastal regions of southern China. In April 2010, circular or irregular pink patches ranging from 5 to 50 cm in diameter were observed in the golf course fairway and rough established with cv. Salam on two golf courses in Haikou, Hainan Province, China. When morning dew was present or rainfall occurred, a pink layer of gelatinous fungal growth could be observed on leaves and sheaths. The green leaves of infected plants initially became water soaked, then tan to bleached, shriveled, and infested with pink or reddish, gelatinous, stranded hyphae. The hyphae matted together, then formed threadlike or antlerlike stromata from the tips of blighted leaves. Two isolates from each golf course were collected by plating diseased leaf blades, stromata, or hyphal aggregates from the blighted leaves directly onto antibiotic (0.01% gentamicin sulfate) amended potato dextrose agar. To confirm pathogenicity, isolates were inoculated on 6-week-old P. vaginatum (cv. Seaspray) planted (0.5 mg seed/cm) in 10-cm pots. Inoculum was prepared by culturing isolates separately on an autoclaved mixture of 100 g of rye grain and 20 ml of water for 3 weeks at 25°C. Pots were inoculated by placing 2 g of infected grain within the center of the turf canopy or 2 g of sterilized, uninfested grains to serve as controls, with four replications of each treatment. After inoculation, each pot was placed in a translucent plastic bag and placed into a greenhouse at 24 ± 2°C with a 12-h photoperiod (1). Two days after inoculation, the fungus was observed on the leaves. Approximately 40% of leaves in inoculated pots were necrotic after 7 days, and this increased to 80% after 21 days. Diseased plants in inoculated pots displayed symptoms similar to those observed in the field and no symptoms were detected on the control plants. The two isolates were successfully reisolated from all symptomatic tissues, completing Koch's postulates. Sequences of mitochondrial small subunit ribosomal RNA (mt-SSU) were amplified from the two isolates by primers MS1 and MS2, and the sequences showed 99% similarity with Laetisaria fuciformis from the NCBI database (Accession No. AY293232). Red thread on turfgrass has been commonly observed in temperate climates during periods of cool and humid weather (3). To our knowledge, this is the first report of L. fuciformis causing red thread on P. vaginatum or from any host plant in China. References: (1) L. L. Burpee and L. G. Goulty. Phytopathology. 74:692, 1984. (2) R. R. Duncan and R. N. Carrow. Seashore Paspalum: The Environmental Turfgrass. John Wiley and Sons, Toronto, ON, Canada, 2000. (3) R. W. Smiley et al. Page 38 in: Compendium of Turfgrass Diseases. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2005.
海滨雀稗（Paspalum vaginatum Swartz.）是一种匍匐生长的多年生暖季型草坪草，原产于热带和沿海地区（2）。由于其良好的质地以及对各种环境胁迫的天然耐受性，海滨雀稗已被引入中国南方沿海地区的高尔夫球场。2010年4月，在中国海南省海口市的两个高尔夫球场中，观察到在使用品种为萨拉姆（cv. Salam）建植的高尔夫球场球道和长草区出现了直径为5至50厘米的圆形或不规则粉红色斑块。当有晨露或降雨时，在叶片和叶鞘上可以观察到一层粉红色的凝胶状真菌生长物。受感染植株的绿色叶片最初出现水渍状，随后变为棕褐色至漂白状，枯萎，并布满粉红色或微红色的、凝胶状的、缠绕的菌丝。菌丝交织在一起，然后从枯萎叶片的尖端形成丝状或鹿角状的子座。从每个高尔夫球场采集了两个分离物，方法是将患病叶片、子座或枯萎叶片上的菌丝聚集体直接接种到添加了抗生素（0.01%硫酸庆大霉素）的马铃薯葡萄糖琼脂平板上。为了确认致病性，将分离物接种到种植在10厘米花盆中（播种量为0.5毫克种子/平方厘米）的6周龄海滨雀稗（品种为海浪花（cv. Seaspray））上。接种物通过将分离物分别在100克黑麦谷物和20毫升水的灭菌混合物上于25°C培养3周来制备。通过在草皮冠层中心放置2克受感染的谷物或2克灭菌的未受感染谷物作为对照进行接种，每个处理重复四次。接种后，每个花盆放入一个半透明塑料袋中，并置于温度为24±2°C、光周期为12小时的温室中（1）。接种两天后，在叶片上观察到真菌。接种花盆中约40%的叶片在7天后坏死，21天后这一比例增加到80%。接种花盆中的患病植株表现出与田间观察到的症状相似的症状，对照植株未检测到症状。从所有有症状的组织中成功重新分离出这两个分离物，完成了柯赫氏法则验证。通过引物MS1和MS2从这两个分离物中扩增出线粒体小亚基核糖体RNA（mt - SSU）序列，这些序列与来自NCBI数据库（登录号AY293232）的丝状炭疽菌（Laetisaria fuciformis）显示出99%的相似性。草坪草上的红线病在温带气候凉爽潮湿时期普遍可见（3）。据我们所知，这是关于丝状炭疽菌在中国导致海滨雀稗或任何寄主植物出现红线病的首次报道。参考文献：（l）L. L. Burpee和L. G. Goulty。《植物病理学》。74:692，1984。（2）R. R. Duncan和R. N. Carrow。《海滨雀稗：环境草坪草》。John Wiley and Sons，加拿大多伦多，安大略省，2000。（3）R. W. Smiley等人。载于：《草坪草病害简编》第三版。美国植物病理学会，明尼苏达州圣保罗，2005，第38页。
