意大利首次报道由立枯丝核菌AG-1-IA引起的迷迭香叶斑病。
First Report of Web Blight on Rosemary (Rosmarinus officinalis) Caused by Rhizoctonia solani AG-1-IA in Italy.
作者信息
Garibaldi A, Bertetti D, Pensa P, Poli A, Gullino M L
机构信息
Center of Competence AGROINNOVA, University of Torino, Via Leonardo da Vinci, 44, 10095 Grugliasco, Italy.
出版信息
Plant Dis. 2013 Jun;97(6):844. doi: 10.1094/PDIS-11-12-1012-PDN.
Rosmarinus officinalis L., family Labiatae, is an evergreen shrub used in gardens as an aromatic or ground cover plant. In the summer of 2012, a blight was observed in a farm located near Albenga (northern Italy) on 20% of 150,000 70-day-old plants, grown in trays. Water soaked lesions appeared on leaves and stems. As the disease progressed, blighted leaves turned brown, withered, clung to the shoots, and matted on the surrounding foliage. A light mycelium spread on the substrate. Disease progressed from infected plants to healthy ones and, eventually, infected plants died. Leaf and stem fragments taken from the margin of the diseased tissues belonging to 10 plants were disinfected for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA). A fungus with the morphological characters of Rhizoctonia solani was consistently and readily recovered. Three isolates of R. solani obtained from affected plants were successfully paired with R. solani tester strains AG 1, 2, 3, 4, 6, 7, or 11 and examined microscopically. Three pairings were made for each recovered isolate. The isolates of R. solani from rosemary anastomosed only with tester strain AG 1 (ATCC 58946). Results were consistent with other reports on anastomosis reactions (2). Tests were repeated once. Mycelium of 10-day-old isolates from rosemary appeared light brown, compact, and radiate. Numerous dark brown sclerotia, 0.7 to 2.0 mm diameter (average 1.3), developed within 10 days at 20 to 26°C. The descriptions of mycelium and sclerotia were typical for subgroup IA Type 2 (4). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 and sequenced (GenBank Accession No. KC005724). BLASTn analysis (1) of the 657-bp showed a 99% similarity with the sequence of R. solani GU596491. For pathogenicity tests, inoculum of R. solani was prepared by growing the pathogen on wheat kernels autoclaved in 1-liter glass flasks for 8 days. One of the isolates assigned to the anastomosis group AG 1 IA was tested. Fifteen 90-day-old rosemary plants were grown in 15-liter pots in a steam disinfested peat:pomice:pine bark:clay mix (50:20:20:10) infested with 3 g/liter of infested wheat kernels, placed at the base of the stem. Fifteen plants inoculated with non-infested wheat kernels served as control treatments. Plants were covered with plastic bags and arranged in a growth chamber at 20 to 24°C with 12 h light/dark for 15 days. The first symptoms, similar to those observed in the farm, developed 10 days after inoculation. About 10 colonies of R. solani were reisolated from infected leaves and stems of each inoculated plant. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. Symptoms caused by R. solani have been recently observed on R. officinalis in United States (3), India, and Brazil. This is, to our knowledge, the first report of blight of R. officinalis caused by R. solani in Italy. This disease could cause serious economic losses, because rosemary is one of the most cultivated aromatic plants in the Mediterranean region. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. Carling. Grouping in Rhizoctonia solani by hyphal anastomosis reactions. In: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease control. Kluwer Academic Publishers, The Netherlands, 1996. (3) G. E. Holcomb. Plant Dis. 76:859, 1992. (4) R. T. Sherwood. Phytopathology 59:1924, 1969.
迷迭香（Rosmarinus officinalis L.），唇形科植物，是一种常绿灌木，在花园中用作芳香植物或地被植物。2012年夏天，在意大利北部阿尔本加附近的一个农场里，人们观察到一种枯萎病，在15万株70日龄、种植在育苗盘中的植株中，有20%受到影响。叶片和茎上出现水渍状病斑。随着病情发展，枯萎的叶片变成褐色、枯萎，附着在嫩枝上，并覆盖在周围的叶子上。一层浅色菌丝体蔓延在基质上。病害从受感染的植株蔓延到健康植株，最终，受感染的植株死亡。从10株患病植株病变组织边缘采集的叶片和茎段，在1%次氯酸钠中消毒10秒，用无菌水冲洗后，接种在马铃薯葡萄糖琼脂（PDA）上。 consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily recovered. consistently and readily 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始终能轻易分离出具有立枯丝核菌形态特征的真菌。从患病植株中获得的3株立枯丝核菌分离株，成功地与立枯丝核菌测试菌株AG 1、2、3、4、6、7或11进行配对，并进行显微镜检查。对每个分离株进行3次配对。从迷迭香中分离出的立枯丝核菌分离株仅与测试菌株AG 1（ATCC 58946）形成融合。结果与其他关于融合反应的报道一致（2）。该测试重复进行了一次。从迷迭香中分离出的10日龄分离株的菌丝体呈浅褐色、致密且呈辐射状。在20至26°C下，10天内形成了许多深褐色菌核，直径为0.7至毫米（平均1.3毫米）。菌丝体和菌核的描述是IA亚组2型的典型特征（4）。使用引物ITS1/ITS4扩增rDNA的内部转录间隔区（ITS）区域并进行测序（GenBank登录号KC005724）。对657碱基对的BLASTn分析（1）显示，与立枯丝核菌GU596491的序列相似度为99%。为了进行致病性测试，通过将病原菌在1升玻璃烧瓶中高压灭菌的小麦粒上培养8天来制备立枯丝核菌接种物。对其中一个归为融合群AG 1 IA的分离株进行了测试。15株90日龄的迷迭香植株种植在15升花盆中，花盆中填充经过蒸汽消毒的泥炭：浮石：松树皮：粘土混合物（50:20:20:10），每升混合物中加入3克受侵染的小麦粒，放置在茎基部。15株接种未受侵染小麦粒的植株作为对照处理。植株用塑料袋覆盖，放置在温度为20至24°C、光照/黑暗周期为12小时的生长室中15天。接种10天后出现了与在农场中观察到的类似的最初症状。从每株接种植株的受感染叶片和茎中大约重新分离出10个立枯丝核菌菌落。对照植株保持健康。致病性测试进行了两次，结果相似。最近在美国（3）、印度和巴西，人们在迷迭香上观察到了由立枯丝核菌引起的症状。据我们所知，这是意大利首次关于立枯丝核菌引起迷迭香枯萎病的报道。这种病害可能会造成严重的经济损失，因为迷迭香是地中海地区种植最广泛的芳香植物之一。参考文献：（1）S. F. Altschul等人，《核酸研究》25:3389，1997年。（2）D. E. Carling，通过菌丝融合反应对立枯丝核菌进行分组。见：《立枯丝核菌物种：分类学、分子生物学、生态学、病理学和病害控制》Kluwer学术出版社，荷兰，1996年。（3）G. E. Holcomb，《植物病害》76:859，1992年。（4）R. T. Sherwood，《植物病理学》59:1924，19
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