Hemnani K, O'Malley P J, Tanović B, Batzer J C, Gleason M L
Iowa State University, Ames.
Pesticide and Environment Research Institute, Zemun-Belgrade, Serbia.
Plant Dis. 2008 Sep;92(9):1366. doi: 10.1094/PDIS-92-9-1366C.
Fungi in the sooty blotch and flyspeck (SBFS) complex cause major economic losses on cultivated pome fruits in humid regions worldwide and also colonize many species of reservoir host plants. In 2007, 10 mature fruit of pawpaw (Asimina triloba), a native tree in eastern North America exhibiting SBFS colonies on the epicuticular wax layer, were collected from wild trees in eastern Iowa. Colonies of SBFS fungi on the fruit were described according to mycelial type (1). Isolates of representative colonies on acidified water agar were subcultured on potato dextrose agar and the morphological characters were observed. After DNA was extracted from cultures and amplified by PCR using primer set ITS-1F/ITS4, 470-bp sequences were compared with those of previously identified SBFS species using NCBI BLAST. The BLAST analysis showed 100% homology of the sequences with six species that had been previously confirmed to cause SBFS on apple fruit by fulfilling Koch's postulates (1): Colletogloeum sp. FG2, Dissoconium aciculare, Peltaster sp. P2.1, P. fructicola, Stomiopeltis versicola, and Stomiopeltis sp. RS1 (GenBank Accession Nos. AY598907, AY598874, AY5988888, AY598887, AY5160165, and AY598882, respectively). Using the NCBI bl2seq application, Dothideomycete sp. CS2, an additional previously confirmed SBFS species, was revealed by sequence homology. Morphology of some SBFS species on pawpaw differed from that on apple. For example, Colletogloeum sp. FG2, which produces the fuliginous mycelial type (1) on apple fruit, developed the ridged honeycomb mycelial type on pawpaw fruit. D. aciculare and Stomiopeltis sp. RS1 produced the compact speck mycelial type on pawpaw, but are known to develop discrete speck and ramose mycelial types, respectively, on apple. These differences may result from host species differences in the epicuticular wax layer of the fruit. To our knowledge, this is the first report of SBFS fungi on A. triloba in North America, although the SBFS species Zygophiala jamaicensis was reported on the same host in Japan (2). Identifying SBFS fungi on reservoir host plants is an important step toward improving disease management strategies. References: (1) J. Batzer et al. Mycologia 97:1268, 2005. (2) H. Nasu and H. Kunoh Plant Dis. 71:361, 1987.
煤污病和蝇粪病（SBFS）复合病害中的真菌，在全球潮湿地区给栽培梨果造成了重大经济损失，并且还侵染许多种类的贮藏寄主植物。2007年，从爱荷华州东部的野生树木上采集了10个北美东部原生树种番荔枝（Asimina triloba）的成熟果实，其表皮蜡质层上有SBFS菌落。根据菌丝类型对果实上的SBFS真菌菌落进行了描述（1）。将在酸化水琼脂上的代表性菌落分离物转接至马铃薯葡萄糖琼脂上，并观察其形态特征。从培养物中提取DNA，使用引物对ITS - 1F/ITS4进行PCR扩增后，将470 bp的序列与先前鉴定的SBFS物种的序列进行比较，使用NCBI BLAST工具进行分析。BLAST分析表明，这些序列与先前通过柯赫氏法则已证实可在苹果果实上引起SBFS的6个物种具有100%的同源性（1）：炭疽菌属（Colletogloeum sp.）FG2、针状散突壳菌（Dissoconium aciculare）、盾星盾炱属（Peltaster sp.）P2.1、果生盾星盾炱（P. fructicola）、变色小孔盾炱（Stomiopeltis versicola）和小孔盾炱属（Stomiopeltis sp.）RS1（GenBank登录号分别为AY598907、AY598874、AY5988888、AY598887、AY5160165和AY598882）。使用NCBI的bl2seq应用程序，通过序列同源性揭示了另一个先前已证实的SBFS物种——座囊菌纲（Dothideomycete）sp. CS2。番荔枝上一些SBFS物种的形态与苹果上的不同。例如，炭疽菌属（Colletogloeum sp.）FG2在苹果果实上产生烟霉状菌丝类型（1），而在番荔枝果实上则发育出脊状蜂窝状菌丝类型。针状散突壳菌（D. aciculare）和小孔盾炱属（Stomiopeltis sp.）RS1在番荔枝上产生紧密斑点状菌丝类型，但已知它们在苹果上分别发育出离散斑点状和分枝状菌丝类型。这些差异可能是由于果实表皮蜡质层中寄主物种的差异所致。据我们所知，这是北美关于番荔枝上SBFS真菌的首次报道，尽管在日本已报道了同一寄主上的SBFS物种牙买加合隔腔孢（Zygophiala jamaicensis）（2）。鉴定贮藏寄主植物上的SBFS真菌是改进病害管理策略的重要一步。参考文献：（1）J. Batzer等人，《真菌学》97:1268，2005年；（2）H. Nasu和H. Kunoh，《植物病害》71:361，1987年。
