Molecular phylogenetic and morphological analyses of Oidium heveae, a powdery mildew of rubber tree
Molecular phylogenetic and morphological analyses of Oidium heveae, a powdery mildew of rubber tree
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DOI：
10.1007/s10267-005-0238-8
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发表时间：
2005-08-01
期刊：
影响因子：
1.4
通讯作者：
Takamatsu, Susumu
中科院分区：
文献类型：
--
作者：
Limkaisang, Saranya;Kom-un, Sawanee;Takamatsu, Susumu
橡胶树白粉病是世界范围内橡胶园的重要病害。该真菌的鉴定和分类仍然是不确定的，因为没有权威的报告，其形态和没有记录的有性阶段。在这项研究中，我们比较了五个标本的橡胶白粉病真菌收集在马来西亚，泰国和巴西的形态和分子特征的基础上。形态学观察结果表明，该菌属于粉孢属（Oidium subgen）。假蕨属通过对橡胶白粉病核糖体DNA内转录间隔区（ITS）和大亚基rRNA基因（28S rDNA）的核苷酸序列分析，确定了橡胶白粉病的亲缘关系，并将该无性型真菌与其同源有性型真菌联系起来。结果表明，马来西亚分离株和泰国分离株的rDNA序列完全相同，而巴西分离株的rDNA序列有3个碱基不同：ITS2的1个碱基和28S的2个碱基。这两个巴西分离物的ITS序列是相同的序列的Erysiphe sp.的Quercus phillyraeoides在日本收集的，虽然28 S序列不同，从这种真菌的序列在一个碱基。利用距离法和简约法构建的系统发育树表明，橡胶白粉病与Q. phillyraeoides与100%的bootstrap支持。比较了两个白粉菌菌株的无性型。phillyraeoides与橡胶树白粉病的亲缘关系不存在明显差异，表明O.橡胶树可能是Q. Phillyraeoides需要交叉接种试验来证实这一结论。
Powdery mildew of rubber tree caused by Oidium heveae is an important disease of rubber plantations worldwide. Identification and classification of this fungus is still uncertain because there is no authoritative report of its morphology and no record of its teleomorphic stage. In this study, we compared five specimens of the rubber powdery mildew fungus collected in Malaysia, Thailand, and Brazil based on morphological and molecular characteristics. Morphological results showed that the fungus on rubber tree belongs to Oidium subgen. Pseudoidium. Nucleotide sequence analysis of the ribosomal DNA internal transcribed spacer (ITS) region and the large subunit rRNA gene (28S rDNA) were conducted to determine the relationships of the rubber powdery mildew fungus and to link this anamorphic fungus with its allied teleomorph. The results showed that the rDNA sequences of the two specimens from Malaysia were identical to a specimen from Thailand, whereas they differed by three bases from the two Brazilian isolates: one nucleotide position in the ITS2 and two positions in the 28S sequences. The ITS sequences of the two Brazilian isolates were identical to sequences of Erysiphe sp. on Quercus phillyraeoides collected in Japan, although the 28S sequences differed at one base from sequences of this fungus. Phylogenetic trees of both rDNA regions constructed by the distance and parsimony methods showed that the rubber powdery mildew fungus grouped with Erysiphe sp. on Q. phillyraeoides with 100% bootstrap support. Comparisons of the anamorph of two isolates of Erysiphe sp. from Q. phillyraeoides with the rubber mildew did not reveal any obvious differences between the two powdery mildew taxa, which suggests that O. heveae may be an anamorph of Erysiphe sp. on Q. phillyraeoides. Cross-inoculation tests are required to substantiate this conclusion.