Phylogenetic relationships of Pythium and Phytophthora species based on ITS rDNA, cytochrome oxidase II and β-tubulin gene sequences
Phylogenetic relationships of Pythium and Phytophthora species based on ITS rDNA, cytochrome oxidase II and β-tubulin gene sequences
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DOI：
10.3852/mycologia.98.3.410
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发表时间：
2006-05-01
期刊：
影响因子：
2.8
通讯作者：
Suga, Haruhisa
中科院分区：
文献类型：
--
作者：
Villa, Neilyn O.;Kageyama, Koji;Suga, Haruhisa
选择代表39种腐霉属（Pythium）的58个菌株和代表9种疫霉属（Phytophthora）的17个菌株，通过3个基因组区域的序列分析，研究了属内和属间的亲缘关系。用通用引物ITS 1和ITS 4 PCR扩增核糖体DNA的内部转录间隔区（ITS 1和ITS 2），包括5.8S基因。另一方面，用用于腐霉属的引物对FM 66和FM 58以及用于疫霉属的引物对FM 75和FM 78扩增了563 bp的细胞色素氧化酶11（考克斯11）基因。用正向引物BT5和反向引物BT 6扩增658 bp的部分β-微管蛋白基因。三个DNA区域的最大简约性分析显示了四个主要分支，反映了孢子囊形态。进化枝1由携带丝状至分叶状孢子囊的腐霉分离物组成。进化枝2代表具有球形至球形游动孢子囊或球形菌丝囊的腐霉分离物。同时，疫霉属分离物被归为进化枝3，其中乳头状、半乳头状和非乳头状物种占据单独的亚进化枝。最后，进化枝4由具有类似于疫霉属中观察到的乳头状孢子囊的近球形孢子囊的腐霉属物种组成。因此，一些物种（波生腐霉、螺旋腐霉、介形腐霉、卷唇腐霉和刺腐霉）被认为是腐霉-疫霉进化系中难以捉摸的中间物种。
Fifty-eight isolates representing 39 Pythium species and 17 isolates representing nine Phytophthora species were chosen to investigate intra- and intergeneric relationships with sequence analysis of three genomic areas. The internal transcribed spacer regions (ITS1 and ITS2), including the 5.8S gene of the ribosomal DNA were PCR amplified with the universal primers ITS1 and ITS4. On the other hand 563 bp of the cytochrome oxidase 11 (cox 11) gene was amplified with the primer pair FM66 and FM58 for Pythium and FM75 and FM78 for Phytophthora. The 658 bp partial beta-tubulin gene was amplified with the forward primer BT5 and reverse primer BT6. Maximum parsimony analysis of the three DNA regions revealed four major clades, reflective of sporangial morphology. Clade 1 was composed of Pythium isolates that bear filamentous to lobulate sporangia. Clade 2 represents Pythium isolates that bear globose to spherical zoosporangia or spherical hyphal swellings. Meanwhile Phytophthora isolates were lumped into Clade 3 wherein the papillate, semipapillate and nonpapillate species occupied separate subclades. Lastly, Clade 4 was composed of Pythium species that bear subglobose sporangia resembling the papillate sporangia observed in Phytophthora. Hence a number of species (Ph. undulata, P. helicoides, P. ostracodes, P. oedochilum and P. vexans) have been proposed to be the elusive intermediate species in the Pythiunb-toPhytophthora evolutionary line.