Phylogenetic and morphological analyses of Pythium graminicola and related species
Phylogenetic and morphological analyses of Pythium graminicola and related species
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DOI：
10.1007/s10327-005-0184-5
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发表时间：
2005-06
影响因子：
1.2
通讯作者：
K. Kageyama;Ayako Nakashima;Yuki Kajihara;H. Suga;E. Nelson
中科院分区：
文献类型：
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作者：
K. Kageyama;Ayako Nakashima;Yuki Kajihara;H. Suga;E. Nelson
利用限制性片段长度多态性（RFLP）技术对禾生腐霉（Pythium graminicola）及其近缘种的rDNA内转录间隔区（ITS）和细胞色素c氧化酶亚基II（考克斯II）基因进行了分析。这些序列用于随后的系统发育分析。最后，物种的系统发育位置进行了比较，确定从形态特征。根据rDNA-ITS区的RFLP分析，将62个供试菌株分为A-G 7个类群。在考克斯II基因的RFLP分析中，分离株被分成与基于ITS-RFLP的那些相似的组。将A组和B组各分为另外两个亚组。RFLP分析结果与形态分化一致。A、B、D、E、F和G组被鉴定为P。graminicola、P. tagomanes、P. aphanidermatum、P. myriotylum、P. torulosum和P. vanterpoolii分别。根据rDNA-ITS区和考克斯II基因的系统发育分析，C群与B群亲缘关系较近，与P群相似。马尼斯其他物种都有自己的分支。虽然P。形态上与P. graminicola，系统发育分析表明，它在进化上与P. graminicola与P.万特普尔。我们的分析还表明，P.卵原细胞较小的torulosum与P.卵原细胞比toP. vanterpoolii，卵原细胞较小，形态与P.具有大的卵原细胞和不规则卵孢子的P. aphanidermatum与形态相似的P.千足虫结果表明，P. graminicola和相关的物种是植物遗传学上不同的，分子分析，除了形态分析，是必要的准确的分类位置的物种在这个复杂的。
Isolates ofPythium graminicolaand related species were differentiated using restriction fragment length polymorphism (RFLP) analyses of the internal transcribed spacer (ITS) regions of rDNA and the cytochrome c oxidase subunit II (COX II) gene. These sequences were used in subsequent phylogenetic analyses. Finally, the phylogenetic placement of species was compared to that determined from morphological characteristics. The 62 isolates tested were divided into seven groups, A–G, based on RFLP analysis of the rDNA-ITS region. In the RFLP analysis of the COX II gene, isolates were divided into groups similar to those based on ITS-RFLP. Groups A and B were each separated into two additional subgroups. Grouping of isolates based on RFLP analyses agreed with the morphological differentiation. Groups A, B, D, E, F, and G were identified asP. graminicola,P. arrhenomanes,P. aphanidermatum,P. myriotylum,P. torulosum, andP. vanterpoolii, respectively. Group C was closely related to group B based on phylogenetic analysis of the rDNA-ITS region and the COX II gene and is similar toP. arrhenomanes. Each of the other species occupied their own individual clades. AlthoughP. arrhenomanesis morphologically similar toP. graminicola, our phylogenetic analyses revealed that it was evolutionarily distant fromP. graminicolaand more closely related toP. vanterpoolii. Our analysis also revealed thatP. torulosumwith smaller oogonia is more closely related toP. myriotylumwith large oogonia than toP. vanterpoolii, which forms smaller oogonia and is morphologically similar toP. torulosum.P. aphanidermatumwith large oogonia and aplerotic oospores was not related to the morphologically similar speciesP. myriotylum. Results suggest thatP. graminicolaand related species are phylogenetically distinct, and molecular analyses, in addition to morphological analyses, are necessary for the accurate taxonomic placement of species in this complex.