Cochliobolus phylogenetics and the origin of known, highly virulent pathogens, inferred from ITS and glyceraldehyde-3-phosphate dehydrogenase gene sequences
Cochliobolus phylogenetics and the origin of known, highly virulent pathogens, inferred from ITS and glyceraldehyde-3-phosphate dehydrogenase gene sequences
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DOI：
10.2307/3761627
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发表时间：
1999-11-01
期刊：
影响因子：
2.8
通讯作者：
Hubbard, S
中科院分区：
文献类型：
--
作者：
Berbee, ML;Pirseyedi, M;Hubbard, S
我们评估了 Cochliobolus 属（子囊菌门、苦孢菌科的有性繁殖物种）中已知的高毒力植物病原体的系统发育分布，并评估了 Cochliobolus 物种与 Curvularia 和 Bipolaris 物种（子囊菌门、苦孢菌科真菌的无性状态）之间的关系。为了推断系统发育，我们使用了两个序列区域：(i) 65 个真菌分离株的完整 ITS 1、ITS 2 和 5.88 rDNA 序列，以及 (ii) 54 个分离株的管家基因 gpd 的 600 bp 片段，编码甘油醛-3-磷酸脱氢酶。我们结合了 41 个物种的 ITS、5.8S 和 gpd 序列数据。在 Cochliobolus 分支中，32 个物种中有 31 个明显属于两个类群之一。有一个物种，Cochliobolushomomorphus，并不明显属于这两个群体。 Cochliobolus I 组的 13 个物种组合在一起，并得到 ITS/gpd 组合数据的 100% bootstrap 支持。该组包括导致严重农作物损失的 Cochliobolus 和 Bipolaris 物种，例如 Co. sativus、Co. miyabeanus、Co.carbonum 和 Co.heterostropus。然而;在第一组中，已知的高毒力病原体并未形成单系物种组。第 1 组中物种对之间的平均替代水平较低，在 ITS 区域约为 1.7%，表明这些物种近期辐射迅速。 Cochliobolus Group 2 中的 18 个物种在 ITS 和 gpd 组合数据的 96% 的简约引导重复中形成单系群。被转移到分离属 Pseudocochliobolus 的 Cochliobolus 物种属于第二组。这项研究包括 9 种没有已知有性状态的弯孢属和双极属物种，它们似乎都是最近源自有性物种的 Cochliobolus。弯孢菌属和双极菌属都是多系的，但只有双极菌状态与第 1 组 Cochliobolus 物种相关。 Curvularia 和 Bipolaris 状态均与 Cochliobolus Group 2 中的物种相关。
We evaluate the phylogenetic distribution of known, highly virulent plant pathogens in the genus Cochliobolus (sexually reproducing species in the Ascomycota, Pleosporaceae) and assess the relationship between Cochliobolus species and species of Curvularia and Bipolaris (asexual states of fungi in the Ascomycota, Pleosporaceae). To infer a phylogeny, we have used two sequence regions: (i) the complete ITS 1, ITS 2, and 5.88 rDNA sequences for 65 fungal isolates and (ii) a 600 bp fragment of the housekeeping gene gpd, coding for glyceraldehyde-3-phosphate dehydrogenase, for 54 isolates. We combined ITS, 5.8S and gpd sequence data from 41 species. Ln the Cochliobolus clade, 31 out of 32 species fit clearly into one of two groups. One species, Cochliobolus homomorphus, did not fit clearly into either group. The 13 species in Cochliobolus Group I grouped together with 100% bootstrap support from the combined ITS/gpd data. This group included Cochliobolus and Bipolaris species that cause serious crop losses, such as Co. sativus, Co. miyabeanus, Co. carbonum and Co. heterostrophus. However; within Group 1, the known, highly virulent pathogens did not form a monophyletic group of species. Average substitution levels between pairs of species in the Group 1 were low, about 1.7% in the ITS region, suggesting that these species had radiated rapidly and recently. The 18 species in Cochliobolus Group 2 formed a monophyletic group in 96% of parsimony bootstrap replicates of the combined ITS and gpd data. The Cochliobolus species that were transferred into the segregate genus Pseudocochliobolus were in this second group. This study included 9 Curvularia and Bipolaris species without known sexual states and they all appear to be recently derived from among sexual species of Cochliobolus. Both Curvularia and Bipolaris were polyphyletic, but only Bipolaris states were associated with Group 1 Cochliobolus species. Both Curvularia and Bipolaris states were associated with species in Cochliobolus Group 2.