Hong Soon Gyu, Cramer Robert A, Lawrence Christopher B, Pryor Barry M
Division of Plant Pathology and Microbiology, Department of Plant Sciences, College of Agriculture, University of Arizona, Tucson, AZ 85721, USA.
Fungal Genet Biol. 2005 Feb;42(2):119-29. doi: 10.1016/j.fgb.2004.10.009. Epub 2004 Nov 25.
A gene for the Alternaria major allergen, Alt a 1, was amplified from 52 species of Alternaria and related genera, and sequence information was used for phylogenetic study. Alt a 1 gene sequences evolved 3.8 times faster and contained 3.5 times more parsimony-informative sites than glyceraldehyde-3-phosphate dehydrogenase (gpd) sequences. Analyses of Alt a 1 gene and gpd exon sequences strongly supported grouping of Alternaria spp. and related taxa into several species-groups described in previous studies, especially the infectoria, alternata, porri, brassicicola, and radicina species-groups and the Embellisia group. The sonchi species-group was newly suggested in this study. Monophyly of the Nimbya group was moderately supported, and monophyly of the Ulocladium group was weakly supported. Relationships among species-groups and among closely related species of the same species-group were not fully resolved. However, higher resolution could be obtained using Alt a 1 sequences or a combined dataset than using gpd sequences alone. Despite high levels of variation in amino acid sequences, results of in silico prediction of protein secondary structure for Alt a 1 demonstrated a high degree of structural similarity for most of the species suggesting a conservation of function.
从52种链格孢属及相关属中扩增出了链格孢主要过敏原Alt a 1的基因，并将序列信息用于系统发育研究。与甘油醛-3-磷酸脱氢酶（gpd）序列相比，Alt a 1基因序列的进化速度快3.8倍，简约信息位点多3.5倍。对Alt a 1基因和gpd外显子序列的分析有力地支持了将链格孢属物种及相关分类单元归为先前研究中描述的几个物种组，特别是侵染组、链格孢组、葱组、芸苔生链格孢组、萝卜链格孢组以及粉棒束孢属组。本研究中新提出了苦苣菜组。对Nimbya组的单系性有一定程度的支持，对匐柄霉组的单系性支持较弱。物种组之间以及同一物种组内亲缘关系较近的物种之间的关系尚未完全解决。然而，使用Alt a 1序列或组合数据集比单独使用gpd序列能获得更高的分辨率。尽管氨基酸序列存在高度变异，但对Alt a 1蛋白质二级结构的计算机模拟预测结果表明，大多数物种具有高度的结构相似性，这表明功能具有保守性。
