title: Alt a 1 allergen homologs from Alternaria and related taxa: analysis of phylogenetic content and secondary structure.
abstract: 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.
authors.affiliation: Division of Plant Pathology and Microbiology, Department of Plant Sciences, College of Agriculture, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Soon Gyu
authors.initials: SG
authors.lastname: Hong
authors.forename: Robert A
authors.initials: RA
authors.lastname: Cramer
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Lawrence
authors.forename: Barry M
authors.initials: BM
authors.lastname: Pryor
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000235:genetics*; D000528:Alternaria / Q000145:classification* / Q000235:genetics*; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D001483:Base Sequence; D019143:Evolution, Molecular; D005091:Exons / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics*; D005800:Genes, Fungal; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017433:Protein Structure, Secondary / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: C096258:ALTA1 protein, Alternaria alternata; D000485:Allergens; D052179:Antigens, Plant; D005656:Fungal Proteins