Genome-wide Identification and Molecular Characterization of Ole_e_I, Allerg_1 and Allerg_2 Domain-containing Pollen-Allergen-like Genes in Oryza sativa

Pollen allergens play important roles in plant development inaddition to their allergenic nature for human. More than 10groups of pollen allergens have been reported. Among them, Pollen_Ole_e_I(Ole), Pollen_allerg_1 (Allerg1) and Pollen_allerg_2 (Allerg2)domain-containing proteins are the majority of allergens. Wehave identified 114 pollen-allergen-like genes in rice genomeby bioinformatics using public databases. Among them, 45 genesencode Ole domain-containing proteins, 62 with Allerg1 and 7with Allerg2. They are distributed on 11 of 12 rice chromosomesexcluding chromosome 11. Comparison analysis of coding regionsfrom both predicted genes and isolated full-length cDNAs showedthat most of predicted genes were correct in the splicing ofexons and introns, and only 7 exhibited wrong predictions. Thefact suggested the applicability of the prediction programsto identify pollen-allergen genes. Phylogenetic analysis revealedthe high diversity within OsOle genes and recent evolutionaryevent in OsAllerg1 genes, and suggested that some of OsOle geneswere new members of the family. Expression analysis by RT–PCRshowed that most of the genes were expressed in all tested tissuesand only eight genes exhibited panicle-specific expression,suggesting that pollen-allergen genes play roles in not onlyproductive but also vegetative development.