title: Characterization of intronic structures and alternative splicing in Phytophthora sojae by comparative analysis of expressed sequence tags and genomic sequences.
abstract: The oomycetes, a distinct phylogenetic lineage of fungus-like microorganisms, are heterokonts (stramenopiles) belonging to the supergroup Chromalveolata. Although the complete genomic sequences of a number of oomycetes have been reported, little information regarding the introns therein is available. Here, we investigated the introns of Phytophthora sojae, a pathogen that causes soybean root and stem rot, by a comparative analysis of genomic sequences and expressed sequence tags. A total of 4013 introns were identified, of which 96.6% contained canonical splice sites. The P. sojae genome possessed features distinct from other organisms at 5' splice sites, polypyrimidine tracts, branch sites, and 3' splice sites. Diverse repeating sequences, ranging from 2 to 10 nucleotides in length, were found at more than half of the intron-exon boundaries. Furthermore, 122 genes underwent alternative splicing. These data indicate that P. sojae has unique splicing mechanisms, and recognition of those mechanisms may lead to more accurate predictions of the location of introns in P. sojae and even other oomycete species.
authors.affiliation: Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Danyu
authors.initials: D
authors.lastname: Shen
authors.forename: Wenwu
authors.initials: W
authors.lastname: Ye
authors.forename: Suomeng
authors.initials: S
authors.lastname: Dong
authors.forename: Yuanchao
authors.initials: Y
authors.lastname: Wang
authors.forename: Daolong
authors.initials: D
authors.lastname: Dou
mesh_terms: D017398:Alternative Splicing; D001483:Base Sequence; D055028:Comparative Genomic Hybridization; D016384:Consensus Sequence; D005091:Exons; D020224:Expressed Sequence Tags; D016678:Genome; D007438:Introns; D010838:Phytophthora / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA