title: Do TE activity and counteracting genome defenses, RNAi and methylation, shape the sex lives of smut fungi?
abstract: The availability of three genomes from smut fungi differing in mating, TE load, and genome defense mechanisms, allowed a comparative analyses and a discussion on evolutionary forces shaping them. A complex balance of selective forces seems at play. A bipolar mating system in Ustilago hordei promotes selfing, advantageous for successful niche occupation but favoring accumulation of repetitive DNA, including TEs. TE activity may have caused genome variations necessary for these obligate parasites under high host selection pressures. Higher TE activity is balanced by genome defenses through recombination, RNAi, methylation and RIP mutagenesis. In tetrapolar U. maydis, lacking silencing and possibly methylation mechanisms, reduced inbreeding potential favors removal of repetitive DNA, presumably by its highly-efficient recombination system.
authors: Agriculture &Agri-Food Canada; Pacific Agri-Food Research Centre; Summerland, BC Canada.
authors: John D
authors: JD
authors: Laurie
authors: Rob
authors: R
authors: Linning
authors: Philip
authors: P
authors: Wong
authors: Guus
authors: G
authors: Bakkeren
mesh_terms: D019175:DNA Methylation; D004251:DNA Transposable Elements; D004271:DNA, Fungal; D016681:Genome, Fungal; D009154:Mutation; D034622:RNA Interference; D012331:RNA, Fungal; D011995:Recombination, Genetic; D012098:Reproduction; D014588:Ustilago / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D004271:DNA, Fungal; D012331:RNA, Fungal
keywords: Sporisorium; Ustilago; gene silencing; genome research; plant pathogen