RESUMO
Heterogenic incompatibility is considered a defense mechanism against deleterious intruders such as mycovirus. Rosellinia necatrix shows strong heterogenic incompatibility. In the heterogenic incompatibility reaction, the approaching hyphae hardly anastomosed, a distinctive barrage line formed, and green fluorescent protein (GFP)-labeled hyphae quickly lost their fluorescence when encountering incompatible hyphae. In this study, transmission of a hypovirulence-conferring mycovirus to strains with different genetic backgrounds was attempted. Various chemical reagents considered to affect the programmed cell death pathway or cell wall modification were examined. Treatment with zinc compounds was shown to aid in transmission of mycoviruses to strains with different genetic backgrounds. In incompatible pairings, treatment with zinc compounds accelerated hyphal anastomosis; moreover, cytosolic GFP was transmitted to the newly joined hyphae. These results suggest that zinc compounds not only increase hyphal anastomosis but also attenuate heterogenic incompatibility.
Assuntos
Técnicas de Transferência de Genes , Hifas/fisiologia , Vírus de RNA/fisiologia , Internalização do Vírus/efeitos dos fármacos , Xylariales/virologia , Compostos de Zinco/farmacologia , Primers do DNA/genética , Hifas/efeitos dos fármacos , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Vírus de RNA/isolamento & purificação , Xylariales/ultraestruturaRESUMO
When mycelia of Rosellinia necatrix encounter mycelia of a different genetic strain, distinct barrage lines are formed between the two. These barrages have variable features such as pigmented pseudosclerotia structures, a clear zone, fuzzy hair-like mycelia, or tuft-like mycelia, suggesting that mycelial incompatibility triggers a number of cellular reactions. In this study, to evaluate cellular reactions we performed genetic analysis of mycelial incompatibility of R. nectarix, using 20 single ascospore isolates from single perithecia. Mycelial interaction zones were removed by spatula and cellular reactions studied on oatmeal agar media. The interaction zones were categorized into types such as sharp or wide lines, with or without melanin, and combinations of these. Although various reaction types were observed, we were able to identify a single genetic factor that appears to be responsible for the barrage line formation within oatmeal agar medium. DNA polymorphism analysis identified parental isolates and revealed that R. necatrix has a heterothallic life cycle.