RESUMO
The ectomycorrhizal (ECM) fungus Amanita caesarea CECT 20127 was tested in vitro with two potentially mycorrhizal-promoting bacterial strains, Pseudomonas fluorescens CECT 844 and Bacillus cereus CECT 148. Although P. fluorescens showed spatial and temporal compatibility with A. caesarea, it did not affect growth of the fungus. Conversely, B. cereus exhibited no such compatibility and also inhibited fungal growth. The expression pattern of the A. caesarea gene AcMST-1 was analysed using real-time quantitative polymerase chain reaction (qPCR) at three time points. This gene displays a high degree of homology with two genes, possible orthologues to AcMST-1, previously described in Amanita muscaria (AmMST-1) and Laccaria bicolor (LbMST-1) and encoding monosaccharide transporter proteins. The transcription levels of AcMST1 increased shortly after initial contact between A. caesarea and B. cereus, but expression of the gene was inhibited in the presence of P. fluorescens. Our results show that A. caesarea may possess orthologous genes of similar ECM fungal species that would allow it to adapt in nature to optimize sugar uptake from the environment depending on the presence of different microorganisms.
Assuntos
Amanita/crescimento & desenvolvimento , Bacillus cereus/fisiologia , Micorrizas/fisiologia , Pseudomonas fluorescens/fisiologia , Amanita/genética , Bioensaio , Meios de Cultura , Liofilização , Proteínas Fúngicas/genética , Proteínas de Transporte de Monossacarídeos/genética , Micélio/crescimento & desenvolvimento , RNA Fúngico/química , RNA Fúngico/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real , EspanhaRESUMO
Genes encoding plant antibiotic peptides show expression patterns that are consistent with a defence role. Transgenic over-expression of defence peptide genes is potentially useful to engineer resistance of plants to relevant pathogens. Pathogen mutants that are sensitive to plant peptides in vitro have been obtained and a decrease of their virulence in planta has been observed, which is consistent with their hypothetical defence role. A similar approach has been followed to elucidate the potential direct anti-microbial role of hydrogen peroxide. Additionally, a scavenger of peroxynitrite has been used to investigate its involvement in plant defence.
