RESUMO
Fusarium graminearum is an important plant pathogen that causes head blight of major cereal crops. The fungus produces mycotoxins that are harmful to animal and human. In this study, a systematic analysis of 17 phenotypes of the mutants in 657 Fusarium graminearum genes encoding putative transcription factors (TFs) resulted in a database of over 11,000 phenotypes (phenome). This database provides comprehensive insights into how this cereal pathogen of global significance regulates traits important for growth, development, stress response, pathogenesis, and toxin production and how transcriptional regulations of these traits are interconnected. In-depth analysis of TFs involved in sexual development revealed that mutations causing defects in perithecia development frequently affect multiple other phenotypes, and the TFs associated with sexual development tend to be highly conserved in the fungal kingdom. Besides providing many new insights into understanding the function of F. graminearum TFs, this mutant library and phenome will be a valuable resource for characterizing the gene expression network in this fungus and serve as a reference for studying how different fungi have evolved to control various cellular processes at the transcriptional level.
Assuntos
Fusarium/genética , Genoma Fúngico , Doenças das Plantas/genética , Triticum/microbiologia , Fusarium/metabolismo , Fusarium/patogenicidade , Expressão Gênica , Regulação Fúngica da Expressão Gênica , Mutação , Fenótipo , Doenças das Plantas/microbiologia , Fenômenos Fisiológicos Vegetais , Sexo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
We identified two syntaxin-like SNARE genes, named GzSYN1 and GzSYN2, from the plant pathogenic ascomycete Gibberella zeae, and characterized the functions and cellular localization of these genes. The GzSYN1 deletion mutant (Deltagzsyn1) had 71% reduced hyphal growth compared to the wild-type strain, but produced perithecia with normal ascospores. Deltagzsyn2 had the same hyphal growth rate as the wild-type, but completely lost both self and female fertility. When Deltagzsyn2 was spermatized for Deltamat1-1 or Deltamat1-2 strains, it retained its male fertility, but the ascus shape was abnormal and ascospore delimitation was delayed. The Deltagzsyn1 and Deltagzsyn2 virulence on barley was reduced by 67% and 75%, respectively, compared to the wild-type. The GFP::GzSYN1 fusion protein was localized in vesicles, vacuoles, plasma membranes, and septa, whereas GFP::GzSYN2 was found only in plasma membranes and septa. These results suggest that syntaxins have key roles in fungal development and virulence in G. zeae.