A cyclic peptide synthetase gene required for pathogenicity of the fungus Cochliobolus carbonum on maize.
AUTOR(ES)
Panaccione, D G
RESUMO
Specificity in many plant-pathogen interactions is determined by single genes in pathogen and host. The single locus for host-selective pathogenicity (TOX2) in the fungus Cochliobolus carbonum governs production of a cyclic tetrapeptide named HC-toxin. We have isolated a chromosomal region, 22 kilobases (kb) long, that contains a 15.7-kb open reading frame (HTS1) encoding a multifunctional cyclic peptide synthetase. The 22-kb chromosomal region is duplicated in toxin-producing isolates of the fungus but is completely absent from the genomes of toxin-nonproducing isolates. Mutants of the fungus with disruptions in both copies of HTS1, at either of two different sites within HTS1, were engineered by DNA-mediated transformation. Disruption of both copies at either site resulted in loss of ability to produce HC-toxin and loss of host-selective pathogenicity, but the mutants displayed different biochemical phenotypes depending on the site of disruption. The results demonstrate that TOX2 encodes, at least in part, a large, multifunctional biosynthetic enzyme and that the evolution of host range in C. carbonum involved the insertion or deletion of a large piece of chromosomal DNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=49547Documentos Relacionados
- Endopolygalacturonase is not required for pathogenicity of Cochliobolus carbonum on maize.
- The Cochliobolus carbonum SNF1 Gene Is Required for Cell Wall–Degrading Enzyme Expression and Virulence on Maize
- Histone Hyperacetylation in Maize in Response to Treatment with HC-Toxin or Infection by the Filamentous Fungus Cochliobolus carbonum.
- Cloning and targeted gene disruption of EXG1, encoding exo-beta 1, 3-glucanase, in the phytopathogenic fungus Cochliobolus carbonum.
- Inhibition of maize histone deacetylases by HC toxin, the host-selective toxin of Cochliobolus carbonum.