Cloning and Characterization of a Cyclic Peptide Synthetase Gene fromAlternaria alternataApple Pathotype Whose Product Is Involved in AM-Toxin Synthesis and Pathogenicity

R. D. Johnson, L. Johnson, Y. Itoh, M. Kodama, H. Otani, K. Kohmoto
2000 Molecular Plant-Microbe Interactions  
Alternaria alternata apple pathotype causes Alternaria blotch of susceptible apple cultivars through the production of a cyclic peptide host-specific toxin, AM-toxin. PCR (polymerase chain reaction), with primers designed to conserved domains of peptide synthetase genes, amplified several products from A. alternata apple pathotype that showed high similarity to other fungal peptide synthetases and were specific to the apple pathotype. Screening of a Lambda Zap genomic library with these
more » ... rated probes identified overlapping clones containing a complete cyclic peptide synthetase gene of 13.1 kb in length with no introns. Disruption of this gene, designated AM-toxin synthetase (AMT), by transformation of wild-type A. alternata apple pathotype with disruption vectors resulted in toxinminus mutants, which were also unable to cause disease symptoms on susceptible apple cultivars. AM-toxin synthetase is therefore a primary determinant of virulence and specificity in the A. alternata apple pathotype/apple interaction.
doi:10.1094/mpmi.2000.13.7.742 pmid:10875335 fatcat:euk6gdzn4vhjvn7zpr5viui6mi