A Polyketide Synthase Gene, ACRTS2, Is Responsible for Biosynthesis of Host-Selective ACR-Toxin in the Rough Lemon Pathotype of Alternaria alternata

• DOI: 10.1094/mpmi-06-12-0155-r
• Publication Date: 2012-07-26T16:27:20Z
• Authors: Y. Izumi; K. Ohtani; Y. Miyamoto; A. Masunaka; T. Fukumoto; K. Gomi; Y. Tada; K. Ichimura; T. L. Peever; K. Akimitsu
• Keywords: Polyketide synthase; Rough lemon

The rough lemon pathotype of Alternaria alternata produces host-selective ACR-toxin and causes leaf spot disease (Citrus jambhiri). structure I (MW = 496) consists a polyketide with an α-dihydropyrone ring in 19-carbon polyalcohol. Genes responsible for toxin production were localized to 1.5-Mb chromosome the genome pathotype. Sequence analysis this revealed 8,338-bp open reading frame, ACRTS2, that was present only genomes ACR-toxin-producing isolates. ACRTS2 is predicted encode putative synthase 2,513 amino acids belongs fungal reducing type synthases. Typical functional domains identified acid sequence, including β-ketoacyl synthase, acyl transferase, methyl dehydratase, β-ketoreductase, phosphopantetheine attachment site domains. Combined use homologous recombination-mediated gene disruption RNA silencing allowed examination role multiple paralogs production. found be essential pathogenicity A. alternata.