title: A polyketide synthase gene, ACRTS2, is responsible for biosynthesis of host-selective ACR-toxin in the rough lemon pathotype of Alternaria alternata.
abstract: The rough lemon pathotype of Alternaria alternata produces host-selective ACR-toxin and causes Alternaria leaf spot disease of rough lemon (Citrus jambhiri). The structure of ACR-toxin I (MW = 496) consists of a polyketide with an α-dihydropyrone ring in a 19-carbon polyalcohol. Genes responsible for toxin production were localized to a 1.5-Mb chromosome in the genome of the rough lemon pathotype. Sequence analysis of this chromosome revealed an 8,338-bp open reading frame, ACRTS2, that was present only in the genomes of ACR-toxin-producing isolates. ACRTS2 is predicted to encode a putative polyketide synthase of 2,513 amino acids and belongs to the fungal reducing type I polyketide synthases. Typical polyketide functional domains were identified in the predicted amino acid sequence, including β-ketoacyl synthase, acyl transferase, methyl transferase, dehydratase, β-ketoreductase, and phosphopantetheine attachment site domains. Combined use of homologous recombination-mediated gene disruption and RNA silencing allowed examination of the functional role of multiple paralogs in ACR-toxin production. ACRTS2 was found to be essential for ACR-toxin production and pathogenicity of the rough lemon pathotype of A. alternata.
authors: Kagawa University, Kagawa, Japan.
authors: Y
authors: Y
authors: Izumi
authors: K
authors: K
authors: Ohtani
authors: Y
authors: Y
authors: Miyamoto
authors: A
authors: A
authors: Masunaka
authors: T
authors: T
authors: Fukumoto
authors: K
authors: K
authors: Gomi
authors: Y
authors: Y
authors: Tada
authors: K
authors: K
authors: Ichimura
authors: T L
authors: TL
authors: Peever
authors: K
authors: K
authors: Akimitsu
mesh_terms: D000528:Alternaria / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D002957:Citrus / Q000382:microbiology*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D048630:Polyketide Synthases