title: Role of the host-selective ACT-toxin synthesis gene ACTTS2 encoding an enoyl-reductase in pathogenicity of the tangerine pathotype of Alternaria alternata.
abstract: ABSTRACT The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease of tangerines and tangerine hybrids. Sequence analysis of a genomic BAC clone identified a previously uncharacterized portion of the ACT-toxin biosynthesis gene cluster (ACTT). A 1,034-bp gene encoding a putative enoyl-reductase was identified by using rapid amplification of cDNA ends and polymerase chain reaction and designated ACTTS2. Genomic Southern blots demonstrated that ACTTS2 is present only in ACT-toxin producers and is carried on a 1.9 Mb conditionally dispensable chromosome by the tangerine pathotype. Targeted gene disruption of ACTTS2 led to a reduction in ACT-toxin production and pathogenicity, and transcriptional knockdown of ACTTS2 using RNA silencing resulted in complete loss of ACT-toxin production and pathogenicity. These results indicate that ACTTS2 is an essential gene for ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and is required for pathogenicity of this fungus.
authors.affiliation: Faculty of Agriculture and Gene Research Center, Kagawa University, Miki, Kagawa 761-0795, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Ajiro
authors.forename: Yoko
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Akira
authors.initials: A
authors.lastname: Masunaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuge
authors.forename: Mikihiro
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ohtani
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fukumoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Gomi
authors.forename: Tobin L
authors.initials: TL
authors.lastname: Peever
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Izumi
authors.forename: Yasuomi
authors.initials: Y
authors.lastname: Tada
authors.forename: Kazuya
authors.initials: K
authors.lastname: Akimitsu
mesh_terms: D000528:Alternaria / Q000235:genetics* / Q000472:pathogenicity; D022202:Chromosomes, Artificial, Bacterial; D002957:Citrus / Q000382:microbiology*; D005656:Fungal Proteins / Q000235:genetics*; D016681:Genome, Fungal; D023281:Genomics; D054884:Host-Pathogen Interactions; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D034622:RNA Interference
chemical_list: D005656:Fungal Proteins