Role of the host-selective ACT-toxin synthesis gene ACTTS2 encoding an enoyl-reductase in pathogenicity of the tangerine pathotype of Alternaria alternata.
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.
Ajiro
Naoya
N
Faculty of Agriculture and Gene Research Center, Kagawa University, Miki, Kagawa 761-0795, Japan.
Miyamoto
Yoko
Y
Masunaka
Akira
A
Tsuge
Takashi
T
Yamamoto
Mikihiro
M
Ohtani
Kouhei
K
Fukumoto
Takeshi
T
Gomi
Kenji
K
Peever
Tobin L
TL
Izumi
Yuriko
Y
Tada
Yasuomi
Y
Akimitsu
Kazuya
K
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
D005656:Fungal Proteins