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 enoylreductase 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.
Original language | English |
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Pages (from-to) | 120-126 |
Number of pages | 7 |
Journal | Phytopathology |
Volume | 100 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2010 |
Keywords
- Citrus
- Host-specific toxin
- Toxin biosynthesis gene cluster
ASJC Scopus subject areas
- Agronomy and Crop Science
- Plant Science