Function of genes encoding acyl-CoA synthetase and enoyl-CoA hydratase for host-selective ACT-toxin biosynthesis in the tangerine pathotype of Alternaria alternata

Y. Miyamoto, Y. Ishii, A. Honda, A. Masunaka, T. Tsuge, M. Yamamoto, K. Ohtani, T. Fukumoto, K. Gomi, T. L. Peever, K. Akimitsu

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease. Sequence analysis of a genomic cosmid clone identified a part of the ACTT gene cluster and implicated two genes, ACTT5 encoding an acyl-CoA synthetase and ACTT6 encoding an enoyl-CoA hydratase, in the biosynthesis of ACT-toxin. Genomic Southern blots demonstrated that both genes were present in tangerine pathotype isolates producing ACT-toxin and also in Japanese pear pathotype isolates producing AK-toxin and strawberry pathotype isolates producing AF-toxin. ACT-, AK-, and AF-toxins from these three pathotypes share a common 9,10-epoxy-8-hydroxy-9- methyl-decatrienoic acid moiety. Targeted gene disruption of two copies of ACTT5 significantly reduced ACT-toxin production and virulence. Targeted gene disruption of two copies of ACTT6 led to complete loss of ACT-toxin production and pathogenicity and a putative decatrienoic acid intermediate in ACT-toxin biosynthesis accumulated in mycelial mats. These results indicate that ACTT5 and ACTT6 are essential genes in ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and both are required for full virulence of this fungus.

Original languageEnglish
Pages (from-to)369-377
Number of pages9
JournalPhytopathology
Volume99
Issue number4
DOIs
Publication statusPublished - Apr 2009

Keywords

  • Citrus
  • Host-specific toxin
  • Toxin biosynthesis gene cluster

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

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    Miyamoto, Y., Ishii, Y., Honda, A., Masunaka, A., Tsuge, T., Yamamoto, M., Ohtani, K., Fukumoto, T., Gomi, K., Peever, T. L., & Akimitsu, K. (2009). Function of genes encoding acyl-CoA synthetase and enoyl-CoA hydratase for host-selective ACT-toxin biosynthesis in the tangerine pathotype of Alternaria alternata. Phytopathology, 99(4), 369-377. https://doi.org/10.1094/PHYTO-99-4-0369