Role of the host-selective ACT-toxin synthesis gene ACTTS2 encoding an enoyl-reductase in pathogenicity of the tangerine pathotype of alternaria alternata

Naoya Ajiro, Yoko Miyamoto, Akira Masunaka, Takashi Tsuge, Mikihiro Yamamoto, Kouhei Ohtani, Takeshi Fukumoto, Kenji Gomi, Tobin L. Peever, Yuriko Izumi, Yasuomi Tada, Kazuya Akimitsu

Research output: Contribution to journalArticle

26 Citations (Scopus)

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 languageEnglish
Pages (from-to)120-126
Number of pages7
JournalPhytopathology
Volume100
Issue number2
DOIs
Publication statusPublished - Feb 1 2010

Keywords

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

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

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    Ajiro, N., Miyamoto, Y., Masunaka, A., Tsuge, T., Yamamoto, M., Ohtani, K., Fukumoto, T., Gomi, K., Peever, T. L., Izumi, Y., Tada, Y., & Akimitsu, K. (2010). Role of the host-selective ACT-toxin synthesis gene ACTTS2 encoding an enoyl-reductase in pathogenicity of the tangerine pathotype of alternaria alternata. Phytopathology, 100(2), 120-126. https://doi.org/10.1094/PHYTO-100-2-0120