The global regulator LaeA controls biosynthesis of host-specific toxins, pathogenicity and development of Alternaria alternata pathotypes

Kazumi Takao, Yasunori Akagi, Takashi Tsuge, Yoshiaki Harimoto, Mikihiro Yamamoto, Motoichiro Kodama

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The global regulator LaeA is required for the expression of biosynthetic genes for secondary metabolites in filamentous fungi such as Aspergillus nidulans. To learn more about the regulation of these genes in Alternaria alternata, which has at least seven pathogenic variants (pathotypes) that produce host-specific toxins (HSTs) and cause severe diseases in their host plants, we identified LaeA homologs encoding methyltransferase in tomato, strawberry and apple pathotypes of A. alternata, designating them AtLAE1, AsLAE1 and AaLAE1, respectively. In the AtLAE1-deleted mutant of the tomato pathotype (∆AtLAE1), expression of the AAL-toxin biosynthetic gene ALT1 was lower than that in the wild type. Correspondingly, AAL-toxin production and virulence of the mutant were significantly lower as were spore production and hyphal growth. Similarly, the AsLAE1-deleted mutant of the strawberry pathotype (∆AsLAE1) and the AaLAE1-deleted mutant of the apple pathotype (∆AaLAE1) produced less of their host-specific toxin (AF- and AM-toxin, respectively), had reduced virulence on the host plant, and hyphal growth and sporulation were defective. Thus, the global regulator gene LaeA positively regulates HST biosynthesis, pathogenicity, growth and differentiation in A. alternata pathotypes.

Original languageEnglish
Pages (from-to)121-131
Number of pages11
JournalJournal of General Plant Pathology
Volume82
Issue number3
DOIs
Publication statusPublished - May 1 2016

Keywords

  • Alternaria alternata pathotypes
  • Global regulator
  • Host-specific toxin
  • LaeA
  • Secondary metabolite

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

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