The production control mechanisms of a mycotoxin

October 06, 2017

Identification of production control factors for tenuazonic acid

RIKEN CSRS researchers have identified two genes for the production control factors for the secondary metabolite tenuazonic acid, a type of mycotoxin.

This mycotoxin was first identified in the phytopathogenic filamentous fungi Alternaria species, but was subsequently found to be produced by many other types of deleterious filamentous fungi, including the rice blast fungus. Tenuazonic acid inhibits protein synthesis and works as a toxin to plants. Identifying the mechanisms of its production is vital to controlling mycotoxins including tenuazonic acid.
The research team previously demonstrated two induction conditions for tenuazonic acid production, identifying the biosynthetic gene TAS1 and clarifying the mechanism of biosynthesis. For this research, the team successfully analyzed using the induction conditions and biosynthetic genes to find the proteins involved in the control of tenuazonic acid production, and clarified the associated mechanisms.

Analysis under induction conditions for tenuazonic acid production clarified that the TAS2 product found in the vicinity of TAS1 is a transcription factor that positively regulates tenuazonic acid production. Researchers also found that manipulating the gene for a homologue of LaeA (a known production control factor for secondary metabolites in filamentous fungi) called PoLAE1also positively regulated tenuazonic acid production. Furthermore, analysis of genetically engineered strains revealed that TAS2 works downstream of PoLAE1.

These results should make possible efficient control of tenuazonic acid production. Proper control of this chemical will make it possible to manage plant diseases.

Original article
ACS Chemical Biology doi:10.1021/acschembio.7b00353
C.-S. Yun, T. Motoyama, H. Osada,
"Regulatory mechanism of mycotoxin tenuazonic acid production in Pyricularia oryzae".
Choong-Soo Yun; Research Scientist
Takayuki Motoyama; Senior Research Scientist
Hiroyuki Osada; Group Director
Chemical Biology Research Group