Impact of nitrogen metabolism-associated culture pH changes on regulation of Fusarium trichothecene biosynthesis: revisi
- PDF / 3,673,325 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 69 Downloads / 184 Views
ORIGINAL ARTICLE
Impact of nitrogen metabolism‑associated culture pH changes on regulation of Fusarium trichothecene biosynthesis: revision of roles of polyamine agmatine and transcription factor AreA Yuichi Nakajima1 · Manami Akasaka1 · Takuya Shiobara1 · Yoshiyuki Kitou1 · Kazuyuki Maeda1,2 · Kyoko Kanamaru1,3 · Shuichi Ohsato2 · Tetsuo Kobayashi1 · Takumi Nishiuchi4 · Makoto Kimura1 Received: 1 May 2020 / Revised: 4 August 2020 / Accepted: 6 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Fusarium graminearum produces trichothecene mycotoxins in infected grains and axenic liquid culture. A proposed regulatory model of trichothecene biosynthesis was examined in relation to nitrogen utilization. First, we showed that an important factor for the stimulation of trichothecene biosynthesis was not the occurrence of agmatine as a specific inducer molecule, but rather continuous acidification of the liquid culture medium arising from agmatine catabolism. When the pH of the -Gln synthetic medium was frequently adjusted to the pH of the agmatine culture, trichothecene productivity of the l-Gln l culture was equal to that of the agmatine culture. For efficient trichothecene biosynthesis, the culture pH should be lowered at an appropriate time point during the early growth stage. Second, we re-evaluated the role of the nitrogen regulatory GATA transcription factor AreA in trichothecene biosynthesis. Since Tri6 encodes a transcription factor indispensable for trichothecene biosynthesis, all fifteen AreA-binding consensus sequences in the Tri6 promoter were mutated. The mutant could catabolize l-Phe as the sole nitrogen source; furthermore, the pH profile of the synthetic l-Phe medium (initial pH 4.2) was the same as that of the wild-type (WT) strain. Under such conditions, the promoter mutant exhibited approximately 72% of the trichothecene productivity compared to the WT strain. Thus, F. graminearum AreA (FgAreAp) is dispensable for the functioning of the Tri6 promoter, but it contributes to the increased production of mycotoxin under mildly acidic conditions to some extent. Further investigations on the culture pH revealed that extremely low pH bypasses the function of FgAreAp. Keywords Agmatine · Deoxynivalenol · Transcription regulator · Tri6 · Trichothecene production
Communicated by M. Kupiec. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00294-020-01102-x) contains supplementary material, which is available to authorized users. * Makoto Kimura [email protected]‑u.ac.jp 1
Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Furo‑cho, Chikusa‑ku, Nagoya, Aichi 464‑8601, Japan
2
Graduate School of Agriculture, Meiji University, 1‑1‑1 Higashi‑Mita, Kawasaki, Kanagawa 214‑8571, Japan
3
Department of Biological Chemistry, Chubu University, 1200 Matsumoto‑cho, Kasugai, Aichi 487‑8501, Japan
4
Institute for Gene Research, Advanced Science Research C
Data Loading...
