Open AccessThe thioredoxin MoTrx2 protein mediates reactive oxygen species (ROS) balance and controls pathogenicity as a target of the transcription factor MoAP1 in Magnaporthe oryzae
Author(s) -
Wang Jingzhen,
Yin Ziyi,
Tang Wei,
Cai Xingjia,
Gao Chuyun,
Zhang Haifeng,
Zheng Xiaobo,
Wang Ping,
Zhang Zhengguang
Publication year - 2017
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.12484
Subject(s) - biology , thioredoxin , reactive oxygen species , transcription factor , mutant , microbiology and biotechnology , oxidative stress , peroxiredoxin , peroxidase , biochemistry , gene , enzyme
Summary We have shown previously that the transcription factor MoAP1 governs the oxidative response and is important for pathogenicity in the rice blast fungus Magnaporthe oryzae . To explore the underlying mechanism, we have identified thioredoxin MoTrx2 as a target of MoAP1 in M. oryzae . Thioredoxins are highly conserved 12‐kDa oxidoreductase enzymes containing a dithiol–disulfide active site, and function as antioxidants against free radicals, such as reactive oxygen species (ROS). In yeast and fungi, thioredoxins are important for oxidative stress tolerance and growth. To study the functions of MoTrx2, we generated Δ Motrx2 mutants that exhibit various defects, including sulfite assimilation, asexual and sexual differentiation, infectious hyphal growth and pathogenicity. We found that Δ Motrx2 mutants possess a defect in the scavenging of ROS during host cell invasion and in the active suppression of the rice defence response. We also found that Δ Motrx2 mutants display higher intracellular ROS levels during conidial germination, but lower peroxidase and laccase activities, which contribute to the attenuation in virulence. Given that the function of MoTrx2 overlaps that of MoAP1 in the stress response and pathogenicity, our findings further indicate that MoTrx2 is a key thioredoxin protein whose function is subjected to transcriptional regulation by MoAP1 in M. oryzae .