Open AccessRole of the transcription factor ChAP1 in cytoplasmic redox homeostasis: imaging with a genetically encoded sensor in the maize pathogen C ochliobolus heterostrophus
Author(s) -
Ronen Mordechai,
Shalaby Samer,
Horwitz Benjamin A.
Publication year - 2013
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.12047
Subject(s) - biology , transcription factor , microbiology and biotechnology , intracellular , mutant , botrytis cinerea , conidiation , reactive oxygen species , cytoplasm , redox , extracellular , biochemistry , gene , chemistry , botany , organic chemistry
Summary The redox‐sensitive transcription factor ChAP1 [ C ochliobolus heterostrophus YAP 1 ( Y east A ctivator P rotein 1 ) orthologue] of C . heterostrophus is required for oxidative stress tolerance. It is not known, however, to what extent the intracellular redox state changes on exposure of the fungus to oxidants, and whether ChAP1 is involved in the return of the cell to redox homeostasis. In order to answer these questions, we expressed a ratiometric redox‐sensitive fluorescent protein sensor, p H yper, in C . heterostrophus . The fluorescence ratio was sensitive to extracellular hydrogen peroxide ( H 2 O 2 ) concentrations that had been shown previously to inhibit the germination of conidia and growth of the pathogen in culture. chap1 mutants showed a slower return to redox homeostasis than the wild‐type on exposure to H 2 O 2 . Plant extracts that mimic oxidants in their ability to promote nuclear retention of ChAP1 reduced, rather than oxidized, the fungal cells. This result is consistent with other data suggesting that ChAP1 responds to plant‐derived signals other than oxidants. pH yper should be a useful reporter of the intracellular redox state in filamentous fungi.