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Respiratory burst oxidase homologue‐dependent H 2 O 2 and chloroplast H 2 O 2 are essential for the maintenance of acquired thermotolerance during recovery after acclimation
Author(s) -
Sun Mintao,
Jiang Fangling,
Cen Benjian,
Wen Junqin,
Zhou Yanzhao,
Wu Zhen
Publication year - 2018
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13351
Subject(s) - acclimatization , nadph oxidase , chloroplast , reactive oxygen species , biology , oxidase test , alternative oxidase , biochemistry , microbiology and biotechnology , enzyme , gene , botany
Thermotolerance is improved by heat stress (HS) acclimation, and the thermotolerance level is “remembered” by plants. However, the underlying signalling mechanisms remain largely unknown. Here, we showed NADPH oxidase‐mediated H 2 O 2 (NADPH‐H 2 O 2 ), and chloroplast‐H 2 O 2 promoted the sustained expression of HS‐responsive genes and programmed cell death (PCD) genes, respectively, during recovery after HS acclimation. When spraying the NADPH oxidase inhibitor, diphenylene iodonium, after HS acclimation, the NADPH‐H 2 O 2 level significantly decreased, resulting in a decrease in the expression of HS‐responsive genes and the loss of maintenance of acquired thermotolerance (MAT). In contrast, compared with HS acclimation, NADPH‐H 2 O 2 declined but chloroplast‐H 2 O 2 further enhanced during recovery after HS over‐acclimation, resulting in the reduced expression of HS‐responsive genes and substantial production of PCD. Notably, the further inhibition of NADPH‐H 2 O 2 after HS over‐acclimation also inhibited chloroplast‐H 2 O 2 , alleviating the severe PCD and surpassing the MAT of HS over‐acclimation treatment. Due to the change in subcellular H 2 O 2 after HS acclimation, the tomato seedlings maintained a constant H 2 O 2 level during recovery, resulting in stable and lower total H 2 O 2 levels during a tester HS challenge conducted after recovery. We conclude that tomato seedlings increase their MAT by enhancing NADPH‐H 2 O 2 content and controlling chloroplast‐H 2 O 2 production during recovery, which enhances the expression of HS‐responsive genes and balances PCD levels, respectively.