Nitric oxide and hydrogen peroxide increase glucose-6-phosphate dehydrogenase activities and expression upon drought stress in soybean roots
Changes in glucose-6-phosphate dehydrogenase (G6PD) isoforms activities and expression were investigated in soybean roots under drought, suggesting that cytosolic G6PD plays a main role by regulating H2O2 signal and redox homeostasis.
G6PD acts a vital role in plant growth, development and stress adaptation. Drought (PEG6000 treatment) could markedly increase the enzymatic activities of cytosolic G6PD (Cyt-G6PD) and compartmented G6PD (mainly plastidic P2-G6PD) in soybean roots. Application of G6PD inhibitor upon drought condition dramatically decreased the intracellular NADPH and reduced glutathione levels in soybean roots. Nitric oxide (NO) and hydrogen peroxide (H2O2) participated in the regulation of Cyt-G6PD and P2-G6PD enzymatic activities under drought stress. Diphenylene iodonium (DPI), an inhibitor of NADPH oxidase, abolished the drought-induced accumulation of H2O2. The exogenous application of H2O2 and its production inhibitor (DPI) could stimulate and inhibit the NO accumulation, respectively, but not vice versa. qRT-PCR analysis confirmed that NO, as the downstream signal of H2O2, positively regulated the transcription of genes encoding Cyt-G6PD (GPD5, G6PD6, G6PD7) under drought stress in soybean roots. Comparatively, NO and H2O2 signals negatively regulated the gene expression of compartmented G6PD (GPD1, G6PD2, G6PD4), indicating that a post-transcriptional mechanism was involved in compartmented G6PD regulation. Taken together, the high Cyt-G6PD activity is essential for maintaining redox homeostasis upon drought condition in soybean roots, and the H2O2-dependent NO cascade signal is differently involved in Cyt-G6PD and compartmented G6PD regulation.
KeywordsDrought Glucose-6-phosphate dehydrogenase Hydrogen peroxide Nitric oxide Redox homeostasis Soybean
Reactive oxygen species
This work was supported by the National Natural Science Foundation of China [31671595; 31670244], The Project of Qinghai Science & Technology Department [2016-ZJ-Y01], The Open Project of State Biotechnology Research and Application Development Program of Gansu Province [GNSW-2016-23].
Author contribution statement
YB and XW designed the research. XW, MR, QW, XL, LH and LY conducted experiments. XW, QW, WH and MR analyzed the data. XW, YB and LY wrote the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that there are no conflicts of interest.
- Cardi M, Zaffagnini M, De Lillo A, Castiglia D, Chibani K, Gualberto JM, Rouhier N, Jacquot JP, Esposito S (2016) Plastidic P2 glucose-6P dehydrogenase from poplar is modulated by thioredoxin m-type: distinct roles of cysteine residues in redox regulation and NADPH inhibition. Plant Sci 252:257–266CrossRefGoogle Scholar
- Debnam PM, Fernie AR, Leisse A, Golding A, Bowsher CG, Grimshaw C, Knight JS, Emes MJ (2004) Altered activity of the P2 isoform of plastidic glucose 6-phosphate dehydrogenase in tobacco (Nicotiana tabacum cv. Samsun) causes changes in carbohydrate metabolism and response to oxidative stress in leaves. Plant J 38:49–59CrossRefGoogle Scholar