2018/10/22 by Thomas Nietzel, Marlene Elsässer, Cristina Ruberti +13 · 18 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Plant Stress Responses and Tolerance #Photosynthetic Processes and Mechanisms #Plant responses to water stress
paper · doi:10.1111/nph.15550
Summary Hydrogen peroxide (H 2 O 2 ) is ubiquitous in cells and at the centre of developmental programmes and environmental responses. Its chemistry in cells makes H 2 O 2 notoriously hard to detect dynamically, specifically and at high resolution. Genetically encoded sensors overcome persistent shortcomings, but pH sensitivity, silencing of expression and a limited concept of sensor behaviour in vivo have hampered any meaningful H 2 O 2 sensing in living plants. We established H 2 O 2 monitoring in the cytosol and the mitochondria of Arabidopsis with the fusion protein ro GFP 2‐Orp1 using confocal microscopy and multiwell fluorimetry. We confirmed sensor oxidation by H 2 O 2 , show insensitivity to physiological pH changes, and demonstrated that glutathione dominates sensor reduction in vivo . We showed the responsiveness of the sensor to exogenous H 2 O 2 , pharmacologically‐induced H 2 O 2 release, and genetic interference with the antioxidant machinery in living Arabidopsis tissues. Monitoring intracellular H 2 O 2 dynamics in response to elicitor exposure reveals the late and prolonged impact of the oxidative burst in the cytosol that is modified in redox mutants. We provided a well defined toolkit for H 2 O 2 monitoring in planta and showed that intracellular H 2 O 2 measurements only carry meaning in the context of the endogenous thiol redox systems. This opens new possibilities to dissect plant H 2 O 2 dynamics and redox regulation, including intracellular NADPH oxidase‐mediated ROS signalling.