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Published on: February 9, 2024
Nitric oxide, stomatal closure, and abiotic stress
Steven Neill1, Raimundo Barros, Jo Bright
1Centre for Research in Plant Science, Faculty of Health and Life Sciences, University of the West of England, Bristol BS16 1QY, UK. Steven.Neill@uwe.ac.uk
Journal of Experimental Botany
|March 12, 2008
Summary
Nitric oxide (NO) acts as a key plant signal, mediating responses to stress. It triggers stomatal closure and activates antioxidant defenses, crucial for plant survival under drought and salinity.
Area of Science:
- Plant Physiology
- Molecular Biology
- Biochemistry
Background:
- Nitric oxide (NO) is recognized as an endogenous signaling molecule in plants, mediating responses to various environmental stimuli.
- Abscisic acid (ABA) initiates stomatal closure through complex intracellular signaling pathways where NO plays a significant role.
Purpose of the Study:
- To elucidate the role of nitric oxide (NO) in plant stress responses, particularly in abscisic acid (ABA)-induced stomatal closure and antioxidant defense mechanisms.
- To investigate the signaling pathways involving NO, hydrogen peroxide (H2O2), mitogen-activated protein kinase (MAPK), and cyclic guanosine monophosphate (cGMP) in plant stress tolerance.
Main Methods:
- Application of NO donors and scavengers to observe effects on stomatal closure.
- Measurement of endogenous NO levels and manipulation of NO content through chemical and genetic means.
- Analysis of gene expression and protein activity, including nitrate reductase (NR) isoforms and MAPK pathways.
- Investigating the role of H2O2 and cGMP in NO-mediated signaling.
Main Results:
- Exogenous NO induces stomatal closure, and ABA application triggers endogenous NO generation.
- ABA-induced stomatal closure is dependent on NO generation, requiring nitric oxide synthase-like activity and NIA1 nitrate reductase in Arabidopsis.
- NO stimulates MAPK activity and cGMP production, both essential for ABA-induced stomatal closure.
- ABA-induced NO accumulation in guard cells is dependent on H2O2 production.
- NO generation, H2O2, and MAPK activation are involved in antioxidant defense induction by water stress and ABA in maize mesophyll cells.
- Drought and salinity induce NO generation, which activates protective cellular processes against oxidative stress.
Conclusions:
- Nitric oxide (NO) is a critical signaling intermediate in plant responses to abiotic stresses like drought and salinity.
- ABA utilizes NO to rapidly induce stomatal closure, reducing water loss, and to activate antioxidant defenses against oxidative stress.
- The signaling cascade involving H2O2, NO, MAPK, and cGMP represents a conserved mechanism for plant stress tolerance.
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