12-OPDA as a drought-responsive regulator of stomatal closure, functioning together with ABA

 

 

Functional convergence of oxylipin and abscisic acid pathways controls stomatal closure in response to drought

by Savchenko T., Kolla V. A., Wang C. Q., Nasafi Z., Hicks D. R., Phadungchob B., Chehab W. E., Brandizzi F., Froehlich J., Dehesh K. (2014)

Department of Plant Biology , University of California, Davis, California 95616.

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in Plant Physiol. 164: 1151–1160 – 10.1104/pp.113.234310 – 

[PMC free article] [PubMed] [Cross Ref] – 

https://www.ncbi.nlm.nih.gov/pubmed/24429214

Abstract

Membranes are primary sites of perception of environmental stimuli. Polyunsaturated fatty acids are major structural constituents of membranes that also function as modulators of a multitude of signal transduction pathways evoked by environmental stimuli.

Different stresses induce production of a distinct blend of oxygenated polyunsaturated fatty acids, “oxylipins.” We employed three Arabidopsis (Arabidopsis thaliana) ecotypes to examine the oxylipin signature in response to specific stresses and determined that wounding and drought differentially alter oxylipin profiles, particularly the allene oxide synthase branch of the oxylipin pathway, responsible for production of jasmonic acid (JA) and its precursor 12-oxo-phytodienoic acid (12-OPDA).

Specifically, wounding induced both 12-OPDA and JA levels, whereas drought induced only the precursor 12-OPDA. Levels of the classical stress phytohormone abscisic acid (ABA) were also mainly enhanced by drought and little by wounding. To explore the role of 12-OPDA in plant drought responses, we generated a range of transgenic lines and exploited the existing mutant plants that differ in their levels of stress-inducible 12-OPDA but display similar ABA levels.

The plants producing higher 12-OPDA levels exhibited enhanced drought tolerance and reduced stomatal aperture. Furthermore, exogenously applied ABA and 12-OPDA, individually or combined, promote stomatal closure of ABA and allene oxide synthase biosynthetic mutants, albeit most effectively when combined.

Using tomato (Solanum lycopersicum) and Brassica napus verified the potency of this combination in inducing stomatal closure in plants other than Arabidopsis.

These data have identified drought as a stress signal that uncouples the conversion of 12-OPDA to JA and have revealed 12-OPDA as a drought-responsive regulator of stomatal closure functioning most effectively together with ABA.

H2O2 is an essential secondary messenger during bicarbonate induced stomatal closure

 

Hydrogen peroxide production is an early event during bicarbonate induced stomatal closure in abaxial epidermis of Arabidopsis

by Kolla V. A., Vavasseur A., Raghavendra A. S. (2007)

in Planta 225, 1421–1429. doi: 10.1007/s00425-006-0450-6 –

PubMed Abstract | CrossRef Full Text | Google Scholar

http://link.springer.com/article/10.1007%2Fs00425-006-0450-6

Abstract

The presence of 2 mM bicarbonate in the incubation medium induced stomatal closure in abaxial epidermis of Arabidopsis. Exposure to 2 mM bicarbonate elevated the levels of H₂O₂ in guard cells within 5 min, as indicated by the fluorescent probe, dichlorofluorescein diacetate (H₂DCF-DA).

Bicarbonate-induced stomatal closure as well as H₂O₂ production were restricted by exogenous catalase or diphenylene iodonium (DPI, an inhibitor of NAD(P)H oxidase). The reduced sensitivity of stomata to bicarbonate and H₂O₂ production in homozygous atrbohD/F double mutant of Arabidopsis confirmed that NADP(H) oxidase is involved during bicarbonate induced ROS production in guard cells.

The production of H₂O₂ was quicker and greater with ABA than that with bicarbonate. Such pattern of H₂O₂ production may be one of the reasons for ABA being more effective than bicarbonate, in promoting stomatal closure.

Our results demonstrate that H₂O₂ is an essential secondary messenger during bicarbonate induced stomatal closure in Arabidopsis.

OPDA and ABA in stomata closure

Photo credit: Google

Stomata On Epidermis Of Rose Leaf

Functional convergence of oxylipin and abscisic acid pathways controls stomatal closure in response to drought.

by Savchenko T., Kolla V. A., Wang C. Q., Nasafi Z., Hicks D. R., Phadungchob B., Chehab W. E., Brandizzi F., Froehlich J,, Dehesh K. (2014)

in Plant Physiol. 2014 Mar;164(3):1151-60.

Abstract

Membranes are primary sites of perception of environmental stimuli. Polyunsaturated fatty acids are major structural constituents of membranes that also function as modulators of a multitude of signal transduction pathways evoked by environmental stimuli. Different stresses induce production of a distinct blend of oxygenated polyunsaturated fatty acids, “oxylipins.” We employed three Arabidopsis (Arabidopsis thaliana) ecotypes to examine the oxylipin signature in response to specific stresses and determined that wounding and drought differentially alter oxylipin profiles, particularly the allene oxide synthase branch of the oxylipin pathway, responsible for production of jasmonic acid (JA) and its precursor 12-oxo-phytodienoic acid (12-OPDA). Specifically, wounding induced both 12-OPDA and JA levels, whereas drought induced only the precursor 12-OPDA. Levels of the classical stress phytohormone abscisic acid (ABA) were also mainly enhanced by drought and little by wounding. To explore the role of 12-OPDA in plant drought responses, we generated a range of transgenic lines and exploited the existing mutant plants that differ in their levels of stress-inducible 12-OPDA but display similar ABA levels. The plants producing higher 12-OPDA levels exhibited enhanced drought tolerance and reduced stomatal aperture. Furthermore, exogenously applied ABA and 12-OPDA, individually or combined, promote stomatal closure of ABA and allene oxide synthase biosynthetic mutants, albeit most effectively when combined. Using tomato (Solanum lycopersicum) and Brassica napus verified the potency of this combination in inducing stomatal closure in plants other than Arabidopsis. These data have identified drought as a stress signal that uncouples the conversion of 12-OPDA to JA and have revealed 12-OPDA as a drought-responsive regulator of stomatal closure functioning most effectively together with ABA.