Stomatal conductance as a screen for osmotic stress tolerance in durum wheat growing in saline soil

2010 ◽  
Vol 37 (3) ◽  
pp. 255 ◽  
Author(s):  
Afrasyab Rahnama ◽  
Richard A. James ◽  
Kazem Poustini ◽  
Rana Munns
Keyword(s):  
Stomatal Conductance ◽  
Osmotic Stress ◽  
Durum Wheat ◽  
Stress Tolerance ◽  
Triticum Turgidum ◽  
Genotypic Variation ◽  
Relative Size ◽  
Shoot Biomass ◽  
Osmotic Stress Tolerance ◽  
The Difference

The change in stomatal conductance measured soon after durum wheat (Triticum turgidum ssp. durum Desf.) was exposed to salinity was verified as an indicator of osmotic stress tolerance. It was a reliable and useful screening technique for identifying genotypic variation. The minimum NaCl treatment needed to obtain a significant stomatal response was 50 mM, but 150 mM was needed to obtain significant differences between genotypes. The response to the NaCl was osmotic rather than Na+-specific. Stomatal conductance responded similarly to iso-osmotic concentrations of KCl and NaCl, both in the speed and extent of closure, and in the difference between genotypes. The new reduced rate of stomatal conductance in response to addition of 50 mM NaCl or KCl occurred within 45 min, and was independent of the concentration of Na+ in leaves. The difference between genotypes was long-lasting, translating into differences in shoot biomass and tiller number after a month. These results indicate that the relative size of the change in stomatal conductance when the salinity is introduced could be a means of screening for osmotic stress tolerance in wheat and other cereals.

scholarly journals CAND2/PMTR1 Is Required for Melatonin-Conferred Osmotic Stress Tolerance in Arabidopsis

2021 ◽  
Vol 22 (8) ◽  
pp. 4014
Author(s):  
Lin-Feng Wang ◽  
Ting-Ting Li ◽  
Yu Zhang ◽  
Jia-Xing Guo ◽  
Kai-Kai Lu ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Stress Tolerance ◽  
Wild Type Plant ◽  
Wild Type ◽  
Melatonin Receptor ◽  
Ros Scavenging ◽  
Exogenous Melatonin ◽  
Osmotic Stress Tolerance ◽  
Osmotic Stress Response ◽  
In The Wild

Osmotic stress severely inhibits plant growth and development, causing huge loss of crop quality and quantity worldwide. Melatonin is an important signaling molecule that generally confers plant increased tolerance to various environmental stresses, however, whether and how melatonin participates in plant osmotic stress response remain elusive. Here, we report that melatonin enhances plant osmotic stress tolerance through increasing ROS-scavenging ability, and melatonin receptor CAND2 plays a key role in melatonin-mediated plant response to osmotic stress. Upon osmotic stress treatment, the expression of melatonin biosynthetic genes including SNAT1, COMT1, and ASMT1 and the accumulation of melatonin are increased in the wild-type plants. The snat1 mutant is defective in osmotic stress-induced melatonin accumulation and thus sensitive to osmotic stress, while exogenous melatonin enhances the tolerance of the wild-type plant and rescues the sensitivity of the snat1 mutant to osmotic stress by upregulating the expression and activity of catalase and superoxide dismutase to repress H2O2 accumulation. Further study showed that the melatonin receptor mutant cand2 exhibits reduced osmotic stress tolerance with increased ROS accumulation, but exogenous melatonin cannot revert its osmotic stress phenotype. Together, our study reveals that CADN2 functions necessarily in melatonin-conferred osmotic stress tolerance by activating ROS-scavenging ability in Arabidopsis.

Precursor processing by SBT3.8 and phytosulfokine signaling contribute to drought stress tolerance in Arabidopsis

2021 ◽  
Author(s):  
Nils Stührwohldt ◽  
Eric Bühler ◽  
Margret Sauter ◽  
Andreas Schaller
Keyword(s):  
Drought Stress ◽  
Osmotic Stress ◽  
Stress Tolerance ◽  
Serine Proteases ◽  
Loss Of Function ◽  
Lateral Root Development ◽  
Osmotic Stress Tolerance ◽  
Stress Symptoms ◽  
C Terminus ◽  
Peptide Precursor

Abstract Increasing drought stress poses a severe threat to agricultural productivity. Plants, however, evolved numerous mechanisms to cope with such environmental stress. Here we report that the stress-induced production of a peptide signal contributes to stress tolerance. The expression of phytosulfokine (PSK) peptide precursor genes, and transcripts of three subtilisin-like serine proteases, SBT1.4, SBT3.7 and SBT3.8 were found to be up-regulated in response to osmotic stress. Stress symptoms were enhanced in sbt3.8 loss-of-function mutants and could be alleviated by PSK treatment. Osmotic stress tolerance was improved in plants overexpressing the precursor of PSK1 (proPSK1) or SBT3.8 resulting in higher fresh weight and improved lateral root development in the transgenic compared to wild-type plants. We further showed that SBT3.8 is involved in the biogenesis of the bioactive PSK peptide. ProPSK1 was cleaved by SBT3.8 at the C-terminus of the PSK pentapeptide. Processing by SBT3.8 depended on the aspartic acid residue directly following the cleavage site. ProPSK1 processing was impaired in the sbt3.8 mutant. The data suggest that increased expression in response to osmotic stress followed by the post-translational processing of proPSK1 by SBT3.8 leads to the production of PSK as a peptide signal for stress mitigation.

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