Drought stress response in winter wheat varieties – changes in leaf proteins and proteolytic activities

Abstract

Radiation mutagenesis has been used in sustainable agriculture as a tool for increasing plant variability and providing new lines for selection. This necessitates a comparison, by using suitable stress markers, of the newly created lines with some well-established varieties, which are stress tolerant or susceptible. Drought is one of the most frequently encountered stresses with deleterious effects on plant performance and crop yield. Winter wheat seedlings (soil cultures at 3–4th leaf stage) from one mutant line (M181/1338K), one drought-tolerant (Guinness) and one sensitive variety (Farmer) were subjected to severe drought stress by water withholding, followed by recovery. Changes in leaf protein profiles, the amount of Rubisco large subunit (RLS), some specific chloroplast proteins such as Rubisco binding protein (RPB), Rubisco activase (RA), the chaperone subunit clpA/C of clp protease, as well as the activities of exo- and endo-proteases were analyzed. At the protein level, some differences were found in the drought response of genotypes – stability of RLS and RBP in M181/1338K and Guinness, diminution of RLS and increase in RBP in Farmer. RA presented strong up-regulation at recovery in Guinness but decreased in content under drought in M181/1338K and Farmer. Increase in ClpA/C level was found in all compared varieties under stress. Strong increase in total proteolytic activity was detected under drought only in Farmer. Inhibitory analysis revealed a predominance of cysteine and serine protease types. Aminopeptidase activities remained higher at recovery in M181/1338K and Farmer. Results are discussed in terms of genotype-linked different stress coping strategies.

Photosynthesis Alterations in Wheat Plants Induced by Herbicide, Soil Drought or Flooding

“…Net photosynthesis (A n ) is the physiological parameter which is most affected by water deficit [4]. Photosynthetic deterioration during water scarcity is mainly caused by either stomatal (stomatal closure due to CO 2 reduction) or non-stomatal (decrease in chlorophyll content, inhibition of Rubisco and Rubisco activase, and lower photochemical efficiency of PSII) limitations [5,22]. A decrease in net photosynthesis, stomatal conductance, and chlorophyll content was observed in maize plants under drought stress conditions.…”

Assessment of the Biochemical Responses of Wheat Seedlings to Soil Drought after Application of Selective Herbicide

“…Then CAT, APX, and POD detoxify H 2 O 2 forming H 2 O. Non-enzymatic antioxidants including glutathione (GSH), ascorbic acid (AsA), carotenoids, tocopherols, and some phenolics like flavonoids are also involved in maintaining ROS homeostasis in plants [26,27]. Wheat is particularly vulnerable to drought at the flowering and grain development stages, but it can tolerate mild and moderate drought during vegetation [28], thus young droughttreated plants are capable to recover after the normal water supply is restored [29,30] as it was confirmed in our experiments (Figures 1 and 2). Wheat also tolerates some selective herbicides like Serrate ® as evident by the lack of growth inhibition in herbicide-treated plants (Figure 2).…”

“…Seventeenday-old seedlings (2-3 leaf phase) were treated with aqueous solution of the herbicide Serrate ® according to manufacturer's instructions (25 g/d). After 72 h part of the plants were exposed to drought stress by withholding watering for 7 days to reach water deficit of 60% below the normally irrigated control variants [29,31,50]. Then the normal irrigation was restored, and the stressed plants were left to recover for 4 days.…”

Plants’ Physio-Biochemical and Phyto-Hormonal Responses to Alleviate the Adverse Effects of Drought Stress: A Comprehensive Review

“…Carotenes are classified into two types: hydro-carbon carotenes [83], which include lycopene and xanthophylls, and carotene, which differs from the former due to the inclusion of lutein. The enzymatic antioxidant system contains carotenes, tocopherol, ascorbate, and enzymes such as APX, POD, SOD, polyphenol oxidase, glutathione reductase (GR), and CAT was, protecting carotenoids from the damaging of ROS [8,88,[94][95][96][97]. The enzymatic antioxidant system, which contains carotenoids, also protects carotenoids from ROS.…”