S‐nitrosoglutathione spraying improves stomatal conductance, Rubisco activity and antioxidant defense in both leaves and roots of sugarcane plants under water deficit

Abstract

Water deficit is a major environmental constraint on crop productivity and performance and nitric oxide (NO) is an important signaling molecule associated with many biochemical and physiological processes in plants under stressful conditions. This study aims to test the hypothesis that leaf spraying of S-nitrosoglutathione (GSNO), an NO donor, improves the antioxidant defense in both roots and leaves of sugarcane plants under water deficit, with positive consequences for photosynthesis. In addition, the roles of key photosynthetic enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC) in maintaining CO assimilation of GSNO-sprayed plants under water deficit were evaluated. Sugarcane plants were sprayed with water or GSNO 100 μM and subjected to water deficit, by adding polyethylene glycol (PEG-8000) to the nutrient solution. Sugarcane plants supplied with GSNO presented increases in the activity of antioxidant enzymes such as superoxide dismutase in leaves and catalase in roots, indicating higher antioxidant capacity under water deficit. Such adjustments induced by GSNO were sufficient to prevent oxidative damage in both organs and were associated with better leaf water status. As a consequence, GSNO spraying alleviated the negative impact of water deficit on stomatal conductance and photosynthetic rates, with plants also showing increases in Rubisco activity under water deficit.

Improving water use efficiency by changing hydraulic and stomatal characteristics in soybean exposed to drought: the involvement of nitric oxide

“…Indeed, the maintenance of water potential usually results in lower cellular damages, which would reduce the occurrence of biochemical limitations to the photosynthetic process. Moreover, NO can increase the activity of Rubisco in stress conditions, as reported in sugarcane exposed to drought (Silveira et al ). In addition to compromising photosynthesis, drought events affect the carbon balance in plants by interfering with de‐assimilation processes, such as respiration and photorespiration (Hasibeder et al ).…”

“…Indeed, the maintenance of water potential usually results in lower cellular damages, which would reduce the occurrence of biochemical limitations to the photosynthetic process. Moreover, NO can increase the activity of Rubisco in stress conditions, as reported in sugarcane exposed to drought (Silveira et al 2017).…”

“…As a signaling molecule, NO participates in several plant processes, including growth, respiration and photosynthesis, in addition to playing an important role in the responses of plants to biotic and abiotic stresses (Sami et al ). During WD, NO has been shown to promote root growth (Silveira et al ), increase the concentration of enzymatic and nonenzymatic antioxidants (Silveira et al ) and stomatal closure (together with abscisic acid; Joudoi et al ). Indeed, pretreatment with NO donors usually prepares plants for future stresses either by stimulating the antioxidant machinery or by inducing the production of endogenous NO, which in turn induces a series of additional events even after removal or degradation of the original NO donor (Santisree et al ).…”

“…Although several studies have clearly demonstrated the involvement of NO in mitigating the damage caused by WD, many questions remain unanswered. Most studies relate increased drought tolerance with the ability of NO to increase antioxidant defenses and to reduce the stomatal aperture (Santisree et al , Silveira et al , , Sami et al ) without considering its possible effects on hydraulic properties of the plant or the structural characteristics involved in the gas exchange. Indeed, studies that address the involvement of NO in the determination of g s have neglected the fact that, in addition to the degree of stomatal opening, maximum stomatal conductance can be determined by the morphological characteristics of stomata, like the stomatal size and density (Galmés et al ).…”

Biochemical and morphophysiological strategies of Myracrodruon

“…An increase in SOD and CAT activities in rehydrated plants (Table 2) suggests that this antioxidative response was related to a greater production of O -2 and H2O2 (Oliveira et al 2014, Choudhury et al 2017. During rehydration, SOD activity may be influenced by the activities of NADPH oxidases, present in the membrane, which play an important role in ROS production, particularly O -2, and may cause an oxidative stimulus during rehydration (Silveira et al 2017).…”