Abiotic stress: Interplay between ROS, hormones and MAPKs

Non‐enzymatic antioxidant accumulations in BR‐deficient and BR‐insensitive barley mutants under control and drought conditions

“…Plants exposed to drought and other adverse environmental conditions have to coordinate morphological, physiological and biochemical changes in order to adapt to the stress (Bajguz and Hayat , Rao and Chaitanya ). Disturbances in metabolic activity occurring as a result of abiotic stresses, including drought, cause overproduction of reactive oxygen species (ROS) and plants need to maintain the redox homeostasis in order to counter the potentially detrimental effects of the enhanced ROS accumulation and oxidative stress (de Carvalho , Gill and Tuteja , Noctor et al , Choudhury et al , Raja et al ). Drought and the ensuing increased accumulation of ROS is a major constraint of crop productivity worldwide (Mittler , Apel and Hirt , Reddy et al , Gill et al ).…”

“…In fact, ROS are commonly produced as a form of plant response to various stresses; therefore, ROS represent a point of convergence of various signaling pathways regulating the response to the stress factors. The integration of various signals through this convergence allows a fine‐tuning of the plant response to environmental conditions, and leads to acclimation (Sewelam et al , Raja et al ). Mutants impaired in the regulation of ROS homeostasis are more sensitive to abiotic stresses, and unable to mediate a systemic signaling during the stress condition (Mittler et al , Suzuki et al , ).…”

“…The complicated molecular mechanisms controlling ROS accumulation include various enzymatic antioxidants, and operate in various cellular compartments (Foyer and Noctor , Mittler ). Apart from the enzymatic antioxidants, plants employ the glutathione‐ascorbate cycle (Foyer–Haliwell–Asada cycle) and other non‐enzymatic antioxidants, which operate in cytosol, mitochondria, plastids and peroxisomes, and regulate the ROS accumulation (Gill and Tuteja , Soares et al , Raja et al ). However, the extent to which an accumulation of antioxidants is induced by drought is variable and dependent on plant species or even cultivars, plant development and metabolic state, and intensity of the stress (Reddy et al ).…”

“…On the contrary, high BR content induces a prolonged ROS accumulation and consequently ABA biosynthesis and stomatal closure (Xia et al ). Therefore, ROS form a convergence point of BR signaling pathway with other phytohormonal and developmental signalosomes (Xia et al , Raja et al ). Relation between BRs and antioxidant system during drought and osmotic stress has been studied almost exclusively through exogenous BR applications, and in some cases led to ambiguous results (Bajguz and Hayat , Vardhini and Anjum ), therefore the role of endogenous BRs in regulation of the antioxidant homeostasis under control and drought stress conditions remains not fully elucidated, especially in crop species (Harb et al , Rao and Chaitanya , Kka et al ).…”

“…Plant. 163, 2018 of abiotic stresses, including drought, cause overproduction of reactive oxygen species (ROS) and plants need to maintain the redox homeostasis in order to counter the potentially detrimental effects of the enhanced ROS accumulation and oxidative stress (de Carvalho 2008, Gill and Tuteja 2010, Noctor et al 2014, Choudhury et al 2016, Raja et al 2017. Drought and the ensuing increased accumulation of ROS is a major constraint of crop productivity worldwide (Mittler 2002, Apel and Hirt 2004, Reddy et al 2004, Gill et al 2013.…”