Roles of enzymatic and nonenzymatic antioxidants in plants during abiotic stress

Abstract

Reactive oxygen species (ROS) are produced in plants as byproducts during many metabolic reactions, such as photosynthesis and respiration. Oxidative stress occurs when there is a serious imbalance between the production of ROS and antioxidant defense. Generation of ROS causes rapid cell damage by triggering a chain reaction. Cells have evolved an elaborate system of enzymatic and nonenzymatic antioxidants which help to scavenge these indigenously generated ROS. Various enzymes involved in ROS-scavenging have been manipulated, over expressed or downregulated to add to the present knowledge and understanding the role of the antioxidant systems. The present article reviews the manipulation of enzymatic and nonenzymatic antioxidants in plants to enhance the environmental stress tolerance and also throws light on ROS and redox signaling, calcium signaling, and ABA signaling.

Effect of water stress on antioxidant systems and oxidative parameters in fruits of tomato (Solanum lycopersicon L, cv. Micro-tom)

“…Drought leads to oxidative stress in the plant cell due to higher leakage of electrons towards O 2 during photosynthetic and respiratory processes leading to enhancement in reactive oxygen species (ROS) generation (Asada 1999;Sánchez-Rodríguez et al 2012). ROS are by-products of aerobic metabolism and their production is enhanced during water stress conditions through the disruption of electron transport system and oxidizing metabolic activities occurring in chloroplasts, mitochondria and microbodies (Asada 1999;Van Breusegem et al 2001;Ahmad et al 2010). ROS, such as superoxide anion (O 2 .− ), hydrogen peroxide (H 2 O 2 ), hydroxyl radical (HO − ) and singlet oxygen ( 1 O 2 ), are damageable for cellular structures and macromolecules, causing photoinhibition of photosynthetic apparatus (Smirnoff 1993;Ahmad et al 2011).…”

Cinnamic acid induced changes in reactive oxygen species scavenging enzymes and protein profile in maize (Zea mays L.) plants grown under salt stress

“…From agricultural perspective, these oxidative stresses are among the most significant factors responsible for substantial losses in crop productivity (Koca et al 2007). The primary effects of abiotic stress is ion imbalance and hyper-osmotic stresses responsible for the induction of molecular network, which in turn activates stress responsive mechanism to reestablish homeostasis through repair mechanism of damaged proteins and membranes (Ahmad et al 2010). During stress, electrons that have a high-energy state are transferred to molecular oxygen (O 2 ) to form reactive oxygen species (ROS) (Mittler 2002).…”

Zinc application mitigates the adverse effects of NaCl stress on mustard [Brassica juncea (L.) Czern & Coss] through modulating compatible organic solutes, antioxidant enzymes, and flavonoid content

“…Zinc is a cofactor of over 300 enzymes and associated proteins involved in carbohydrate metabolism, nucleic acid and protein synthesis, as well as cell division (Osredkar and Sustar 2011;Singh et al 2015). Moreover, Zn can impart stress tolerance through the formation of Cu/Zn-SOD, a major antioxidant (Ahmad et al 2010).…”

“…Salinity stress induces the excessive generation of reactive oxygen species (ROS), which can cause cell death through causing damages to proteins, lipids, and DNA (Ahmad et al 2010;Gill and Tuteja 2010;Anjum et al 2015). Plants possess endogenous oxidative defense mechanisms (enzymatic and non-enzymatic antioxidant) to counteract salinity-induced ROS.…”

“…Plants possess endogenous oxidative defense mechanisms (enzymatic and non-enzymatic antioxidant) to counteract salinity-induced ROS. ROS scavengers include superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and glutathione-S-transferase (GST), whereas non-enzymatic components primarily include ascorbic acid (ASA) and glutathione (GSH), both low-molecular-weight metabolites (Ahmad et al 2010;Gill and Tuteja 2010). Plant flavonoid content is also believed to confer stress tolerance ).…”