Involvement of cytosolic ascorbate peroxidase and Cu/Zn-superoxide dismutase for improved tolerance against drought stress

Abstract

In order to understand the role of cytosolic antioxidant enzymes in drought stress protection, transgenic tobacco (Nicotiana tabacum cv. Xanthi) plants overexpressing cytosolic Cu/Zn-superoxide dismutase (cytsod) (EC 1.15.1.1) or ascorbate peroxidase (cytapx) (EC 1.11.1.1) alone, or in combination, were produced and tested for tolerance against mild water stress. The results showed that the simultaneous overexpression of Cu/Znsod and apx or at least apx in the cytosol of transgenic tobacco plants alleviates, to some extent, the damage produced by water stress conditions. This was correlated with higher water use efficiency and better photosynthetic rates. In general, oxidative stress parameters, such as lipid peroxidation, electrolyte leakage, and H(2)O(2) levels, were higher in non-transformed plants than in transgenic lines, suggesting that, at the least, overexpression of cytapx protects tobacco membranes from water stress. In these conditions, the activity of other antioxidant enzymes was induced in transgenic lines at the subcellular level. Moreover, an increase in the activity of some antioxidant enzymes was also observed in the chloroplast of transgenic plants overexpressing cytsod and/or cytapx. These results suggest the positive influence of cytosolic antioxidant metabolism on the chloroplast and underline the complexity of the regulation network of plant antioxidant defences during drought stress.

Coupled expression of Cu/Zn-superoxide dismutase and catalase in cassava improves tolerance against cold and drought stresses

“…14 The different cellular compartment localization of the MeCu/ZnSOD and MeCAT1 enhanced scavenge ability of ROS both in the cytoplasm and peroxidsome, which is strongly consistent with the report by Faiz M et al 7 The increased SOD and CAT enzyme activities were able rapidly to scavenge ROS at the site of generation, as well as preventing the production of hydroxyl radicals, thereby enhancing stress tolerance. Thus, our study confirmed that improved cold and drought tolerance is probably attributed to enhanced expression of ROS-scavenging genes (jointly by SOD and CAT genes) resulting in increased ROS homeostasis under the abiotic stress.…”

“…13 Severe abiotic stress disrupts the metabolic balance of plant cells, resulting in a perturbed equilibrium between the production and the scavenging of ROS in the cytoplasm, chloroplasts and mitochondria in plants. Therefore, it is essential to have an efficient antioxidant network in order to scavenge ROS effectively and to maintain low levels of intracellular ROS pools.14 The different cellular compartment localization of the MeCu/ZnSOD and MeCAT1 enhanced scavenge ability of ROS both in the cytoplasm and peroxidsome, which is strongly consistent with the report by Faiz M et al 7 The increased SOD and CAT enzyme activities were able rapidly to scavenge ROS at the site of generation, as well as preventing the production of hydroxyl radicals, thereby enhancing stress tolerance. Thus, our study confirmed that improved cold and drought tolerance is probably attributed to enhanced expression of ROS-scavenging genes (jointly by SOD and CAT genes) resulting in increased ROS homeostasis under the abiotic stress.…”

“…4,5 Therefore, it has been suggested and shown that pyramiding of ROS scavenging enzymes (e.g., SOD and CAT or APX) may provide better stress tolerance than overproduction of a single enzyme. [6][7][8] In a recent publication, we co-expressed the cytosolic superoxide dismutase (MeCu/ZnSOD) and peroxisomal catalase (MeCAT1) (Fig. 1) in transgenic cassava in order to explore the intrinsic relationship recently we reported that the joint expression of cassava Cu/Zn superoxide dismutase (MeCu/ZnSoD) and catalase (MeCat1) prolonged the shelf life of cassava storage-roots by the stabilization of reactive oxygen species (roS) homeostasis after harvest.…”

Effect of Restricted Irrigation on Water Relation Traits and Antioxidant Activity

“…During water stress reduction was found between osmotic potential (Zhang et al (2015), water potential (Iqubal et al (2014) and relative water content (Vaezi et al 2010) in barley genotypes (Sharma et al, 2016;Aboughadareh et al 2017). When plant expose to adverse environment (drought) reactive oxygen species (ROS) such as superoxide (O 2 • ), hydrogen peroxide (H 2 O 2 ), hydroxyl radicals (OH • ) and singlet oxygen ( 1 O 2 ) are produced (Faize et al 2011). Multiple antioxidant enzymes like superoxide dismutases (SOD), catalases (CAT) and peroxidases (POX) are involved in the enzymatic scavenging of ROS (Apel and Hirt, 2004;de Carvalho, 2008;Farooq et al 2009).…”

Impact of Enhanced Capacity to Scavenge Reactive Oxygen Species on Cold Tolerance of Tobacco

“…Several studies on different enzymes have found that overexpression of only some of those enzymes enhanced performance under a particular stress (Foyer et al 1995;Payton et al 2001;Faize et al 2011;Le Martret et al 2011;Poage et al 2011). Photosynthetic processes are often the first physiological/metabolic processes to be inhibited by chilling temperature (Berry and Bjö rkman 1980).…”