Interdependency of Reactive Oxygen Species generating and scavenging system in salt sensitive and salt tolerant cultivars of rice

Abstract

BackgroundSalinity stress is a major constrain in the global rice production and hence serious efforts are being undertaken towards deciphering its remedial strategies. The comparative analysis of differential response of salt sensitive and salt tolerant lines is a judicious approach to obtain essential clues towards understanding the acquisition of salinity tolerance in rice plants. However, adaptation to salt stress is a fairly complex process and operates through different mechanisms. Among various mechanisms involved, the reactive oxygen species mediated salinity tolerance is believed to be critical as it evokes cascade of responses related to stress tolerance. In this background, the present paper for the first time evaluates the ROS generating and the scavenging system in tandem in both salt sensitive and salt tolerant cultivars of rice for getting better insight into salinity stress adaptation.ResultsComparative analysis of ROS indicates the higher level of hydrogen peroxide (H2O2) and lower level of superoxide ions (O2-) in the salt tolerant as compared to salt sensitive cultivars. Specific activity of ROS generating enzyme, NADPH oxidase was also found to be more in the tolerant cultivars. Further, activities of various enzymes involved in enzymatic and non enzymatic antioxidant defence system were mostly higher in tolerant cultivars. The transcript level analysis of antioxidant enzymes were in alignment with the enzymatic activity. Other stress markers like proline were observed to be higher in tolerant varieties whereas, the level of malondialdehyde (MDA) equivalents and chlorophyll content were estimated to be more in sensitive.ConclusionThe present study showed significant differences in the level of ROS production and antioxidant enzymes activities among sensitive and tolerant cultivars, suggesting their possible role in providing natural salt tolerance to selected cultivars of rice. Our study demonstrates that the cellular machinery for ROS production and scavenging system works in an interdependent manner to offer better salt stress adaptation in rice. The present work further highlights that the elevated level of H2O2 which is considered as a key determinant for conferring salt stress tolerance to rice might have originated through an alternative route of photocatalytic activity of chlorophyll.

Chemical Defoliant Promotes Leaf Abscission by Altering ROS Metabolism and Photosynthetic Efficiency in Gossypium hirsutum

“…The increase of ROS accumulation and MDA content alter superoxide dismutase (SOD) activity and catalase (CAT) activity, and damage photosynthesis and cell structure under stress conditions [45,46]. Moreover, a previous study suggested that the activated enzymatic antioxidant system contributed to ROS scavenging and inhibition of lipid peroxidation [47,48]. This study showed that POD and SOD activity increased at 48 h after TDZ treatment; however, CAT activity decrease.…”

Osa‐miR398b boosts H2O2 production and rice blast disease‐resistance via multiple superoxide dismutases

“…The SODs catalyze the conversion of O • 2 À into H 2 O 2 , which acts as a signal molecule to trigger resistance to various biotic and abiotic stresses (Quan et al, 2008;Kaur et al, 2016;Saxena et al, 2016). However, the excess H 2 O 2 results in the occurrence of oxidative stress and leads to programmed cell death (PCD), Fig.…”

“…Therefore, SODs act as key defense factors against versatile stresses by regulating the H 2 O 2 concentration in plants. H 2 O 2 is a vital ROS in biological processes leading to tolerance against various stresses (Kaur et al, 2016;Saxena et al, 2016).Consistent with the role of ROS in rice immunity, the resistant rice cultivar IRBLKm-Ts displays higher H 2 O 2 concentrations than the susceptible cultivar Lijiang XinTuan Hegu (LTH) upon M. oryzae infection (Li et al, 2014). In addition, overexpression of L-ascorbate oxidase (AO) enhanced AO-mediated H 2 O 2 accumulation, thereby improving resistance to rice stripe virus (Wu et al, 2017).…”

Identification and Validation a Major QTL from “Sea Rice 86” Seedlings Conferred Salt Tolerance

“…Transcription factors play an essential role in rice development and responses to biotic and abiotic stresses [36][37][38][39]; these five TFs have been reported to respond to salt stress in rice to varying degrees [40,41]. The reactive oxygen species signaling pathway mediated by peroxidase was also critical, as it evoked a cascade of responses related to stress tolerance [42][43][44]. The aggregation of related genes in the same chromosome region might be a key feature underlying the salt tolerance of SR86.…”