Exogenously-Sourced Ethylene Positively Modulates Photosynthesis, Carbohydrate Metabolism, and Antioxidant Defense to Enhance Heat Tolerance in Rice

Abstract

The effect of exogenously-applied ethylene sourced from ethephon (2-chloroethyl phosphonic acid)was studied on photosynthesis, carbohydrate metabolism, and high-temperature stress tolerance in Taipei-309 and Rasi cultivars of rice (Oryza sativa L.). Heat stress increased the content of H2O2 and thiobarbituric acid reactive substances (TBARS)more in Rasi than Taipei-309. Further, a significant decline in sucrose, starch, and carbohydrate metabolism enzyme activity and photosynthesis was also observed in response to heat stress. The application of ethephon reduced H2O2 and TBARS content by enhancing the enzymatic antioxidant defense system and improved carbohydrate metabolism, photosynthesis, and growth more conspicuously in Taipei-309 under heat stress. The ethephon application enhanced photosynthesis by up-regulating the psbA and psbB genes of photosystem II in heat-stressed plants. Interestingly, foliar application of ethephoneffectively down-regulated high-temperature-stress-induced elevated ethylene biosynthesis gene expression. Overall, ethephon application optimized ethylene levels under high-temperature stress to regulate the antioxidant enzymatic system and carbohydrate metabolism, reducing the adverse effects on photosynthesis. These findings suggest that ethylene regulates photosynthesis via carbohydrate metabolism and the antioxidant system, thereby influencing high-temperature stress tolerance in rice.

Nitric Oxide and Abscisic Acid Mediate Heat Stress Tolerance through Regulation of Osmolytes and Antioxidants to Protect Photosynthesis and Growth in Wheat Plants

“…Heat stress adversely affects the photosynthesis and growth of plants [ 12 , 13 , 70 ] by affecting the thylakoid membrane, chloroplast protein complexes, photosystem II, and activity of Rubisco [ 13 , 100 ]. In order to protect plants from heat stress, the photosynthetic efficiency of plants should be improved.…”

“…The method of Xu et al [ 88 ] and Gautam et al [ 13 ] were adopted for estimation of total soluble sugar content. Trehalose content in leaves was determined following the method described by Li et al [ 64 ], with some modifications.…”

“…Among the alterations, excessive temperature stress during the crop reproductive phase has a likely detrimental influence on agricultural productivity [ 6 , 7 ]. It has been shown that high temperatures adversely affected plant molecular, biochemical, and physiological characteristics [ 8 , 9 , 10 , 11 , 12 , 13 ]. Heat stress causes an oxidative burst, membrane lipid peroxidation, pigment bleaching, protein degradation, enzyme inactivation, and macromolecule damage in plants [ 2 , 14 , 15 , 16 ].…”

Plants’ Physio-Biochemical and Phyto-Hormonal Responses to Alleviate the Adverse Effects of Drought Stress: A Comprehensive Review

“…However, in these newly found activities of ethylene, there has been significantly less investigation on the drought stress response. According to a recent study, the dry shoot weight of six wheat genotypes ranging from tolerant to sensitive was more significant in the tolerant group under mild drought stress, related to an increase in ethylene [242,243]. Interestingly, several investigations on the influence of ethylene on stomata closure have shown contradictory results.…”

Physiological and Proteomic Analyses Indicate Delayed Sowing Improves Photosynthetic Capacity in Wheat Flag Leaves Under Heat Stress

“…At present, most studies promote crop resistance to heat stress through the application of exogenous hormones. Ethylene regulates photosynthesis through carbohydrate metabolism and antioxidant system, thus affecting the high temperature tolerance of rice ( Gautam et al, 2022 ). Methyl jasmonate is a potential tool to protect PS II and D1 proteins in wheat plants under heat stress conditions, accelerating the recovery of photosynthetic capacity ( Fatma et al, 2021 ).…”