Methyl Jasmonate Protects the PS II System by Maintaining the Stability of Chloroplast D1 Protein and Accelerating Enzymatic Antioxidants in Heat-Stressed Wheat Plants

Abstract

The application of 10 µM methyl jasmonate (MeJA) for the protection of wheat (Triticum aestivum L.) photosystem II (PS II) against heat stress (HS) was studied. Heat stress was induced at 42 °C to established plants, which were then recovered at 25 °C and monitored during their growth for the study duration. Application of MeJA resulted in increased enzymatic antioxidant activity that reduced the content of hydrogen peroxide (H2O2) and thiobarbituric acid reactive substances (TBARS) and enhanced the photosynthetic efficiency. Exogenous MeJA had a beneficial effect on chlorophyll fluorescence under HS and enhanced the pigment system (PS) II system, as observed in a JIP-test, a new tool for chlorophyll fluorescence induction curve. Exogenous MeJA improved the quantum yield of electron transport (ETo/CS) as well as electron transport flux for each reaction center (ET0/RC). However, the specific energy fluxes per reaction center (RC), i.e., TR0/RC (trapping) and DI0/RC (dissipation), were reduced by MeJA. These results indicate that MeJA affects the efficiency of PS II by stabilizing the D1 protein, increasing its abundance, and enhancing the expression of the psbA and psbB genes under HS, which encode proteins of the PS II core RC complex. Thus, MeJA is a potential tool to protect PS II and D1 protein in wheat plants under HS and to accelerate the recovery of the photosynthetic capacity.

In-Vivo Biophoton Emission, Physiological and Oxidative Responses of Biostimulant-Treated Winter Wheat (Triticum eastivum L.) as Seed Priming Possibility, for Heat Stress Alleviation

“…Besides the negative effects of heat on morphological and physiological parameters, elevated temperature affects the membrane integrity of wheat, inducing ROS formation and triggering the antioxidative defense system of plants [ 35 ]. In addition to antioxidant enzymes, non-enzymatic antioxidants that are low molecular-weight compounds, such as ascorbic acid, carotenoids, tocopherol, polyphenols, polyamines, flavonoids, hormonal compounds (melatonin, serotonin) and amino acids, are capable of eliminating ROS without enzymatic reactions [ 36 ], and despite their small presence, greatly inhibit the oxidation of substrates [ 37 ], and are possible to characterize by the measurement of ferric reducing antioxidant capacity, i.e., FRAP [ 38 ].…”

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

“…The demand for wheat is increasing and a 2.0% annual increase is predicted [ 67 ]; however, is threatened by heat and water stress [ 68 ]. Heat stress reduces its photosynthetic potential and growth [ 69 , 70 ] and affects wheat’s physiological, biological, and biochemical processes [ 71 ]. The present study explored the interaction between NO and ABA in mitigating heat stress in the wheat crop through their impact on osmolytes accumulation and the activity and expression of antioxidant enzymes.…”

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

“…In this study, the J-step and I-step in the fast chlorophyll fluorescence kinetic curve were higher under normal sowing than delayed sowing, indicating that the Q A –Q B process of photosynthetic electron transfer in flag leaves was inhibited under heat stress with normal sowing. Previous studies also showed that heat stress influences electron transport, which damages the function of PS II ( Chen et al, 2014 ; Bi et al, 2016 ; Fatma et al, 2021 ). And our research shows that RC/CSm, TRo/CSm, ETo/CSm, and DIo/CSm were lower under normal sowing than delayed sowing.…”

“…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 ). Melatonin and H 2 S protect against heat stress-induced photosynthetic inhibition by regulating carbohydrate metabolism ( Iqbal et al, 2021 ).…”