Exogenous Application of Methyl Jasmonate at the Booting Stage Improves Rice’s Heat Tolerance by Enhancing Antioxidant and Photosynthetic Activities

Abstract

With the intensification of global warming, high temperatures during rice’s growth and development could further lead to a deterioration in rice yields. Therefore, it is particularly important to further clarify the response of the rice booting stage to high temperatures, and to explore reasonable countermeasures on this basis to reduce yield losses. Methyl jasmonate (MeJA) is a derivative of jasmonates and is widely used for stress resistance. However, the role of MeJA in alleviating high temperatures during the rice booting stage has not been given enough attention. This study aimed to further evaluate the alleviation effect of methyl jasmonate on high-temperature stress during the key growth period of local conventional japonica rice. The results showed that high temperatures (37.5 °C/27.0 °C) at the booting stage had a significant impact on the antioxidant system of rice and also significantly reduced the photosynthetic capacity of the plant, resulting in a decrease in the final yields. The exogenous spraying of 0.1 mmol/L MeJA at the booting stage could effectively alleviate the influence of high-temperature stress on rice photosynthesis. Exogenous MeJA increased the stomatal conductance (Gs) of rice leaves under high-temperature stress, and correspondingly increased the transpiration rate (Tr) and decreased the organ temperature of rice plants, thereby reducing the damage to the actual photochemical efficiency (ΦPSII) caused by high temperatures. By increasing the carotenoid content (Car) and reducing the malondialdehyde content (MDA), the antioxidant capacity of the plants was restored to a certain extent under exogenous MeJA, and the yield factor showed an increase in the number of grains per panicle and the seed-setting rate of Wuyunjing 24, which alleviated the booting stage yield losses induced by high-temperature stress. In conclusion, the application of exogenous MeJA at the booting stage alleviated the negative consequences of high temperatures by enhancing the plants’ antioxidant and photosynthetic capacity. Therefore, MeJA may have a potential role in mitigating the challenges of global warming in rice production.

Improving berry quality and antioxidant ability in ‘Ruidu Hongyu’ grapevine through preharvest exogenous 2,4-epibrassinolide, jasmonic acid and their signaling inhibitors by regulating endogenous phytohormones

“…Furthermore, under both exogenous EBR and JA treatments, KT contents were higher than the control group at DAA 30 and 70 (Figure S3I). Tang et al (2022) also reported that the application of exogenous MeJA significantly increased the total CTKs content in 'Wuyunjing 24' and 'Ningjing' 3 rice. In addition, we discovered both BRz and DIECA had inhibiting effects on the accumulations of stress resistance-related phytohormones (ABA, SA) and planted growth-related phytohormones (GA 3 , ZT, ZR, iP, KT) at almost all sampling stages.…”

Phytohormones methyl jasmonate (MeJA) and gamma-aminobutyric acid (GABA) up-regulates growth and PS II photochemistry in brinjal and tomato seedlings exposed to cadmium toxicity

“…In another study, GABA enhanced these activities under heat and drought stress in the Helianthus annuus plant (Abdel Razik et al 2021). Similarly, MeJA also enhanced the values of these attributes of photosynthesis which are reported in rice plant which was exposed to heat stress (Tang et al 2022). When Gs values were found to increase, the mesophyll cell's capacity to take up CO 2 may increase and this would enhance the Calvin cycle's capacity to take up CO 2 (Messinger et al 2006).…”

Exogenous Methyl Jasmonate Mediated MiRNA-mRNA Network Improves Heat Tolerance of Perennial Ryegrass

“…For instance, MeJA application during rice ( Oryza sativa L.) anthesis reduced the buildup of reactive oxygen species, increased stigma vitality, and consequently promoted fertilization and seed-setting rates under heat stress [ 13 ]. Moreover, the exogenous application of MeJA during the booting stage mitigated the negative effects of heat stress by boosting the antioxidant and photosynthetic capacities of rice [ 14 ]. Recently, it was reported that exogenous application of MeJA improved heat tolerance in perennial ryegrass through modulating various biological pathways, such as JAs and chlorophyll biosynthesis and the heat shock factor (HSF)–heat shock protein (HSP) network [ 9 ].…”