Ethylene: A Master Regulator of Plant–Microbe Interactions under Abiotic Stresses

Abstract

The plant phytohormone ethylene regulates numerous physiological processes and contributes to plant–microbe interactions. Plants induce ethylene production to ward off pathogens after recognition of conserved microbe-associated molecular patterns (MAMPs). However, plant immune responses against pathogens are essentially not different from those triggered by neutral and beneficial microbes. Recent studies indicate that ethylene is an important factor for beneficial plant–microbial association under abiotic stress such as salt and heat stress. The association of beneficial microbes with plants under abiotic stresses modulates ethylene levels which control the expression of ethylene-responsive genes (ERF), and ERFs further regulate the plant transcriptome, epi-transcriptome, Na+/K+ homeostasis and antioxidant defense mechanisms against reactive oxygen species (ROS). Understanding ethylene-dependent plant–microbe interactions is crucial for the development of new strategies aimed at enhancing plant tolerance to harsh environmental conditions. In this review, we underline the importance of ethylene in beneficial plant–microbe interaction under abiotic stresses.

Enhancing cold tolerance and quality characteristics of Carica papaya Linn through the application of 1‐methylcyclopropene, geranium and lavender oil

“…Additionally, EO exhibits a favourable antibacterial effect due to its hydrophobic nature, which increases bacterial cell permeability by disrupting the lipid structure of the cell membrane and mitochondria, leading to cell death (Chen et al ., 2021). Pathogen attack triggers elevated ethylene levels in fruit owing to rapid increases in ethylene biosynthesis during plant–pathogen interactions, driven by the activated plant stress adaptation response to fend off the pathogen (Jhalegar et al ., 2015; Shekhawat et al ., 2023). EO treatments such as lemongrass, eucalyptus, clove and neem oil have been demonstrated to reduce the rise in ethylene in pathogen‐attacked mandarin fruit (Jhalegar et al ., 2015).…”

Genome-wide identification of polyamine metabolism and ethylene synthesis genes in Chenopodium quinoa Willd. and their responses to low-temperature stress

“…Ethylene, known as the plant stress hormone, is a gaseous small molecule (C 2 H 4 ) that is involved in numerous developmental processes in plants, such as seed germination, cell elongation, tissue differentiation, senescence and abscission of leaves and flowers, and fruit ripening [ 45 , 46 ]. Moreover, it is also involved in various plant responses to biotic and abiotic stresses [ 47 , 48 ]. ACS and ACO are the two key enzymes involved in ethylene synthesis.…”

B. subtilisCNBG‐PGPR‐1 induces methionine to regulate ethylene pathway and ROS scavenging for improving salt tolerance of tomato

“…Numerous studies have shown the effects of PGPR on the concentration, signaling, and metabolism of plant hormones, and the plant growth promotion or stress tolerance triggered by PGPR may depend on these associated changes in phytohormone homeostasis (Samaras et al., 2022; Shekhawat et al., 2022). Likewise, we found plant hormone signal transduction induced by CNBG‐PGPR‐1 plays a unique role in plant salt tolerance (Figure 3d; Tables S5 and S6).…”

“…Indeed, in our study, exogenous L‐methionine largely mimicked the beneficial effects of CNBG‐PGPR‐1 (Figure 7a–c). The biosynthesis of ethylene triggers the subsequent signaling cascade, resulting in transcriptional regulation of ethylene‐responsive genes (Shekhawat et al., 2022). Genes involved in ethylene synthesis and signal transduction were significantly induced by exogenous L‐methionine (Figure 7d), which verified the previous speculation.…”