A Review on the Role of Endophytes and Plant Growth Promoting Rhizobacteria in Mitigating Heat Stress in Plants

Abstract

Among abiotic stresses, heat stress is described as one of the major limiting factors of crop growth worldwide, as high temperatures elicit a series of physiological, molecular, and biochemical cascade events that ultimately result in reduced crop yield. There is growing interest among researchers in the use of beneficial microorganisms. Intricate and highly complex interactions between plants and microbes result in the alleviation of heat stress. Plant–microbe interactions are mediated by the production of phytohormones, siderophores, gene expression, osmolytes, and volatile compounds in plants. Their interaction improves antioxidant activity and accumulation of compatible osmolytes such as proline, glycine betaine, soluble sugar, and trehalose, and enriches the nutrient status of stressed plants. Therefore, this review aims to discuss the heat response of plants and to understand the mechanisms of microbe-mediated stress alleviation on a physio-molecular basis. This review indicates that microbes have a great potential to enhance the protection of plants from heat stress and enhance plant growth and yield. Owing to the metabolic diversity of microorganisms, they can be useful in mitigating heat stress in crop plants. In this regard, microorganisms do not present new threats to ecological systems. Overall, it is expected that continued research on microbe-mediated heat stress tolerance in plants will enable this technology to be used as an ecofriendly tool for sustainable agronomy.

The role of plant-associated rhizobacteria in plant growth, biocontrol and abiotic stress management

“…Plant cells accumulate reactive oxygen species and intermediate intermediates due to reaction decoupling. The cytoskeleton of plant cells is disrupted by heat stress that alters the fundamental dogma (Ali et al, 2020; Hassan et al, 2021; Shaffique et al, 2022). Photosynthesis in photosystem II (PSII) is impaired when the chloroplast thylakoid membrane detaches from the chloroplast in response to heat stress (Naik et al, 2019).…”

Photosynthesis and chlorophyll fluorescence of Iranian licorice (Glycyrrhiza glabra l.) accessions under salinity stress

“…PGPRs enhance soluble sugar, protein, proline content leading to a higher water potential gradient and improving water uptake and plant growth under stress condition. They also produce growth regulators such as auxin, cytokinin and gibberellin which are important to stimulate cell division (Shaffique et al, 2022). Other various PGPB-mediated mechanisms, whether direct or indirect, include biofilm formation, extracellular polymeric substance production, enhancement of nutrient uptake, phosphate solubilization and mineralization, siderophore production, improvement of antioxidant activities, and 1-aminocyclopropane-1-carboxylic acid (ACC-deaminase) activity (Khatami et al, 2022;Tran et al, 2022).…”

Evaluating the adhesive potential of the newly isolated bacterial strains in research exploitation of plant microbial interaction

“…All the bacteria showed the presence of exopolysaccharides in which the bacteria were trapped. Bacteria interact with plant cells in diverse ways (Shaffique et al, 2022c). The main feature of this interaction is to make colonies, in which the microbes adhere to plant cells as individual cells or in the form of clusters (Morris and Monier, 2003;Tshikantwa et al, 2018).…”