Recent advances in PGPR-mediated resilience toward interactive effects of drought and salt stress in plants

Abstract

The present crisis at hand revolves around the need to enhance plant resilience to various environmental stresses, including abiotic and biotic stresses, to ensure sustainable agriculture and mitigate the impact of climate change on crop production. One such promising approach is the utilization of plant growth-promoting rhizobacteria (PGPR) to mediate plant resilience to these stresses. Plants are constantly exposed to various stress factors, such as drought, salinity, pathogens, and nutrient deficiencies, which can significantly reduce crop yield and quality. The PGPR are beneficial microbes that reside in the rhizosphere of plants and have been shown to positively influence plant growth and stress tolerance through various mechanisms, including nutrient solubilization, phytohormone production, and induction of systemic resistance. The review comprehensively examines the various mechanisms through which PGPR promotes plant resilience, including nutrient acquisition, hormonal regulation, and defense induction, focusing on recent research findings. The advancements made in the field of PGPR-mediated resilience through multi-omics approaches (viz., genomics, transcriptomics, proteomics, and metabolomics) to unravel the intricate interactions between PGPR and plants have been discussed including their molecular pathways involved in stress tolerance. Besides, the review also emphasizes the importance of continued research and implementation of PGPR-based strategies to address the pressing challenges facing global food security including commercialization of PGPR-based bio-formulations for sustainable agricultural.

Synergistic interactions of nanoparticles and plant growth promoting rhizobacteria enhancing soil-plant systems: a multigenerational perspective

“…In terms of soil quality, salt influences the composition of the microbial community in the soil and reduces biomass and microbial activity. Furthermore, under saline conditions, Na + exceeds K + transport channels, resulting in decreased and inhibited development of plants ( Al-Turki et al., 2023 ). Despite this, it has been demonstrated that co-application of PGPR and NPs in salty conditions induces salt tolerance and plant development, mostly through lowering Na + absorption and elevating the K + /Na + ratio.…”

“…Using two endophytic bacteria, such as Burkholderia phytofirmans or Enterobacter sp., and NPs drastically reduced saline stress in crop plants by minimizing the uptake of xylem Na + content. On the contrary, combined application greatly enhanced the K + and K + /Na + ratio, reducing plant saline stress ( Kumawat et al., 2022 ; Al-Turki et al., 2023 ; Rajput et al., 2023b ). In the same demonstration, the sodium adsorption ratio and Na + in soil solution were reduced by the latter application to adsorption sites and desorption of K + by interactive combination.…”

“…However, a consequence of drought stress is increased plant ethylene levels. It has been demonstrated that the use of ACC-producing deaminase-producing PGPR with NPs may reduce the higher ethylene level in plants caused by drought because the latter increases colonization in the plant rhizosphere and promotes the inoculant survival rate ( deMoraes et al., 2021 ; Al-Turki et al., 2023 ). In terms of comparison, this resulted in higher plant yields than using PGPR or NPs alone.…”

“…(2021) . When combined with NPs, several additional PGPRs that produce ACC deaminase, such as Agrobacterium fabrum and Bacillus amyloliquefaciens have also been shown to increase wheat productivity during severe water stress conditions [ Table 1 ] ( Al-Turki et al., 2023 ; Rajput et al., 2023a ).…”

Osmolyte-producing microbial biostimulants regulate the growth of Arachis hypogaea L. under drought stress

“…Drought is a severe abiotic factor constraining plants and the human population due to decreased precipitation worldwide in the 21st century. Drought severity, water scarcity, and extreme temperatures alter soil moisture, affecting plant survival and crop productivity [ 2 , 3 ]. This stress results in stunted plant growth, lowers crop yield, hampers molecular metabolism, increases cellular reactive oxygen species (ROS), and affects morphological, physiological, and biochemical attributes that negatively impact plant health growth and crop productivity [ 4 , 5 ].…”