Mechanistic Insights of Plant Growth Promoting Bacteria Mediated Drought and Salt Stress Tolerance in Plants for Sustainable Agriculture

Abstract

Climate change has devastating effects on plant growth and yield. During ontogenesis, plants are subjected to a variety of abiotic stresses, including drought and salinity, affecting the crop loss (20–50%) and making them vulnerable in terms of survival. These stresses lead to the excessive production of reactive oxygen species (ROS) that damage nucleic acid, proteins, and lipids. Plant growth-promoting bacteria (PGPB) have remarkable capabilities in combating drought and salinity stress and improving plant growth, which enhances the crop productivity and contributes to food security. PGPB inoculation under abiotic stresses promotes plant growth through several modes of actions, such as the production of phytohormones, 1-aminocyclopropane-1-carboxylic acid deaminase, exopolysaccharide, siderophore, hydrogen cyanide, extracellular polymeric substances, volatile organic compounds, modulate antioxidants defense machinery, and abscisic acid, thereby preventing oxidative stress. These bacteria also provide osmotic balance; maintain ion homeostasis; and induce drought and salt-responsive genes, metabolic reprogramming, provide transcriptional changes in ion transporter genes, etc. Therefore, in this review, we summarize the effects of PGPB on drought and salinity stress to mitigate its detrimental effects. Furthermore, we also discuss the mechanistic insights of PGPB towards drought and salinity stress tolerance for sustainable agriculture.

Bacillus H47 triggers Olea europaea metabolism activating DOXP and shikimate pathways simultaneously and modifying leaf extracts’ antihypertensive activity

“…Photosynthesis determined by fluorescence indicated that the three Bacillus strains were able to improve plant fitness, bringing (Fv/Fm) to optimal values and decreasing basal stress according to F o values (Lucena et al, 2012). The decrease of PSII efficiency (ePSR; Figure 1C) together with the significant increase of energy dissipation support the ability of the three strains to alleviate oxidative stress induced by excess UV radiation and water stress, enabling a better use of resources (Ilangumaran and Smith, 2017;Sachdev et al, 2021;Gupta et al, 2022).…”

Is Endophytic Colonization of Host Plants a Method of Alleviating Drought Stress? Conceptualizing the Hidden World of Endophytes

“…Endophytes promote the availability of Fe 3+ ions under stress, alleviating Fe 3+ shortage for their hosts and, thus, interfere with this regulatory process (cf. [ 189 ]).…”

Arbuscular Mycorrhizal Fungi Mediated Alleviation of Drought Stress via Non-Enzymatic Antioxidants: A Meta-Analysis

“…Drought represents the alarming global abiotic stress phenomenon disturbing production and productivity in agriculture [ 1 , 2 , 3 ]. The ever-increasing population addresses the efficient use of dehydrated soils in drought-prone regions.…”

“…The ever-increasing population addresses the efficient use of dehydrated soils in drought-prone regions. Drought stress resilience mechanisms are unavoidable even in non-arid regions owing to seasonal changes [ 3 , 4 , 5 ]. Drought stress like other abiotic stress factors causes metabolic imbalance due to the accumulation of reactive oxygen species (ROS) including hydroxyl radicals (OH●), hydrogen peroxide (H 2 O 2 ), singlet oxygen ( 1 O 2 ), and superoxide radicals (−O 2 ) [ 3 , 4 , 6 , 7 ].…”

“…Drought stress resilience mechanisms are unavoidable even in non-arid regions owing to seasonal changes [ 3 , 4 , 5 ]. Drought stress like other abiotic stress factors causes metabolic imbalance due to the accumulation of reactive oxygen species (ROS) including hydroxyl radicals (OH●), hydrogen peroxide (H 2 O 2 ), singlet oxygen ( 1 O 2 ), and superoxide radicals (−O 2 ) [ 3 , 4 , 6 , 7 ]. However, upon culmination of ROS in cells leading to phytotoxic levels, ROS initiates oxidative cascades in an uncontrolled manner.…”