Molecular Mechanisms Determining the Role of Bacteria from the Genus Azospirillum in Plant Adaptation to Damaging Environmental Factors

Abstract

Agricultural plants are continuously exposed to environmental stressors, which can lead to a significant reduction in yield and even the death of plants. One of the ways to mitigate stress impacts is the inoculation of plant growth-promoting rhizobacteria (PGPR), including bacteria from the genus Azospirillum, into the rhizosphere of plants. Different representatives of this genus have different sensitivities or resistances to osmotic stress, pesticides, heavy metals, hydrocarbons, and perchlorate and also have the ability to mitigate the consequences of such stresses for plants. Bacteria from the genus Azospirillum contribute to the bioremediation of polluted soils and induce systemic resistance and have a positive effect on plants under stress by synthesizing siderophores and polysaccharides and modulating the levels of phytohormones, osmolytes, and volatile organic compounds in plants, as well as altering the efficiency of photosynthesis and the antioxidant defense system. In this review, we focus on molecular genetic features that provide bacterial resistance to various stress factors as well as on Azospirillum-related pathways for increasing plant resistance to unfavorable anthropogenic and natural factors.

The underground world of plant disease: Rhizosphere dysbiosis reduces above‐ground plant resistance to bacterial leaf spot and alters plant transcriptome

“…The physiological parameters measured pointed to a lower CO 2 assimilation in the tomato plants under dysbiosis, accompanied by higher intercellular CO 2 concentrations, suggesting that the plant is not efficiently converting CO 2 into sugars through photosynthesis, indicating a possible stress (Ethier et al, 2006). Beneficial plant-microbe interactions can influence photosynthesis by producing plant hormones like auxins, cytokinins, gibberellins, and abscisic acid (Costacurta & Vanderleyden, 1995;Gureeva & Gureev, 2023). Auxins and cytokinins can stimulate root growth, expanding nutrient uptake surface area, while gibberellins enhance nutrient translocation within the plant (Ravelo-Ortega et al, 2023).…”