The Impact of Non-Nodulating Diazotrophic Bacteria in Agriculture: Understanding the Molecular Mechanisms That Benefit Crops

Abstract

Agriculture is facing increasing challenges with regard to achieving sustainable growth in productivity without negatively impacting the environment. The use of bioinoculants is emerging as a sustainable solution for agriculture, especially bioinoculants based on diazotrophic bacteria. Brazil is at the forefront of studies intended to identify beneficial diazotrophic bacteria, as well as in the molecular characterization of this association on both the bacterial and plant sides. Here we highlight the main advances in molecular studies to understand the benefits brought to plants by diazotrophic bacteria. Different molecular pathways in plants are regulated both genetically and epigenetically, providing better plant performance. Among them, we discuss the involvement of genes related to nitrogen metabolism, cell wall formation, antioxidant metabolism, and regulation of phytohormones that can coordinate plant responses to environmental factors. Another important aspect in this regard is how the plant recognizes the microorganism as beneficial. A better understanding of plant–bacteria–environment interactions can assist in the future formulation of more efficient bioinoculants, which could in turn contribute to more sustainable agriculture practices.

Dual RNA-seq of maize and H. seropedicae ZAE94 association, in different doses of nitrate, reveals novel insights into Plant-PGPB-environment relationship

“…The association process of H. seropedicae with poaceous species begins with the attraction of bacteria to the host roots, subsequently the bacteria attachment on the root surfaces occurs and finally the emergence points of the lateral roots are colonized ( Monteiro et al., 2012 ; Thiebaut et al., 2022 ). The RNA-seq analyses revealed that genes related to adhesion were down-regulated in the INN+ vs CTN+ comparison, including three genes coding for lipopolysaccharides (LPS) biosynthesis proteins ( rfaC , waaA and htrB ).…”

“…Plant associations with beneficial bacteria are combined to components of the environment such as soil, water or the atmosphere, functioning as a coordinated unit to generate plant adaptive responses, improving growth ( Carvalho et al., 2016 ). Many studies have shown that the efficiency of the plant association with PGPB is dependent on external factors, such as the plant genotype, the bacterial genotype, and the soil nutritional status ( Ballesteros et al., 2021 ; Carvalho et al., 2022 ; Thiebaut et al., 2022 ). Among the environmental factors, the nutritional composition of the soil plays a pivotal role in shaping the growth and development of plants.…”

“…The interactions between plants, beneficial bacteria and their environment are profoundly shaped by various environmental factors, including light, temperature, water availability, and soil quality ( Vargas et al., 2014 ; Li et al., 2019 ; Thiebaut et al., 2022 ; Leisner et al., 2023 ). These factors dictate a plant’s ability to thrive, affecting growth, resilience, and overall health.…”

Harnessing Green Helpers: Nitrogen-Fixing Bacteria and Other Beneficial Microorganisms in Plant–Microbe Interactions for Sustainable Agriculture

“…All these bacteria hold the potential to improve plant performance by enhancing the availability of nutrients and to improve soil fertility, mainly through BNF and also through other features such as phosphate solubilization or iron sequestration by siderophores [27,47,48]. In addition, they produce plant growth regulators and are involved in the modulation of phytohormone and defense responses, the production of antioxidants, osmotic adjustment, and plant tolerance against biotic and abiotic stresses, as reviewed in detail by Thiebaut et al [49].…”

Effect of inoculation with diazotrophs and treatment with solution of trace elements obtained by nanotechnology on wheat

“…Also, beneficial microorganisms colonizing the roots prevent infection of plants by phytopathogens (Mawarda et al, 2020). To optimize the interaction between associative microorganisms and non-legumes, various biotechnological approaches are used (Nag et al, 2020;Thiebaut et al, 2022).…”