Plant Growth-Promoting Microbe Mediated Uptake of Essential Nutrients (Fe, P, K) for Crop Stress Management: Microbe–Soil–Plant Continuum

Abstract

The indiscriminate and intensive use of agrochemicals in developing nations to enhance crop productivity has posed an alarming threat to soil quality, fertility, biodiversity, food safety, agricultural sustainability, and groundwater quality, thus critically affecting planetary health and food productivity. Additionally, both abiotic and biotic stresses and developmental disorders, i.e., disease susceptibility, hormonal imbalance, and nutritional deficiency, are the major constraints on crop productivity. In this context, the use of soil–plant associated microbiomes “phytomicrobiome,” especially rhizospheric microbiota, in combination with agronomic practices (nutrient, water, and resource management, as integrated management options: INM/IPM/IWM) is the most promising alternative for managing soil health and crop productivity. The global recognition of plant/soil-associated microbiome has generated substantial investment of public and private bodies to grow microbe-based food products. However, understanding the molecular, genetic, physiological, and ecological aspects of phytomicrobiome toward sustainable agriculture would require broad attention along with associated environmental/physico-chemical control points. The underpinning mechanisms of plant–microbe interactions are of immense significance for strategizing host selection (single culture/consortia) and its field application. Taxa such as Rhizobium, Pseudomonas, Alcaligenes, Burkholderia, Sphingomonas, Stenotrophomonas, Arthrobacter, Bacillus, and Rhodococcus have emerged as promising plant growth-promoting (PGP) candidates with diverse beneficial traits, such as, producing phyto-hormones, volatile organics, antibiotics for disease suppression, N2-fixation, Fe uptake, and extracellular enzymes, but several physico-chemical constraints/extremities limit the field application (on-site) of such microbes. Hence, a detailed overview on genomic, physiological, metabolic, cellular, and ecological aspects is necessitated. Thorough insights into nutrient acquisition (especially limiting nutrients like Fe and P) during abiotic stress are still under-studied, so the use OMICS, robust bioinformatics pipeline/tools, might greatly revolutionize the field of PGP microbial ecology (complex plant–microbe interactions) for application in agricultural sustainability, nutritional security, and food safety. This review focusses on critical aspects of mechanisms of Fe and P transport-uptake (nutrient acquisition) by various PGP microbes, and their metabolism, genetics, and physiology relevant for managing stress and better crop production.

Impact assessment of cold-adapted Pseudomonas jesenii MP1 and Pseudomonas palleroniana N26 on Phaseolus vulgaris yield and soil health

“…In addition, it has been observed that MP1 treatment altered the microbial diversity with an increment in Firmicutes percentage over uninoculated control at both locations. Previous studies have positively correlated the proteobacterial and firmicute abundance with higher nutrient mobilization and improved soil fertility (Pattnaik et al, 2021;Suyal et al, 2021a). Further, in accordance with the present study, cold adaptive Cyanobacteria, Acidobacteria, Planctomycetes, Gemmatimonadetes, Firmicutes, and Nitrospirae phylum were also reported from higher altitude agroecosystems (Suyal et al, 2015;Suyal et al, 2021b).…”

Sulfur-Oxidizing Bacteria From Coal Mine Enhance Sulfur Nutrition in Pigeonpea (Cajanus cajan L.)

“…Some of them are responsible for the acquisition of minerals and nutrients from soil solutes, while others play important role in the transport of minerals from root hairs to sieve tubes and xylem bundles and subsequent transport to shoots. In plants, some of the key phosphate transporters are phosphate transporter PHO1 homolog 3, phosphate transporter PHO, inorganic phosphate transporters 1-4, probable inorganic phosphate transporters 1-3, and phosphate transporter PHO1 homolog 9 (Kulcheski et al, 2015;Suleman et al, 2018;Pattnaik et al, 2021). Several reports indicated the role of potassium transporters in the acquisition and transport of potassium from soil to plant roots and then shoot.…”

“…Several reports indicated the role of potassium transporters in the acquisition and transport of potassium from soil to plant roots and then shoot. However, potassium can be easily acquired by roots via Na + /K + flux and other ion channels (Kulcheski et al, 2015;Pattnaik et al, 2021). Similarly, in the recent past, a number of sulfate transporters were identified in a large number of plant species.…”

Dynamic microbial regulation of triiron tetrairon phosphate nanomaterials in the tomato rhizosphere

“…23 Ion (Fe) plays a crucial role in cell metabolism, encompassing vital processes such as chlorophyll synthesis, maintenance of chloroplast function, respiration, DNA synthesis, and severing as a prosthetic group for numerous metallo-enzymes involved in redox reactions. 24 Previous studies have indicated that foliar application with the Fe 2 O 3 NMs (30 mg L −1 ) significantly increased the nodule and shoot biomass of soybeans by 99.0 and 55.4%, respectively. These improvements were found to be 2.6- and 2.0-fold higher compared to the use of commercially available iron fertilizers containing equivalent amounts of Fe.…”