Phosphate Solubilizing Microorganisms: Promising Approach as Biofertilizers

Abstract

Phosphorus (P) is a macronutrient required for the proper functioning of plants. Because P plays a vital role in every aspect of plant growth and development, deficiencies can reduce plant growth and development. Though soil possesses total P in the form of organic and inorganic compounds, most of them remain inactive and thus unavailable to plants. Since many farmers cannot afford to use P fertilizers to reduce P deficits, alternative techniques to provide P are needed. Phosphate solubilizing microbes (PSMs) are a group of beneficial microorganisms capable of hydrolyzing organic and inorganic insoluble phosphorus compounds to soluble P form that can easily be assimilated by plants. PSM provides an ecofriendly and economically sound approach to overcome the P scarcity and its subsequent uptake by plants. Though PSMs have been a subject of research for decades, manipulation of PSMs for making use of increasing fixed P in the soil and improving crop production at the field level has not yet been adequately commercialized. The purpose of this review is to widen the understanding of the role of PSMs in crop production as biofertilizers.

Plant growth promoting rhizobacteria isolated from halophytes and drought-tolerant plants: genomic characterisation and exploration of phyto-beneficial traits

“…In the case of SAVSo04, the association between the very low levels of P in the soil (Vlichada, Santorini), the in vitro ability of strain to solubilize P, and the appearance of P-solubilizing genes within its genome, highlights the importance of such bacteria for plant survival under P-deficient conditions. Although the pqq coenzyme is not exclusively linked to P uptake 21 , the co-existence of these genes along with the in vitro evidence described above, support the notion that these two strains are P-solubilizing microorganisms in line with previous studies 61,63 . By contrast, the in vitroP-solubilizing bacteria (AXSa06 and SSTh08) lacked orthologs of the pqq or gds genes, implying a putative alternative mechanism that requires further elucidation.…”

Isolation and Identification of Phosphate Solubilizing and Nitrogen-Fixing Bacteria from Lake Ol’Bolossat Sediments, Kenya

“…Although soil possesses total phosphorous in organic and inorganic forms, essentially, they remain inactive and or bound to soil constituents making them unavailable for utilization by plants. Even with supplemented phosphorous, about 70-90% of chemical phosphorus fertilizers added to the soil become fixed by forming metal-cation precipitate complexes thus making them unavailable (Kalayu, 2019). Therefore, the insoluble forms of phosphate are converted into soluble forms via phosphate solubilizing microbes through the organic acid production, chelation and exchange reactions (Behera et al, 2017).…”

Phosphate-Solubilizing Rhizobacteria: Diversity, Mechanisms, and Prospects in Sustainable Agriculture

“…Phosphorus (P) is the second-most important nutrient after nitrogen in terms of plant growth and development (Alori et al, 2017;Kalayu, 2019;Mitra et al, 2020;Pradhan et al, 2017). This nutrient element is important in virtually every metabolic process in plants from photosynthesis, biosynthesis of macromolecules, and respiration to energy transfer and signal transduction (Billah et al, 2019;M.…”

“…B. Sharma et al, 2013). It is a fundamental component of enzymes, proteins, coenzymes, nucleotides, phospholipids, and nucleic acids (Alaylar et al, 2020;Kafle et al, 2019;Kalayu, 2019). According to Mitra et al, (2020), P availability also improves other basic plant functions such as cell division, cell enlargement, and transformation of starches and sugars.…”

“…Contrary to the expectation, the continuous application of P fertilizers has even been shown to contribute to loss of soil fertility through the constant disturbance of natural microbial ecosystems in soil (Gyaneshwar et al, 2002). The efficiency of applied chemical P fertilizers is also reported to rarely exceed 30% due to its fixation in the form of iron/aluminium phosphate in acidic soils or calcium phosphate in neutral/alkaline soils (Alori et al, 2017;Kalayu, 2019;A. Kumar et al, 2018;Satyaprakash et al, 2017).…”