Microbial Phytases and Phytate: Exploring Opportunities for Sustainable Phosphorus Management in Agriculture

Abstract

Myo-inositol phosphates (phytates) are important biological molecules produced largely by plants to store phosphorus. Phytate is very abundant in many different soils making up a large portion of all soil phosphorus. This review assesses current phytase science from the perspective of its substrate, phytate, by examining the intricate relationship between the phytate-hydrolyzing enzymes and phytate as their substrate. Specifically, we examine available data on phytate's structural features, distribution in nature and functional roles. The role of phytases and their localization in soil and plant tissues are evaluated. We provide a summary of the current biotechnological advances in using industrial or recombinant phytases to improve plant growth and animal nutrition. The prospects of future discovery of novel phytases with improved biochemical properties and bioengineering of existing enzymes are also discussed. Two alternative but complementary directions to increase phosphorus bioavailability through the more efficient utilization of soil phytate are currently being developed. These approaches take advantage of microbial phytases secreted into rhizosphere either by phytase-producing microbes (biofertilizers) or by genetically engineered plants. More research on phytate metabolism in soils and plants is needed to promote environmentally friendly, more productive and sustainable agriculture.

Phosphobacteria as key actors to overcome phosphorus deficiency in plants

“…As mentioned before, in addition to inorganic phosphates, a large fraction of total soil P is present in organic form (Balaban et al, 2017). Although organic P forms can account from 30% to 65% of total soil P, they are usually not accessible for plants (Richardson, 2001).…”

“…Although organic P forms can account from 30% to 65% of total soil P, they are usually not accessible for plants (Richardson, 2001). Frequently, a high proportion of organic soil P is represented by phytate ( myo ‐inositol phosphate) and phytate‐metal complexes (Balaban et al, 2017). As opposed to plants, some soil phosphobacteria produce phosphohydrolases, known as phytases, a particular class of phosphatases able to mineralise organic P from phytate and related organic P sources, thus playing a central role in soil P cycling (Singh et al, 2020).…”

“…Phytases have several applications in food and feed industries, in the preparation of myo ‐inositol phosphates and as soil amendments for plant growth promotion (Jain et al, 2016). In phosphobacteria, phytases are widespread and have been reported in a variety of genera (Azeem et al, 2015; Balaban et al, 2017). Phytases of soil and plant‐associated phosphobacteria of the genera Bacillus , Enterobacter and Pseudomonas are extracellular, while those of Pantoea and Escherichia coli are located in the periplasm (Gessler et al, 2018).…”

Soil Fertility Management for Better Crop Production

“…For example, genetic variation between and within plant species in root exudation of organic acids has been demonstrated to enhance solubility and mobilization of soil P, thus increasing P use efficiency [9]. In addition, phytase enzyme exudation by plant roots is genetically controlled; therefore, development of transgenic plants that increase phytase concentration in the rhizosphere can increase P mineralization and P uptake [10].…”

Production of Plant Beneficial and Antioxidants Metabolites by Klebsiellavariicola under Salinity Stress

“…The beneficial effects of PGPR are sometimes not obtained due to various reasons such as the production of a limited number of plant growth-promoting (PGP) traits, competition with the native soil microflora, less root colonization, and sensitivity to biotic and abiotic stresses [ 2 , 3 , 20 ]. A multifarious and stress-tolerant PGPR can serve as an effective bioinoculant and stress elevator [ 25 ] that also helps in restoring soil health [ 26 , 27 ]. To be used as an effective bioinoculant, it is desired to confirm the multifarious plant growth-promoting, salinity ameliorating, and antioxidant ability of such PGPR.…”