Phosphobacteria as key actors to overcome phosphorus deficiency in plants

• Published in: Annals of applied biology 2021-03, Vol.178 (2), p.256-267
• Main Authors: Castagno, Luis N., Sannazzaro, Analía I., Gonzalez, María E., Pieckenstain, Fernando L., Estrella, María J.
• Format: Article
• Language: English
• Subjects: Bacteria; Bioavailability; biofertilisers; Biofertilizers; Enzymes; Fertilization; Microbial activity; Microbiota; Microorganisms; Nutrition; Perturbation; phosphate‐mineralising bacteria; phosphate‐solubilising bacteria; phosphobacteria; Phosphorus; phosphorus deficiency; phytases; Plant growth; rhizospheric microbiota; Soil structure; Soils
• ISSN: 0003-4746; 1744-7348
• DOI: 10.1111/aab.12673

Phosphorus (P), an essential macronutrient for all living organisms, is required in large amounts for the growth and development of plants. Although total soil P level is high, P bioavailability to plants is suboptimal in most soils because of high fixation rates into inorganic and organic insoluble complexes. Hence, plants are highly dependent on mechanisms that allow them to adapt to low‐phosphate stress and/or achieve suitable levels of soluble P on the root surface. In this regard, the rhizospheric microbiota plays a key role in facilitating P nutrition and has long been recognised for their potential use as an environmental‐friendly alternative to chemical P fertilisation. Herein, we outline the advances in the identification of phosphate solubilising bacteria and phosphate mineralising bacteria, collectively known as phosphobacteria, and their role in rendering P accessible to plants. We review and discuss research progress related to the introduction of phosphobacteria and/or P‐mineralising enzymes into soil, as well as plant transformation with bacterial genes that encode such enzymes, as strategies to improve plant growth and P nutrition. We also provide an overview of studies about the impact of variations in soil P levels on the structure of soil and rhizospheric microbial communities and the potential consequences of such perturbations on plant growth. Finally, we discuss possible directions for future research to optimise the efficiency of biofertilisation strategies based on the use of phosphobacteria. Phosphobacteria play key roles in agriculture by rendering soil P available for plants. Here we review current knowledge about the mechanisms of P solubilisation and mineralisation by phosphobacteria and their application for biofertilisation purposes. Biofertilisation approaches based on the mineralisation of organic P by microbial phytases, as well as advances in P acquisition by means of using transgenic plants that express microbial phytases, are also discussed. In addition, an overview of the impact of variations in soil P levels on rhizospheric bacterial communities is provided. Finally, possible directions for further improving P biofertilisation strategies are analysed.