PhoPR system of Bacillus sp. RZ2MS9 and its response to phosphate fertilization in corn

Abstract

Phosphorus is an essential nutrient for the development and growth of plants. In tropical regions, this element is strongly retained in the soil matrix. Thus, in these places, producers need to apply high doses of phosphate fertilizers, a non-friend environmentally practice and not economically sustainable. Plant growth promoting rhizobacteria (PGPR) are microorganisms capable of solubilizing nutrients, such as phosphorus and, consequently, making them available to their hosts. The genus Bacillus is known as a microorganism capable of promoting plant growth and its effect is widely described in several important crops and has already been used in the formulation of bioinoculants, biopesticides and biofungicides. The Bacillus sp. (RZ2MS9) plays an important role in promoting maize and soybean growth and some genes have already been identified for the pathway of AIA biosynthesis, flagellar motility, chemotaxis and biofilm synthesis, which help the bacteria to move towards the exudates of the plant and facilitate adherence. Genes related to phosphate mineralization and solubilization have been identified, as well as genes regulating environmental phosphorus signaling, such as the phoR and phoP genes. These genes belong to the two-component system (TCS), a cellular mechanism responsible for responding to environmental changes. The PhoPR TCS is specific for signaling and responding to lack of phosphorus. Thus, this project aims to study a two-component PhoPR system and its participation in the phosphorus solubilization process by the RZ2MS9 strain using the phoP and phoR gene knockout technique via CRISPR-Cas9. (AU)