Biodissolution of silica by rhizospheric silicate-solubilizing bacteria

Silicon (Si) remains mostly unavailable for plant uptake despite its status as the second most copious element on earth, due to its low solubility in the soil. Microorganisms are known to be crucial in dissolving minerals like phosphates and silicates. Silicon availability is known to be enhanced when insoluble silicon is solubilized by the organic acids produced by microbes. Silicon is known to be released by different bacterial strains of the genera Burkholderia, Bacillus, Proteus, Pseudomonas, Rhizobia, and Enterobacter to improve plant growth. Therefore silicate solubilizing bacteria (SSB) inoculation of soils, seeds and crops is a promising, environmentally friendly strategy for enhancing the worldwide food production. A better understanding of the recent developments in mode of actions and functional diversity regarding SSB should facilitate the use of SSB as a reliable component of sustainable agricultural systems. The current chapter discusses various SSB can solubilize silicates, and thus potentially be used as biofertilizers. The mechanisms with which SSB solubilize, isolate, and screen silicates are also highlighted. In addition, the information gaps related to SSB in soils, as well as the current and future aspects for SSB in crop productivity are addressed.