Sulfur-oxidizing Bacteria: A Novel Bioinoculant for Sulfur Nutrition and Crop Production

Abstract

Sulfur is an essential nutrient for plant growth as sulfur-deficient conditions cause severe losses in crop yield. Sulfur nutrition has received little attention for many years, since fertilizers and atmospheric inputs have provided adequate amounts. However, recent reductions in sulfur inputs from atmospheric depositions have resulted in a negative sulfur balance in agricultural soils, making crop plants increasingly dependent on the soil to supply sulfur. Thus to alleviate this deficiency, sulfur fertilizers are invariably added to soils, usually in a reduced form, such as elemental sulfur. Yet, reduced sulfur fertilizers must be oxidized to sulfate before they become available to the plant, a process that is mediated by microorganisms. Sulfur and sulfur fertilizers and physiological role of sulfur in crop plants and interaction of sulfur with other elements along with ecological niches for isolation of sulfur-oxidizing bacteria and their role in sulfur oxidation in soil and sulfur nutrition to crop plants are discussed.