Selenium Accumulation and Speciation in Chickpea (Cicer arietinum) Impacted by S in Soils: Potential for Biofortification

Abstract

Dietary selenium (Se) deficiency is a well-known global problem originating from food crops grown in Se-deficient soil. Agronomic Se biofortification is one of the suitable options to minimize Se deficiency. Sulfur (S) is chemically similar to Se, and the role of S on the uptake and transformation of Se in grain has not been resolved. Considering this, our study examines the influence of S on the speciation and accumulation of Se in two chickpea cultivars (Amber and PBA sheamer) grown in Se-deficient soil under glasshouse conditions. Two doses of S (0 and 14 mg kg–1) as sulfate and three doses of Se (0, 1, and 2 mg kg–1) as selenate (SeVI) were used in a randomized factorial design. The addition of SeVI increased the Se content in grain in both cultivars compared to the control treatment. Speciation of Se analysis in grain showed that most (85%) of the Se accumulated in chickpea grain in the organic forms of Se as SeCys and MeSeCys. At 2 mg/kg Se addition, the biomass and grain yield was significantly reduced (P < 0.01), while S addition tended to increase the yield. Inorganic Se was below 15%, primarily as SeVI. PBA Sheamer, a desi type and widely grown chickpea cultivar, showed the most significant proportion of organic Se species, SeCys (57%) and SeMeCys (40%). Application of S contemporarily with Se showed increased SeMeCys production in the grain of PBA Sheamer cultivar. These findings indicated that the accumulation and speciation of Se in chickpea grain was dependent on both Se and S fertilization.