Sulfur in Seeds: An Overview

Abstract

Sulfur is a growth-limiting and secondary macronutrient as well as an indispensable component for several cellular components of crop plants. Over the years various scientists have conducted several experiments on sulfur metabolism based on different aspects of plants. Sulfur metabolism in seeds has immense importance in terms of the different sulfur-containing seed storage proteins, the significance of transporters in seeds, the role of sulfur during the time of seed germination, etc. The present review article is based on an overview of sulfur metabolism in seeds, in respect to source to sink relationships, S transporters present in the seeds, S-regulated seed storage proteins and the importance of sulfur at the time of seed germination. Sulfur is an essential component and a decidable factor for seed yield and the quality of seeds in terms of oil content in oilseeds, storage of qualitative proteins in legumes and has a significant role in carbohydrate metabolism in cereals. In conclusion, a few future perspectives towards a more comprehensive knowledge on S metabolism/mechanism during seed development, storage and germination have also been stated.

Keywords: seed germination; seed priming; seed storage proteins; sulfate transporters; sulfur.

Figure 1

A schematic representation of source-sink relationship of sulfur (S) in plants: an insight in uptake and transportation of sulfate (SO₄²⁻) in different plant parts by various transporters (SULTRs) and its assimilation, accumulation of S-containing seed storage proteins (SSPs) and regulation of S-mediated seed germination. (Abbreviations: OAS, O-acetylserine; SDI genes, sulfur deficiency induced genes; MYB28, myeloblastosis28; MYC2, master regulator of cell cycle entry and proliferative metabolism2; ABA, abscisic acid).