Inorganic sulfate serves as the foundational sulfur source assimilated by plants, microbes, and fungi for the biosynthesis of the sulfur-containing amino acids cysteine and methionine.
The retrieved literature consistently supports the fundamental biochemical pathway wherein organisms take up inorganic sulfate, assimilate and reduce it, and utilize it as the sulfur source to synthesize cysteine and methionine. Papers [0], [4], and [5] all discuss inorganic sulfate uptake and reduction to supply sulfur for sulfur amino acid biosynthesis.