Functional Analysis of Cytoplasmic Serine Acetyltransferase (SAT-c) Involved in Sulfur Assimilation in Arabidopsis

Abstract

Serine acetyltransferase (SATase) catalyzes the formation of O-acetyl-L-serine (OAS) which is the essential precursor of cysteine biosynthesis. There are five SATase isozyme genes on Arabidopsis genome. The activity of cytoplasmic SATase (SAT-c) is highly sensitive to the feedback inhibition by cysteine, therefore, SAT-c seems to play an important role in sulfur assimilation in Arabidopsis. To clarify the role of SAT-c in sulfur assimilation pathway, we first identified T-DNA insertion knock-out mutant in SAT-c gene (KOC). The content of cysteine in KOC was reduced by approximately 50% as compared to that of wild-type Arabidopsis, although no significant changes in OAS and glutathione contents were observed in KOC plant. We are currently dealing with the DNA array analysis and comprehensive non-targeted metabolome analysis by FT-MS to investigate the impact of SAT-c mutation.