Global expression profiling of sulfur‐starved Arabidopsis by DNA macroarray reveals the role of O‐acetyl‐l‐serine as a general regulator of gene expression in response to sulfur nutrition

Abstract

SummaryTo investigate the changes in profiles of mRNA accumulation in response to sulfur deficiency, approximately 13 000 non-redundant Arabidopsis thaliana ESTs corresponding to approximately 9000 genes were analyzed using DNA macroarray. Three-week-old Arabidopsis plants grown on an agarose-solidified control medium were transferred to a sulfate-free medium and grown for 48 h for the analyses of sulfur-related metabolites and global gene expression profiles. Concentrations of sulfate, O-acetyl-L-serine (OAS), a positive regulator of sulfur deficiency-responsive genes, cysteine and glutathione (GSH) were determined. Plants transferred to sulfate-free media had reduced concentrations of sulfate and GSH, and OAS concentrations increased. Macroarray analysis revealed a number of genes, including APR2 and Sultr1;2, whose mRNA accumulation was increased by sulfur deficiency. Profiling was also carried out with plants treated with OAS under sulfate-sufficient condition. Scatter plot analysis revealed a positive correlation between the changes of expression levels by sulfur deficiency and by OAS treatment among the clones tested, suggesting that mRNA accumulation of a number of genes under sulfur deficiency is mainly controlled by OAS concentrations in tissues. It was also revealed that the sets of genes regulated under sulfur deficiency in leaves and roots differ considerably.

Metabolite profiling of Arabidopsis seedlings in response to exogenous sinalbin and sulfur deficiency

“…The contents of O-acetyl-L-serine (17) increased significantly in sulfur-deficient Arabidopsis seedlings, consistent with earlier reports (Nikiforova et al, 2003(Nikiforova et al, , 2005. Under short-term sulfur deficiency or with exogenous supplementation of O-acetyl-L-serine (17), the endogenous content of O-acetyl-L-serine (17) increased significantly in both leaves and roots of Arabidopsis (Hirai et al, 2003). Under sulfur deficiency, the decreased levels of cysteine resulted in the accumulation of its upstream metabolites, namely O-acetyl-L-serine (17), serine (19) and glycine (27) (Nikiforova et al, 2005).…”

“…Herein, however, it was demonstrated that the levels of galactinol (45) were elevated in response to sinalbin (1) supplementation only. O-Acetyl-L-serine (17) is a general regulator of gene expression associated with sulfur nutrition (Hirai et al, 2003). The contents of O-acetyl-L-serine (17) increased significantly in sulfur-deficient Arabidopsis seedlings, consistent with earlier reports (Nikiforova et al, 2003(Nikiforova et al, , 2005.…”

Cooperative Ethylene and Jasmonic Acid Signaling Regulates Selenite Resistance in Arabidopsis

“…Col-0 appears to also be better able to maintain a sufficiently large pool of reduced S compounds, especially glutathione, when treated with selenite, which may in part be responsible for its resistance. Incidentally, a reduction in GSH content was also observed in S-starved Arabidopsis (Hirai et al, 2003), indicating that selenite treatment induced S starvation in Ws-2 plants.…”

“…In view of the finding that both ethylene and JA appear to play important roles in selenite resistance in Arabidopsis, it is interesting to note that in earlier studies JA was implicated to be involved in the regulation of S metabolism because S starvation induced genes involved in JA synthesis, as well as JA-responsive genes (Hirai et al, 2003;Maruyama-Nakashita et al, 2003;Nikiforova et al, 2003). The above-mentioned studies showed no indication that ethylene plays a role in S deficiency responses.…”

“…Thus, the induction of some genes by selenite treatment may occur via S starvation, while others may be induced in a different, selenite-specific response. Earlier studies have shown that S deficiency induces the expression of 12-oxophytodienoate reductase, involved in JA biosynthesis (Hirai et al, 2003;Nikiforova et al, 2003). JA is known to be a plant hormone whose production is induced by various environmental stresses (Pieterse and van Loon, 1999).…”