Figure 4.

Effect of sulfate supply on the regulation of cysteine synthesis in Vitis vinifera cv Touriga Nacional cell suspensions. Thiols; GSH (A), cysteine (B), and OAS (C) content was analyzed in sufficient (+S) and deficient sulfate cell cultures (−S) and media. (D) Transcript levels of VvSERAT genes were determined by RT-qPCR from the +S and −S cells. From cell suspensions grown in −S (50 μM SO²⁻₄) or +S (1.5 mM SO²⁻₄) medium, samples were taken at day 1, 3, 5 and 7 of growth. cDNA obtained from RNA extracted from cell suspensions was normalized against the expression of Act2 RNA as described in Methods. The raw Ct values for Act2 expression in V. vinifera cells were 18.3 and 19.1 at day1, 18.1 and 17.8 at day 3, 18.9 and 18.2 at day 5, and 19.6 and 19.1 at day 7, respectively under −S and +S conditions. Error bars represent ± SD; n = 6. Different letters indicate statistically significant differences using Two-Away ANOVA (p < 0.05).