2.1 Strains and media
All strains and plasmids used in this study were listed in supplementary tables S1 and S2, respectively. S. cerevisiae were cultivated in YPD medium containing 10 g/L yeast extract, 20 g/L peptone and 20 g/L glucose. Escherichia coli DH5α was grown in LB medium (5 g/L yeast extract, 10 g/L NaCl and 10 g/L tryptone), and 100 mg/mL ampicillin was added. Synthetic Dropout (SD) medium was composed of 20 g/L glucose and 6.7 g/L amino acid-free yeast nitrogen source (YNB). Minimal (Delft) medium was adopted to cultivate S. cerevisiaestrains [20] containing 20 g/L glucose, 2.5 g/L (NH4)2SO4, 14.4 g/L KH2PO4, 0.5 g/L MgSO4•7H2O, 2 ml/L trace metals, 1 ml/L vitamin solution, and amino acids were supplemented if necessary. Solid plates contain 20 g/L agar.
The specific amounts of exogenous amino acids or nucleotides added in media are as follows. In preliminary experiments, low (20-60 mg/L, Figure S2) and high (100 mg/L, Figure S3) concentrations of amino acids or nucleotides were added in the culture medium, respectively, to determine the growth and production of the auxotrophic strains. Furthermore, we set 100 mg/L as the baseline to test the essential amounts of amino acids and nucleotides for each auxotroph to restore cell growth and bio-productions. For example, the concentrations of leucine, tryptophan, lysine (Figure 2) and methionine (Figure 3) were increased from 100 mg/L to 500 and 1,000 mg/L, respectively. The concentrations of histidine, arginine (Figure 4), uracil and adenine (Figure 5) were decreased from 100 mg/L to 20 and 60 mg/L.