Yeast cells under glucose-limitation environment need increased response cost for osmostress defense

Cells always make responses to environmental changes, involving dynamic expression of tens to hundreds of proteins. This response system may demand substantial cost and thus affect cell growth. Here, we studied the cell’s responses to osmostress under glucose-limitation environments. Through analyzed thirteen osmotic-downstream proteins and two related transcription factors, we found that the cells required stronger responses under low glucose concentrations than normal glucose condition after being stimulated by osmostress, even the cell growth rate was unchanged in these two constant conditions. We proposed and verified that under a glucose-limitation environment, the glycolysis intermediates were limited (defense reserve saving), which caused that cells needed more glycerol production enzymes to adapt to the osmostress. Further experiments proved that this ‘defense reserve-saving’ strategy required cells to spend more response cost when facing stress, which on the other hand, enhanced the fitness for the coming environment variations via protein accumulation reserve.