Abstract
Yeast giant colonies pass through developmental phases that are characterized by changes in the surrounding pH from acidic to alkali and vice versa. At the start of the alkali phase, colonies produce ammonia as a quorum sensing signal and extensively reprogram metabolism of their cells.
The ammonia signal is important for both horizontal and vertical colony differentiation. The latter is characterized by formation of two main cell subpopulations in central parts of differentiated colony: a subpopulation of metabolically active, stress resistant and vital cells in upper layers of the colony (U cells) and a subpopulation of stressed starving cells in colony interior (L cells) (Mol Cell 46:436, 2012).
We show here that the microcolonies originated from one cell develop similarly to giant colonies. Although the microcolonies are relatively young they also differentiate upon ammonia signal to cells similar to U and L cells of aged giant colonies.
U cells of microcolonies also activate metabolism controlled by TORC1 and decrease respiration capacity and L cells increase ROS production. These findings show that absolute colony age is not key factor of colony differentiation.
Only stress resistance of L cells, which significantly differs in microcolonies and giant colonies, is related to colony aging