Pleiotropic signaling pathways orchestrate yeast development

Developmental phenotypes in Saccharomyces cerevisiae and related yeasts include responses such as filamentous growth, sporulation, and the formation of biofilms and complex colonies. These developmental phenotypes are regulated by evolutionarily conserved, nutrient-responsive signaling networks. The signaling mechanisms that control development in yeast are highly pleiotropic — all the known pathways contribute to the regulation of multiple developmental outcomes. This degree of pleiotropy implies that perturbations of these signaling pathways, whether genetic, biochemical, or environmentally induced, can manifest in multiple (and sometimes unexpected) ways. We summarize the current state of knowledge of developmental pleiotropy in yeast and discuss its implications for understanding functional relationships.

► Nutrient stress induces developmental switches in Saccharomyces cerevisiae (baker’s yeast) and related fungi.
► The signaling pathways that control development are highly pleoiotropic.
► Because of signaling pathway pleiotropy, developmental phenotypes can be strongly correlated.
► Pleiotropy can be exploited in functional studies to discover or understand interactions within and between signaling pathways.
► Understanding the causes and consequences of pleiotropy is important in ecological, clinical, and agricultural contexts.