The protein Compromised Hydrolysis of Triacylglycerols 7 (CHT7) acts as a repressor of cellular quiescence in Chlamydomonas

Abstract

Significance Microalgae accumulate valuable compounds under conditions adverse to growth. For example, nutrient starvation causes accumulation of triacylglycerols but also induces cellular quiescence, characterized by the reversible cessation of growth. Among other factors, this inverse relationship between biomass productivity and triacylglycerol accumulation has long hampered efforts toward the efficient generation of biofuel feedstocks from microalgae. The discovery of a mutant and corresponding protein of Chlamydomonas reinhardtii affecting the orderly transition of algal cells from quiescence to normal growth provides mechanistic insights to address this problem. Quiescent cells also are found in plants and animals. Thus, understanding how Chlamydomonas CHT7 affects the exit out of quiescence promises to provide important insights into the regulation of cellular behavior in multicellular organisms as well.