MAL64 c is a global regulator of α-glucoside fermentation: identification of a new gene involved in melezitose fermentation

Summary Maltase constitutive mutants at the MAL6 locus have been mapped to the newly identified regulatory gene MAL64^c. We show here that MAL64^c has in addition pleiotropic effects on sugar fermentation: MAL64^c strains constitutively synthesize an -methylglucosidase and can complement a new gene, MTP1, for the fermentation of melezitose and -methylglucoside. MTP1, maps near MAL1, and either encodes a permease which transports melezitose, -methylglucoside, and maltose or regulates the activity of such a permease. This work shows that MAL64^c, a trans-acting regulatory gene, is a global regulatory gene affecting several different pathways of -glucoside metabolism.