Increase of hybrids in yeast electrofusion by mitochondrial mutations

Yeast mitochondria were found to affect the zeta-potential of protoplasts, resulting in electrofusion of membrane behavior. For modeling purposes, two fusion systems were investigated: (1) parent yeasts of Saccharomyces cerev isiae G706 (rho(+)) x O708-11-16A (rho(+)), with zeta-potentials of -10 to -27 mV and -28 to -45 mV, depending on MgCl2 concentration in the medium, r espectively; and (2) parent yeasts of S. cerevisiae G706-1 (rho(-)) x O708- 11-16A (rho(+)), with zeta-potentials of -30 to -60 mV, depending on MgCl2. Yields of the hybrids in system (2) were over 100-fold higher than those i n system (1). Thus, regulation of yeast electrofusion was found to be possi ble by mitochondrial mutations. (C) 2000 John Wiley & Sons, Inc.