 These "U. botrytis" MAT genes are essential for controlling colony size and asexual traits such as conidial size and number in "U.botrytis".The "U. botrytis" MAT genes have lost the ability to regulate sexual reproduction in "U. botrytis"; however, they have the ability to partially induce sexual reproduction in "Cochliobolus heterostrophus", a heterothallic species, upon heterologous complementation.