Required for the promotion of megasporogenesis, or promotion of germ cell formation from somatic precursor cells. Acts redundantly with WIH1. Functions in a genetic pathway downstream of SPL/NZZ and WUS and together with TRN2 in promoting megasporogenesis. Expressed in floral organ primordia. During ovule development, expressed in the nucellus from early stage until embryo sac maturity. In mature ovules, expressed in the nucellus and the outer integument. No visible phenotype under normal growth conditions, but flowers of the double mutants wih1-1 and wih2-1 have defect in megasporgogenesis. Doubl mutant plants display retarded growth, and twisted leaves, siliques and roots. Belongs to the CYSTM1 family.