Essential for the progression of premeiotic mitosis and meiosis during sporogenesis. Regulates the cell division of premeiotic germ cells, the proper modification of meiotic chromosomes, and the faithful progression of meiosis, probably via small RNA-mediated gene silencing. May be involved in histone H3 'Lys-9' demethylation in the pericentromeric region. Expressed specifically in male and female archesporial cells and sporogenous cells (SC) before meiosis but not in the nursery cells supporting SC. Arrest of meiosis in male and female germ cells, causing seed sterility. Belongs to the argonaute family. Ago subfamily.