AINTEGUMENTA, AN APETALA2-LIKE GENE OF ARABIDOPSIS WITH PLEIOTROPIC ROLES IN OVULE DEVELOPMENT AND FLORAL ORGAN GROWTH

To understand better the role of genes in controlling ovule developmen t, a female-sterile mutant, aintegumenta (ant), was isolated from Arab idopsis. In ovules of this mutant, integuments do not develop and mega sporogenesis is blocked at the tetrad stage. As a pleiotropic effect, narrower floral organs arise in reduced numbers. More complete loss of floral organs occurs when the ant mutant is combined with the floral homeotic mutant apetala2, suggesting that the two genes share function s in initiating floral organ development. The ANT gene was cloned by t ransposon tagging, and sequence analysis showed that it is a member of the APETALA2-like family of transcription factor genes. The expressio n pattern of ANT in floral and vegetative tissues indicates that it is involved not only in the initiation of integuments but also in the in itiation and early growth of all primordia except roots.