DIVERSIFICATION OF C-FUNCTION ACTIVITY IN MAIZE FLOWER DEVELOPMENT

The Arabidopsis gene AGAMOUS is required for male and female reproduct ive organ development and for floral determinacy. Reverse genetics all owed the isolation of a transposon-induced mutation in ZAG1, the maize homolog of AGAMOUS. ZAG1 mutants exhibited a loss of determinacy, but the identity of reproductive organs was largely unaffected. This sugg ested a redundancy in maize sex organ specification that led to the id entification and cloning of a second AGAMOUS homolog, ZMM2, that has a pattern of expression distinct from that of ZAG1. C-function organ id entity in maize (as defined by the A, B, C model of floral organ devel opment) may therefore be orchestrated by two closely related genes, ZA G1 and ZMM2, with overlapping but nonidentical activities.