Genetic Control by Arabidopsis Genes LEUNIG and FILAMENTOUS FLOWER in Gynoecium Fusion

Arabidopsis

gene FILAMENTOUS FLOWER (FIL) has been demonstrated to control the formation and development of inflorescence and floral meristems. This includes an early step in the establishment of a flower-forming domain within the floral primordium and the establishment of floral meristem identity. Another Arabidopsis gene LEUNIG (LUG) was previously found to specify the identity of the floral organ and control gynoecium fusion. In this paper, we describe floral phenotypes of a newly isolated fil allele, fil-21, and the phenotypic comparison of gynoecia between the fil-21 single mutant and fil-21 lug-101 double mutant. The gynoecium of fil-21 displays a well-fused structure, while that of the strong lug allele, lug-101, is unfused except at the gynoecium apex. However, gynoecia are markedly affected in the fil-21 lug-101 double mutant, being unfused. In late-appearing flowers of the double mutant, the gynoecia can even separate completely into several parts. These results suggest that LUG and FIL have a functional domain that is partially redundant in flower development, and synergistically regulate the gynoecium fusion.