Poster: Reproductive Development
Abs #
485: COCH and PIM redundantly regulate floral meristem identity in pea
COCHLEATA (COCH) affects both stipule and floral development, while PROLIFERATING INFLORESCENCE MERISTEM (PIM) regulates the floral transition in pea. PIM is the ortholog of AP1 (Taylor et al. 2002. Plant Physiol.129, 1150.) Here we report that COCH and PIM redundantly function as floral meristem identity genes in pea. We have anlayzed double mutants of four COCH alleles, coch-w, coch-p, coch, and coch-het, in combination with pim-1, a large deletion mutation. The interactions range from complete suppression of floral meristem development (coch-w pim-1) to loss of second order inflorescence (I2) bract suppression resulting in compound leaves on the I2 (coch-het pim-1). We have followed the crosses through the F4 generation and find the expected ratios for two recessive alleles that are not linked. In one study, coch pim-1 plants segregated into early and late flowering backgrounds. Only a small delay in flowering is expected in otherwise wild-type late flowering lines under long day conditions, but late flowering lines of coch pim-1 could not initiate floral meristems even after producing 120 nodes. Those lines that flowered had clustered inflorescences with almost no internode elongation. Flowering was variable in coch-p pim-1 plants, but the variability does not appear to correspond to segregating floral time genes. We are continuing to pursue an explanation for this variable phenotype. In all our double mutants, carpels were absent, a more extreme phenotype than seen in pim-1 or any of the coch alleles. Supported by NSF 9977087.
