Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

McCarthy, Elizabeth [1], Mohamed, Abeer [1], Litt, Amy [2].

The consequences of gene duplication: Functional divergence of APETALA1 and FRUITFULL in Arabidopsis thaliana.

Ancient gene and whole genome duplications have shaped the evolution of flowering plants.  We are interested in a duplication in the APETALA1/FRUITFULL gene lineage, which occurred at the base of the core eudicots and yielded the euAP1 and euFUL clades.  In Arabidopsis thaliana, APETALA1 (AP1) and FRUITFULL (FUL) have diverged functionally:  AP1 is involved in sepal and petal identity and FUL is best known for its role in fruit development.  However, both genes share a role in promoting floral meristem identity.  These genes are expressed in mutually exclusive domains during flower development and their proteins contain unique conserved motifs.  In order to determine whether the functional divergence of AP1 and FUL is due to changes in regulation or changes in coding sequence or both, we performed promoter swap experiments in which each gene was expressed under the promoter of the other gene and transformed into the corresponding mutant.  Our results show that under these conditions, FUL cannot substitute for AP1 in sepal and petal identity, but can partially substitute for AP1 function in floral meristem identity.  These results are consistent with published observations that ap1 ful double mutants show more severe loss of floral meristem identity than either single mutant.  We also examined the role of the unique conserved motifs in protein function.  One such motif results in post-translational modification of the AP1 protein; published data are contradictory regarding the necessity of this modification.  We performed site-directed mutagenesis to alter the amino acid sequence to prevent this modification. Transformants resemble wild type plants, suggesting that the protein modification is not necessary for proper AP1 function.  These results are corroborated by yeast two-hybrid experiments that show that mutant AP1 proteins interact with the same suite of proteins as AP1.  Our results suggest that divergence in both regulation and coding sequence are important in driving divergence in function of gene duplicates.  Experiments examining whether AP1 can substitute for FUL function and the importance of conserved motifs in FUL protein function are ongoing.

1 - The New York Botanical Garden, Plant Genomics, 2900 Southern Blvd., Bronx, NY, 10458, USA
2 - The New York Botanical Garden, 2900 Southern Boulevard, Bronx, NY, 10458, USA

Keywords:
floral development
functional divergence of gene duplicates
APETALA1
FRUITFULL
petal identity.

Presentation Type: Oral Paper:Papers for Topics
Session: 41
Location: Payette/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 1:30 PM
Number: 41001
Abstract ID:449
Candidate for Awards:None