Phylogenetic and evolutionary analysis of A-, B-, C- and E-class MADS-box genes in the basal eudicot Platanus acerifolia

London plane tree ( Platanus acerifolia Willd.) is an important member of the Platanaceae family, being popular as an urban landscaping tree. Here, we report the isolation of five MADS-box genes from the basal angiosperm, Platanus acerifolia . Sequence and phylogenetic analyses identified FRUITFUL -like, APETELA3 -like, AGAMOUS -like, SEPALLATA1 -like and SEPALLATA3 -like sequences and, hence, we term the respective Platanus acerifolia genes as PlacFUL , PlacAP3 , PlacAG , PlacSEP1 and PlacSEP3 . From these identities we infer that they represent candidate A-, B-, C-class and two E-class genes, respectively. The conserved MIK or MIKC domains from the nucleotide and protein sequences of PlacFUL , PlacAP3 , PlacAG , PlacSEP1 and PlacSEP3 were analyzed using the maximum-likelihood, MrBayes and neighbor-joining methods. The results confirmed P . acerifolia as a basal eudicot. Expression pattern was determined by reverse transcriptase PCR, which showed all paralogous genes have distinct expression patterns, suggesting that they had undergone functional divergence.