Phylogenetic analysis and molecular evolution of the dormancy associated MADS-box genes from peach.
BACKGROUND
Dormancy associated MADS-box (DAM) genes are candidates for the regulation of growth cessation and terminal bud formation in peach. These genes are not expressed in the peach mutant evergrowing, which fails to cease growth and enter dormancy under dormancy-inducing conditions. We analyzed the phylogenetic relationships among and the rates and patterns of molecular evolution within DAM genes in the phylogenetic context of the MADS-box gene family.


RESULTS
The peach DAM genes grouped with the SVP/StMADS11 lineage of type II MIKCC MADS-box genes. Phylogenetic analyses suggest that the peach SVP/StMADS11-like gene family, which contains significantly more members than annual model plants, expanded through serial tandem gene duplication. We found evidence of strong purifying selection acting to constrain functional divergence among the peach DAM genes and only a single codon, located in the C-terminal region, under significant positive selection.


CONCLUSIONS
Because all DAM genes are expressed in peach and are subjected to strong purifying selection we suggest that the duplicated genes have been maintained by subfunctionalization and/or neofunctionalization. In addition, this pattern of selection suggests that the DAM genes are important for peach growth and development.
Jiménez
Sergio
S
Department of Horticulture, Clemson University, Clemson, SC 29634-0319, USA. sergij@clemson.edu
Lawton-Rauh
Amy L
AL
Reighard
Gregory L
GL
Abbott
Albert G
AG
Bielenberg
Douglas G
DG
D000595:Amino Acid Sequence; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D017343:Genes, Plant; D018745:Genome, Plant; D026161:MADS Domain Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D027861:Prunus / Q000235:genetics*; D012641:Selection, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D018744:DNA, Plant; D026161:MADS Domain Proteins; D010940:Plant Proteins