Genetic diversity of LEAFY homologues in Chrysanthemum argyrophyllum L

The LEAFY (LFY) gene encodes a key transcription factor involved in flower development. In this study, we identified the LFY homolog in Chrysanthemum argyrophyllum L. (CaFL) and sequenced eight clones from a single plant. The cloned genes varied in length (2915-3075 bp) and each had three exons and two introns. The three exons were highly conserved, so intron variance was primarily responsible for gene length differences. The putative CaFL proteins from the eight clones were 99% identical to one another and greater than 97% identical to Chrysanthemum lavandulifolium DFL and Chrysanthemum nankingense CnFL. Intraspecific and interspecific sequence comparisons of the two introns indicated that they varied considerably in both length and sequence composition. Phylogenetic analysis showed that CaFL is more similar to dicotyledonous FLO/LFY-like proteins than to those from monocotyledons or gymnosperms.