Divergence of TERMINAL FLOWER1-like genes in Rosaceae

Rosaceae is a large family, however, our understanding of its phylogeny is based largely on morphological observations. To understand the relationship between subfamilies Rosoideae, Amygdaloideae, Maloideae and Spiraeoideae at a molecular level, we isolated and compared the plant phosphatidyl ethanolamine-binding protein-like genes TERMINAL FLOWER1 (TFL1)-like and CENTRORADIALIS (CEN)-like, which are involved in the control of shoot meristem identity and flowering time. A comparison of gene structures and phylogenetic tree analyses by the Neighbor-Joining method showed that each of the two TFL1-like (MdTFL1-1 and MdTFL1-2) and CEN-like genes (MdCENa and MdCENb) in Maloideae were classified into two distinct clades. The TFL1-like and CEN-like genes of Gillenia in Spiraeoideae belonged to monophyletic Maloideae groups, suggesting that Gillenia and Maloideae have a common near ancestor. However, the Gillenia TFL1-like gene does not contain the insertion sequence of the third intron that is found in MdTFL1-2-like genes of the members of Maloideae such as apple, Korean whitebeam, quince, and Siberian mountain ash. Therefore, after the Maloideae ancestor genome became polyploid through hybridization between Gillenia-like species or genome doubling, an insertion sequence of the third intron of MdTFL1-2-like genes was generated.