The phylogenetic trees were constructed by the neighbor-joining method implemented by MEGA software, version 4.1. The numbers at each branch point represent the bootstrap scores (1,000 replicates). A branch with a bootstrap score of below 50 was usually considered unreliable. a Phylogenetic tree of Brassica and Arabidopsis NF-YA promoters. Due to low levels of nucleotide similarity, BnNF-YA4 homologues in B. oleracea were not included here. b Phylogenetic tree of Brassica and Arabidopsis NF-YB promoters. Due to low levels of nucleotide similarity, BnNF-YB14 homologues in B. oleracea were not included here. c Phylogenetic tree of Brassica and Arabidopsis NF-YC promoters. Bol and Bra represent B. oleracea and B. rapa, respectively. The numbers after the species abbreviation correspond to the individual gene name. Most promoters were at least 1000bp in length, except for those of BnNF-YA1 (595bp), BnNF-YA4/5 (577), BnNF-YA6 (806), BnNF-YA10 (892), BnNF-YB1 (519), BnNF-YB7 (988), BnNF-YB8 (391), and BnNF-YB13 (867) and their homologues in B. oleracea, B. rapa, and Arabidopsis.