Fig. 2

Phylogeny, structures and functions of expressed banana SPL family members. a Expression heat maps of 12 highly expressed MaSPLs under cold stress (left). Phylogenetic grouping and gene structure of expressed MaSPLs. Asterisks indicate highly expressed MaSPLs (brown) and down-regulated MaSPLs (green) under cold stress, respectively (right). The miR156 target sites are indicated with red boxes. b Protein motif arrangement, predicted stereostructure and evolutionary relationship of expressed MaSPLs and functionally characterized SPLs from Arabidopsis and rice. Phylogeny of these SPLs was determined based on their complete amino acid sequences by MEGA-X using the maximum-likelihood method. Bootstrap values were obtained using 1000 bootstrap replicates and shown next to the branches if > 50%. Three-dimensional structure of SPL proteins was predicted using SWISS-MODEL webserver. MEME motif search was based on the full-length protein sequences of SPLs. Conserved motifs are indicated by numbered colored boxes. Motif 1 and 3 indicate the two zinc fingers of the SBP domain. At, A. thaliana; Os, Oryza sativa; Ma, Musa acuminata