SBP-domain alignment of the CclSBPs and polymerase chain reaction (PCR) cloning. (a) Multiple alignment of the SBP domains from the citrus SBP-box protein based on ClustalW program, and the two conserved zinc finger structures (Zn-1, Zn-2) and nuclear localization signal (NLS) are demonstrated; (b) sequence logo of the citrus SBP domain. The overall height of each stack represents the degree of conservation at this position, while the height of the letters within each stack indicates the relative frequency of the corresponding amino acids; (c) Detection of 15 the CclSBP family members in Citrus clementina. Lane 1: M, molecular marker, Marker 5000; From Lane 2 to Lane 16 is CclSBP1, CclSBP2, CclSBP3, CclSBP4, CclSBP5, CclSBP6, CclSBP7, CclSBP8, CclSBP9, CclSBP10 CclSBP11, CclSBP12, CclSBP13, CclSBP14, and CclSBP15, respectively.