EVOLUTIONARY EXPANSION OF NUCLEAR FACTOR-YB GENE FAMILY IN SWEET ORANGE (Citrus sinensis)

Abstract

Transcription factors, such as Nuclear factor-Y (NF-Y), formed by 3 subunits, NF-YA, NF-YB and NF-YC, were considered to naturally operate as regulators of biological processes in crop plants. In this study, 3 duplicated gene pairs, including CsNF-YB11/-YB13, CsNF-YB3/-YB7 and CsNF-YB9/-YB17, have been computationally predicted in 19 previously published members of CsNF-YB gene family in sweet orange (Citrus sinensis). The subtelomeric regions of chromosomes are more permissive to the expansion of all segmental CsNF-YB duplicated genes. During the evolution process, natural selection had positively prevented the mutagenesis in the duplicated pairs. The conserved domain of NF-YB subunit in sweet orange was characterized by 3 regions, including DNA binding, NF-YA interaction and NF-YC interaction domains. Among them, the existences of several specific amino acids in these sequences showed that whole members of NF-YB not only play significant role in the construction of NF-Y but also may be involved in various biological processes in sweet orange.