INSIGHT INTO THE NUCLEAR FACTOR-YA TRANSCRIPTION FACTOR FAMILY IN SWEET ORANGE (Citrus sinensis)

Nuclear factor Y (NF-Y), including NF-YA, NF-YB and NF-YC is well-established to play an important role in regulation of the developmental processes and stress responses in plants. In this study, 6 members of the NF-YA gene family were identified in the sweet orange (Citrus sinensis) genome. Among them, 2 members, CsNF-YA1 and CsNF-YA6 might be localized in the chloroplast, while CaNF-YA3 was thought to be associated with the secretary pathway. The common motif of the exon/intron organization of the CaNF-YA contains 5 exons and 4 introns. The conserved region of NF-YA is characterized by 2 typical domains, including the interaction NF-YB/C domain and the DNA binding domain. Next, various cis- regulatory elements related to the light responsiveness, tissues-specific expression and hormonal/stress responsiveness were predicted to be distributed on the promoter regions of NF-YA family, suggesting that this gene family might be related to the light conditions, tissue-specific expression and response to hormonal/stresses. Based on the available RNA-Seq, all of CsNF-YA genes were up-regulated in at least 1 organ/tissue. Interestingly, two genes, CsNF-YA1 and CsNF-YA6 were specific in callus, while CsNF-YA4 was preferentially expressed in fruit. Three remaining genes were highly expressed in all 4 tissues/organs, including callus, flower, fruit and leaf.