Identification and expression of FLOWERING LOCUS C homologous genes in Carya cathayensis

Based on two open reading frames （ORFs） of Carya cathayensis FLOWERING LOCUS C （CcFLC） genes which were acquired from 454 sequencings of Carya cathayensis buds，primers were designed and amplified with polymerase chain reaction （PCR）. An amino acid hydrophobicity analysis was also conducted. Acquired the sequencing revealed 639 bp and 612 bp，coded 212 amino acids and 203 amino acids，and GenBank accession numbers of JQ829074 and JQ829075，respectively. These had typical MADS-box structures with a nucleotide homology of 78% and an amino acid homology of 67%. The 5 end homology was high，but there was a big difference in the 3 end. Compared to amino acids coded from the FLOWERING LOCUS C （FLC）-like genes of Taihangia rupestris and Pyrus pyrifolia，the two ORFs were 40%-57% similar. Amino acid hydrophobicity analysis showed that carboxyl terminals were hydrophobic amino acid and amino terminals were hydrophilic amino acid with most amino acid residues being hydrophobic. Results of the Real-time PCR showed that the two ORFs of the CcFLC gene were expressed in the stem，young leaf，terminal bud，female flower，and male flower of C. cathayensis，but their relative expression for the same tissue was higher for ORF1 than ORF2. ORF1 was maximum in the stem，but minimum in the leaf and male flower; whereas ORF2 was maximum in the female flower and minimum in the stem.［Ch，7 fig. 23 ref.］