Objective To clone the homologous gene of SOC1 from Camellia oleifera (CoSOC1-like) and to analyze its sequence structure, expression pattern and protein evolution.

Method Total RNA was extracted from the young leaves of three-years-old C. oleifera, and the CoSOC1-like gene was cloned by using RT-PCR technology and RACE (rapid amplification of cDNA ends) technology. The sequence and expression pattern of CoSOC1-like were analyzed using the bioinformatic tools and fluorescence quantitative PCR, respectively. The subcellular localization and evolution of CoSOC1-like protein were analyzed using the method of gene transient expression and MEGA7 software, respectively.

Result The full length cDNA of CoSOC1-like contained 654 bases, encoding 217 amino acids, and the relative molecular weight was 24.958 kD and the isoelectric point was 6.8. The Genbank accession number of CoSOC1-like is MT036382. The CoSOC1-like protein had the structure of MADS-box family transcription factors of plant type Ⅱ, and there was a SOC1 MOTIF in C-domain. The CoSOC1-like protein had 31 phosphorylative loci in its amino acid sequence, and its tertiary structure based on secondary structure had obvious active sites, and the transient expression of CoSOC1-like gene showed the CoSOC1-like protein located in nuclear, which was consistent with the nuclear localization characteristics of transcription factors. The phylogenetic analysis showed that the CoSOC1-like protein was clustered in the same evolutionary branch with SOC1-like protein of Camellia sinensis. Fluorescence quantitative PCR analysis showed that the CoSOC1-like gene could be detected in all organs, and there was a maximal relative expression level in flower buds of C. oleifera.

Conclusion The CoSOC1-like gene may play an important role in the flower bud differentiation, and participate in the growth and development of other organs such as root, stem, leaf and seed of C. oleifera.