Molecular cloning and characterization of three CoIDA genes in Camellia oleifera

The INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) controls floral organ abscission in plants. IDA belongs to IDA-LIKE (IDL) gene family that is involved in regulation of Arabidopsis development. Herein, we identified three genes, CoIDA1, CoIDA2 and CoIDA3 in Camellia oleifera (Camellia oleifera Abel. cv. Huashuo) and suggested their involvement in the regulation of fruits abscission. The full-length cDNA sequences of CoIDA1, CoIDA2 and CoIDA3 were of 207 bp, 276 bp and 273 bp, encoding proteins of 68, 91 and 90 amino acids, respectively. These CoIDA genes were single exon genes (SEGs) with a conserved extended PIP motif (EPIP) at C-terminal that has been implicated to play an important role in governing protein function for enhanced flower abortion rate. The highest expression of CoIDA1 was in young peduncles and the lowest in young fruits. However, the highest expressions of CoIDA2 and CoIDA3 were both in young roots, and the lowest in young fruits. The expressions of CoIDA1 and CoIDA2 significantly increased in abscission zones (AZs) of both abnormal fruits (AF) and ethephon treated fruits (ETH-F) with respect to normal fruits (NF), which suggest that CoIDA1 and CoIDA2 genes are related to fruits abscission in C. oleifera. This study provided a preliminary understanding about CoIDA genes which could lead to their detailed functional analysis and utilization for improving C. oleifera yield potential.