Molecular cloning and characterization of cold-responsive gene Cbrci35 from Capsella bursa-pastoris

A new rare cold-inducible (RCI) gene designated Cbrci35 was cloned from Capsella bursa-pastoris, an edible wild herb, using the rapid amplification of cDNA ends (RACE) method. The full-length cDNA of Cbrci35 (Database Accession No.: AY566573) was 1300 bp and contained a 978 bp ORF encoding a precursor of 326 amino acid residues with a 23 amino acids signal peptide. The predicted Cbrci35 protein contained a peroxidase active site and proximal heme-ligand signatures, an RGD cell attachment sequence motif and two leucine zipper pattern motifs. Bioinformatics analysis revealed that Cbrci35 has a high level of similarity with RCI genes from Arabidopsis thaliana and peroxidases genes from other plants. RT-PCR analysis revealed that Cbrci35 expressed only in root. A cold acclimation assay showed that Cbrci35 was expressed immediately after cold triggering, but this expression was transient, suggesting that it concerns cold acclimation. But expression was not induced exposed to dehydration, salt stress or abscisic acid, indicating that it might be subjected specifically to cold regulation. These results indicate that Cbrci35 is an analogue of RCI genes and may participate in cold-response or increasing the freezing tolerance of plants.