cDNA cloning and characterization of a new stress‐responsive gene BoRS1 from Brassica oleracea var. acephala

A new stress‐responsive gene BoRS1 (GenBank accession No. AY373021 ) was isolated from Brassica oleracea var. acephala by rapid amplification of cDNA ends (RACE). The full‐length cDNA of BoRS1 was 2076 bp and contained a 1851 bp open reading frame (ORF) encoding 617 amino acids. Sequence analysis indicated that the deduced BoRS1 shared some identities with LTI65 , RD29A, RD29B and COR78 from Arabidopsis thaliana. Southern blot analysis of genomic DNA indicated that other related genes existed and there were two copies of BoRS1 in the genome of B. oleracea. Northern blot analysis revealed that BoRS1 was up‐regulated by cold, mannitol, NaCl and abscisic acid (ABA). Expressional fluctuation of time course with ABA implied a two‐step induction process. Tissue‐specific expression analysis indicated that BoRS1 was expressed in all the tested plant tissues including leaves, stems and roots. Our studies imply that BoRS1 is a new gene that is responsive to environmental stresses such as low temperature, salinity and osmotic stress.