Cloning and Expression Analysis of a BnMKK4 Gene from Brassica napus L.

In this study,we isolated a novel MAPKK gene,BnMKK4,from Brassica napus.The cloned full-length cDNA was 1 317 bp,contained a 993-bp opening reading frame(ORF),a 5'-untranslated region(5' UTR) of 159 bp,and a 3'-untranslated region(3' UTR) of 165 bp.The BnMKK4 exhibited closest homology to AtMKK4,so it was named the BnMKK4(GenBank accession No.JF268686).The deduced protein was 330 amino acids with molecular weight 36.5 kDa and isoelectric point 9.01.RT-PCR analysis revealed that the transcript level of BnMKK4 was higher in experimental plants than in control plants.The results suggested that the BnMKK4 gene is involved in response to cold and salt stresses and that BnMKK4 played an important role during cold and salt stresses in Brassica napus.