Cloning, Evolution and Expression Features of MAPK1 Gene Family from Brassica Species (B. napus, B. oleracea, B. rapa)

Objective】The objective of this study is to isolate MAPK1 gene family from Brassica napus,Brassica oleracea and Brassica rapa and analyze the transcriptional expression profiles of MAPK1 in various organs of these three species【.Method】On the basis of in silico cloning,the full-length cDNA and gDNA of MAPK1 genes were isolated from the three species using RACE(Rapid Amplification of cDNA Ends) technology.Organ specificity of MAPK1 in various organs of the three species was detected by quantitative real-time PCR(qRT-PCR).【Result】In this study,four MAPK1 genes including BnMAPK1-1,BnMAPK1-2,BoMAPK1 and BrMAPK1 were isolated from B.napus,B.oleracea and B.rapa.Their gDNA sequences were 2 512-2 525 bp,containing three exons and two introns.Standard mRNA lengths of these genes were 1 599-1 620 bp,all with an ORF of 1 100 bp.Phylogenetic tree showed that BnMAPK1 gene family was originated from the assemblage of B.oleracea and B.rapa MAPK1 genes,BnMAPK1-1 and BnMAPK1-2 corresponding to BoMAPK1 and BrMAPK1,respectively.qRT-PCR showed that MAPK1 genes expressed in all tested organs,but organ specificity showed significant differences among species implying quick evolution【.Conclusion】 In this study,the full-length cDNA and gDNA of MAPK1 genes were isolated from B.napus,B.oleracea and B.rapa.It supports the assumption that B.napus is a heterotetraploid species of B.oleracea and B.rapa by natural interspecific hybridization.Brassica MAPK1 genes show much conservation in gene and protein sequences and structures,but the transcription organ specificity evolves very fast and show significant differences among closely related species.