Cloning and expression analysis of ERF transcription factor gene MeERF5 in cassava

【Objective】To clone ERF transcription factor gene MeERF5 and analyze expression pattern of the gene under stress conditions,so as to provide reference for studying regulation mechanism of MeERF5 gene in cassava.【Method】The full length of coding sequence(CDS)of MeERF5 gene in cassava variety SC8 was amplified by PCR and bioinformatics analysis was conducted. Subcellular localization was performed through Agrobacterium tumefaciens mediation method. Then relative expression of MeERF5 gene in different tissues and organs under different abiotic stress was identified by quantitative real-time PCR(qRT-PCR).【Result】CDS sequence of MeERF5 gene obtained through cloning was 948bp,which was 100.00% similar with a nucleotide sequence of reference sequence(accessing number:Manes.01G085200.1)in the Phytozome database,encoding 315 amino acid residues. MeERF5 protein had a theoretical molecular weight of77.84 kD and theoretical isoelectric point(p I)of 5.08,indicating it was an acidic protein. In its secondary structure,α-helix accounted for 16.51%,β-turn 3.81%,and random coil 62.22%,extended strand 17.46%. Subcellular localization was in the cytoplasm. Multiple sequence alignment and phylogenetic analysis showed that MeERF5 protein contained a conserved AP2/ERF domain,sharing a highest sequence similarity(76.8%)and close genetic relationship with ERF proteins in Hevea brasiliensis. MeERF5 gene was expressed in various tissues and organs of cassava,and its highest expression showed in stem,while the expression was the lowest in lateral bud. MeERF5 gene could quickly response to low temperature stress,drought stress,oxidation stress,salt stress and ABA treatment,thus showing up-regulated of induction expression. Under oxidation stress,relative expression of MeERF5 gene was up-regulated. Under drought stress,salt stress and ABA treatment,the expression of MeERF5 gene was increased firstly and then decreased. Under low temperature stress,the expression of MeERF5 gene peaked at 5 h and then decreased,but increased again at 48 h.【Conclusion】MeERF5 gene obtained through cloning is AP2/ERF transcription factor participates in abiotic stress responses in cassava.