Cloning,expression and function analysis of DOLEA2 gene from Dendrobium officinale / 药学学报

ABSTRACT

LEA (late embryogenesis abundant) proteins that are highly hydrophilic and thermally stable play a role in plant defense. The full-length cDNA of DoLEA2 was cloned by rapid amplification of cDNA ends (RACE) from Dendrobium officinale (GenBank numberKY626329). The cDNA is 1 224 bp and encodes 313 amino acids. The deduced DoLEA2 protein contained LEA_2 and WHy domains. Multiple sequence alignment revealed that DoLEA2 shared a high homology with other species. Phylogenetic tree showed that DoLEA2 belonged to the monocotyledon and its closest relative was P. aphrodite. DoLEA2 was differentially expressed in the different organ. The expression was most abundant in the leaves, followed by that of the roots and stem. DoLEA2 could express in Escherichia coli BL21 (DE3), and the best induction conditions were 0.5 mmol·L-1 IPTG at 37℃ for 4 h. The growth curves of E. coli BL21 (DE3) showed that the recombinant DoLEA2 protein improved tolerate against salt stress over the control. This study represents the first time of cloning and identification of the function of LEA2 in D. officinale. The result sets up an important foundation for the molecular mechanism of stress resistance in Dendrobium officinale.