An expressed sequence of tags (EST) which was highly similar to the calmodulin-like13 (CML13) gene of Arabidopsis was obtained,through sequencing of clones randomly selected from previously constructed cDNA library of Olimarabidopsis pumila leaves.This gene was cloned from leaf cDNA of O.pumila by RT-PCR technique,which was designated as OpCML13.Bioinformatics analysis showed that the open reading frame (ORF) of OpCML13 gene contained 447 bp encoding a peptide of 148 amino acids residues.The structural analysis of OpCML13 showed that it included four EF-hands motifs,and it is a hydrophilic protein,and no signal peptide and no transmembrane domain were found in OpCML13 protein indicating it is not a transmembrane protein.The tertiary structural analysis of OpCML13 through Swiss-model showed that it contained eight α-helixes and 10-β-turns.Phylogenetic tree revealed that OpCML13 showed closer genetic kinship with AtCML13 and AtCML14 of A.thaliana indicating that they belonged to the same evolutionary branch.Expression analysis by RT-PCR indicated that OpCML13 displayed a much broader expression range in different tissues in O.pumila,with a maximum expression in root.Under stress,expression of OpCML13 was induced with different kinetics and magnitude.The expression of OpCML13 was up-regulated as early as 6~24 h of salt treatment before rapidly returning normal level.OpCML13 mRNA significantly increased after cold,drought and ABA treatment for 6 h and remained elevated for at least 6 h.Our research indicated that OpCML13 played an important role in adversity stress.