Objective To research the CaM/CML gene family's characteristics in different tissues and symbiosis with mycorrhizal fungi of Orchidaceae.

Method Genome-wides of Phalaenopsis equestris and Dendrobium officinale were separately predicted and determined with bioinformatics methods based on the publishing protein sequences of CaM/CML gene family of Arabidopsis. The protein structures, phylogenetic trees, exon-intron structures of CaM/CML gene family in P. equestris and D. officinale were analyzed using different biological softwares. Gene expression analysis of different tissues (flower, leave, stem and root) in P. equestris and symbiotic with Tulasnella calospora and asymbiotic germination seeds from D. officinale were conducted by using RNA-seq data.

Result Four CaMs and fifty-four CMLs were separately predicted from P. equestris and D. officinale genomes. In P. equestris, forty-one genes did not have intron, seventeen genes had intron in CaM/CML gene family; and thirty-nine genes did not have intron, nineteen genes had intron in D. officinale. Phylogenetic analysis results showed that the CaMs and CMLs could be separately divided into ten subfamilies. The results of CaMs and CMLs genes expression analysis in different tissues of P. equestris indicated that nine genes were up-regulated in the leaf relative to the flower, stem and root, two genes were down-regulated; three genes were up-regulated in the flower relative to the leaf, stem and root; three genes were up-regulated in the flower and leaf relative to the stem and root. The results of gene expression analysis in symbiotic with T. calospora and asymbiotic germinated seeds from D. officinale by using RNA-seq data indicated that four genes were up-regulated, and four genes down-regulated.

Conclusion These results will lay the basis for the further studying of potential biological function and molecular mechanism of CaMs and CMLs genes in orchid.