Identification and expression analysis of four CIPKs genes from a rare and medicinal plant, Dendrobium officinale / 药学学报

ABSTRACT

The calcineurin B-like protein (CBL)-interacting protein kinase (CIPK) plays a vital role in the growth, development, and stresses adaptation in plants by interaction with the calcium signaling. In this study, four full length cDNAs of CIPKs genes, namely DoCIPK1, DoCIPK2, DoCIPK3 and DoCIPK4 (GenBank accession No. KT957557, KT957558, KT957559 and KT957560, respectively) were cloned from the rear and medicinal plant, Dendrobium officinale, by rapid amplification of cDNA ends (RACE) for the first time. The corresponding encoded proteins, consisting of 473, 449, 451 and 440 amino acids (aa), respectively, with a molecular weight of 53.50, 50.93, 51.50 and 50.16 kDa, and an isoelectric point (pI) of 7.99, 9.25, 8.81 and 9.11, respectively, shared 70%-90%, 69%-80%, 78%-93%, and 66%-82% identities CIPKs with various plants. Each deduced protein contained a conserved protein kinase domain (respectively at 21 -275, 14-268, 16-271 and 12-266 aa position), a CIPKs family characteristic NAF/FISL domain (respectively at 335-391, 313-370, 310-369 and 305-362 aa position) and some functional motifs. The four DoCIPK proteins, without signal peptide or transmembrane region, were located in the plasma membrane and endoplasmic reticulum at the subcellular level. The three dimensional structure of the proteins were similar to that of Arabidopsis AtCIPK24. DoCIPK1 and DoCIPK3 were respectively clustered in the group E and A of the Arabidopsis and rice CIPK evolutionary tree, while DoCIPK2 and DoCIPK4 belonged to group C. The relative expression of DoCIPK1 showed no significant difference in the leaves and stems, and its transcripts in the roots was 0.35 fold over that in the leaves. The abundance of DoCIPK3 transcripts in the stems and the roots were 3.36 fold and 3.47 fold higher, respectively, than those in the leaves. DoCIPK2 exhibited similar expression pattern to DoCIPK4. Their relative expression in the leaves and the stems had no apparent difference, and the transcript levels were higher in the roots than that in the leaves, with 2.08 fold and 7.86 fold, respectively. Cloning, bioinformatics analyses, and expression patterns of the four DoCIPK genes provide a basis for functional elucidation of these genes further during the physiological responses in D. officinale.