Abstract：Calcium/calmodulin-dependent protein kinases (CaMKs) are important downstream targets of calmodulin. The activation of CaMKs can lead to the phosphorylation of various metabolic key enzymes or transcription factors, and complete the regulation of cell metabolic activity or the expression of numerous genes. In this research, 4 different CaMK gene fragments of Setosphaeria turcica named as CAK1, CAK2, CAK3 and CAK4 were obtained using degenerate primers. The full-length cDNAs of CAK1 (GenBank No. EU605885), CAK2 (GenBank No. EU605886) and CAK3 (GenBank No. EU605887) were cloned through 3'RACE and 5'RACE. The lengths of ORF, 3' UTR and 5' UTR of CAK1 were 1 218, 317 and 500 bp; those of CAK2 were 1 194, 400 and 563 bp; and those of CAK3 were 2 304, 405 and 207 bp, respectively. And the encoded products length of CAK1, CAK2 and CAK3 were 405, 397 and 767 amino acid residues (aa), respectively. The bioinformatics analysis revealed that these 4 CaMKs all belonged to multifunctional CaMKs and each contained 12 conserved kinase motifs. The conserved kinase domains of both CAK1 and CAK2 belonged to the catalytic domain of CaMK Ser/Thr protein kinase while that of CAK4 belonged to the RCK1-like Ser/Thr protein kinase. Unlikely, the conserved kinase domain of CAK3 was similar to the catalytic domain of liver kinase B1 (LB1) and calmodulin dependent protein kinase kinase (CaMKK). And they related to fungal CaMKs, CaMKKs and MAPK-activated protein kinases (MAPKAPKs) in the phylogenetic tree, respectively. Results of Real-time quantitative PCR (qRT-PCR) showed that during the conidial germination process, CAK2 and CAK3 were actively transcribed, and the transcriptional levels at every stage were higher than that at 0 h post induction. Especially, the expression levels of both CAK2 and CAK3 were significantly up-regulated at 6 and 24 h post induction (P＜0.05). On the contrary, the transcription levels of CAK1 and CAK4 at all stages were significantly lower than the mock (P＜0.05). In this research, we isolated 4 CaMK genes, preliminarily clarified their expression patterns during the conidial germination process, which provided informative references for the subsequent functional dissection of calcium signal pathway in S. turcica.
