Abstract: Calcium-dependent protein kinases (CDPKs) are Ca²⁺ sensor proteins, and they play an important role in plant growth, development and stress responses. On the basis of BoCDPK1 gene isolation, sequence analysis, phylogenetic analysis and expression analysis were performed to provide a foundation for both gene function identification and stress-resistance breeding in the future. PCR method was applied to isolate a CDPK gene from broccoli, and sequence analysis was performed by using bioinformatics. Expression patterns of this CDPK gene during Hyaloperonospora parasitica and Sclerotinia sclerotiorum infection were obtained by qRT-PCR. Sequencing results indicated that the full genomic DNA of BoCDPK1 was 2 414 bp in size with six introns. The complete coding sequence was 1 647 bp in length, encoding 548 amino acids. BoCDPK1 contained one S_TKc and four EF-hand domains. Multiple sequence alignment results revealed that BoCDPK1 shared the highest similarity with homologous sequences from Brassica plants and had a few amino acid differences, and they grouped to the same clade. qRT-PCR results showed that the expression of BoCDPK1 was induced by both H. parasitica and S. sclerotiorum, and the expression levels increased firstly and then decreased with the increasing of inoculation time. The highest expression level of BoCDPK1 was observed at 72 h after H. parasitica inoculation, with 3.4 fold higher than the control. When inoculated by S. sclerotiorum, the highest level was observed at 36 h after inoculation. Sequence characteristics, phylogenetic relationships and expression patterns of BoCDPK1 gene isolated from broccoli were confirmed.

Key words: Brassica oleracea var. italica, BoCDPK1, expression, Hyaloperonospora parasitica, Sclerotinia sclerotiorum