CDPK gene family in Camellia nitidissima: genome-wide identification and expression analysis during petal development...

Calcium-dependent protein kinases (CDPKs) serve as key sensors and transducers of intracellular calcium signals, playing crucial regulatory roles in diverse physiological processes. However, research on CDPK genes in Camellia nitidissima remains limited.

In this study, we identified 34 CDPK genes distributed across 15 chromosomes in the C. nitidissima genome. Phylogenetic analysis further classified the CDPK gene family into five distinct subfamilies. Promoter cis-element analysis revealed regulatory motifs associated with hormone responses, growth and development, and abiotic stress tolerance. Expression analysis revealed that six CnCDPKs are specifically and highly expressed in petals at the bud stage. In contrast, CnCDPK15/28/31/34 exhibited significantly elevated expression during the senescence phase, suggesting their potential role in petal aging. Eight CnCDPK genes were highly expressed in stamens, with CnCDPK18 showing the highest expression, implicating these genes in stamen development. Collectively, CnCDPK9 and CnCDPK30 responded rapidly to MeJA treatment, whereas CnCDPK3, CnCDPK23, and CnCDPK31 responded rapidly to ET treatment, suggesting that these genes are key regulatory in MeJA- and ET-mediated physiological responses, respectively. Both CnCDPK3 and CnCDPK31 were significantly upregulated by MeJA, ET, and GA₃, suggesting their key roles in hormone signal crosstalk.

Our study identified the CDPK gene family in C. nitidissima, providing new insights into its regulatory roles in floral organ development and hormone signaling.