Genome-wide identification of the CDPK gene family reveals the CDPK-RBOH pathway potential involved in improving chilling tolerance in peach fruit

Calcium-dependent protein kinase (CDPK), as an essential calcium receptor, plays a major role in the perception and decoding of intracellular calcium signaling in plant development and stress responses. Here, the CDPK gene family was analyzed at the genome-wide level in peach. This study identified 17 PpCDPK gene members from the peach genome, and systematically investigated phylogenetic relationships, conserved motifs, exon-intron structures, chromosome distribution, and cis-acting elements of each PpCDPK gene using bioinformatics. Furthermore, the expression levels of most PpCDPK genes were significantly changed under the CaCl2, EBR, GB, cold shock, hot water treatments, and various temperatures in the cold storage of peach fruits. RNA-seq data showed that PpCDPK2, PpCDPK7, PpCDPK10, and PpCDPK13 were related to postharvest chilling stress in peach. The interaction network of PpCDPK7 protein showed that the interaction between PpCDPK7 and PpRBOH may be the intersectional point of Ca2+ and ROS signal transmission during cold storage of peach fruits. These systematic analyses are helpful to further characterize the regulation of PpCDPKs and CDPK-RBOH mediated signal cascades in postharvest chilling injury in peach fruit.