The Cucumber Kinome: genome-wide, identification, characterisation and expression analysis of the Cucumis sativus protein kinases in response to Powdery Mildew, Alternaria Leaf Spot and Root-Knot Nematode

It is widely known that protein kinases (PKs) play a fundamental role in regulating various metabolic processes in plants, from development to response to the environment. However, a detailed characterization of this superfamily is still lacking for several species, such as cucumber (Cucumis sativus), especially regarding their involvement in the response to Powdery Mildew (PM) caused by Podosphaera xanthii. This study aimed to characterize the cucumber PK family, shedding light on its genomic distribution, classification, and expression patterns triggered by P. xanthii. The hidden Markov models (HMMs) analysis uncovered 835 PKs in the cucumber kinome, distributed across its seven chromosomes, and categorized into 20 distinct groups and 123 families, with the RLK group being the most abundant. Evidence of tandem duplication of PK genes was also observed, enriching our understanding of cucumber PKs. To investigate the expression profiles of PK genes in cucumber, we analyzed the transcription levels of all 835 PK genes in RNA-seq data from leaves of resistant and susceptible cultivars of cucumber to P. xanthii, which were artificially inoculated. Depending on the treatment, DEGs ranged from 319 to 1,690, with PK DEGs ranging from 8 to 105. The number of PK DEGs varied between the different contrasts analyzed. Notably, we observed a greater number of PK DEGs in susceptible genotypes when challenged by the pathogen. Our findings indicate the role of specific cucumber PKs in regulating metabolic processes in the context of plant-pathogen interactions and pave the way for further research into the intricate mechanisms underlying cucumber responses to Powdery Mildew. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=169 SRC="FIGDIR/small/532963v3_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@11340b8org.highwire.dtl.DTLVardef@fe1896org.highwire.dtl.DTLVardef@5de8org.highwire.dtl.DTLVardef@1564d0_HPS_FORMAT_FIGEXP M_FIG C_FIG