Genome-wide identification and expression profiling of WRKY family suggest their potential role in cannabinoid regulation in Cannabis sativa L

Abstract

The WRKY transcription factors are unique and essential for plant development and various external stresses. The recent advancements in the genome and transcriptome research in Cannabis pave the path to discovering the transcription factors. However, minimal and non-reductant studies have been done to identify the complete WRKY transcription factor family based on the high-quality whole genome available in Cannabis sativa. With the recent surge in the therapeutic potential of cannabinoids, there is increased interest in the research on the developmental and adaptive potential of Cannabis sativa. The present study revealed a complete chromosomal-based identification of 48 WRKYs in Cannabis sativa and differentiated them into three main groups and one sub-group based on the physiochemical and phylogeny analysis. Furthermore, based on the composition of gene structure, motif analysis, and gene duplication analysis, the CsWRKY genes have remained conserved during evolution. Our study revealed that the upstream sequences of all the CsWRKYs had abiotic and biotic stress-related elements present that might display the role of the specific CsWRKY gene. Furthermore, to predict the potential regulatory network of CsWRKYs, functional analysis and protein-protein interaction were carried out and revealed their close networking and signalling. Recently, it has been shown that the CsWRKY might regulate the respective cannabinoid enzymes. Therefore, the expression patterns of CsWRKY genes in two accessions from different altitudes of Cannabis sativa -were evaluated. Most of the CsWRKY genes were significantly (p ≤ 0.05) highly expressed in the inflorescence of CAN2 (high altitude) accession, suggesting their possible role in inflorescence development or cannabinoid accumulation. CsWRKY18, CsWRKY27 and CsWRKY37 have shown similarities with the AtWRKY75, AaGSW1, and AaWRKY9, respectively and might be the candidate genes to explore further in determining the functions during inflorescence development and cannabinoid regulation. The present study lays the foundation to explore the biological processes and regulatory mechanism of CsWRKY genes during the growth, development, various stresses, and accumulation of secondary metabolites in Cannabis sativa.