Genome-Wide Identification of MYB Gene Family Reveals Their Potential Functions in Cadmium Stress Response and the Regulation of Cannabinoid Biosynthesis in Hemp (Cannabis sativa L.)

Backgroud: Heavy metal pollutant, Cadmium (Cd), is an inorganic pollutant in China. Hemp (Cannabis sativa L.) is an important fiber crop to remediate heavy metal-contaminated soils. The MYB family is one of the largest and most important gene families that influences plant growth and produce secondary metabolites. Results: 115 CsMYB genes were identified in the hemp genome. The 1R-MYB subfamily had 17 genes, the 2R-MYB subfamily 88 genes, and the 3R-MYB subfamily 8 genes. The synteny analysis of the CsMYB genes indicated that there were 3 pairs of tandem repeats, 21 pairs of segmental duplication, 6 CsMYB genes present before species differentiation, and 60 genes belonging to the hemp-specific CsMYB genes. 7 CsMYB genes were identified to influence the response to Cd stress by combining the transcriptome data of two hemp species under Cd stress. Based on the changes in the Cannabinoid content of hemp under Cd stress, the expression of different CsMYB genes in hemp with high and low cannabidiol (CBD) contents, and tissue-specific expression, it was inferred that CsMYB024 may be affected by Cd stress and mediate the CBD synthesis pathway.Conclusions: This study provides a comprehensive analysis of the hemp MYB family. These results should be helpful in understanding of their potential functions in Cd-Stress Response and the Regulation of Cannabinoid Biosynthesis in Hemp. In addition, lays the foundation for the further study of biological functions of CsMYBs in hemp.