The synthesis of secondary metabolites plays a central role in the survival of plants and their resistance to biotic and abiotic stress. Nevertheless, fundamental and applied studies of plant secondary metabolites, polyisoprenols, remain underdeveloped. The wide distribution of polyisoprenols in plants shows their important role in cellular metabolism. Plant polyisoprenols are synthesized by cis-prenyltransferases (CPTs), the study of which is necessary to understand the synthesis pathways, localization, and functions of plant polyisoprenols. Bryophytes, including the liverwort Marchantia polymorpha, are a unique group of plants with great potential for the study of CPTs. We analyzed the genome of M. polymorpha and identified seven CPT genes, which are homologous to the AtCPT7 and AtCPT3 genes of Arabidopsis thaliana, involved in the synthesis of polyisoprenols. Four individual lines of M. polymorpha plants with mutations in the MpCPT7.37 gene were obtained. It was shown that in three lines the mutation led to a translational frameshift and gene knockout. However, knockout of only the type 7 CPTs had no effect on plant growth and survival. Analysis of the antibacterial activity of mutant plant tissue extracts did not reveal significant changes compared to wild-type tissue extracts, this could be related to a compensatory effect of the activity of other CPTs. These data give us the required base for the further studies of bryophytes CPTs and their products.