Meristem culture is an effective biotechnology tool widely employed to eliminate systemic endophytes, including viruses, bacteria, and fungi, from plants. In Cannabis sativa, endophytic contaminants can significantly affect plant health and cannabinoid yield and pose a challenge for large-scale cultivation. Meristematic tissue, located at the growing tips of plants, is free of vascular connections, where many endophytes commonly reside, and spread. Thus, meristems are an ideal source of pathogen-free plants. Through the isolation and cultivation of meristems, clean and robust cannabis clones can be developed, enhancing quality control and consistency in cannabinoid production. To evaluate the effectiveness of meristem culture in removing endophytic contaminants, advanced sequencing techniques and microbial profiling were used to compare endophytic communities before and after meristem culture.

Krona plots visualized and analyzed the endophytic loads of four cannabis strains (1512, 1354, 1513, and 1500) was evaluated using Next Generation Sequencing (NGS) following both nodal and meristem intake. PDA plate indexing further identified colonies of endophytic contaminants. Plants derived from nodal tissue exhibited endophytic loads of 22-30% of the total DNA genome. Strains 1500 and 1513 showed high bacterial contamination, primarily Bacillus and Pseudomonas species, whereas strains 1512 and 1354 contained more pathogenic fungi, such as Fusarium. In contrast, plants from meristem culture exhibited a substantial reduction in endophytic load, down to 2-3%, with no pathogens detected. The presence of endophytes identified through NGS Krona plots, included Fusarium, Alternaria, Penicillium, Aspergillus, and Pseudomonas, was confirmed with PDA plate indexing. These results confirm that meristem culture is an effective approach for enhancing the health and quality of cannabis strains by significantly reducing endophytic contamination.

Learning Objectives:

• Effectiveness of Meristem Culture

• Use of Advanced Profiling Techniques to analyze and visualize shifts in microbial communities

• Analyze and visualize shifts in microbial communities