Harnessing culturable endophytic bacteria to enhance cultivation and Δ9-tetrahydrocannabinol (THC) production in drug-type Cannabis sativa

Global legislative changes have spurred a resurgence in interest in cannabis and its commercial cultivation. However, strict regulations have hindered scientific research into the endophytic microbiome of cannabis, particularly its potential to enhance crop yields. This study investigates how soil and planting material-derived bacteria affect the endospheres of ‘Foi Thong Suranaree 1’, a Thai drug-type cultivar of Cannabis sativa L. subspecies indica . The 16S rRNA sequencing revealed that soil significantly influences the bacterial endophytic microbiome diversity in various parts of the cannabis plant. Gammaproteobacteria emerged as the predominant endophytic bacterial community. Culturable endophytic bacteria, also dominated by Gammaproteobacteria , were isolated from cannabis buds, leaves, and roots. These bacteria exhibited plant growth-promoting (PGP) traits and meaningfully enhanced cannabis growth. Assessed individually and as a group, Gammaproteobacteria significantly increased the total dry weight at both the seedling (151.21 % increase individually, 106.36 % increase as a group) and harvesting stages (64.25 % increase individually, 43.86 % increase as a group). Remarkably, Δ 9 -tetrahydrocannabinol (THC) production increased by 237.50 % in a group of eight isolates. However, denaturing gradient gel electrophoresis (DGGE) found that some isolates had limited ability to recolonize. This stresses the importance of compatibility between introduced strains and hosts. Our findings highlight the potential of synthetic microbial communities (SynComs), which can be used to precisely manipulate cannabis endophytic microbiomes and boost sustainable agricultural practices. • Soil influences the diversity of cannabis endophytic bacterial microbiomes. • Gammaproteobacteria are the predominant endophytic bacteria in cannabis. • Cultivable endophytic bacteria markedly enhance cannabis growth. • Some bacterial isolates struggle to recolonize, stressing strain-host compatibility. • Consortium inoculation to create SynComs can customize bacterial matches for cannabis.