Evaluating the Microbiome of Hemp

Plant microbiomes contribute to plant fitness and crop yields through a variety of mechanisms. Determining variability in microbiome composition among individuals of a species, and identifying core microbiome membership, are essential first steps for exploring host-microbe interactions. Members of a core microbiome are microorganisms that are tightly associated with and are found widespread across individuals of a plant genotype or species. Hemp (Cannabis sativa L.) is an economically important crop that has gained a resurgence following its removal from the list of controlled substances by the U.S. government. Despite renewed interest in this crop, the microbiome of hemp has not been well studied. We analyzed the bacterial and fungal communities associated with four plant compartments (rhizosphere, root tissue, leaf surface, and flowers) of C. sativa 'Anka' across six fields in the Finger Lakes region of New York, United States. We found that both bacterial and fungal community composition varied significantly among plant compartments. Rhizosphere communities were largely similar to the bulk soil communities but root tissue, leaf, and flower communities had distinct compositions. We identified candidate core microbiome members of each plant compartment (bacterial core taxa: root tissue [n = 6], leaves [n = 11], and flowers [n = 7]; fungal core taxa: rhizosphere [n = 1], leaves [n = 14], and flowers [n = 2]). Many of these candidate core microbiome members were related to organisms previously associated with plant growth promotion or pathogen resistance in various plants. The core microbiome identified in this study can be further investigated to improve cultivation of this important crop.