Exploring the hemp virome and utilizing the results to screen for resistance to emerging viruses

While cannabis has become an emerging industry worldwide, the diversity and distribution of associated pathogens have yet to be adequately studied. As production increases and the crop diversifies, the emergence and spread of these pathogens are imminent. The goal of this study is to describe the diversity and distribution of viruses/viroids infecting hemp in Colorado to help prevent crop loss due to diseases. In this study, four major hemp-producing regions in Colorado were analyzed. Tissue samples were collected from two cultivars of hemp from each farm visited in these regions throughout the growing season. These samples were submitted for Next Generation Sequencing and upon bioinformatic analysis, candidate virus/viroid sequences were validated. In the 2021 virome, alfalfa mosaic virus, beet curly top virus (BCTV), cannabis cryptic virus, among others were identified in our samples. Additionally, the 2022 virome has shown an increase of prevalence of BCTV as well as the presence of tomato bushy stunt virus in addition to others previously described in 2021. With metagenomic data from previous work, 26 different lines of hemp were screened for resistance via qPCR to the top 2 predominant viruses/viroids found in the hemp virome in 2019, BCTV and hop latent viroid (HLVd). These 26 lines are genetically diverse which will facilitate the discovery of candidate genes involved in virus resistance. Beet curly top resistance screening has shown varying viral loads between lines while the HLVd screening is still underway. This work aims to further IPM strategies to promote sustainable agriculture.