D3278: Transcriptional response of cannabis aphid to different hemp cultivars

Cannabis aphid (Phorodon cannabis) is a newly recognized pest species on hemp in North America. It causes feeding damage by primarily extracting fluids from the plant’s phloem using its piercing-sucking mouthparts and it may potentially transmit viruses and other pathogens, causing indirect damage. The aphid usually appears indoor or outdoor in early spring and autumn. We observed that in the greenhouse, it is commonly found on fiber hemp cultivars but seldom on cannabidiol (CBD) hemp cultivars. Furthermore, our preliminary studies found that the aphid population is high on fiber hemp cultivars such as Henola and Bialobrzeskie, but low on CBD hemp cultivars such as Citrus, BaOx, and Cherry Dwarf. A major difference between fiber and CBD hemp cultivars is their CBD content. CBD hemp cultivars contain a more significant amount of CBD than fiber hemp cultivars. Thus, we hypothesized that CBD contents of different hemp cultivars mediate the feeding preference of cannabis aphids to fiber hemp cultivars over CBD cultivars and inhibit the aphid growth and development. In this study, adult cannabis aphids were collected from five hemp cultivars (two fiber hemp cultivars and three CBD hemp cultivars). RNA was isolated and reversed transcribed into cDNA, then followed with high throughput sequencing and data analysis. We investigated specific genes of the cannabis aphid associated with the hemp cultivars to reveal the possible transcriptional regulatory mechanisms underlying the different responses of the cannabis aphid to different hemp cultivars. The ecological significance of the result is discussed.