Comparative transcriptomics reveals how domestication of blueberries has shaped herbivore-induced gene expression

While previous studies have highlighted the differences in plant defenses between domesticated plants and their wild counterparts that impact insect-plant interactions, there remains a gap in our understanding regarding how domestication influences the expression of herbivore-induced defense genes in plants. Highbush blueberry (Vaccinium corymbosum), a perennial shrub native to the northeastern United States, has been under domestication for approximately a century. This plant is known to be rich in plant secondary metabolites, including phenolic compounds, likely associated in defense against herbivores. In this study, we investigated changes in the transcriptomes of wild and domesticated highbush blueberry plants when subjected to herbivory by the spongy moth (Lymantria dispar). Our results showed that a total of 3,106 genes were differentially expressed in domesticated plants, while 3,107 genes were differentially expressed in wild plants, upon exposure to herbivory by L. dispar as compared to undamaged plants. Particularly, our results revealed differential expression of genes associated with the biosynthesis of plant defense compounds between domesticated and wild damaged plants. Notably, we observed the upregulation of phenylalanine ammonia-lyase (PAL) in wild plants, which catalyzes the initial step in the biosynthesis of defensive phenolic compounds. This study aims to identify genes implicated in defense against herbivores in both domesticated and wild plants, offering valuable insights for future breeding initiatives aimed at enhancing insect resistance in highbush blueberries.