Title : Coupling of gland development and secondary metabolite synthesis in cotton
Abstract:
Cotton (Gossypium spp.) has evolved pigment glands (PGs) that accumulate toxic terpenoids, such as gossypol, which serve as a defence mechanism against pests. Laboratory experiments and field trials have confirmed that PGs are essential for tolerance to chewing pests in cotton. The intricate genetic mechanisms underlying the development of PGs and their role in the accumulation of secondary metabolites in cotton represent a significant focus for enhancing pest resistance in agricultural biotechnology. Our research identifies the gene GhVQ22, specific to PG tissues, as a pivotal regulator influencing both the size of these glands and the synthesis of secondary metabolites, notably gossypol. Through laser-capture microdissection transcriptome analysis and gene editing techniques, we demonstrate that the suppression of GhVQ22 results in enlarged PGs and modified secondary metabolite profiles, including a reduction in gossypol content and alterations in other key metabolites like kaempferol and catechin. The downregulation of GhVQ22 correlates with marked changes in the expression of PG development-related genes, offering new insights into the genetic interplay responsible for gland morphogenesis and metabolic pathways. Furthermore, our study reveals that GhVQ22 interacts with the core PG regulatory factors Gl2 and Gl3, suggesting a genetic network that finely balances the gland development with secondary metabolite synthesis. These findings not only contribute to our understanding of glandular trichomes in plants but also underscore the potential for genetic interventions in cotton to produce varieties with enhanced natural defence against pests.
