A transcriptional response atlas of Chrysanthemum morifolium to dodder invasion

Abstract

Abstract Chrysanthemum (Chrysanthemum morifolium), as one of the most commercially important ornamental crops, is threatened by dodder (Cuscuta spp.) during cultivation. When chrysanthemum was parasitized by dodder, growth of chrysanthemum slowed down and the leaves became dry and yellow. In the study, RNA sequencing assays were used for elucidating the immune response of chrysanthemum after dodder invasion and a total of 20,789 genes were differentially expressed. KEGG enrichment analysis revealed that these differentially expressed genes were involved in multiple pathways, “plant hormone signal transduction”, “cutin, suberine and wax biosynthesis”, and “plant-pathogen interaction”, etc. Combined with weighted gene co-expression network analysis (hereafter named WGCNA), we found that when the vascular connections were formed through haustoria, chrysanthemum recognized and fended off pathogens by the two stages of plant immune systems (PTI and ETI). Membrane bound receptors RLKs and the intracellular NLR proteins perceived pathogen-derived proteins and delivered the defense signals to trigger a series of defense responses in chrysanthemum. Reactive oxygen species (ROS), calcium, and MAPK-related pathways were triggered and a series of defense genes were up‐regulated. Besides, in stems of chrysanthemum, ET and SA signal transduction pathways played vital roles and had strong regulatory relationship with each other in response to dodder invasion. Our study provides an understanding of how chrysanthemum responds to dodder’s invasion, which could lay the basis for further revealing the interaction mechanism between chrysanthemum and dodder.