Potential role of DNA methylation and histone H3 acetylation in parasitism of Cuscuta

Abstract

Cuscuta campestris, or field dodder, is a non-photosynthetic, parasitic weed and a prominent agricultural pest. It is widely distributed in various climatic conditions and parasitizes over 100 different host plants in Bulgaria. The objective of the present study was to test the hypothesis that epigenetic regulation is key to the adaptation of Cuscuta spp. to different environments and host plants, as well as the response of host plants to parasitism. First, we tested 12 populations of C. campestris. Still, we found no correlation between the percentage of methylated DNA or acetylated histones and the most common host plant species, although significant differences were found. However, the effect of Cuscuta parasitism was much more pronounced on the enzymes, responsible for both DNA methylation and histone acetylation in the host plants. While changes were not so notable in the susceptible model host, Arabidopsis thaliana, the resistant host Solanum lycopersicum responded to parasitism with increased DNA methyltransferase and histone deacetylase activities and decreased DNA demethylation. All this suggests adaptation to parasitism, which is partially guided by epigenetic regulation. Further studies, including mapping of the methylated regions, are needed to better understand the epigenetic mechanisms of host adaptation to Cuscuta parasitism.