Format: ORAL

Laura vila Robledillo1, Aaryan Bhatia1, Andr Marques1

1. Max Planck Institute for Plant Breeding Research, Cologne, Germany

Sundews are carnivorous plants that grow in nutrient-poor habitats, such as bogs, swamps, and sand dunes. They are distributed globally, with more than 200 species described. In addition to carnivory, sundews are reported to have great diversity of genomic and chromosomal features. The chromosomes of sundews have been studied for over a century revealing extraordinary variability in chromosome number and ploidy across species. But perhaps, one of the most fascinating features of sundews chromosomes is the fact that several species analyzed within the genus Drosera lack a visible primary constriction, leading to the assumption that holocentricity is common in the genus. This is very exciting as it points to the occurrence of both monocentric and holocentric species in a single genus. Combining genomics and cytogenetics we are analyzing the genome of Drosera species differing in centromere organization. We assembled the genome of 5 selected species from the main clades using a combination of long-read sequencing technologies. In addition we made use of low-coverage Illumina short reads for the characterization of the repetitive fraction of the genome in additional species. Our preliminary data reveals the different genome architecture of mono- and holocentric Drosera and suggest that satellite repeats are associated with centromeres in both types. However, satDNAs are rarely conserved among Drosera species contrary to other reported holocentric species. Moreover, the development of specific centromere markers allowed us to verify the centromere type of our set of species. In addition our data gives insights into the evolution of the karyotypes of Drosera species. Synteny analyses among Drosera and its sister clade such as Nepenthes showed that events of fission and fusion are common in the group. This work could provide the bases for the understanding of the genomic changes associated with holocentricity as well as the drivers of this transition.