The Genome of the Hornwort, Anthoceros agrestis

The monophyletic group of hornworts is believed to represent the immediate sister group of all vascular land plants. However, this traditional view is still debated and cannot be satisfactorily resolved owing to the lack of detailed knowledge on the general biology and genomic features of hornworts. Until now, advancement in this field was primarily hindered by the lack of genomic resources for a hornwort model species. Here we provide an update on the efforts towards a high-quality genome draft of the model hornwort, Anthoceros agrestis, and some of its relatives. We show that A. agrestis has a remarkably small genome, with few recent paralogs, which makes it approriate for genetic analysis. We also provide an overview of the A. agrestis gene space and a preliminary gene expression atlas which shed light on the regulation of morphological and developmental traits that are either shared with other embryophytes or unique to hornworts. Furthermore, we report our first achievements on the genetic transformation of A. agrestis using various techniques. Finally, we summarize our achievements and provide a list of issues that need to be resolved in the future.