Pan-phylum genomes of hornworts reveal conserved autosomes but dynamic accessory and sex chromosomes.

Hornworts, one of the three bryophyte phyla, show some of the deepest divergences in extant land plants, with some families separated by more than 300 million years. Previous hornwort genomes represented only one genus, limiting the ability to infer evolution within hornworts and their early land plant ancestors. Here we report ten new chromosome-scale genomes representing all hornwort families and most of the genera.

The ancestral chromatin landscape of land plants.

Recent studies have shown that correlations between chromatin modifications and transcription vary among eukaryotes. This is the case for marked differences between the chromatin of the moss Physcomitrium patens and the liverwort Marchantia polymorpha. Mosses and liverworts diverged from hornworts, altogether forming the lineage of bryophytes that shared a common ancestor with land plants.

PURC Provides Improved Sequence Inference for Polyploid Phylogenetics and Other Manifestations of the Multiple-Copy Problem.

Inferring the true biological sequences from amplicon mixtures remains a difficult bioinformatics problem. The traditional approach is to cluster sequencing reads by similarity thresholds and treat the consensus sequence of each cluster as an "operational taxonomic unit" (OTU). Recently, this approach has been improved by model-based methods that correct PCR and sequencing errors in order to infer "amplicon sequence variants" (ASVs).

Talks Back: Temporal Patterns of Differential Gene Expression During Establishment of Symbiosis.

Endosymbiotic associations between hornworts and nitrogen-fixing cyanobacteria form when the plant is limited for combined nitrogen (N). We generated RNA-seq data to examine temporal gene expression patterns during the culturing of N-starved in the absence and the presence of symbiotic cyanobacterium . In symbiont-free .

Homoploid hybrids, allopolyploids, and high ploidy levels characterize the evolutionary history of a western North American quillwort (Isoëtes) complex.

Polyploidy and hybridization are important processes in seed-free plant evolution. However, a major gap lies in our understanding of how these processes affect the evolutionary history of high-ploidy systems. The heterosporous lycophyte genus Isoëtes is a lineage with many putative hybrids and high-level polyploid taxa (ranging from tetraploid to dodecaploid).

Low-copy nuclear markers in (Isoëtaceae) identified with transcriptomes.

Premise Of The Study: Few genetic markers provide phylogenetic information in closely related species of (Isoëtaceae). We describe the development of primers for several putative low-copy nuclear markers to resolve the phylogeny of , particularly in the southeastern United States.

Methods And Results: We identified regions of interest in transcriptomes based on low-copy genes in other plants.

: A new quillwort from Mississippi, USA.

S.W. Leonard, W.