Hornworts reveal a spatial model for pyrenoid-based CO-concentrating mechanisms in land plants.

Pyrenoid-based CO-concentrating mechanisms (pCCMs) turbocharge photosynthesis by saturating CO around Rubisco. Hornworts are the only land plants with a pCCM. Owing to their closer relationship to crops, hornworts could offer greater translational potential than the green alga Chlamydomonas, the traditional model for studying pCCMs.

Unique biogenesis and kinetics of hornwort Rubiscos revealed by synthetic biology systems.

Hornworts are the only land plants that employ a pyrenoid to optimize Rubisco's CO fixation, yet hornwort Rubisco remains poorly characterized. Here we assembled the hornwort Anthoceros agrestis Rubisco (AaRubisco) using the Arabidopsis thaliana SynBio expression system and observed the formation of stalled intermediates, prompting us to develop a new SynBio system with A. agrestis cognate chaperones.

ReFernment: An R package for annotating RNA editing in plastid genomes.

Premise Of The Study: In the absence of cDNA, the annotation of RNA editing in plastomes must be done manually, representing a significant time cost to those studying the organellar genomes of ferns and hornworts.

Methods And Results: We developed an R package to automatically annotate apparent nonsense mutations in plastid genomes. The software successfully annotates such sites and results in no false positives for data with no sequencing or assembly errors.

Mobile Elements Shape Plastome Evolution in Ferns.

Plastid genomes display remarkable organizational stability over evolutionary time. From green algae to angiosperms, most plastid genomes are largely collinear, with only a few cases of inversion, gene loss, or, in extremely rare cases, gene addition. These plastome insertions are mostly clade-specific and are typically of nuclear or mitochondrial origin.

Target sequence capture of nuclear-encoded genes for phylogenetic analysis in ferns.

Premise Of The Study: Until recently, most phylogenetic studies of ferns were based on chloroplast genes. Evolutionary inferences based on these data can be incomplete because the characters are from a single linkage group and are uniparentally inherited. These limitations are particularly acute in studies of hybridization, which is prevalent in ferns; fern hybrids are common and ferns are able to hybridize across highly diverged lineages, up to 60 million years since divergence in one documented case.