We published a recent review on the “Evolutionary Origin of a Terrestrial Flora” in Current Biology. It is a part of a special issue on the History of Life on Earth. It walks through a general overview of morphological and physiological transitions in the movement from charophyte green algae to a terrestrial flora. I had originally intended the article to emphasize genomic data much more heavily, but as I got started writing, much of the most compelling content revolved around how phylogenetic reconstruction can help focus models of how key events like the origin of a terrestrial flora took place.

The origin of a terrestrial flora is a topic that has really been heating up in recent years, largely, but not exclusively because of the availability of genome scale data. We have very few charophyte genomes available, but a number of groups have put out substantial transcriptome-based studies. The 1KP project has done a great job of broadly sampling plant and green algal transcriptomes, and although the data have not yet been fully released, it is clear that their efforts will have a huge impact on the field. My own lab is in the final stages of a Tree of Life project, and have a set of about 30 green algal transcriptomes of our own, which will be released to GenBank in early 2016.

There are a lot of exciting findings on the relationship between green algae and land plants. In January of 2015 we published a paper showing that Spirogyra has very plant-like ethylene response system. I plan to write more about that project later on, but I’ll just mention here that David Gallie has put out several excellent articles on the evolution of the plant ethylene receptors and their diversity, although his work focuses more on diversity within the embryophytes. This was complemented by some very nice work on desiccation responses in Klebsormidium by Burkhard Becker’s group, with an addendum here, showing multiple hormone systems activated in Klebsormidium in response to drying. Wonderful work on the evolution of cell wall biochemistry has been done by Joss Rose, Iben Sorenson and Michael Scanlon, as well by their collaborators David Domozych, and William Willats. Pierre-Marc Delaux et al. published on the signaling mechanism involved in establishing arborescent mycorrhizal symbioses. Pushing back a little bit to the end of 2014, Tom Viaene looked at the evolution of directional auxin transport in early-diverging land plants.

I’m sure I’ve forgotten some very important papers, but 2015 was a good year for the study of land plant (embryophyte) origin and diversification.