Neochrome evolution in ferns

Photo by Fay-Wei Li, via phys.org

Some very exciting new research on fern evolution was just published in the Proceedings of the National Academy of Sciences! Researchers have known for years that ferns possess a chimeric photoreceptor, called neochrome, that allows them to use both red and blue light for photosynthesis. This is a significant advantage in forest understories where blue light has often been filtered out by overhanging leaves of taller plants. In the new paper published yesterday, a team of researchers led by Fay-Wei Li at Duke has discovered that neochrome in ferns is actually most closely related to neochromes in hornworts, and that it likely passed from hornworts to ferns via horizontal gene transfer about 179 million years ago. The timing of this event suggests that this transfer, and the low-light photosynthetic ability it conferred on ferns, allowed them to subsequently diversify "in the shadow" of angiosperms, as the latter exploded in diversity starting around 120 million years ago. This is a really cool finding, and expands our understanding of fern evolution and diversification tremendously!

Check out more coverage of this story in the Economist:
Time and change: The survival of ferns to the present depended on an ancient accident

And at Phys.org:
Ferns borrowed genes to flourish in low light

And read the abstract of the paper here (subscription to PNAS required for full article):
Horizontal transfer of an adaptive chimeric photoreceptor from bryophytes to ferns