In an article to be published on January 16th, Liam Dolan and colleagues report the discovery that a transcriptional regulator called RSL controlled the development of unicellular and multicellular structures in the common ancestor of land plants that lived some time before 450 million years ago.
This discovery is important because it demonstrates that the RSL protein, which first appeared around the time plants colonized the land, played a key role in the evolution of new plant structures that helped plants survive on land.
When plants colonized the continental surfaces they evolved a number of new structures – adaptations – that allowed them to flourish in the new dry environment. These included single celled, thread like rooting structures that provided access to essential nutrients and multicellular structures involved in producing substances that stopped the plants drying out.
Dolan said “we were surprised to discover that RSL proteins controlled the development of a diversity of structures. We predicted that these regulatory proteins might regulate the development of the primitive rooting structures but the discovery that they controlled the formation of a range of structures that developed from the outer layer of the plant – the epidermis – was a real surprise”.
He also said “ this discovery tells us how new plant parts can evolve”. Understanding how the plethora of structures in the living world evolved is one of the major aims of contemporary biology. This not only provides insights into genetic events that occurred half a billion years ago, but it also provides tools that can be used by engineers to generate useful structures in plants.
Proust H, Honkanen S, Jones V, Morieri G, Prescott H, Kelly S, Ishizaki K, Kohchi T, Dolan L 2016 RSL class I genes controlled the development of epidermal structures in the common ancestor of land plants Current Biology