Figure: Nearly 200 scientists published gene sequences from more than 1,100 green plants, yielding insights into the complex evolutionary history of species including green algae (left), gymnosperms (center) and flowering cherry trees (right). (Photo Source: Michael Melkonian and Walter S. Judd)

An international group of more than 200 scientists have now published the gene sequences of more than 1,100 green plants providing insights into everything from algae and ferns to farm crops and forest trees. The study, One Thousand Plant Transcriptomes and Phylogenomics of Green Plants, published in Nature reveals the history of how and when plants gained the ability to grow tall and make seeds, flowers and fruits, providing a framework for understanding plant diversity around the planet. The group, belonging to the One Thousand Plant Transcriptomes Initiative (1KP) examined the diversification of plant species, genes, and genomes across the more than one-billion-year history of green plants dating back to the ancestors of flowering plants and green algae.

James Leebens-Mack, professor of plant biology at the University of Georgia and co-corresponding author on the study, said their research shows that over the last billion years, ancestral green algal species split into two separate evolutionary lineages. One lineage included flowering plants, land plants, and related algal groups. The other lineage comprised a diverse array of green algae. He also noted plant evolution has been punctuated with innovations and periods of rapid diversification.

According to Mike Barker, an ecologist and evolutionary biologist at the University of Arizona, the biggest surprise of their study was the near absence of whole genome duplications in the algae. They found that the average flowering plant genome has nearly four rounds of ancestral genome duplication dating as far back as the common ancestor of all seed plants more than 300 million years ago. They also found multiple rounds of genome duplication in fern lineages, but found little of genome doubling in algal lineages. Aside from genome duplications, the expansion of key gene families contributed to the evolution of multicellularity and complexity in green plants.

For more details, read the University of Alberta's Folio.

http://www.isaaa.org/kc/cropbiotechupdate/article/default.asp?ID=17812