Scientists have speculated for more than 200 years about the success and remarkable diversity of flowering plants, which have fueled a significant portion of modern animal diversity and serve as the basis of our food system.
Writing Thursday in the journal PLOS Biology, the team shows that the plants’ dominance stems from a small genome.
“The flowering plants are the most important group of plants on earth, and now we finally know why they have been so successful,” the authors write.
Research over the past 30 years shows flowering plants have unrivaled rates of photosynthesis, enabling them to develop faster and outcompete conifers and ferns that had dominated ecosystems for hundreds of millions of years.
Flowering plants’ metabolic success stems from their specialized leaves, which accelerate water transport and carbon dioxide uptake.
These anatomical advancements are directly linked to genome size, according to the team.
Since each cell features a copy of a plant’s genome, smaller genomes enable cells to be smaller, which, in turn, allows more cells to be packed into a specific volume of space. Shrinking the size of each cell can also make nutrient and water delivery more efficient.
After examining hundreds of species, the researchers determined that genome downsizing began around 140 million years ago during the early Cretaceous period, and aligned with the global spread of the first flowering plants.
“The flowering plants are highly competitive in almost every terrestrial ecosystem, and their rapid rise during the early Cretaceous period irrevocably altered terrestrial primary productivity and global climate,” the researchers write.
While the report answers a long-standing question, the findings present several mysteries.
Future research could examine how flowering plants were able to shrink their genomes more than other plant species, which innovations in genome packing and structure the plants capitalized on, and how ferns and conifers managed to avoid extinction despite their comparatively large genomes and cells.