Exploring environmental selection on genome size in angiosperms

Angiosperms show a remarkable range in genome size (GS), yet most species have small genomes, despite the frequency of polyploidy and repeat amplification in the ancestries of most lineages. It has been suggested that larger genomes incur costs that have driven selection for GS reduction, although the nature of these costs and how they might impact selection remain unclear. We explore potential costs of increased GS encompassing impacts on minimum cell size with consequences for photosynthesis and water-use efficiency and effects of greater nitrogen and phosphorus demands of the nucleus leading to more severe trade-offs with photosynthesis. We suggest that nutrient-, water-, and/or CO2-stressed conditions might favour species with smaller genomes, with implications for species' ecological and evolutionary dynamics.

Automated summary

Despite the frequency of polyploidy and repeat amplification in the ancestries of most lineages, most angiosperm species have small genomes. Increased genome size may incur costs impacting minimum cell size, photosynthesis, water-use efficiency, and nucleus demands, leading to more severe trade-offs. Species with smaller genomes may be favored under stressed conditions, suggesting implications for ecological and evolutionary dynamics.