Evolutionary rates of nuclear and organellar genomes are linked in land plants

Plants carry genetic material in three compartments, the nuclear, mitochondrial, and chloroplast genomes. These genomes interact with each other to various degrees and are subject to shared evolutionary drivers exerted by their host organisms. However, it is not clear whether the three plant genomes display covarying evolutionary signals.

We tested for correlated evolutionary rates between nuclear and organellar genomes using extensive data sets from the major clades of land plants (Embryophyta), including mosses, ferns, gymnosperms, and angiosperms. To examine the evolutionary dynamics in parasitic angiosperms, which are under distinctive selective pressures, we analysed data sets from mistletoes, broomrapes, sandalwoods, and rafflesias.

Evolutionary rates of nuclear and organellar genomes were positively linked in land plants, except in the parasitic angiosperms. We also found similar positive correlations for rates of nonsynonymous and synonymous change between nuclear and organellar genomes. Our results also reveal extensive evolutionary rate variation across land plant taxa.

Overall, we find that nuclear, mitochondrial, and chloroplast genomes in land plants share similar drivers of mutaNon rates, despite considerable variaNon in life history, morphology, and genome sizes among clades. Our findings lay the foundaNon for further exploraNon of the impact of co-evoluNonary interacNons on shared evoluNonary rates between genomes.