Rapid Multilocus Adaptation of Clonal Cabbage Leaf Curl Virus Populations to Arabidopsis thaliana

Abstract

Cabbage leaf curl virus (CabLCV) has a bipartite single-stranded DNA genome and infects the model plant Arabidopsis thaliana. CabLCV serves as a model for the genus Begomovirus, members of which cause tremendous crop losses worldwide. We have used CabLCV as a model for within-plant virus evolution by inoculating individual plants with infectious clones of either a wild-type or mutagenized version of the CabLCV genome. Consistent with previous reports, detrimental substitutions in the replication-associated ( Rep) gene were readily compensated for by direct reversion or alternative mutations. A surprising number of common mutations were detected elsewhere in both viral segments (DNA-A and DNA-B), indicating convergent evolution and suggesting that CabLCV may not be as well adapted to A. thaliana as commonly presumed. Consistent with this idea, a spontaneous coat protein variant consistently rose to high allele frequency in susceptible accession Columbia-0, at a higher rate than in hypersusceptible accession Sei-0. Numerous high-frequency mutations were also detected in a candidate Rep binding site in DNA-B. Our results reinforce the fact that spontaneous mutation of this type of virus occurs rapidly and can change the majority consensus sequence of a within-plant virus population in weeks. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .