Speaker
Description
Understanding how plants respond to drought is crucial for predicting the impacts of global change on plant distributions. However, little is known about the eco-evolutionary drivers of intraspecific variation in belowground drought responses. Comparisons between native and non-native populations offer a promising approach to study rapid evolution in belowground traits, as introduced plants encounter novel interaction partners that may trigger alternative drought strategies.
We investigated belowground drought responses in 94 native and 106 non-native populations of Conyza canadensis, grown under controlled dry and mesic greenhouse conditions. We recorded fine root traits, root exudation profiles, and fungal root colonization, and accounted for population co-ancestry in our models using ddRADseq-based genotype data.
Native populations responded to drought with pronounced changes in fine root morphology, including increased specific root length. In contrast, non-native populations showed limited morphological plasticity but increased both the quantity and chemical diversity of root exudates. These changes were associated with shifts in the root-associated fungal community, especially an increase in the relative abundance of Rhizophagus irregularis. The abundance of this key arbuscular mycorrhizal fungus correlated positively with plant performance under drought. Across the investigated belowground traits, population co-ancestry explained a substantial proportion of variation, leading to more conservative assessments of rapid evolution between ranges.
Our findings indicate rapid evolution in drought strategies among non-native populations. Instead of directly investing in soil exploration ("do-it-yourself strategy"), these populations increasingly rely on fungal partners. This shift appears to be mediated by root exudation ("call-for-support strategy") and may be promoted by novel biotic interactions in the non-native range. The observed flexibility in belowground responses may contribute to the invasive success of C. canadensis and underscores the evolutionary potential of plant–microbe interactions under drought. Our results also highlight the need to account for demographic history when assessing eco-evolutionary dynamics.
| Status Group | Postdoctoral Researcher |
|---|---|
| Poster Presentation Option | Undecided/No preference |
