Phylogenomics to study the co-occurrence of two nutrient acquisition strategies: arbuscular mycorrhizal symbiosis and carnivory

H. MONTERO, M. FREUND, K. FUKUSHIMA

Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, D-97082, Germany

Plants have evolved diverse strategies for nutrient acquisition. One of the most ancient and widespread is the arbuscular mycorrhizal (AM) symbiosis, while a more derived nutrient acquisition strategy is carnivory, which has evolved independently in unrelated plant orders. The two associations result in the supply of nutrients such as phosphorus and nitrogen to the plant. Little is known about root biology in carnivorous plants, and their mycorrhizal status is uncertain. This study aims to test the hypothesis that the independent emergence of carnivory co-occurred with independent losses of mycorrhizal symbioses, by tracking the presence of symbiotic genes in carnivorous plants. To this end, we generated a dataset of 70 plant genomes supplemented with 12 transcriptomes covering 5 independent origins of carnivorous plants and performed a functional phylogenomic analysis to infer the evolutionary history of symbiosis-related genes. Our analysis revealed that several carnivorous plants lack the genetic toolkit needed for symbiosis while some carnivorous plants have retained most or part of the symbiotic genes. Our findings support in most cases a non-mycorrhizal status for carnivorous plants but also suggest that the two nutrient acquisition strategies can coexist. The possible mechanisms that may underpin these patterns will be discussed.