Online data of: Exploring the potential of root-associated bacteria to control an outbreak weed

In this study, we explored the potential of root-associated bacteria to control an outbreak weed, Jacobaea vulgaris. Twenty root-associated bacteria strains isolated from roots of J. vulgaris were used to examine bacterial effects on seed germination, root morphology and early plant growth. Moreover, we tested direct effects of the bacteria on a specialist herbivore of J. vulgaris, the leaf chewing caterpillar (Tyria jacobaeae), commonly used in biocontrol. We also tested indirect effects of bacteria, via the plant, on the performance of T. jacobaeae and the aphid species Aphis jacobaeae. Lastly, we examined the host specificity of two tested bacteria on three other forbs. Two Gammaproteobacteria, Pseudomonas brassicacearum and Serratia plymuthica, significantly reduced root growth of seedlings in-vitro, while seed germination was unaffected. However, these negative effects were observed across other forb species as well. Bacillus spp. injection led to the highest T. jacobaeae caterpillar mortality, while ingestion had no effect. Inoculation of the plants with bacteria did not affect aphid performance, but significantly affected T. jacobaeae preference. Specifically, P. syringae and one Bacillus sp. strain significantly increased T. jacobaeae preference.
The corresponding paper has been published on Plant and soil. More details of hypotheses and data acquisition and analysis are presented in the original paper.