LRES M.S. Thesis Defense: Shealyn Malone
- Monday, April 20, 2020 at 9:00am
Soil legacy effects alter plant volatile emissions in response to diversified cropping systems
Soil microbes can influence the emissions of plant volatile organic compounds (VOCs) that serve as host-location cues for insects and their natural enemies. The influence of the soil microbial community on the plasticity of plant VOC synthesis and emissions is particularly important in agricultural settings where crop rotations and management practices cause significant shifts in the soil microbiome. Studies have shown agricultural soils to influence plant-insect interactions through changes in foliar chemistry, but their potential to alter VOC emissions is unknown.
The primary goals of this research were to 1) characterize the effects of diversified cropping systems on VOC emissions by wheat through soil legacy effects and 2) examine the effects of agricultural soil inoculation on constitutive- and herbivore-induced VOC emissions by wheat. Altered emissions by wheat may have important implications for insect pests, particularly the wheat stem sawfly (Cephus cinctus), which relies on volatiles cues to identify suitable plant hosts for oviposition and is a major pest of wheat in the northern Great Plains.
Across all studies, we found that compared to fallow rotations, plants grown in soils from diversified cropping systems tended to emit more total VOCs and blends that would likely increase pest resistance to the wheat stem sawfly through 1) shifts in key bioactive compounds and 2) enhanced herbivore-induced VOC emissions. Results also suggest that soil microbes may be more likely to alter plant VOCs when plants experience abiotic or biotic stressors. Together, these results suggest that agricultural practices may indirectly influence plant resistance through microbe-altered VOCs, and these effects are more likely to occur when plants experience additional stressors, such as herbivory or drought.
- Department of Land Resources and Environmental Sciences