Invasive plants can have devastating effects on native species and ecosystem processes. Garlic mustard (Alliaria petiolata) is a problematic invader in North American deciduous forests. It produces chemicals that are thought to be allelopathic by disrupting arbuscular mycorrhizal fungi (AMF), which are important symbionts in the microbiomes of competing plants. However, the effect of garlic mustard chemicals on soil pathogens has received little attention, even though accumulating pathogens that are harmful to plant competitors could also explain the success of garlic mustard.
In a recent study, members of the Colautti lab (former MSc student Katherine Duchesneau, former BSc thesis student Anneke Golemeic, Dr. Rob Colautti), and Dr. Pedro Antunes (Algoma University Biology) use a natural, field setting to examine differences in the soil microbiome and roots of plants found co-occurring with and without garlic mustard.
Contrary to experimental studies, the authors find no changes in diversity or abundance of AMF in plants growing with garlic mustard, indicating that AMF suppression is not critical to the invasion success of garlic mustard. Instead, they find changes in microbial pathogen communities and slight increases in the root lesions of plants associated with garlic mustard. Additionally, the authors report changes in microbial communities cycling nitrogen, in line with earlier reports of increased nitrogen in soils from garlic mustard litter.
Their study is one of the first to investigate garlic mustard invasion in a natural setting and provides new insights into the ecological mechanisms of plant invasion. To learn more, read their article in the Pedobiologia.
