Root, Nodule and Soil Bacterial Communities Associated With the Invasive Nitrogen-Fixing Lupinus polyphyllus

Area of Science:

• Plant-microbe interactions
• Invasive species ecology
• Microbiome research

Background:

• Invasive plants can be facilitated by their associated microorganisms.
• Established plant invasions offer insights into microbiome dynamics.
• Lupinus polyphyllus is an invasive herbaceous legume known for N-fixing bacterial associations.

Purpose of the Study:

• Investigate endophytic bacterial communities in invasive Lupinus polyphyllus.
• Examine alpha diversity and composition in roots, nodules, rhizosphere, and bulk soil.
• Compare microbial communities between core and edge locations of established invasion sites.

Main Methods:

• Sampling from roots, nodules, rhizosphere, and bulk soil at 10 established invasion sites.
• Analysis of endophytic bacterial communities and soil bacterial communities.
• Comparison of alpha diversity (richness, Shannon diversity) and community structure.

Main Results:

• Roots and nodules exhibited distinct endophytic bacterial communities; roots had higher alpha diversity.
• Nodules were dominated by Bradyrhizobiaceae, including N-fixing bacteria.
• Soil bacterial communities were influenced by soil type, with bulk soil showing higher diversity than rhizosphere.
• No significant differences in endophytic or soil bacterial communities were found between core and edge invasion sites.

Conclusions:

• Lupinus polyphyllus does not appear to induce significant changes in its associated bacterial communities during local invasion.
• Established plant invasions may have limited impact on the plant microbiome over time.
• Plant-microbe associations in invasive species warrant further investigation regarding long-term dynamics.