Root-associated bacterial microbiome shaped by root selective effects benefits phytostabilization by Athyrium wardii...

Area of Science:

• Environmental microbiology
• Plant-microbe interactions
• Biogeochemistry

Background:

• Root-associated microbiomes are crucial for plant growth and metal accumulation, especially in contaminated environments.
• Athyrium wardii is a metal-accumulating plant found in lead-zinc mine tailings, but its root microbiome is poorly understood.
• Understanding this microbiome is key to its role in phytostabilization.

Purpose of the Study:

• To investigate the structural and functional variations of the root-associated bacterial microbiome in Athyrium wardii.
• To determine the influence of contamination levels on microbiome assembly in mine tailings.
• To elucidate the role of the microbiome in plant adaptation and metal accumulation.

Main Methods:

• Field study of Athyrium wardii in lead-zinc mine tailings with varying contamination.
• Analysis of bacterial microbiome structure and function across root compartments (rhizosphere, rhizoplane, endosphere).
• Bioinformatic analysis of microbial community composition, co-occurrence networks, and functional gene profiles.

Main Results:

• Microbiome structure varied significantly across root compartments, with less impact from contaminant levels.
• Microbial co-occurrence networks were more complex in the rhizosphere and rhizoplane than the endosphere.
• Dominant phyla included Proteobacteria, Chloroflexi, Actinobacteria, Cyanobacteria, and Acidobacteriota; specific genera (Crossiella, Bradyrhizobium) and cyanobacteria were enriched.
• Functional genes for metabolism and membrane transporters (ABC transporters) were abundant, suggesting roles in metal tolerance and bioavailability.

Conclusions:

• The root microbiome assembly of Athyrium wardii is non-random and strongly influenced by root selective effects.
• Rhizosphere and endophytic microbiomes play vital roles in plant adaptation to harsh mine environments and in metal tolerance/accumulation.
• This study highlights the potential of root-associated microbes in phytostabilization strategies for contaminated mine sites.