Plant compartment and genetic variation drive microbiome composition in switchgrass roots

Area of Science:

• Plant biology
• Microbiology
• Ecology

Background:

• Switchgrass (Panicum virgatum) is a key biofuel crop in the US.
• Plant-microbe symbioses are common, but switchgrass's microbial communities are understudied.
• Understanding these associations is crucial for optimizing switchgrass cultivation.

Purpose of the Study:

• To investigate switchgrass's root-associated bacterial and fungal communities.
• To determine if host selection of microbiota persists after soil transfer.
• To identify genotype-specific microbial associations in switchgrass.

Main Methods:

• Analysis of 16S rRNA and ITS gene sequencing data.
• Comparison of rhizosphere and root endosphere compartments.
• Evaluation of four distinct switchgrass genotypes.

Main Results:

• Microbial community composition varied significantly by plant compartment and switchgrass genotype/ecotype.
• Root-associated microbes showed enrichment in Alphaproteobacteria, Actinobacteria, Sordariales, and Pleosporales compared to soil.
• Lowland genotypes were enriched in Streptomyces (Actinobacteria), while upland genotypes favored Sphingobium (Alphaproteobacteria).

Conclusions:

• Switchgrass exhibits host-specific bacterial and fungal associations.
• These host-selected microbiomes are maintained after transfer to non-native soils.
• Findings provide a foundational understanding of switchgrass-microbe interactions.