Genome-Resolved Metagenomics of Nitrogen Transformations in the Switchgrass Rhizosphere Microbiome on Marginal Lands

Switchgrass (Panicum virgatum L.) remains the preeminent American perennial (C4) bioenergy crop for cellulosic ethanol, that could help displace over a quarter of US current petroleum consumption. Intriguingly, there is often little response to nitrogen fertilizer once stands are established. The rhizosphere microbiome plays critical role in cycling and overall plant nutrient uptake. We used high-throughput metagenomic sequencing characterize switchgrass microbial community before after fertilization event established on marginal land. examined structure bulk metabolic potential, resolved 29 individual bacteria genomes via de novo assembly. Community diversity were not significantly different fertilization; however, potential carbohydrate-active enzymes was depleted fertilization. assembled genomes, including some from ‘most wanted’ soil taxa such as Verrucomicrobia, Candidate phyla UBA10199, Acidobacteria (rare subgroup 23), Dormibacterota, very rare Candidatus Eisenbacteria. Dormibacterota (formally candidate division AD3) we identified have autotrophic CO utilization, which may impact carbon partitioning storage. Our study also suggests be involved providing associative fixation (ANF) novel diazotroph Janthinobacterium switchgrass.