D. lanuginosum rhizosphere and bulk soil 16S across a steep geothermal gradient in Yellowstone National Park

The plant rhizosphere microbial community provides a wide variety of benefits to the plant including improving response to abiotic stresses such as high temperatures. Although temperature is one of the strongest drivers of global plant distribution, the effect of temperature on rhizosphere community assembly is poorly understood and has rarely been studied in natural ecosystems. Yellowstone National Park offers a unique environment in which to better understand plant-microbe interactions in relation to soil temperature due to its high distribution of geothermal features. We investigated the bacterial and archaeal rhizosphere assembly of the highly thermotolerant panic grass (Dichanthelium lanuginosum) across a natural temperature gradient from 24-61C at six distinct geothermal areas in Yellowstone National Park. We utilized 16S (primers 515f/r808b) amplicon sequencing on the Illumina Miseq paired-end v3 600-cycle platform. In this first characterization of the D. lanuginsum rhizosphere bacterial + archaeal community, we observed that phylogenetic diversity significantly decreased with increasing soil temperature, suggesting increased rhizosphere selection at higher temperatures. We also observed rhizosphere-specific increases in relative abundance of Thermoproteota and Chloroflexota with increasing temperatures which suggested that thermotolerant microbes may benefit from plant colonization at high temperatures. This study provides valuable insights into naturally occurring high-temperature rhizospheres which can benefit our understanding of rhizosphere assembly and function considering climate change-induced global warming and may have significant potential for high-temperature soil bioprospecting