Graduate Student Arkansas State University Doniphan, Missouri
Body of Abstract: The soil microbiome displays structural and functional dynamism driven by plant, microbial, and environmental factors. This is exemplified in the rhizosphere — the soil immediately adjacent/adhered to plant roots — where selective pressures imposed by a host encourage the colonization of fitness-promoting microorganisms. While such interaction is a known determinant of plant health, individual and community-level behavior in the rhizosphere remains poorly understood, due in part to the insufficient taxonomic resolution achieved through traditional marker gene amplicon sequencing. To this end, the present study leveraged the Element Biosciences LoopSeq™ for AVITI™ platform to investigate eukaryotic and prokaryotic microbiome dynamics within the soybean (Glycine max) rhizosphere under field conditions. In doing so, a randomized, split-block design composed of two soybean cultivars was deployed in the absence/presence of a biostimulant regimen. Composite soil samples were collected at four growth stages, and isolated gDNA was subjected to long-read sequencing on the short-read Element AVITI System. All mapped prokaryotic amplicon sequence variants (ASVs) displayed species-level classification, as did the majority of mapped eukaryotic ASVs. Standard microbiome metrics (e.g., α and β diversity, differentially abundant taxa) were compared across treatments, cultivars, and growth stages, and community membership dynamics were inferred through co-occurrence networks. Lastly, edaphic (soil nutrient and enzyme levels) and agronomic (e.g., belowground biomass and yield) characteristics were determined to better contextualize trends in microbiome structure. Findings herein will be used to investigate rhizosphere influences on disease prevalence in soybean production environments and thus poses benign implications for increased soybean production.