TECHNICAL SESSION: Virus discovery and virus populations
The phytovirome: viral communities in soil and plants
Joanne Emerson - University of California, Davis. Aurelie Bak- University of California, Davis, Sara Geonczy- University of California, Davis, Bryce Falk- University of California, Alena Schroeder- University of California, Davis, Rose Bolle- University of California, Davis, Winston Bess- University of C
Our group uses metagenomics and metatranscriptomics to characterize viral communities in soil and plants and their contributions to microbial ecology, nutrient cycling, and plant health in natural and agricultural ecosystems. Here we report the recovery of thousands of previously unknown viral population sequences from these ecosystems. For example, we recovered 3,488 viral populations from 16 near-surface soil samples from eight agricultural tomato plots at two time points: pre-planting in April 2018 and at harvest in August 2018. Significant differences in viral community composition were observed between pre-planting and harvest samples and between viral size-fraction metagenomes (viromes) and bulk soil metagenomes. Nearly all viral populations recovered in bulk soil metagenomes were also recovered in viromes, and the vast majority of viral diversity was recovered in viromes alone, highlighting the utility of purifying viral particles prior to DNA extraction. A significant shift in viral community composition between pre-planting and harvest samples suggests the potential for recruitment of a distinct virome to rhizosphere soils. Separately, high dsRNA yields from oak leaves and conifer needles suggest the potential for thriving viral communities in and on these plants, which we will explore through metatranscriptomics. Together, these results highlight the vast untapped diversity of the phytovirome.