Developing methods to identify plant species from seedbanks using amplicon sequencing

Mari R. Irving and Angela T. Chu, Evolution, Ecology, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, Stephanie A. Ma, Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, Ryoko Oono, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, Carla D'Antonio, Environmental Studies, University of California Santa Barbara, Santa Barbara, CA

Background/Question/Methods
Ecosystem monitoring and biodiversity assessments often utilize plant community composition to infer site quality and history. Traditional methods for identifying species in a seedbank often require significant time and training while not necessarily capturing the complete presence of viable seeds in the field. We aimed to circumvent these issues through the utilization of molecular methods, specifically amplicon sequencing, which reduces the time and extensive training required by traditional methods, while potentially identifying more plant species at lower cost per soil volume. We compared pre-extraction soil condition (wet vs. dry), and four recommended DNA barcoding regions (ITS2, rbcL, matK, and trnL) to establish the suitability of each for providing the most comprehensive view of plant diversity at a site from a single assessment. DNA barcoding was paired with a traditional greenhouse grow out to further compare the efficiency and practicality of each strategy.
Results/Conclusions
We will examine the taxonomic breadth and complementarity of each locus resulting from differences in recovery, annotation, and resolution of vascular plant sequences. Preliminary results indicate ITS2 and rbcL are overall recommended for DNA metabarcoding of vascular plants from eDNA. These results may be useful to land managers and restoration ecologists attempting to understand the historic biodiversity of vascular plants at degraded, developing, or natural sites.