Whither the species? Phytophthora taxa, MOTUs and barcodes in the world of metagenomics

The study of ecosystem diversity is being transformed by high throughput sequencingtechnology that allows an unparalleled depth of sampling of DNA barcode sequences.The opportunities are great at this fascinating interface of pathology, ecology,taxonomy and molecular biology but there are pitfalls. It is important to consider thepotential for bias at all steps in the process from sampling through to data analysis.Increasingly Phytophthora diversity is being examined by metabarcoding of the PCR amplifiedrDNA ITS regions from soil, water or plant sample DNA. We have appliedbaiting and isolation, cloning and Sanger sequencing and Illumina MiSeq analysis to atime-series of filtered water samples from several Scottish streams within a UK-widesampling network. These data, the literature and other presentations in this session willbe explored in a critical analysis of the field. A specific focus will be placed onexploring the range of species and their boundaries, the potential for speciesquantification and possible benefits of the technology for plant health legislation.