Draft genome resource for the ex-types of Phytophthora ramorum, P. kernoviae, and P. melonis, species of regulatory concern, using ultra–long read MinION Nanopore sequencing

Phytophthora ramorum, P. kernoviae, and P. melonis are each species of current regulatory concern in the United States, the United Kingdom, and other areas of the world. Ex-type material are cultures and duplicates of the type that was used to describe each species and that are deposited in additional culture collections. Using these type specimens as references is essential to designing correct molecular identification and diagnostic systems.

Here, we report a whole genome sequence for the Ex-type material of P. ramorum, P. kernoviae, and P. melonis generated using high-throughput sequencing via the MinION third generation platform from Oxford Nanopore Technology. We assembled the quality filtered reads into contigs for each species. We assembled the continuous contigs of P. ramorum, P. kernoviae, and P. melonis (1,322, 545, and 2,091 contigs, respectively). The ab initio prediction of genes from these species reveals that there are 16,838, 12,793, and 34,580 genes in P. ramorum, P. kernoviae, and P. melonis, respectively. Of the 34,580 P. melonis genes, 10,164 genes were conserved among all three of these Phytophthora species which may include pathogenicity genes.

We compared the ex-type of P. ramorum EU1 lineage assembly with another selected isolate of EU1 available at the National Center for Biotechnology Information and found 251,859 single nucleotide polymorphisms (SNPs) genome-wide; the comparison with the EU2 lineage genome isolate revealed 441,859 SNPs genome-wide. This genome resource of the ex-types of P. ramorum, and P. kernoviae is a significant contribution as these species are among the most important pathogens of regulatory concern in different regions of the world.