Multiplex Sequencing of SARS-Cov-2 genome directly from clinical samples using the Ion Personal Genome Machine (PGM)

Various methods have been developed for rapid and high throughput full genome sequencing of SARS-CoV-2. Here, we described a protocol for targeted multiplex full genome sequencing of SARS-CoV-2 genomic RNA directly extracted from human nasopharyngeal swabs using the Ion Personal Genome Machine (PGM). This protocol involves concomitant amplification of 237 gene fragments encompassing the SARS-CoV-2 genome to increase the abundance and yield of viral specific sequencing reads. Five complete and one near-complete genome sequences of SARS-CoV-2 were generated with a single Ion PGM sequencing run. The sequence coverage analysis revealed two amplicons (positions 13751-13965 and 23941-24106), which consistently gave low sequencing read coverage in all isolates except 4Apr20-64-Hu. We analyzed the potential primer binding sites within these low covered regions and noted that the 4Apr20-64-Hu possess C at positions 13730 and 23929, whereas the other isolates possess T at these positions. The genetic variations observed suggest that the naturally occurring genome variations present in the actively circulating SARS-CoV-2 strains affected the performance of the target enrichment panel of the Ion AmpliSeq™ SARS‑CoV‑2 Research Panel. The possible impact of other genetic sequence variations warrants further investigation, and an improved version of the Ion AmpliSeq™ SARS‑CoV‑2 Research Panel, hence, should be considered.

Complete Genome Sequence of the Attenuated Corynebacterium pseudotuberculosis Strain T1

We present here the genome sequence of the attenuated Corynebacterium pseudotuberculosis strain T1. The sequencing was performed with an Ion Torrent Personal Genome Machine platform. The genome is a circular chromosome of 2,337,201 bp, with a G+C content of 52.85% and a total of 2,125 coding sequences (CDSs), 12 rRNAs, 49 tRNAs, and 24 pseudogenes.