Emergence of an ancient and pathogenic mammarenavirus.

Emerging zoonoses of wildlife origin caused by previously unknown agents are one of the most important challenges for human health. The Qinghai-Tibet Plateau represents a unique ecological niche with diverse wildlife that harbours several human pathogens and numerous previously uncharacterized pathogens. In this study, we identified and characterized a novel arenavirus (namely, plateau pika virus, PPV) from plateau pikas (Ochotona curzoniae) on the Qinghai-Tibet Plateau by virome analysis. Isolated PPV strains could replicate in several mammalian cells. We further investigated PPV pathogenesis using animal models. PPV administered via an intraventricular route caused trembling and sudden death in IFNαßR-/- mice, and pathological inflammatory lesions in brain tissue were observed. According to a retrospective serological survey in the geographical region where PPV was isolated, PPV-specific IgG antibodies were detected in 8 (2.4%) of 335 outpatients with available sera. Phylogenetic analyses revealed that this virus was clearly separated from previously reported New and Old World mammarenaviruses. Under the co-speciation framework, the estimated divergence time of PPV was 77-88 million years ago (MYA), earlier than that of OW and NW mammarenaviruses (26-34 MYA).

The sequence structure and phylogenetic analysis by complete mitochondrial genome of kohlrabi (Brassica oleracea var. gongylodes L.).

Kohlrabi (Brassica oleracea var. gongylodes L.) is an important dietary rhizome vegetable in the Brassicaceae family. However, to date, few mitochondrial genomic resources have been reported for kohlrabi. In this study, we obtained the complete mitochondrial DNA sequence of 219,964 bp from an individual green kohlrabi. A total of 61 genes were annotated, including 33 protein-coding genes, 23 transfer RNA genes, three ribosomal RNA genes, and two pseudo genes. In addition, 1,001 open reading frames and five RNA editing sites were annotated. Relative synonymous codon usage analysis revealed significant difference in usage frequency of synonymous codon. Phylogenetic inference showed that kohlrabi is closely related to B. oleracea var. botrytis. This study provides a good foundation for further understanding the relationship and evolutionary origins among Brassicaceae crops.