A Polyvalent Tool for Detecting Coguviruses in Multiple Hosts Allowed the Identification of a Novel Seed-Transmitted Coguvirus Infecting Brassicaceae.

The genus Coguvirus, a recently established genus in the family Phenuiviridae, includes several species whose members infect both woody and herbaceous hosts, suggesting a broader host range and wider distribution than previously. To gain insights into the epidemiology and biology of coguviruses, a polyvalent reverse transcription-PCR assay using degenerate primers was developed. The specificity of the assay for coguviruses was confirmed by testing citrus and apple plants infected by previously reported coguviruses and/or several unrelated viruses. The expected 236-bp amplicon was obtained from citrus, apple, pear, watermelon, and several species of the family Brassicaceae. Sequencing of the PCR amplicons allowed the identification, for the first time in Italy and/or Europe, of several coguviruses in multiple hosts, confirming the effectiveness of the assay. Moreover, a new virus, tentatively named Brassica oleracea Torzella virus 1 (BoTV1), was detected in several plants of Torzella cabbage. The complete +genome of BoTV1, determined by high-throughput sequencing and 5' rapid amplification of cDNA ends, revealed that it has the typical molecular features of coguviruses and fulfils the current criteria to be classified as a member of a new species, for which the tentative name Coguvirus torzellae is proposed. The same polyvalent assay was also used to investigate and confirm that BoTV1 is transmitted through seeds in black cabbage, thus providing the first evidence on the relevance of this natural transmission mode in the epidemiology of coguviruses. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

A New Jasmine Virus C Isolate Identified by Nanopore Sequencing Is Associated to Yellow Mosaic Symptoms of Jasminum officinale in Italy.

Some plants of Jasminum officinale were selected in a nursery for investigation of sanitary status of candidate mother plants before vegetative propagation. The presence of yellow spots and leaf discoloration symptoms pushed for a generic diagnosis through deep sequencing to discover systemic pathogens. Either dsRNA or total RNA were extracted and used in nanopore and Illumina platform for cDNA-PCR, direct RNA and total RNA rRNA-depleted sequencing. A few single reads obtained by nanopore technology or assembled contigs gave unequivocal annotation for the only presence of a jasmine virus C (JaVC, a putative member of genus Carlavirus) isolate. The full-length genome of this isolate was reconstructed, spanning 8490 nucleotides (nt). This isolate shared 90.9% similarity with coat protein sequences and 84% with the entire ORF1 polyprotein, with the other two available JaVC full genomes, isolated from infections in J. sambac in Taiwan and China. The overall nucleotide identity shared by the newly discovered Italian isolate with the Chinese JaVC full genomes was 76.14% (Taiwan) and 75.60% (Fujian). The application of quick nanopore sequencing for virus discovery was assessed. The identification of the virus in a new ornamental host species, largely used in gardening, creates a concern for the potential virus spread and need of testing for production of clean vegetative material.