Genetic diversity and evolutionary analyses of potyviruses infecting narcissus in Iran

Occurrence and Characterization of Wheat Streak Mosaic Virus Found in Mono- and Mixed Infection with High Plains Wheat Mosaic Virus in Winter Wheat in Ukraine

Although wheat streak mosaic virus (WSMV) is a well-known pathogen inducing significant crop losses and endangering wheat production worldwide, the recent discovery of High Plains wheat mosaic virus (HPWMoV) in Ukraine raises questions on the co-existence of these two viruses having a similar host range and the same mite vector. Here we report on the screening of winter wheat industrial plantings in several important regions of Ukraine for WSMV and HPWMoV. WSMV was identified in an extremely high number of symptomatic plants (>85%) as compared to HPWMoV detected in 40% of wheat samples. Importantly, the preferred mode of HPWMoV circulation in Ukraine was mixed infection with WSMV (>30%) as opposed to WSMV, which was typically found in monoinfection (60%). Screening wheat varieties for possible virus resistance indicated that all but one were susceptible to WSMV, whereas over 50% of the same varieties were not naturally infected with HPWMoV. Overall, phylogenetic analysis of the collected WSMV and HPWMoV isolates indicated their high identity and similarity to other known isolates of the respective viruses. Here we first characterize WSMV isolates found in winter wheat plants in mono- or mixed infection with HPWMoV, which was recently reported as a typical wheat pathogen in Ukraine.

Narcissus Plants: A Melting Pot of Potyviruses

Our paper presents detailed evolutionary analyses of narcissus viruses from wild and domesticated Narcissus plants in Japan. Narcissus late season yellows virus (NLSYV) and narcissus degeneration virus (NDV) are major viruses of Narcissus plants, causing serious disease outbreaks in Japan. In this study, we collected Narcissus plants showing mosaic or striped leaves along with asymptomatic plants in Japan for evolutionary analyses. Our findings show that (1) NLSYV is widely distributed, whereas the distribution of NDV is limited to the southwest parts of Japan; (2) the genomes of NLSYV isolates share nucleotide identities of around 82%, whereas those of NDV isolates are around 94%; (3) three novel recombination type patterns were found in NLSYV; (4) NLSYV comprises at least five distinct phylogenetic groups whereas NDV has two; and (5) infection with narcissus viruses often occur as co-infection with different viruses, different isolates of the same virus, and in the presence of quasispecies (mutant clouds) of the same virus in nature. Therefore, the wild and domesticated Narcissus plants in Japan are somewhat like a melting pot of potyviruses and other viruses.