Contents lists available at ScienceDirect Virus Research journal homepage: www.elsevier.com/locate/virusres Novel nanovirus and associated alphasatellites identified in milk vetch plants with chlorotic dwarf disease in Iran Parisa Hassan-Sheikhi a , Jahangir Heydarnejad a,b, *, Hossain Massumi a , Simona Kraberger c , Arvind Varsani c,d a Department of Plant Protection, College of Agriculture, Shahid Bahonar University of Kerman, Kerman 7616914111, Iran b Research and Technology Institute of Plant Production (RTIPP), Shahid Bahonar University of Kerman, 7616914111, Iran c The Biodesign Center of Fundamental and Applied Microbiomics, School of Life Sciences, Center for Evolution and Medicine, Arizona State University, 1001 S. McAllister Ave, Tempe, AZ 85287-5001, USA d Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Observatory, Cape Town, South Africa ARTICLE INFO Keywords: Milk vetch chlorotic dwarf virus Nanovirus Astragalus myriacanthus Alphasatellitidae ABSTRACT Members of the family Nanoviridae are multi-component single-stranded DNA viruses that infect a variety of plant species. Using a combination of conventional PCR and high throughput sequencing-based approach, we identified a novel nanovirus infecting two symptomatic milk vetch plants (Astragalus myriacanthus Boiss.; family Fabaceae) showing marginal leaf chlorosis, little leaves and dwarfing in Iran. All eight segments (DNA-C, DNA- M, DNA-N, DNA-R, DNA-S, DNA-U1, DNA-U2 and DNAU4) were recovered and Sanger sequenced. The genome of this new nanovirus, hereby referred to as milk vetch chlorotic dwarf virus (MVCDV), shares 62.2–74.7 % nucleotide pairwise identity with the genomes of other nanoviruses. DNA-C, DNA-M, DNA-N, DNA-S components are most closely related to those of black medic leaf roll virus (BMLRV), sharing between 67.8–81.2 % identity. We also identified three nanoalphasatellites (family Alphasatellitidae) associated with the nanovirus which be- long to species Faba bean necrotic yellows alphasatellite 1 (genus Subclovsatellite), Faba bean necrotic yellows al- phasatellite 2 (genus Fabenesatellite) and Sophora yellow stunt alphasatellite 5 (genus Clostunsatellite). Given the significant diversity of Astragalus spp. in Iran, it is likely that there could be more nanoviruses circulating in these plants and that these may play a role in the spread of these nanovirus to cultivated fabaceous hosts. 1. Introduction The family Nanoviridae comprises of multipartite plant-infecting viruses with 6–8 circular single-stranded DNA (ssDNA) components (Vetten et al., 2012). Each circular ssDNA (∼1 kb) is packaged into an individual small isometric particle (17-20 nm diameters). Based on host range and the number of genomic components, nanovirids are divided into two genera, Nanovirus and Babuvirus. Members of the genus Nanovirus infect dicotyledonous plants (mainly the family Faba- ceae) and have eight genome components. Whereas, members of the genus Babuvirus infect monocotyledonous plants in the families Musa- ceae and Zingiberaceae and their genome comprises of six components. All officially known nanovirids as well as recently reported sophora yellow stunt associated virus (SYSaV) are transmitted by aphids in circular and non-propagative manner (Heydarnejad et al., 2019; Vetten et al., 2012). The genomic components of nanoviruses, i.e., DNA-R, DNA-S, DNA- M, DNA-C, DNA-N, DNA-U1, DNA-U2 and DNA-U4, each encode one major open reading frame (ORF). DNA-R encodes the replication-as- sociated protein (Rep) which initiates the replication of all genomic components (Timchenko et al., 1999, 2000). DNA-S encodes the capsid protein (CP) which encapsidates the individual components (Chu et al., 1993; Katul et al., 1997). DNA-M encodes movement protein (MP) that is required for cell-to-cell movement (Wanitchakorn et al., 2000). DNA- C encodes the Clink protein which is involved in regulation of host cell cycle (Aronson et al., 2000; Lageix et al., 2007). DNA-N encodes nu- clear shuttle protein (NSP) (Wanitchakorn et al., 2000). Lastly, DNA- U1, DNA-U2 and DNA-U4 encode ORFs of unknown function. All na- novirus DNA components have a common region-stem loop (CR-SL), also referred to as a CR-I, and a second common region referred to as CR-M or CR-II (Stainton et al., 2017; Vetten et al., 2012). Nanoviruses are also found to be associated with ssDNA Rep encoding satellite molecules in the family Alphasatellitidae (subfamily Nanoalphasatelli- tinae) that are ∼1 kb (Briddon et al., 2018). https://doi.org/10.1016/j.virusres.2019.197830 Received 21 September 2019; Received in revised form 27 November 2019; Accepted 29 November 2019 ⁎ Corresponding author at: Department of Plant Protection, College of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran. E-mail address: jheydarnejad@uk.ac.ir (J. Heydarnejad). Virus Research 276 (2020) 197830 Available online 29 November 2019 0168-1702/ © 2019 Elsevier B.V. All rights reserved. T