Short Communication Cherry chlorotic rusty spot and Amasya cherry diseases are associated with a complex pattern of mycoviral-like double-stranded RNAs. II. Characterization of a new species in the genus Partitivirus Robert H. A. Coutts, 1 Laura Covelli, 2,3 Francesco Di Serio, 4 Ahmet Citir, 5 Serap Ac ¸ ıkgo ¨z, 6 Carmen Herna ´ ndez, 2 Antonio Ragozzino 3 and Ricardo Flores 2 Correspondence Ricardo Flores rflores@ibmcp.upv.es 1 Department of Biological Sciences, Imperial College London, Imperial College Road, London SW7 2AZ, UK 2 Instituto de Biologı ´a Molecular y Celular de Plantas (UPV-CSIC), Universidad Polite ´ cnica de Valencia, Avenida de los Naranjos s/n, 46022 Valencia, Spain 3 Dipartimento di Arboricoltura, Botanica e Patologia Vegetale, Universita ` di Napoli, 80055 Portici, Italy 4 Dipartimento di Protezione delle Piante e Microbiologia Applicata, Universita ` degli Studi and Istituto di Virologia Vegetale del CNR, Sezione di Bari, 70126 Bari, Italy 5 Tekirdag Ziraat Faku ¨ ltesi, Trakya Universitesi, 59030 Tekirdag, Turkey 6 Adnan Menderes University, Agricultural Faculty, Plant Pathology Department, 09100 Aydin, Turkey Received 8 April 2004 Accepted 19 July 2004 Two dsRNAs from cherry trees affected with cherry chlorotic rusty spot (CCRS) in Italy and Amasya cherry disease (ACD) in Turkey were sequenced and found to be essentially identical. The larger dsRNA 1 (2021 or 2006 bp, respectively) potentially encoded a protein of 621 aa containing the conserved motifs of the RNA-dependent RNA polymerases (RdRp) of dsRNA mycoviruses, having highest similarity with those in the genus Partitivirus. The smaller dsRNA 2 (1841 or 1839 bp, respectively) had properties consistent with the second genomic component of a partitivirus and potentially encoded the coat protein (CP) of 504 aa. Phylogenetic analysis based on the RdRp and CP was coincidental and indicated that species in the genus Partitivirus could be separated into two subgroups. Because species of this genus only infect fungi, these observations suggest a fungal aetiology for CCRS and ACD, further substantiating a previous proposal (see accompanying paper by Covelli et al., 2004, in this issue). In the accompanying paper (Covelli et al., 2004), we illustrated that two cherry diseases, cherry chlorotic rusty spot (CCRS) from Italy and Amasya cherry disease (ACD) from Turkey are very similar diseases probably caused by a fungus (Alioto et al., 2003), which, in turn, is associated with multiple species of double-stranded RNAs (dsRNAs), presumably of viral origin (Covelli et al., 2004; Di Serio et al., 1996, 1998). In confirmation of the mycoviral nature of these dsRNAs, we reported that four of them comprised the genome of a new species in the genus Chrysovirus (Covelli et al., 2004; Ghabrial & Casto ´ n, 2004) and here we have shown that two other dsRNAs comprise the genome of a new species in the genus Partitivirus. Members of the family Partitiviridae (Ghabrial et al., 2004), which together with the Chrysoviridae, Hypoviridae and Totiviridae constitute the four fungal dsRNA virus families (Ghabrial, 2001; Ghabrial & Casto ´ n, 2004), are isometric, non-enveloped viruses, 30–40 nm in diameter, with a genome composed of two linear dsRNAs of approximately 1400–3000 bp (Ghabrial et al., 2004). The smaller dsRNA encodes the coat protein (CP) and the larger the virion- associated RNA-dependent RNA polymerase (RdRp) (Ghabrial et al., 2004). Additional satellite or defective The GenBank/EMBL/DDBJ accession numbers of the sequences reported in this paper are AJ781168 and AJ781167 for ACD- associated dsRNAs 1 and 2 and AJ781401 and AJ781402 for CCRS-associated dsRNAs 1 and 2. 0008-0182 G 2004 SGM Printed in Great Britain 3399 Journal of General Virology (2004), 85, 3399–3403 DOI 10.1099/vir.0.80182-0