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Detection of Both Subgroups I and II of Cucumber Mosaic Cucumovirus and Their Satellite RNAs on Pepper in Argentina

Pepper plants (Capsicum annuum L.) showing stunting, mild to severe mosaic, leaf narrowing and deformation, prominent veins, fruit atrophy or malformation, and necrotic patterns on leaves and fruits were collected from commercial and experimental farms from seven districts in the central western neighboring provinces of Mendoza and San Juan. Cucumber mosaic cucumovirus (CMV) was identified directly from field samples from crude RNA extracts by reverse transcription-polymerase chain reaction (RT-PCR) (1). The PCR-amplified products were analyzed by restriction enzyme digestion with PvuII and VspI to distinguish the CMV subgroups. Serological assays (double immunodiffusion tests and indirect triple antibody sandwich enzyme-linked immunosorbent assay) with subgroup-specific monoclonal and polyclonal antisera also differentiated between the subgroups, although with lower sensitivity than found with PCR. Both subgroups I and II were found, no mixed infections were detected, and subgroup membership was related to geographical distribution: subgroup-I samples were detected in San Juan sites (north), and samples collected from the southern area (Mendoza) were of subgroup II. Some samples were sap-transmitted and passed repeatedly through tobacco and pepper. Satellite RNAs (satRNAs) were detected from total RNA extracts by RT-PCR with specific primers (5′-end oligonucleotide: 5′GGGTTATATCTGCGTGAG3′ and 5′CACGGAGATCAGCATAGC3′ as 3′-end primer). One satRNA isolate from each area was amplified and cloned. Three and five clones, respectively, were sequenced, obtaining 313/315 nucleotide and 334 nucleotide consensus sequences that appear to be similar (98.2 and 98.9%, respectively) to CMV-Y satRNA. This is the first report of CMV subgrouping and detection of CMV satRNAs in Argentina.

Reference: (1) H. Rizos et al. J. Gen. Virol. 73:2099, 1992.