Complete genome sequence of a Brome Mosaic Virus isolate from the Czech Republic

An isolate of Brome mosaic virus (BMV) was originally isolated from Agropyron repens and maintained in Hordeum vulgare. The full-length genome of this isolate (BMV-CZ) was sequenced. Phylogenetic analysis revealed that BMV-CZ shared a minimum of 95.6% sequence identity, localized in the 5′-UTR of RNA-1 with the other BMV isolates from the database, and a maximum of divergence of 30.8% with Broad bean mottle virus localized in the 5′-UTR of RNA-3. This is the first sequence report of full-length BMV from the Czech Republic.

Effect of the Host and Temperature on the Formation of Defective RNAs Associated with Broad bean mottle virus Infection

Previously, we demonstrated that Broad bean mottle virus (BBMV), a member of the genus Bromovirus, could accumulate RNA 2-derived defective interfering (DI) RNAs during infection. In this work, we study how host and environmental factors affect the accumulation of DI RNAs. Serial passages of BBMV through selected plant species reveal that, with low-multiplicity inocula, some systemic hosts (Vicia faba, Nicotiana clevelandii, and N. tabacum cv. Samsum) support DI RNA accumulation after the first passage cycle but other hosts (Phaseolus vulgaris, Pisum sativum, and Glycine max) do not. However, several passages with the high-multiplicity inocula can generate DI RNAs in pea plants. Local lesion hosts (Chenopodium quinoa, C. amaranticolor, and C. murale) remain free of the DI RNA components. The size of the de novo-formed DI RNAs depends on the host and on environmental conditions. For instance, broad bean plants cultivated in a greenhouse or in a growth chamber at 20°C accumulated DI RNAs of 2.4 or 1.9 kb in size, respectively. A reverse trend was observed in pea plants. Lower temperatures greatly facilitated the formation of DI RNAs in broad bean and pea hosts after the first passage. The importance of these findings for the studies on DI RNAs are discussed.