Bromovirus

Bromovirus are tripartite positive single stranded RNA viruses, which reportedly have evolved in two specific manners. First of all, theses type of viruses are highly known for recruiting host factors which play an important role for virus replication, more in detail, according to some reports the replication complex machineries apparently are assembled in membrane sites in the infected host and also for its formation another crucial cell replication factors not known yet might be implicated as well. Secondly, coinfecting virus factors might also implicated in the evolution pathway, specifically, when RNAs cannot exert a proper function because of defectiveness due to plant defense mechanisms, allegedly, other family virus entering the same cell could exchange genetic material with the affected virus by RNA recombination (genetic shift), such scenario can actually be supported in experimental data, for instance, it has been observed that the coat gene from the Tobamovirus SHMV (Sunn Hemp mosaic virus) can functionally replace the same gene in the Bromovirus BMV (Brome mosaic virus), situation that was confirmed when in vivo experiments were performed, resulting in a proper encapsidation of BMV virions.


Following the same line, the host range specificity of these viruses could also be justified, for example, when comparing RNA2 and RNA3 from CCMV (Cowpea chlorotic mottle virus) with respect to sequences of BMV, it was found that they both have some sequence similarities in 2a (flanking regions) and 3a (intercistronic) genes, which potentially can contribute with host specificities, thus, giving another support for the idea of a sequence rearrangement derived from a common evolutionary ancestor. These information eventually can be used for developing strategies to cope these infections. For instance one strategy that could be applied is lethal mutagenesis directed to the conserved regions previously related, since specific viral regions are going to be compromised that will lead to an eventual inhibition of its pathogenicity. Besides, since mutations are also used in benefit of the viruses themselves (evolutionary strategy) and can also be transmitted by inheritance, the study of such crucial mutations are quietly important in order to understand the factors that can be encoded and their importance in replication and infectious mechanisms. Therefore, once those procedures can be well known, a prevention strategy for shutting down those pathways can be applied in bigger scale.


Thanks.

Please if there is any question I would be more than happy to answer it. 



Dear Omar

Since these viruses have tripartite genomes as you mentioned recombination is a positive way of creating hybrids, Do you know among these 3 RNAs which RNAs can get recombined inter and intra specifically? Is there any RNAs that are less prone to have recombination? And can there be any recombination hot spots for this virus? 

From what I have read, there are not successful reports on plant resistance for this viruses, but what I found is that there is some models in yeast systems that could eventually be produced in plants for future experiments. It is also important to mention that even in those yeast models the viral replication was not completely eliminated but just get reduced. Hope these info helped in some way. Thanks.

Thanks, Omar for the post. I was curious to know what are the most important hosts of bromoviruses? Where are they most reported from geographically? Economic importance?