Why are plant meristems not affected by virus?
This is due to the low titre or absence of viral particles in the meristem growth which grow faster as well as ,inhibition of virus replication was brought about by the basipetal movement of a root meristem signaling. also the frequently occurring chromosome abnormalities in callus cultures may become a strong drawback for regenerating virus-free plants from callus. Rigid virus-testing procedures must be applied to reveal the virus-free status of the regenerated plants. From moleclual point of view: In eukaryotes, small RNA molecules engage in sequence-specific interactions to inhibit gene expression by RNA silencing. This process fulfils fundamental regulatory roles, as well as antiviral functions, through the activities of microRNAs and small interfering RNAs. As a counter-defence mechanism, viruses have evolved various anti-silencing strategies that are being progressively unravelled. These studies have not only highlighted our basic understanding of host–parasite interactions, but
