Chapter 47 - Plant translation factors and virus resistance

Abstract

The interaction between virus and host cell always appears to be enigmatic. Plant viruses utilize cellular translation factors not merely for fulfillment of viral translation of RNA but also for replication and cell-to-cell and long-distance systemic movement. The virus is an obligate parasite, as it largely depends on host translation factors for protein synthesis by arresting the host ribosomes. It is perhaps not unrealistic, nor is it striking that a significant estimate of many naturally encountered resistance genes in plants have their mapping area restricted to saltation within the initiation factors eukaryotic initiation factors 4E and 4G (eIF4E and eIF4G) or their isoforms, eIFiso4E and eIFiso4G. This isoform-dependent flexible (nonrigid) redundancy is the basis for developing new therapies in which these isoforms are the actual candidates that are targeted via different strategies, such as delimiting the expression levels of isoform via single isoform knockdown to bestow immunity to viruses without compromising plant health. Along with the usual workforce of eIF4E and eIFiso4E, new strategies to explore the candidatures of other entities have also been found. These include the factors such as eIF4A-like helicases, eIF3, eEF1A, and eEF1B, which are peculiar for their specificity in viral protein and RNA interactions and control of a multitude of aspects pertaining to the infection of a plant cell. Repression of the translation process falls under antiviral RNA silencing leading to another alternative strategy. Discerning the underlying mechanisms involved in the establishment of natural viral resistance of the plant and unraveling of the viral counter strategies towards the defense put forth by the plants might help to reduce production loses. The integrated approaches of genetics and plant breeding, molecular biology, recombinant DNA technology, and computational biology may lead to the characterization of a novel source of factors to achieve the broad-spectrum resistance by plants against many viruses.