Modern technologies for the diagnosis and assay of plants viruses

Abstract Emerging, reemerging, and endemic viruses continue to challenge our ability to safeguard plant health and can be managed most effectively if virus-free certified seed and other planting material is used and control measures are introduced at an early stage. Early, sensitive, and accurate diagnosis is indispensable for the application of mitigation strategies. Since both seeds and vegetative propagules (such as bulbs, rhizomes, suckers, and rooted cuttings) are efficient carriers of viruses, infection is progressively transmitted through generations. Further, if the in vitro cultures are raised from a virus-infected mother plant, the plantlets are bound to carry the virus infection. The selection of a diagnostic method for evaluating plant health depends on the host to be tested and the type of viruses that may be carried in the seed/vegetative propagules/in vitro cultures. The technique should be reliable for field performance and quarantine requirements, reproducible within statistical limits, and economical with regard to time, labor and equipment and should be rapid in order to provide results of large samples in a short time. The challenges in virus detection include availability of antisera, viral genome sequences in GenBank, and detection methods for an unknown/exotic virus. Attention is now given to issues such user-friendly lateral flow strips, databases on sequences of virus-specific primers, multiplex polymerase chain reaction (PCR), real-time PCR, loop-mediated isothermal amplification, helicase-dependent amplification, and next-generation sequencing. Adopting the right strategy and appropriate technique for virus detection would go a long way toward ensuring the biosecurity of Indian agriculture from indigenous and transboundary plant viruses.