Molecular Identification of Viruses Infecting Pea and Beans

 

Diseases caused by plant viruses are causing significant damages to crops. Among them, diseases caused by a group of plant viruses called potyviruses cause major losses to agricultural and horticultural crops worldwide. Due to the lack of curative measures, preventive measures are implemented in controlling virus diseases. Accurate diagnosis of a virus is the first critical step in designing preventive measures. The main objective of this study is to use molecular tools and techniques for the identification of virus(es) in a given sample.  For this purpose, total nucleic acids from bean and pea samples imprinted on FTA Classic cards were eluted and used in Reverse Transcription-Polymerase Chain Reaction (RT-PCR) to amplify a specific portion of virus genome. Appropriate controls were used in RT-PCR assays for validation of test results and amplified products were resolved by agarose gel electrophoresis.  So far, we have been able to amplify two specific regions of potyvirus genome using primers targeting the cylindrical inclusion (CI) and nuclear inclusion (NiB) proteins. The amplified DNA fragments were cloned and sequenced and nucleotide sequences were compared with corresponding sequences from GenBank. The results have shown that potyvirus sequences obtained from bean and pea samples are highly similar to Bean common mosaic virus. These results demonstrated that molecular approaches can be used to identify viruses present in a given plant sample within a relatively short period of time. Further research is being pursued to clone and sequence entire genome of viruses present in bean and pea samples for their identification.