National Symposium on “Plant Pathology in the Changing Global Scenario” held at National Bureau of Plant Genetic Resources, New Delhi on February 27–28, 2009
French bean (Phaseolus vulgaris L.) is an important pulse crop grown widely in India.. The crop is affected by seed and aphid-transmitted Bean common mosaic virus (BCMV), thereby, reducing the yield and quality leading to economic losses. In order to find out the presence of BCMV in French bean germplasm, 104 accessions were tested by growing-on test, infectivity test, electron microscopy, double antibody sandwich - enzyme-linked immunosorbent assay (DAS-ELISA) and dot immunobinding assay (DIBA). Out of 84 accessions subjcted to growing-on test, 80 accessions showed BCMV symptoms such as leaf rolling, leaf distortion, mottling, puckering, vein banding, stunted growth, etc. and the presence of BCMV was confirmed by DAS-ELISA. The seed transmission rate ranged from 1 to 82%. Flexuous particles of 800–900 nm in length and 11 nm in width were observed under Transmission Electron Microscope. The virus was detected in leaves, testa (seed coat) and embryo by DAS-ELISA. BCMV was found to be located more often in the testa than in the embryo. The successful detection of BCMV in different parts of the seeds and leaves by adopting and adapting variants of ELISA holds promise for developing a comprehensive programme for detection and elimination of BCMV in French bean germplasm. Also, the rate of seed transmission is very high in the germplasm that highlights the need for testing the germplasm for virus-free status prior to conservation, a strategy that is crucial for the future crop improvement programmes.
