Production of yam mosaic virus monoclonal antibodies in mice peritoneum

Yam mosaic virus (YMV) is one of the most economically important virus infecting yams. Immunoassays are routinely used for laboratory diagnosis of YMV and for certification of planting materials. However, YMV antibodies, the key reagents, needed for these immunoassays are not readily available. We describe in this paper, the production of YMV monoclonal antibodies for the detection of YMV. The monoclonal antibody was produced by immunizing six weeks old BALB/c mice with YMV hybridoma cells and tapping soft peritoneal tumor tissues for antibody. Antibody titre was determined by triple antibody sandwich-enzyme-linked immunosorbent assay (TAS-ELISA) using YMV infected yam leaves and non-infected tissue culture yam leaves. The antibody produced had a titre of 1:1,310,720 and an optimal TAS-ELISA detection dilution of 1:80,000. This high-titre YMV monoclonal antibody is useful for monitoring and certification purposes.Key words: Monoclonal antibodies, ascetic fluid, yam mosaic viru

Characterization of cucumber mosaic virus isolated from yam (Dioscorea spp.) in West Africa

Millions of people in the West African sub-region depend on yam for food and income. In 2008, cucumber mosaic virus (CMV), one of the most economically important plant viruses was detected in yam fields in Ghana, Benin and Togo, three of the five topmost yam producing countries in the world. Some strains of CMV are reportedly more virulent than others thus the need to characterise the strain isolated from yam. Sap inoculation of the yam strain induced systemic mosaic on Cucumis sativus and systemic chlorosis, necrotic lesions and leaf distortion on Nicotiana glutinosa. Sequence analysis of the 3' end of the coat protein gene and C-terminal noncoding region revealed 98 to 99, 93 to 98 and 78 to 79% nucleotide homology with members of the subgroups IA, IB and II, respectively. This analysis further revealed the absence of the EcoR1 restriction site characteristic of subgroup II strains and the presence of 15 nucleotide deletions dispersed along the C-terminal noncoding region of subgroup IA strains. At the amino acid level, the virus had 99 to 100% homology with subgroup I strains and 89% homology with subgroup II strains. Phylogenetic analysis of the amino acid confirms that the yam strain of CMV belongs to subgroup I while nucleotide sequence phylogeny confirms its placement in subgroup IA.Keywords: Yam viruses, cucumber mosaic virus, sequence analysisAfrican Journal of Biotechnology Vol. 12(22), pp. 3472-348

Chromogenic detection of yam mosaic virus by closed-tube reverse transcription loop-mediated isothermal amplification (CT-RT-LAMP)

A closed-tube reverse transcription loop-mediated isothermal amplification (CT-RT-LAMP) assay was developed for the detection of yam mosaic virus (YMV, genus Potyvirus) infecting yam (Dioscorea spp.). The assay uses a set of six oligonucleotide primers targeting the YMV coat protein region, and the amplification products in YMV-positive samples are visualized by chromogenic detection with SYBR Green I dye. The CT-RT-LAMP assay detected YMV in leaf and tuber tissues of infected plants. The assay is 100 times more sensitive in detecting YMV than standard RT-PCR, while maintaining the same specificity