|Gillaspie, Athey - Graves|
Submitted to: Phytopathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/24/2001
Publication Date: 11/1/2001
Citation: Gillaspie Jr, A.G., Pio-Ribeiro, G., Andrade, G.P., Pappu, H.R. 2001. Rt-pcr detection of cowpea aphid-borne mosaic virus in peanut from brazil. Phytopathology 91(Supplement):2002. 2001 Interpretive Summary: A new viral pathogen of peanut, Cowpea aphid-borne mosaic virus, has been reported to cause a severe disease problem in Brazil. The virus poses a significant problem in the distribution of germplasm to other countries since the virus is seedborne. We developed an improved method based on viral nucleic acid for detection of this virus in peanut and cowpea. The new method is more sensitive than the currently used method, especially when used to detect the virus in leaves of peanut and cowpea, and can be used to detect the virus in pooled samples from a large number of plants. Therefore, this method is useful in the detection of cowpea aphid-borne mosaic virus in all peanuts imported into the U.S. from Brazil.
Technical Abstract: The Brazil strain of Cowpea aphid-borne mosaic virus (CABMV) has been reported as a severe pathogen in peanut and is a significant problem in the distribution of germplasm to other countries. This virus is seedborne at ~1% in peanut, depending upon the cultivar. Detection of the virus among a large number of seed lots would strengthen quarantine programs. Utilizing 3' sequence data (GenBank acc. # AF241233), primers have been designed from the coat protein gene for the detection of CABMV from seeds and leaves. Use of the forward primer 5'-CGCTCAAACCCATTGTAGAA-3' and the reverse primer 5'-TATTGCTTCCCTTGCTCTTTC-3' results in an RT-PCR product of 221 bp. The thick seed slices necessary for a reliable test dictates a workable sample size of 12-25 seeds, which does not provide a significant advantage over ELISA for testing large seed lots. The PCR approach also detects more seeds containing viral RNA than there are infected plants arising from seed dlots from infected parents. There are advantages in detecting the virus i quarantined seedlings from seeds imported from Brazil rather than from the seeds themselves. First, there are no false positives and second, RT-PCR is sensitive enough to detect one infected leaf among 99 leaves from healthy plants compared with ELISA, which detects one infected leaf among nine healthy leaves. Thus, the RT-PCR method offers improved detection of Cowpea aphid-borne mosaic virus.