DETECTION OF GEMINIVIRUSES IN SWEET POTATO PLANTLETS BY PCR

Authors: Li, Ruhui; Salih, Sarbagh; Hurtt, Suzanne

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2003
Publication Date: 8/9/2004
Citation: Li, R., Salih, S.S., Hurtt, S.S. 2003. Detection of geminiviruses in sweet potato plantlets by pcr. BARC Poster Day.

Interpretive Summary:

Technical Abstract: Genetic resources of sweet potato (Ipomoea batatas) from foreign origins are commonly infected with geminiviruses, including Sweet potato leaf curl virus (SPLCV). Graft-inoculation to an indicator host, I. setosa, to detect the viruses is laborious and takes up to 8 weeks. Infected sweet potatoes undergo meristem tip culture to eliminate the viruses, but the eradication rate is low. In this work, polymerase chain reaction (PCR) assays using degenerate primers or virus-specific primers were evaluated for diagnosis of geminiviruses in in vitro sweet potato plantlets. DNA was extracted from small piece of plant tissue in a simple and fast process. PCR products of predicted sizes were amplified from infected plants, but not from healthy plants. The identities of amplicons were confirmed by sequencing. PCR assays detected a range of 10 uncharacterized isolates from Asia and America. The PCR assay using degenerate primers SPG1/SPG2 was able to detect SPLCV in dilutions of 109 of the original sample. Forty of the 64 plantlets examined gave positive results when this set of primers was used, comparing to 29 positive when primers PW285-1/PW285-2 were used. The detection system developed is as reliable as the bioassay. Moreover, it could be used year-round, and required no greenhouse space for growing the candidate sweet potato plants and indicator plants. The assays will accelerate detection of geminiviruses and subsequent selection of virus-free propagations after in vitro therapy, as well as aid in developing better techniques for the therapy.