COMPARATIVE EVALUATION OF NEW RESISTANCE SOURCES AND
DEVELOPMENT OF FIELD-BASED SEROLOGICAL DETECTION OF
Crop Improvement and Protection Research
2013 Annual Report
1a.Objectives (from AD-416):
Evaluate exotic melon germplasm from India for potential new sources of resistance to CYSDV; Characterize host plant resistance to CYSDV in PI 313970 and TGR-1551, and select and introgress resistance to western U.S. shipping type background adapted to the desert southwest U.S.; Evaluate virus content in PI 313970, TGR-1551 and lines derived from these sources to determine ability of lines to suppress CYSDV accumulation; and develop antiserum for field diagnosis of CYSDV using an immunostrip format.
1b.Approach (from AD-416):
Resistant, susceptible and segregating germplasm will be field tested for
resistance to CYSDV in field trials and tested for virus by molecular method.
Resistant and susceptible germplasm will be grown under controlled conditions,
inoculated in standardized tests and screened for virus concentration and
transmission efficiency by whiteflies. Virus protein will be expressed and
antiserum developed for use in immunodetection of CYSDV.
This project relates to objective 2 in the parent project. Two polyclonal antisera against the E. coli-expressed capsid protein of an isolate of Cucurbit yellow stunting disorder virus (CYSDV) from the Imperial Valley of California were raised. They detected the virus in Western blot and Enzyme-linked immunosorbent (ELISA) assays. One of these antibodies was tested in collaboration with a commercial company that specializes in this technology for ELISA detection of CYSDV in a rapid, in-field lateral flow device. The collaborator purified the IgG component of the antisera to make ‘agristrips’ that were tested with the E. coli-expressed CYSDV coat protein (CP) and a field sample of CYSDV from Lebanon. The strip did not detect either the expressed CP or the virus in the CYSDV field sample. This was considered a preliminary test and the company is interested in continued testing. It is also possible that the antibody is not suitable for the lateral flow technology, and there are examples of antibodies that work in ELISA tests but not in lateral flow tests.