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First Report of Papaya ringspot virus and Zucchini yellow mosaic virus in Luohanguo (Siraitia grosvenorii) in China

Luohanguo, Siraitia grosvenorii (Swingle) C. Jeffrey, is a perennial cucurbitaceous plant that is an economically important medicinal and sweetener crop in Guangxi province, China. Surveys conducted during the summer to fall seasons of 2003-2004 in northern Guangxi showed symptoms typical of a viral disease, including leaf mottling, mosaic, vein clearing, curling, and shoestring-like distortion in the field. Mechanical inoculation of sap from leaves of symptomatic plants collected from the surveyed areas caused similar symptoms on tissue culture-derived healthy Luohanguo plants. Two sequences of 0.7 and 1.6 kb with 88 and 97% identity to Papaya ringspot virus (PRSV) and Zucchini yellow mosaic virus (ZYMV) were amplified using reverse transcription-polymerase chain reaction (RT-PCR) with purified flexuous viral particles or total RNA extracted from the symptomatic Luohanguo leaves as templates with conserved degenerate potyvirus primers (1). To confirm the results, primers specific for PRSV (PP1/PP2, genome coordinates 4064-4083/5087-5069, GenBank Accession No X97251) and ZYMV (ZP1/ZP2, genome coordinates 5540-5557/7937-7920, GenBank Accession No L31350) were used to perform RT-PCR from the same RNA templates. The expected 1.0- and 2.3-kb fragments were amplified and they were 90 and 95% identical to PRSV and ZYMV in sequence, respectively. Watermelon mosaic virus was not detected. To our knowledge, this is the first report of the occurrence of PRSV and ZYMV in Luohanguo.

Reference: (1) A. Gibbs et al. J. Virol. Methods 63:9, 1997.