Host-associated selection of a P3 mutant of zucchini yellow mosaic virus affects viral infectivity in watermelon
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In this study, we found that the infectivity of zucchini yellow mosaic virus (ZYMV) in watermelon lines H1 and K6 changed from partial to complete after propagation in the susceptible watermelon line ZXG637. When using cucumber infected with strain ZYMV-CH87 as an inoculum (named ZYMV-CH87C), the mean incidences of infection in lines H1 and K6 were 6% and 11%, respectively. However, when these lines were inoculated with ZXG637 infected with ZYMV-CH87C (named ZYMV-637), 100% of the plants became infected. Sequencing of ZYMV from these different inoculums revealed two nucleotide changes in the P3 cistron in ZYMV-637, which resulted in changes in the amino acids at positions 768 and 857 of the P3 protein, compared with the original strain ZYMV-CH87. We named this variant the M768I857-variant. The M768I857-variant was detected at low levels (3.9%) in ZYMV-CH87C. When ZYMV-CH87C was passaged with ZXG637, the M768I857-variant was selected by the host, and the original sequence was replaced entirely after two passages. These results may be explained by host-associated selection due to an unknown host-encoded factor. Using the M768I857-variant as an inoculum, 100% of the H1 and K6 plants showed systemic symptoms. These results suggest that (1) changing the individual amino acids at the end of the P3 N-terminus induces resistance-breaking, and (2) the P3 N-terminus may be involved in host recognition.
This work was funded by the Central Public-Interest Scientific Institution Basal Research Fund and by the Agricultural Science and Technology Innovation Program.
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Conflict of interest
All authors declare that they have no conflicts of interest.
The work has not been published previously and is not under consideration for publication elsewhere. All authors have agreed to the submission and to the order of their names on the title page; this article does not contain any studies with human participants or animals performed by any of the authors.
- 4.Choi SH, Hagiwara-Komoda Y, Nakahara KS, Atsumi G, Shimada R, Hisa Y, Naito S, Uyeda I (2013) Quantitative and qualitative involvement of P3N-PIPO in overcoming recessive resistance against Clover yellow vein virus in pea carrying the cyv1 gene. J Virol 87:7326–7337CrossRefPubMedPubMedCentralGoogle Scholar
- 8.Desbiez C, Gal-On A, Girard M, Wipf-Scheibel C, Lecoq H (2003) Increase in zucchini yellow mosaic virus symptom severity in tolerant zucchini cultivars is related to a point mutation in P3 protein and is associated with a loss of relative fitness on susceptible plants. Phytopathology 93:1478–1484CrossRefPubMedGoogle Scholar
- 18.Lech WJ, Wang G, Yang YL, Chee Y, Dorman K, McCrae D, Lazzeroni LC, Erickson JW, Sinsheimer JS, Kaplan AH (1996) In vivo sequence diversity of the protease of human immunodeficiency virus type 1: presence of protease inhibitor-resistant variants in untreated subjects. J Virol 70:2038–2043PubMedPubMedCentralGoogle Scholar
- 19.Ling KS, Harris KR, Meyer JD, Levi A, Guner N, Wehner TC, Bendahmane A, Havey MJ (2009) Non-synonymous single nucleotide polymorphisms in the watermelon eIF4E gene are closely associated with resistance to zucchini yellow mosaic virus. TAG Theor Appl Genet Theoretische und angewandte Genetik 120:191–200CrossRefPubMedGoogle Scholar
- 22.Murphy JF, Dane F (2009) Evaluation of ‘AU-Performance’ watermelon for its response to virus inoculation. Horttechnology 19:609–612Google Scholar