Suppression of Papaya ringspot virus infection in Carica papaya with CAP-34, a systemic antiviral resistance inducing protein from Clerodendrum aculeatum
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CAP-34, a protein from Clerodendrum aculeatum inducing systemic antiviral resistance was evaluated for control of Papaya ringspot virus (PRSV) infection in Carica papaya. In control plants (treated with CAP-34 extraction buffer) systemic mosaic became visible around 20 days that intensified up to 30 days in 56% plants. During this period, CAP-34-treated papaya did not show any symptoms. Between 30 and 60 days, 95% control plants exhibited symptoms ranging from mosaic to filiformy. In the treated set during the same period, symptoms appeared in only 10% plants, but were restricted to mild mosaic. Presence of PRSV was determined in induced-resistant papaya at the respective observation times by bioassay, plate ELISA, immunoblot and RT-PCR. Back-inoculation with sap from inoculated resistant plants onto Chenopodium quinoa did not show presence of virus. The difference between control and treated sets was also evident in plate-ELISA and immunoblot using antiserum raised against PRSV. PRSV RNA was not detectable in treated plants that did not show symptoms by RT-PCR. Control plants at the same time showed a high intensity band similar to the positive control. We therefore suggest that the absence/delayed appearance of symptoms in treated plants could be due to suppressed virus replication.
KeywordsInduced systemic resistance Inhibition of virus replication RT-PCR Immunoblot ELISA
The authors gratefully acknowledge Dr R K Jain, Indian Agricultural Research Institute for the gift of the PRSV antiserum. Financial assistance from the Department of Science and Technology, New Delhi, is also gratefully acknowledged.
- Jain, R. K., Sharma, J., Shivakumar, A. S., Sharma, P. K., Byadgi, A. S., Verma, A. K., et al. (2004). Variability in the coat protein gene of Papaya ringspot virus isolated from multiple locations in India. Archives of Virology, 149, 2435–2442. doi: 10.1007/s00705-004-0392-x.PubMedCrossRefGoogle Scholar
- Jensen, D. D. (1949). Papaya virus diseases with special references to papaya ringspot. Phytopathology, 39, 191–211.Google Scholar
- Prasad, V., & Srivastava, S. (2001). Inducible mechanisms of plant resistance to virus infection. Journal of Plant Biology, 28, 1–11.Google Scholar
- Towbin, H., Stahelin, T., & Gordon, J. (1979). Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: Procedure and some applications. Proceedings of the National Academy of Sciences of the United States of America, 76, 4350–4354. doi: 10.1073/pnas.76.9.4350.PubMedCrossRefGoogle Scholar
- Tripathi, S., Bau, H. J., Chen, L. F., & Yeh, S. D. (2004). The ability of Papaya ringspot virus strains overcoming the transgenic resistance of papaya conferred by the coat protein gene is not correlated with higher degrees of sequence divergence from the transgene. European Journal of Plant Pathology, 110, 871–882. doi: 10.1007/s10658-004-0607-8.CrossRefGoogle Scholar
- Verma, H. N., & Prasad, V. (1986). Virus diseases in Papaw (papaya). In S. P. Raychaudhuri, & J. P. Verma (Eds.), Review of tropical plant pathology (vol. II, (pp. 311–327)). New Delhi, India: Today and Tomorrows.Google Scholar