Detection and partial characterization of two distinct walnut isolates of cherry leaf roll virus (CLRV)

Two new cherry leaf roll virus (CLRV) isolates (Ah and Ad) were isolated and detected from traditionally-grown walnuts that showed severe apical necrosis and chlorotic spots in systemically infected Cheneopodium amaranticolor, in the eastern part of Turkey. The 404 and 405 bp long DNA fragments of the 3’-non-coding region of both isolates from PCR reactions were cloned and sequenced. A significant genetic variability (up to 14% divergence between sequences) was found within the 3’ terminal region of viral genome of CLRV Turkish isolates compared with the isolates in databases. The sequence of Ad isolate was found to share 84 to 98% and the Ah isolate was found to share 85 to 97% nucleotide identity with corresponding sequences of the selected world isolates. An RNA riboprobe generated for CLRV-Ad isolate reacted also with the CLRV-Ah isolate in dot blot molecular hybridization test. Positive reactions were still visible in hybridization test when the extracts of infected fresh and dried leaf tissues of C. amaranticolor diluted 1:20. Western blot analysis revealed that the molecular mass of the coat protein of about 52 kDa for both isolates.Keywords: Walnut, CLRV, 3’ non coding regio

Pokeweed (Phytolacca americana L.) antiviral protein inhibits Zucchini yellow mosaic virus infection in a dose-dependent manner in squash plants

[EN] Pokeweed antiviral protein (PAP) of Phytolacca americana L. (pokeweed) is a single-chain ribosome-inactivating protein (RIP) characterized by its ability to depurinate plant ribosomes. Here, we isolated, cloned, and expressed the ribosome inactivating protein (RIP) gene, designated as pokeweed antiviral protein type 1 (PAP I), from the summer leaves of pokeweed collected from the Black Sea region (Turkey). Our findings presented here provide direct evidence that exogenous application of PAP I causes concentration-dependent inhibition of Zucchini yellow mosaic virus (ZYMV) infection on squash plants. Squash plants were exposed to PAP I protein with and without DMSO for four consecutive days. Regular spraying of approximately 30 kDa recombinant PAP I at 2 µg mL¿1 concentration prevented treated plants from mechanical virus infection. PAP I showed antiviral activity in 9 plants out of 15 inoculated plants. Remarkably, simultaneous application of PAP, DMSO, and ZYMV did not prevent virus infection, suggesting that PAP did not have any effect on viral RNA. In the absence of ZYMV the purified peptide was not cytotoxic for squash plants, although a reduction of plant size, possibly caused by host ribosome depurination, was observed.Financial support for this study was provided by the Scientific and Technological Research Council of Turkey (TUBITAK Project No: 110 O 180).Sipahioglu, HM.; Kaya, I.; Usta, M.; Unal, M.; Ozcan, D.; Ozer, M.; Guller, A.... (2017). Pokeweed (Phytolacca americana L.) antiviral protein inhibits Zucchini yellow mosaic virus infection in a dose-dependent manner in squash plants. Turkish Journal of Agriculture and Forestry. 41(4):256-262. https://doi.org/10.3906/tar-1612-30S25626241