First Report of the Necrotic Strain of Potato virus Y (PVY^N) on Potatoes in the Northwestern United States

Abstract

More than 50 isolates of Potato virus Y (PVY) with characteristics of strains that cause tobacco veinal necrosis (PVYN) were obtained from potatoes (Solanum tuberosum L.) grown in the northwestern United States. These isolates are being characterized at the biological and molecular levels. Isolate RR1 was obtained from leaves of potato cv. Ranger Russet showing distinct mottling and leaf deformity, which is in contrast to the leaf-drop and necrosis usually observed with ordinary strains of PVY (PVYO) in this variety. Isolate AL1 was obtained from tubers of potato cv. Alturas showing distinct internal light brown rings and blotches. When RR1 and AL1 were transmitted to tobacco (Nicotiana tabacum L. cvs. Samsun NN and 423), they caused systemic veinal necrosis, including stem and petiole lesions typical of PVYN strains (2). Symptoms induced by RR1 and AL1 on tobacco appeared 9 to 11 days after inoculation, whereas some other isolates caused delayed veinal necrosis. All isolates that produced veinal necrosis on tobacco were detectable with PVY polyclonal antisera. Potato virus X was not detected by enzyme-linked immunosorbent assay in tobacco plants showing veinal necrosis. Some isolates, including AL1, failed to react in serological tests using PVYN-specific monoclonal antibodies obtained from three commercial sources. Other isolates, including RR1, were detectable with these monoclonal antibodies. Reverse transcription-polymerase chain reaction (RT-PCR) products obtained with primers specific for the coat protein (CP) open reading frame (ORF) were cloned and sequenced. AL1 possesses a CP more closely related to PVYO type isolates, which would account for its failure to react with PVYN monoclonal antibodies. In this regard, AL1 is similar to the PVYN-Wilga isolate (1). Other isolates that are detectable with the PVYN monoclonal antibodies possess a CP more consistent with N strains of the virus. Results of RT-PCR tests using primers derived from the P1 ORF sequence (3), and the restriction enzyme analysis and sequencing of the RT-PCR products, all suggest that AL1 and RR1 are related to European-type members of PVY tuber necrotic (NTN) or N strains. However, other isolates under investigation appear to be more closely related to previously reported North American NTN types (3). The symptomatology of these viruses on tobacco and potato, and the serological and molecular data clearly show that at least two distinct variants of PVYN have been found for the first time in a major potato production area of the United States, and pose a potential threat to the potato industry. References: (1) B. Blanco-Urgoiti et al. Eur. J. Plant Pathol. 104:811, 1998. (2) J. A. de Bokx and H. Huttinga. Potato virus Y. Descriptions of Plant Viruses. No. 242, CMI/AAB, Surrey, England, 1981. (3) R. P. Singh et al. Can J. Plant Pathol. 20:227, 1998.

Incidence of potato viruses and characterisation of Potato virus Y variability in late season planted potato crops in Northern Tunisia

“…Very few of our isolates belonged to the PVY O group and this finding is in agreement with other studies showing the spread of the PVY N group during the last decade such as in Poland (Chrzanowska 1991), Spain (Blanco-Urgoiti et al 1998), France (Kerlan et al 1999), United States (Crosslin et al 2002), Canada (Nie and Singh 2002) and Germany (Lindner and Billenkamp 2005).…”

“…to the presence of necrotic lesions on tubers making them unmarketable for export, fortunately only on cv Monalisa which is not widely cultivated (BoukhrisBouhachem et al 2008). Recent outbreaks of this disease in the last twelve years have occurred in France (Crouau and Gokelaere 1997), Italy (Tomassoli and Lumia 1998), Greece (Bem and Varveri 1999), Japan (Ohshima et al 2000), Peru (Salazar et al 2000), USA and Canada (Crosslin et al 2002).…”

Census Report of the Potato Virus Y (PVY) Population in Swiss Seed Potato Production in 2003 and 2008

“…In the present study, the one-step triplex RT-PCR (Rigotti and Gugerli 2007) combined with serological and biological assays allowed to typify and to (Boonham et al 2002;Lindner and Billenkamp 2005); for a review see Rolland et al (2008). The incidence of PVY NTN seems therefore to increase as in most potato growing countries (Nie and Singh 2003), reaching sometimes epidemic levels (Crosslin et al 2002;Djilani-Khouadja et al 2010). A breakdown of the resistance of potato cultivars with immunity or partial resistance to PVY N and PVY O could be responsible (Beczner et al 1984;Van den Heuvel et al 1994), but climatic and agronomic changes might also drive this evolution.…”

“…The effort to eradicate the strain allowed the level of the PVY N to stay relatively constant there. Reports from potato growing regions in the west, east and north of the USA still underline a low frequency of the necrotic PVY isolates (2%) (Crosslin et al 2002;Piche et al 2004;Baldauf et al 2005;Rolland et al 2008). PVY C was present until the middle of the 1990s in many regions such as South Africa, Asia, India, North and South America, Ecuador and Europe (Fernandez-Northcote and Lizarraga 1990;Singh 1992;Singh et al 1993;Hataya et al 1994;Ellis et al 1997;Jeffries 2008).…”

Differentiation and molecular detection of Canadian necrotic strains ofPotato virus Y

“…However, the emergence of new pathotypes of PVY N and PVY NTN with different symptomology is raising concerns over their impact on commercial potato production. Isolates of PVY N and PVY NTN from North America differ in the sequence of their P1 protein gene from those isolated in European countries (Nie and Singh 2002a), although both the European and North American types have now been found in the United States (Crosslin et al 2002). In addition to the necrotic strains, resistance breaking isolates (PVY Z ), as well as abnormally infectious but symptomologically mild isolates (PVY N -Wilga), have been described (Blanco-Urgoiti et al 1998;Jones 1990;Chrzanowska 1991 not yet been reached as to whether all or some of the newly described isolates should be considered new strains or whether they represent pathotypes of PVY N .…”