Pest categorisation of potato virus X (non‐EU isolates) (original) (raw)
Related papers
Pest categorisation of potato virus V (non‐EU isolates)
EFSA Journal
Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of non-EU isolates of potato virus V (PVV). The information currently available on geographical distribution, biology, epidemiology, potential entry pathways, potential additional impact and availability of control measures of non-EU isolates of PVV has been evaluated with regard to the criteria to qualify as a potential Union quarantine pest. Because non-EU isolates of PVV are absent from the EU, they do not meet one of the requirements to be regulated as a regulated non-quarantine pest (RNQP) (presence in the EU); as a consequence, the Panel decided not to evaluate the other RNQP criteria for these isolates. This categorisation was performed considering two lineages, PVV-I (present in and outside the EU) and PVV-II (not reported in the EU), and isolate PVV-PA4 (unknown distribution). Non-EU isolates of PVV-I and PVV-PA4 do not meet one of the criteria evaluated by EFSA to be regarded as a potential Union quarantine pest, since they are not expected to have an additional impact in the EU. With the exception of the criterion regarding the potential consequences in the EU territory, for which the Panel is unable to conclude, non-EU isolates of PVV-II meet all the other criteria to qualify as a potential Union quarantine pest.
Pest categorisation of potato virus M (non‐EU isolates)
EFSA Journal
Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of non-EU isolates of potato virus M (PVM). The information currently available on geographical distribution, biology, epidemiology, potential entry pathways, potential additional impact compared to the current situation in the EU and availability of control measures of non-EU isolates of PVM has been evaluated with regard to the criteria to qualify as a potential Union quarantine pest. Because non-EU isolates of PVM are absent from the EU, they do not meet one of the requirements to be regulated as a regulated non-quarantine pest (RNQP) (presence in the EU); as a consequence, the Panel decided not to evaluate the other RNQP criteria for these isolates. Populations of PVM can be subdivided into two strains: the ordinary strain (PVM-O) is present in the EU, while the divergent strain (PVM-D) is absent from the EU or considered to have at most a limited distribution in the EU. Non-EU isolates of PVM-O are not expected to have an additional impact in the EU compared to EU isolates and therefore do not meet the corresponding criterion to qualify as a potential Union quarantine pest. The Panel is unable to conclude on the potential impact of non-EU PVM-D isolates in the EU territory, but PVM-D isolates meet all the other criteria to qualify as a potential Union quarantine pest.
Pest categorisation of potato virus A (non‐EU isolates)
EFSA Journal
Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of non-EU isolates of potato virus A (PVA). The information currently available on geographical distribution, biology, epidemiology, potential entry pathways, potential additional impact over the current situation and availability of control measures of non-EU isolates of PVA has been evaluated with regard to the criteria to qualify as potential Union quarantine pest. Because non-EU isolates of PVA are absent from the EU, they do not meet one of the requirements to be regulated as a regulated non-quarantine pest (RNQP) (presence in the EU); as a consequence, the Panel decided not to evaluate the other RNQP criteria for these isolates. This categorisation was performed considering two groups of isolates: those reported in Solanum betaceum (PVA-TamMV, not reported from the EU) and all other isolates (hereafter referred to as PVA, worldwide distribution). Non-EU isolates of PVA and of PVA-TamMV do not meet one of the criteria evaluated by EFSA to be regarded as a potential Union quarantine pest, since they are not expected to have an additional impact in the EU.
Pest categorisation of potato virus S (non‐EU isolates)
EFSA Journal
Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of non-EU isolates of potato virus S (PVS). The information currently available on geographical distribution, biology, epidemiology, potential entry pathways, potential additional impact compared to the current situation in the EU, and availability of control measures of non-EU isolates of PVS has been evaluated with regard to the criteria to qualify as potential Union quarantine pest. Because non-EU isolates of PVS are absent from the EU, they do not meet one of the requirements to be regulated as an RNQP (presence in the EU); as a consequence, the Panel decided not to evaluate the other RNQP criteria for these isolates. Populations of PVS can be subdivided into two strains: the ordinary strain (PVS-O) with a worldwide distribution (including the EU), and the Andean strain (PVS-A) which is absent from the EU or considered to have at most a limited distribution in the EU. Two additional divergent isolates (PVS-A/PVS-O recombinants and PVS-arracacha) have also been categorised. Non-EU isolates of PVS-A are expected to have an additional impact as compared to the PVS isolates currently present in the EU, and therefore meet all the criteria to qualify as potential Union quarantine pests; the magnitude of the additional impact is, however, unknown. Non-EU isolates of PVS-A/PVS-O recombinants and of PVS-arracacha also meet these criteria, with the exception of the criterion regarding the potential additional consequences in the EU territory for which the Panel was unable to conclude. Non-EU PVS-O isolates are not expected to have an additional impact in the EU as compared to EU isolates and therefore do not meet the corresponding criterion.
Pest categorisation of non‐EU viruses and viroids of potato
EFSA Journal
Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of those viruses and viroids (hereafter referred to as viruses) of Solanum tuberosum and other tuber-forming Solanum spp. (hereafter referred to as potato) which are considered to be either non-EU or of undetermined standing based on a previous EFSA opinion. These viruses belong to different families and genera and either have an established identity or produce consistent symptoms. Plants for planting is the main pathway for entry for all categorised viruses as they can all be transmitted by vegetative propagation. Several categorised viruses have a relatively wide host range and/or are vector-transmitted, increasing the potential for entry. The information currently available on geographical distribution, biology, epidemiology, impact and potential entry pathways has been evaluated with regard to the criteria to qualify as potential Union quarantine pest or as Union regulated non-quarantine pest (RNQP). Since this opinion addresses specifically the non-EU potato viruses, in general these viruses do not meet the criteria assessed by EFSA to qualify as potential Union regulated non-quarantine pests. The following viruses meet the criteria to qualify as potential Union quarantine pest:
Pest categorisation of potato leafroll virus (non‐EU isolates)
EFSA Journal, 2020
Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of non-EU isolates of potato leafroll virus (PLRV). The information currently available on geographical distribution, biology, epidemiology, potential entry pathways, potential additional impact and availability of control measures of non-EU isolates of PLRV has been evaluated with regard to the criteria to qualify as a potential Union quarantine pest. Because non-EU isolates of PLRV are absent from the EU, they do not meet one of the requirements to be regulated as a regulated non-quarantine pest (RNQP) (presence in the EU); as a consequence, the Panel decided not to evaluate the other RNQP criteria for these isolates. This categorisation was performed considering two groups of PLRV isolates: those associated with the tomato yellow top disease (PLRV-TYTV), not reported from the EU, and all other isolates (hereafter referred to as PLRV), with a worldwide distribution. Isolates of PLRV-TYTV could potentially have an additional impact over the current situation in the EU and therefore meet all the criteria to qualify as a potential Union quarantine pest. All other non-EU PLRV isolates, should they be introduced, are not expected to have additional impact and therefore do not meet this criterion to qualify as a potential Union quarantine pest.
Pest categorisation of potato virus Y (non‐EU isolates)
EFSA Journal
Following a request from the EU Commission, the Panel on Plant Health has addressed the pest categorisation of non-EU isolates of potato virus Y (PVY). The information currently available on geographical distribution, biology, epidemiology, potential entry pathways and potential additional impact of non-EU isolates of PVY, has been evaluated with regard to the criteria to qualify as a potential Union quarantine pest. Because non-EU isolates of PVY are absent from the EU, they do not meet one of the requirements to be regulated as a regulated non-quarantine pest (RNQP) (presence in the EU); as a consequence, the Panel decided not to evaluate the other RNQP criteria for these isolates. Populations of PVY can be subdivided into several strains and groups of isolates: strain C (PVY-C), strain N (PVY-N), strain O (PVY-O) and a wide range of recombinant isolates (PVYrecombinants) which have a worldwide distribution (including the EU). Two groups of isolates, i.e. the Brazilian (PVY-Br) and Chilean (PVY-Ch) isolates, are considered absent from the EU. Non-EU isolates of PVY-C, PVY-N, PVY-O and PVY-recombinants identified so far are not expected to have an additional impact in the EU compared to the PVY isolates already present and, therefore, do not meet the corresponding criterion to qualify as a potential Union quarantine pest. The Panel is unable to conclude on the potential additional impact of isolates of PVY-Br and PVY-Ch in the EU territory, but these isolates meet all the other criteria to qualify as potential Union quarantine pests.
2012
Interactions between Potato virus X (PVX) and Potato virus S (PVS) were studied in potato plants, and isolates of PVX were inoculated to potato cultivars from four continents to identify occurrence of PVX resistance genes. Mixed infection with PVX and PVS increased the titer of PVS and enhanced expression of foliar symptoms in primarily and secondarily infected plants of 'Royal Blue'. PVX isolates belonging to strain groups 1 and 3 (WA1+3) or 3 (XK3 and TAS3) were sap and graft inoculated (1 to 3 isolates each) to 38 cultivars and one breeding line. Presence of extreme PVX resistance gene Rx was identified in four Australian ('Auski', 'Billabong', 'Flame', and 'Ruby Lou') and two European ('Mondial' and 'Rodeo') cultivars, and in a clone of North American 'Atlantic'. PVX hypersensitivity gene Nx was identified for the first time in two Australian ('Bliss' and 'MacRusset'), four European ('Almera', 'Harmony', 'Maxine', and 'Nadine'), and one North American ('Ranger Russet') cultivars, and in Australian breeding line 98-10713. PVX hypersensitivity gene Nb was identified for the first time in one Australian ('White Star'), five European ('Innovator', 'Kestrel', 'Kipfler', 'Laurine', and 'Royal Blue'), and one North American ('Shepody') cultivars. Probable ancestral sources of the resistance genes found in different cultivars were identified. Thus, although PVX resistance genes often occur in parents used in crosses, knowledge of their occurrence in parents and cultivars is often lacking. On sap inoculation, systemic hypersensitive phenotypes that caused shoot death often developed in cultivars with Nx but not necessarily in all shoots. This phenotype caused severe necrotic symptoms in infected tubers. In some instances, passage through cultivars with Nb separated strain group 3 from mixed isolate WA1+3.
Resistance of Potato Cultivars as a Determinant Factor of Potato virus Y (PVY) Epidemiology
Potato Research
Potato virus Y (PVY) is considered the most economically damaging virus for seedpotato production. PVY isolates are usually divided into three historical PVY strains, namely PVY C , PVY O and PVY N. More recently, recombinant strains named PVY NTN and PVY N-Wi appeared in Europe and North America, rapidly spread into seed-potato production and gradually replaced historical strains. This progression can be explained by several factors, including the differential susceptibility of cultivars to PVY strains. This article presents the results of a Swiss survey of PVY strains conducted in 2012 in which the progressive increase of the prevalence of PVY N-Wi was observed. The occurrence of PVY strains in the two main potato cultivars grown in Switzerland, cv. Agria and cv. Charlotte, is described through the 2012 survey and one additional PVY strain survey conducted in 2014. Both surveys were completed with a mechanicalinoculation assay. The inoculation assay showed that cv. Agria is more susceptible to PVY N-Wi than to PVY NTN , whereas cv. Charlotte is susceptible to both strains. The inoculation assay also showed that the expression of symptoms on cultivars is straindependent. These results stress the major role of the resistance profile of cultivars to explain the balance of the PVY strains in potato crops.
Screening of Potato Germplasm through ELISA against Potato Virus X (PVX)
Ten varieties / lines of potato germplasm were screened out against PVX to find the resistant source. Out of 10, four varieties were susceptible, three moderately susceptible and three were moderately resistant. DAS-ELISA detected the PVX in leaves samples of different Potato varieties. Mechanical transmission produced the local lesion and insect transmission through aphid (Myzus Persicae) was failed due to unknown reasons.