Distribution of PMTV
Objectives 1. Distribution of PMTV in Norway 2. Variability of PMTV in Norway 3. Resistance to PMTV Distribution of PMTV Finnmark Troms Potatoes grown all over the country How to map the distribution of PMTV? How to test for PMTV ? Nordland Nord Trøndelag Sør Trøndelag Møre og Romsdal Sogn og Fjordane Hedmark Hordaland Oppland Rogaland Buskerud Vest Agder Aust Agder Akershus Østfold Vestfold Telemark Finnmark (2) (9) (9) Troms Nordland (37) Nord Trøndelag 345 soil samples (4) Sør Trøndelag (4) Møre og Romsdal (3) Sogn og Fjordane (1) Hordaland (21) (2) Rogaland Vest Agder Hedmark (112) Oppland (41) Buskerud (6) Akershus (12) Østfold Vestfold (8) Aust Agder Telemark (21) (46) (7) % PMTV in the largest potato producing areas 57 % Nord Trøndelag Hedmark 67 % Oppland 66 % 100% Rogaland Østfold 76 % Vestfold 78 % Finnmark Troms Nordland Nord Trøndelag PMTV found in at least one field of each county Sør Trøndelag Møre og Romsdal Sogn og Fjordane Hordaland Rogaland Vest Agder Hedmark Oppland Buskerud Akershus Østfold Vestfold Aust Agder Telemark Variability of PMTV in Norway Do we have different strains of PMTV ? Finnmark Troms Nordland Nord Trøndelag Choose isolates Sør Trøndelag Møre og Romsdal Sogn og Fjordane Hordaland Rogaland Vest Agder Hedmark Oppland Buskerud Akershus Østfold Vestfold Aust Agder Telemark Propagate the isolates Inoculate to a set of test plants Nicotiana debneyi Nicotiana tabacum Nicotiana rustica Nicotiana glutinosa Capsicum annum Chenopodium quinoa Chenopodium amaranticolor Lycopersicon esculentum Systemic infection Symptomatology Temperature Low temperature (16° - 18° C ) Increase in symptom intensity Delay in systemic infection High temperature (22° - 25° C ) Attenuation of symptoms Enhanced systemic infection How about genetic variability ? 97 – 99 % similarity Conclusions Finnmark Distribution of PMTV ? Troms Why ? o Movement of planting material o Resistant varieties o Symptomless infection o Seed potato testing Nordland Nord Trøndelag Sør Trøndelag Møre og Romsdal Sogn og Fjordane Hordaland Rogaland Vest Agder Hedmark Oppland Buskerud Akershus Østfold Vestfold Aust Agder Telemark Variability of PMTV in Norway Conclusions According to test plant assays (Yes) However, little variability in the 8K Does this explain why sometimes we can have symptomless infections? Is it worth it to start giving ”strain” names to these PMTV isolates? Resistance to PMTV • • • • • • • • • • Berle Bruse Dorado Gladiator Jupiter Kerrs Pink N-93-7-6 NCT-95-14-62 Oleva Saturna (control) Finnmark Three fields chosen Different climatic conditions • • • • • • • • • • Berle Bruse Dorado Gladiator Jupiter Kerrs Pink N-93-7-6 NCT-95-14-62 Oleva Saturna (control) Troms Nordland Nord Trøndelag Sør Trøndelag Møre og Romsdal Sogn og Fjordane Hordaland Rogaland Vest Agder Hedmark Oppland Buskerud Akershus Østfold Vestfold Aust Agder Telemark Finnmark Troms Take soil fields And do test in Graminor Nordland Nord Trøndelag Sør Trøndelag Møre og Romsdal Sogn og Fjordane Hordaland Rogaland Vest Agder Hedmark Oppland Buskerud Akershus Østfold Vestfold Aust Agder Telemark % of tubers showing spraing Is any variety resistant ? % tubers with spraing Spraing in tubers on the 3 locations 40 35 30 25 20 15 10 5 0 Jæ ren Stjørdal Vestfold All varieties can be infected by PMTV % tubers with spraing Spraing in tubers on the 3 locations 40 35 30 25 20 15 10 5 0 Jæ ren Stjørdal Vestfold % tubers with Spraing % tubers with spraing from pot-trial 40 35 30 25 20 15 10 5 0 Jæ ren Stjørdal Vestfold Strain of PMTV ? % tubers with spraing Spraing in tubers on the 3 locations 40 35 30 25 20 15 10 5 0 Jæ ren Stjørdal Vestfold Incidence of spraing ? Some varieties seem to be more succeptible to spraing, But does not correlate with resistance Climatic conditions Doesn’t seem to be due to a specific strain PVY “Théâtre de l'Absurde” PVY makeup and diagnostics 5’ NTR P1 5’ NTR P1 5’ NTR P1 5’ NTR P1 HCPro P3 HCPro P3 ELISA 4C3 C1 PVYO C1 PVYN HCPro P3 HCPro P3 C1 PVYN:O C1 PVYNTN ELIS A 1F5 NI a NI b CP 3’ NTR NI a NI b CP 3’ NTR + NI a NI b CP 3’ NTR NI a NI b CP 3’ NTR + + RT-PCR Primers – based on P1 or NTN PVY • It can be PVYN • It can be PVYC • It can be PVYO • It can be a recombinant ! PVYN-NA PVYC-O, Ext…. What is really PVYNTN ? •Is a phisiological response to PVY (in general) in: Specific potato varieties under specific evironmental conditions Var. Atlantic (summer) Necrotic ringspots PVYNTN SB32 Potato mop top virus PMTV We also have strains Not useful to Use the «strain concept» Biological strains Genetic strains All can generate rings Depends on the climatic Conditions and/or variety! Plant virus elimination by inducing RNA silencing in vivo Silencing-based resistance to PnMV Degradation of viral RNA TG susceptible to PnMV did not express siRNA Transcription and processing of the transgene is required Detection of PnMV in the inoculated leaves (ELISA) Detection of PnMV in the inoculated leaves hpRNA-based resistance to PnMV Prevents replication of the virus in the inoculated leaves Using a viral vector to induce silencing Virus A Virus A Virus B Killing a virus with another virus? Tales of a suicidal virus SPFMV SPFMV CMV CMV SPFMV SPFMV CMV SPFMV + CMV SPFMV SPFMV Inverted repeat CMV-SP CMV-SP SPFMV CMV-SP SPFMV CMV-SP SPFMV Screening for TRV Wait some weeks and evaluate symptoms Huge task ! 60 fields Detection of TRV in weed roots Why not trying to detect TRV from weeds fround in the field? Farmers ar very efficeint in removing weeds How about the roots ? PCR detection is not so difficult RNA extraction RNA PCR amplification 3. Third step: device how to collect samples Select a number of samples to test 1. First step: RNA extraction for roots RNA 2. Second step: PCR from RNA extracted from the roots TRV Kontrol TRV
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