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 Akershus Vest Agder Østfold Vestfold Aust Agder Telemark (2) Finnmark
(9) Troms
(9) Nordland
(37) Nord Trøndelag 345 soil samples (4) Sør Trøndelag
(4) Møre og Romsdal
(112) (3) Sogn og Fjordane Hedmark
Oppland (41) (1) Hordaland
(21) Rogaland Buskerud (6) Akershus (12) (2) Vest Agder Østfold (21) Vestfold (46) (8) Aust Agder Telemark (7) % PMTV in the largest potato producing areas
57 %
Nord Trøndelag
Hedmark 67 %
Oppland 66 % 100% Rogaland
76 % Østfold Vestfold
78 % Finnmark
Troms
Nordland
Nord Trøndelag Sør Trøndelag PMTV found in at least
Møre og Romsdal one field of each county
Sogn og Fjordane Hedmark
Oppland Hordaland
Rogaland Buskerud Akershus Vest Agder 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 Hedmark
Oppland Hordaland
Rogaland Buskerud Akershus Vest Agder 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 High temperature (16° - 18° C ) (22° - 25° C )
Increase in symptom intensity Attenuation of symptoms
Delay in systemic infection Enhanced systemic infection How about genetic variability ?
97 – 99 % similarity Conclusions
Finnmark Distribution of PMTV ? Troms Why ? o Movement of planting material Nordland o Resistant varieties o Symptomless infection o Seed potato testing Nord Trøndelag Sør Trøndelag
Møre og Romsdal
Sogn og Fjordane Hedmark Oppland Hordaland
Rogaland Buskerud Akershus Vest Agder 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 Troms Different climatic conditions
Nordland • Berle • Bruse • Dorado • Gladiator Nord Trøndelag • Jupiter Sør Trøndelag • Kerrs Pink Møre og Romsdal • N-93-7-6 • NCT-95-14-62 Sogn og Fjordane Hedmark • Oleva Oppland • Saturna (control) Hordaland
Rogaland Buskerud Akershus Vest Agder Østfold Vestfold Aust Agder Telemark Finnmark
Troms
Take soil fields Nordland And do test in Graminor Nord Trøndelag
Sør Trøndelag
Møre og Romsdal
Sogn og Fjordane Hedmark
Oppland Hordaland
Rogaland Buskerud Akershus Vest Agder Østfold Vestfold Aust Agder Telemark
% of tubers showing spraing Is any variety resistant ?
Spraing in tubers on the 3 locations
40 35 30 25 Jæ ren 20 Stjørdal 15 10 Vestfold 5
0 % tubers tubers spraing with % All varieties can be infected by PMTV Spraing in tubers on the 3 locations
40 35 30 25 Jæ ren 20 Stjørdal 15 Vestfold 10 5
% tubers tubers spraing with % 0
% tubers with spraing from pot-trial
40 35 30 Jæ ren 25 20 Stjørdal 15 10 Vestfold 5
0 % tubers% with Spraing Strain of PMTV ?
Spraing in tubers on the 3 locations
40 35 30 25 Jæ ren 20 Stjørdal 15 Vestfold 10 5
% tubers tubers spraing with % 0 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 ELIS ELISA A and diagnostics 4C3 1F5
5’ P1 HC- P3 C1 NI NI b CP 3’ NTR Pro PVYO a NTR
5’ P1 HC- P3 C1 NI NI b CP 3’ NTR Pro PVYN a NTR +
5’ P1 HC- P3 C1 NI NI b CP 3’ NTR Pro PVYN:O a NTR
5’ P1 HC- P3 C1 NI NI b CP 3’ NTR Pro PVYNTN a NTR + + RT-PCR Primers – based on P1 or recombination junctures PVYNTN
• 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 SB- 32 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 CMV
SPFMV CMV SPFMV CMV SPFMV +
SPFMV CMV SPFMV CMV-SP SPFMV
Inverted repeat 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 PCR amplification
RNA 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