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