Case study: Interaction Solanum spp. –
Oidium neolycopersici
RNDr. Barbora Mieslerová, Ph.D.
Katedra botaniky
Přírodovědecká fakulta
Univerzita Palackého
Olomouc
„There are only two ways to live your life. One is as though nothing is a
miracle. The other is as though everything is a miracle. „
Albert Einstein
Solanum
 Solanum spp. is a large and diverse genus of annual and perennial plants.
 They grow as forbs, vines, subshrubs, shrubs, and small trees, and often
have attractive fruit and flowers.
 Many formerly independent genera like Lycopersicon (the tomatoes) or
Cyphomandra are included in Solanum as subgenera or sections today.
 Thus, the genus nowadays contains roughly 1,500-2,000 species.
 Several species are cultivated, including three globally important food crops:
Tomato, S. lycopersicum Potato, S. tuberosum
Eggplant, S. melongena
Solanum (Lycopersicon) spp.
Variability of fruits and flowers of r. Solanum sect. Lycopersicon, sect.
Juglandifolia a sect. Lycopersicoides (Peralta et al., 2008).
Taxonomy of genus Solanum – earlier taxonomy
 According to the former concept of Rick (1979; 1995) there were
discriminated two large species-complexes within genus Lycopersicon,
namely Esculentum-complex and Peruvianum-complex.
 Esculentum-complex encompassed 7 species: L. esculentum (newly
Solanum lycopersicum), L. cheesmanii (S. cheesmaniae), L. chmielewskii
(S. chmielewskii), L. hirsutum (S. habrochaites), L. parviflorum (S.
neorickii), L. pennellii (S. pennellii) and L. pimpinellifolium (S.
pimpinellifolium).
 In Peruvianum-complex were placed two species: L. chilense (S. chilense)
and L. peruvianum (S. peruvianum).
Crossability polygon of Solanum (Lycopersicon) species
(Lindhout et al., 1994)
Esculentum-complex
PENN
ESC
HIRS
CHEES
PIM
PARV
CHMIE
Strong barrier of interspecific hybridization
PER
CHIL
PERHU
Peruvianum-complex
Lycopersicon esculentum var.
cerasiforme (Solanum
lycopersicum)
L. pimpinellifolium (S.
pimpinellifolium )
Lycopersicon hirsutum f. glabratum
(Solanum habrochaites)
L. pennellii (S. pennellii)
http://digi.azz.cz/Book001/images/Solanum_peruvianum_A327.j
pg
L. peruvianum (S. peruvianum)
L. chmielewskii (S. chmielewskii)
Taxonomy of genus Solanum – recent taxonomy
•Recently, it is widely accepted that tomato and its wild relatives belong to
the genus Solanum subgen. Potatoe (G. Don) D´Arcy, sect. Lycopersicon
(Mill.) Wettst., subsect. Lycopersicon (e.g. Child, 1990; Spooner et al.,
2005; Ji and Scott, 2007; Peralta et al., 2008)
•Child (1990) also propounded representatives of Solanum sect.
Lycopersicoides Child (including S. lycopersicoides and S. sitiens), and
sect. Juglandifolium (Rydb.) Child (included S. juglandifolium and S.
ochranthum) as the closest relatives of subsect. Lycopersicon.
•Peralta et al. (2008) recently distinguished 13 species belonging to Solanum
sect. Lycopersicon and four closely related species (S. juglandifolium, S.
lycopersicoides, S. ochranthum and S. sitiens).
Comparison of earlier (Rick, 1979) and recent classification (Peralta et al.,
2008) of genus Solanum sect. Lycopersicon (according to Grandillo et al.,
2011)
Tomato powdery mildew (Oidium neolycopersici)
 Tomato powdery mildew (Oidium neolycopersici) belongs to the order
Erysiphales (powdery mildews) and it is arelatively new disease
occurring predominantly on glasshouses tomato crops throughout Europe
and New World
Distribution of Oidium neolycopersici
 Information is given on the geographical distribution in
 EUROPE (Bulgaria, Czech Republic, Denmark, France, Germany,
Greece, Hungary, Italy (mainland Italy), Netherlands, Poland, Spain,
Switzerland, UK (England)),
 ASIA (Bhutan, China (Hong Kong), India (Jammu and Kashmir,
Karnataka, Uttar Pradesh), Japan, Malaysia, Nepal, Taiwan, Thailand),
 AFRICA (Tanzania),
 NORTH AMERICA (Canada (Alberta, British Columbia, Ontario,
Quebec), USA (California, Connecticut, Florida, Maryland, New Jersey,
New York)),
 CENTRAL AMERICA AND CARIBBEAN (Guadeloupe, Jamaica),
 SOUTH AMERICA (Argentina, Venezuela).
Distribution of Oidium neolycopersici
http://agro.biodiver.se/2007/04/whats-so-special-about-oidium-neolycopersici/
The map of the first records of Oidium neolycopersici
occurrence in Europe
Lebeda, A., Mieslerová, B. Plant Prot. Sci. 36
(4):156-162, 2000.
Symptoms of disease
 The first symptoms of the disease start to occur in EARLY SUMMER,
seldom in late spring.
 On the UPPER, seldom on the lower LEAF SURFACES white
pustules of powdery mildew appear.
 YOUNGER LEAVES are mostly WITHOUT SYMPTOMS.
 The SMALL CIRCULAR INITIAL PUSTULES, 3-10 mm diam., enlarge
quickly and can COVER THE WHOLE LEAF SURFACE within a few
days.
 In highly suscpetible tomato cultivars, the STEMS AND PETIOLES
are also affected
 Infected plant parts GROW SLOWLY, which is followed by
CHLOROSIS of the colonized tissue, DEFOLIATION AND DRYING of
the plant.
 NO SYMPTOMS are recorded on tomato FRUIT.
Symptoms of tomato powdery mildew (O. neolycopersici) infection on
susceptible S. lycopersicum. (A) The initial symptoms of powdery mildew. (B)
Intensive disease infestation. (C) Necrosis after intensive disease
development. Photo B. Mieslerová
Tomato powdery mildew (Oidium neolycopersici). (A) Conidiophores. (B)
Conidia. (C) Germinating conidium. (D) Dense mycelial coat with
conidiophores on leaf of susceptible tomato. Photo R. Novotný (A, B) and B.
Mieslerová (C, D)
Chemical protection - registered preparations against
tomato powdery mildew in the Czech Republic
Preparation
Effective compound
BIOAN
Lecitihin, Albumin, Milk Cassein
KUMULUS WG
Sulphur
ORTIVA
Azoxystrobin
SCORE 250 EC
Difenoconazole
TALENT
Myclobutanil
TOPAS 100 EC
Penconazole
Morphological characterization and possible taxonomic
position
 The exact taxonomic determination of Oidium neolycopersici is
difficult
 Till now the TELEOMORPH STAGE was NOT FOUND. The attempt
to initiate formation of cleistothecia under laboratory conditions
failed
 Jones et al. (2000) on the basis of the complex study including light
microscopy, SEM analysis and ITS sequence analysis this species
assign to ERYSIPHE SECT. ERYSIPHE, and found that is very close
relative (nearly identical) to Erysiphe aquilegiae var. ranunculi and
clearly distinguish from Golovinomyces orontii and G.
cichoracearum.
 Kiss et al. (2001) identified earlier described powdery mildew on
tomatoes from AUSTRALIA (OIDIUM LYCOPERSICI) as a species
different from tomato powdery mildew widespread in EUROPE,
AFRICA, NORTH AND SOUTH AMERICA AND ASIA (OIDIUM
NEOLYCOPERSICI).
Parsimony tree of the
phylogenetic analysis
of ITS4 -5,8S- ITS 5
regions.
Jones et al.. Can. J.
Bot.78:1361-1366, 2000.
Kiss et al.
Mycol.
Res. 105:
684-697,
2001
O. neolycopersici isolate
Pseudoidium type
O. lycopersici isolate from South
Australia – Euoidium type
Taxonomical position
Phylogenetic analysis of the internal transcribed spacer (ITS) region of the
ribosomal RNA gene for 12 Pseudoidium anamorphs (according to Kiss et al., 2001)
Morphological comparative study
 Trying to solve the problem of taxonomical position of O.
neolycopersici, comparative morphological studies of 14 isolates of
powdery mildew – 10 of O. neolycopersici (OL),
1 – Golovinomyces cichoracearum (GC)
1 - Golovinomyces orontii (GO)
1 – Sphaerotheca fusca (SF)
1 – Erysiphe aquilegiae var. ranunculi (EAR)
– using light and Scanning electron microscopy
 Our COMPARATIVE MORPHOLOGICAL STUDY revealed
DIFFERENCE of Oidium neolycopersici from Golovinomyces
cichoracearum, G. orontii and Sphaerotheca fusca and close
SIMILARITY to Erysiphe aquilegiae var. ranunculi
Mieslerová, B., Lebeda, A., Kennedy, R., Novotný, R.
Acta Phytopathol. Entomol. Hungar., 37 (1-3): 57-74,
2002.
Dendrogram constructed on morphological data showing
similarity between isolates of O. neolycopersici (OL), Erysiphe
aquilegiae var. ranunculi (EAR), G. cichoracearum (GC), G. orontii
(GO) and Sphaerotheca fusca (SF).
SF
13
GC
GO
EAR
5
OL E-1
OLC1CS
OL CKV
OL G-5
OL G-4
OL G-2
OL RZ-1
OL W-2
OL G-3
OL W-1
OL C-1
2.00
1.50
1.00
0.50
0.00
Dissimilarity
Mieslerová, B., Lebeda, A., Kennedy, R., Novotný, R.
Acta Phytopathol. Entomol. Hungar., 37 (1-3): 57-74,
2002.
SEM photographs of selected powdery mildews
Oidium
neolycopersici
Golovinomyces
cichoracearum
Sphaerotheca
fusca
Mieslerová, B., Lebeda, A.,
Kennedy, R., Novotný, R.
Acta Phytopathol. Entomol.
Hungar., 37 (1-3): 57-74,
2002.
BIOLOGY OF THE PATHOGEN (Oidium neolycopersici)
 The influence of environmental conditions on development of tomato
powdery mildews has been reported by various authors (e.g. (Fletcher et al.,
1988; Hannig, 1996; Whipps and Budge, 2000; Jacob et al. 2008; Mieslerová
and Lebeda, 2010). ).
The EFFECT OF TEMPERATURE and LIGHT CONDITIONS (spectral quality,
intensity and photoperiod) on germination, development and conidiation of
tomato powdery mildew (Oidium neolycopersici) on the highly susceptible
tomato cv. Amateur were studied. CONIDIA GERMINATED across the whole
range of tested temperatures (10– 35°C); however, at the end-point
temperatures, germination was strongly limited.
 Suitable conditions for O. neolycopersici development were narrower than
for germination. At temperatures slightly lower than optimum (20–25°C),
MYCELIAL DEVELOPMENT and time of appearance of the first conidiophores
was delayed. CONIDIATION occurred within the range of 15–25°C, however
was most intense between 20–25°C.
 Basic conditions important for development and conidia formation of O.
neolycopersici have also been studied (Fletcher et al., 1988; Hanning, 1996;
Whipps and Budge 2000; Jacob et al., 2008) – with similar results concerning
temperature conditions. As for RELATIVE HUMIDITY, the highest percentage of
infections was found on tomatoes growing at 60-80% R.H.
Mean length of the germ tube
(um)
Mieslerová, B., Lebeda, A. J. Phytopathol. 1–12 (2010)
220
200
180
160
140
120
100
80
60
40
20
0
6hpi
11 hpi
24 hpi
48 hpi
Hours post inoculation
T10
T15
T20
T25
T30
T35
Mean length of the conidial germ tubes of Oidium neolycopersici in
various temperature conditions
Light conditions
 Pathogen development was also markedly influenced by the LIGHT
CONDITIONS. At each light regime, the percentage of CONIDIA
GERMINATION was relatively HIGH, and after 48 hpi ranged 78–95%
 Light intensity significantly influenced pathogen development. Conidiation
and mycelium development was greatest at light intensities of approximately
55–62 umol ⁄m2 per second.
 At LOWER INTENSITIES, pathogen DEVELOPMENT WAS DELAYED, and in
the dark, conidiation was completely inhibited.
 The results regarding the effect of LIGHT SPECTRUM are more complicated.
Pathogen development was MORE RAPID UNDER RED, blue and green
plastic foil, that under white light. However, CONIDIATION was PROFUSE
after 8 dpi under ALL COLOUR foils.
 A dark period of 24 h after inoculation had no stimulatory effect on later
mycelium development, however complete dark for 8 days reduced mycelium
development and no sporulation occurred.
 Very interesting results were obtaineed when only inoculated LEAF was
COVERED WITH ALUMINIUM FOIL while whole plant was placed in
photoperiod 12h/12h. - intensive mycelium development and slight
subsequent sporulation on covered leaf was recorded.
Mieslerová, B., Lebeda, A. J. Phytopathol. 1–12 (2010)
Mean length of the germ tube (um)
120,00
100,00
80,00
60,00
40,00
20,00
0,00
6 hpi
11 hpi
24 hpi
48 hpi
Hours post inoculation
A white light
B blue light
C red light
D green light
E reduced light intensity
F reduced light intensity
G reduced light intensity
H dark
Mean length of the conidial germ tubes of Oidium neolycopersici in
various light conditions
Host range of O. neolycopersici
•O. neolycopersici is NOT ABLE TO INFECT economicaly important species
from the families Brassicaceae (Brassica oleracea var. botrytis; Brassica
oleracea var. capitata), Compositae (Asteraceae), Leguminosae (Phaseolus
lunatus, Pisum sativum) and Poaceae (Zea mays, Triticum aestivum)
(Arredondo et al., 1996; Whipps et al., 1998).
•On the other hand, some SUSCEPTIBLE SPECIES WERE FOUND in the
families Apocynaceae, Campanulaceae, Crassulaceae, Cistaceae, Linaceae,
Malvaceae, Papaveraceae, Pedialiaceae, Scrophulariaceae, Valerianaceae a
Violaceae (Whipps et al., 1998).
•We tested in host-range studies 70 species of 20 genera of Solanaceae and 7
species of Cucurbitaceae. The most interesting findings were the results
concerning the family Solanaceae; there were confirmed the completely
resistant genotypes, moderatelly resistant genotypes (e.g. Ancistus spp.,
Atropa sp., Browalia sp., most of the representatives of Capsicum spp.,
Hyoscyamus, some Solanum)
•On the end of this spectrum are susceptible genotypes of genera Datura sp.,
Nicotiana sp., Petunia sp., Schizanthus sp., and Solanum capsicoides, S.
jamaicense, S. laciniatum, S. lycopersicoides, S. melongena, S.
sysimbriifolium (Lebeda and Mieslerová, 1999)
Records on ability of different Oidium neolycopersici
isolates to infect cucumber, tobacco and eggplant
Plant species
Origin Report
Lebeda, Mieslerová
CS
HU
SW
NL
UK
UK
RUS
(1999)
Kiss (1996)
Corbaz (1993)
Huang et al. (1998)
Fletcher et al. (1988)
Whipps et al. (1998)
Ignatova et al. (1997)
+ - susceptible
- resistant
nd - not determined
Cucumis
sativus
+
Nicotiana
tabacum
-
Solanum
melongena
-
+
+
+
+
+
+
+
+
nd
nd
+
+
+
nd
Lebeda, A., Mieslerová, B.: Plant Prot. Sci. 36 (4):156162, 2000.
Lebeda, A., Mieslerová, B. Acta Phytopathologica and
Entomologica Hungarica, 34 (1-2), 13-25, 1999.
Wild Solanum and Lycopersicon germplasm as sources
of resistance
•Extensive screening of tomato cultivars, foregoing the study of wild
relatives of tomato (Solanum spp.), showed that in assortments of TOMATO
CULTIVARS (SOLANUM LYCOPERSICUM) available till the end of 20th
century, DIDN´T EXIST ANY EFFECTIVE SOURCES OF RESISTANCE to O.
neolycopersici. Therefore the effort of breeders and phytopathologist turned
out to wild relatives of tomato.
•Generally, among the most important SOURCES OF RESISTANCE in earlier
genus Lycopersicon (recently Solanum) can be considered some genotypes
of S. habrochaites (L. hirsutum), S. parviflorum (L. parviflorum), S.
peruvianum (L. peruvianum) and S. pennellii (L. pennellii) (Lindhout et
al., 1994a; Ignatova et al., 1997; Milotay a Dormanns-Simon, 1997; Ciccarese
et al., 1998; Mieslerová et al., 2000; Matsuda et al., 2005).
•On the other hand within species S. lycopersicon (L. esculentum) and
S. pimpinellifolium (L. pimpinellifolium), which are the closest relatives
of cultivated tomatoes, there were found only few resistant genotypes
(Georgiev a Angelov, 1993; Kumar et al., 1995; Ciccarese et al., 1998;
Mieslerová et al., 2000) and most of the closest relatives are highly
susceptible to infection of powdery mildew.
Succesive clustering of Lycopersicon spp. based on
inoculation experiments with Oidium neolycopersici (C-1)
(154 Lycopersicon spp. accessions)
L. esculentum
L. pimpinellifolium
L. esc. cerasiforme
L. chmielewskii
L. peruvianum
L. parviflorum
L. pennellii
L. hirs. glabratum
L. hirsutum
L. chilense
L. cheesmanii
2,00
1,00
0,00
Dissimilarity
Mieslerová, B., Lebeda, A., Chetelat, R.T.
Journal of Phytopathology 148, 303-311,
2000.
Intraspecific pathogenic variability within Oidium
neolycopersici
 Differences in host range experiments postulate existence of DIFFERENT
PATHOTYPES (formae speciales) of O. neolycopersici
 The COMPARISON OF PATHOGENICITY of four O. neolycopersici isolates
originating from the CZECH REPUBLIC, GERMANY, THE NETHERLANDS AND
ENGLAND on Lycopersicon spp. genotypes revealed variability on level of race
specialization. The English isolate of O. neolycopersici considerably differs from
others – higher % of susceptible responses (according inoculation experiments
on 35 accessions of wild Lycopersicon species).
 The PRELIMINARY DIFFERENTIAL SET OF LYCOPERSICON spp. genotypes
was proposed.
 Existence of three races was proposed.
Comparison of O. neolycopersici isolates originating
from the Czech Republic (C1/96), Germany (G/97), the
Netherlands (W1/97) and England (E/98) based on
inoculation tests with 35 Lycopersicon spp. accessions
E/98
W1/97
G/97
C1/96
2.00
1.50
1.00
0.50
0.00
Dissimilarity
Lebeda, A., Mieslerová, B. J. Plant. Dis. Prot.
109 (2) 129-141, 2002.
The list of Lycopersicon spp. accessions recommended
as a base for preliminary differential set and postulated
pathogen races
Lycopersicon spp.
Accession
L. esculentum
L. hirsutum
L. hirsutum
L. hirsutum
L. hirsutum f.
glabratum
cv.
Amateur
LA 94
LA 1738
LA 1731
LA 2128
O. neolycopersici isolate / race/
response
W1/97
C1/96
G/97
E/98
OL1
OL2
OL2
OL3
S
S
S
S
R
R
R
R
S
R
R
R
S
R
R
R
M
S
M
R
Lebeda, A., Mieslerová, B. J. Plant. Dis. Prot.
109 (2) 129-141, 2002.
Reaction pattern:
R - resistant (% max ID between 0-30)
M - moderately resistant/susceptible (% max ID between 30-60)
S - susceptible (% max ID between 60-100)
Intraspecific variability within Oidium neolycopersici
In the Netherland Huang et al. (2001) studied O. neolycopersici
variability by AFLP analysis of four Dutch isolates. They revelaed at
least two different patterns related to two types of O. neolycopersici
isolates.
•Study of intraspecific variability of Oidium neolycopersici isolates
originating from various countries of Europe, North America and
Japan showed that ITS SEQUENCES were identical for all 10 isolates
of O. neolycopersici, however AFLP ANALYSIS discovered high
diversity of all isolates and they were represented by different
genotypes (Jankovicz et al., 2008).
•Probably may exist UNKNOWN MANNER OF SEXUAL
RECOMBINATION or other genetic mechanisms, who is responsible
for such broad genetic variability of O. neolycopersici. Nevertheless,
until now was not found any clear relationship betweeen virulence
and AFLP patterns of studied of O. neolycopersici isolates.
In the research of this subject is the most difficult problem separate study
of intraspecific variation by molecular genetic methods and study of
virulence variation.
Infection cycle of O. neolycopersici
•Some detailed studies of infection cycle of O. neolycopersici on tomato and
wild Solanum spp. were realized (Huang et al., 1998; Jones et al., 2000;
Lebeda and Mieslerová, 2000; Lebeda et al., 2002; Mieslerová et al., 2004).
3-6 hpi
germination started
3-24 hpi
deposits of extracellular matrix (ECM)
8- hpi
primary short germ tube, ending in a primary
appressorium, from which a primary haustorium
Till 24 hpi
secondary appressorium, secondary haustorium
Till 72 hpi
third and fourth germ tubes
89-120 hpi
the first conidiophores
Huang et al., 1998; Jones et al., 2000; Lebeda and Mieslerová, 2000; Lebeda et al., 2002; Mieslerová
et al., 2004
168 hpi
http://beta-media.padil.gov.au/species/136595/2723large.jpg
Schematic representation of Oidium neolycopersici development at 8, 24 and 72
hpi on leaf discs of susceptible genotype Solanum lycopersicum cv. Amateur.
(according to Mieslerová and Lebeda, 2010)
Comparison of Oidium neolycopersici germination on
Lycopersicon spp. accessions in various intervals after
inoculation
% germination
100%
6h
24 h
48 h
80%
60%
40%
20%
0%
L.
c
es
m
.A
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L.
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6
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L.
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44
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Mieslerova, B., Lebeda, A., Kennedy, R.:
Ann. appl. Biol. 144: 237-248, 2004.
Comparison of Oidium neolycopersici development on
Lycopersicon spp. accessions (72 hpi)
100%
Conidia with the
third germ tube
80%
Conidia with the
second germ tube
60%
Conidia with the first
appressorial germ
tube
40%
20%
Conidia with the first
non-appressorial
germ tube
0%
r
J
J
A
63 347 738 128 322 560 445
1A 08
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6
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Mieslerova, B., Lebeda, A., Kennedy, R.:
Ann. appl. Biol. 144: 237-248, 2004.
Resistance mechanisms of Lycopersicon spp. to O.
neolycopersici
•Both Huang et al. (1998) and Mieslerová et al. (2004) reported that in resistant
Solanum (sect. Lycopersicon) accessions, many epidermal cells, in which a
primary haustorium was formed, became necrotic, indicating a
HYPERSENSITIVE RESPONSE (HR). Another resistance MECHANISM NOT
BASED ON HYPERSENSITIVITY was revealed in L. hirsutum (LA 1347)
(Mieslerová et al., 2004)
•Huang et al. (1998), who recorded papillae beneath some appressoria at very
low frequencies in all accessions including the susceptible control. Haustoria
were present in at least 50% of the cells where papilla was induced. Therefore,
papilla formation seems NOT TO BE AN EFFECTIVE OR A COMMON
MECHANISM OF SOLANUM SPP. RESISTANCE TO O. NEOLYCOPERSICI.
•The phenomenon of CALLOSE DEPOSITION in the sites of pathogen
penetration was described in pathosystems with powdery mildew.
Experiments realized by Li et al. (2007) found that accumulation of callose are
related with the resistance given by genes Ol-1 and Ol-4, what is manifested by
hypersensitive response and also linked with the resistance based on
recessive gene ol-2, which is connected with papillae formation.
•In our experiments no changes in the deposition of LIGNIN were observed in
diseased or healthy plants of wild Solanum spp. during the first 120 hpi
(Tománková et al., 2006).
Mieslerova, B., Lebeda, A.,
Kennedy, R.: Ann. appl. Biol. 144:
237-248, 2004.
Hypersensitive response of tomato leaf tissue after
infection of powdery mildew (Oidium neolycopersici)
Papilae formation after initial infection of tomato leaf tissue of
powdery mildew (Oidium neolycopersici)
Mieslerova, B., Lebeda, A., Kennedy, R.:
Ann. appl. Biol. 144: 237-248, 2004.
Resistance mechanisms of Lycopersicon spp. to O.
neolycopersici
• The existence of ADULT PLANT RESISTANCE in tomato line OR 4061 was
confirmed. Rapid development and profuse sporulation of O.
neolycopersici was observed on juvenile plants (6-8 w), however this was
in contrast to the slow development and sporadic sporulation observed on
4 month old plants.
• The phenomenon of FIELD RESISTANCE is only very little known in
interaction between wild Solanum spp. and tomato and O. neolycopersici.
Glasshouse infection experiment with ten Solanum accessions (Mieslerová
and Lebeda, unpubl. results) showed significant differences in the disease
progress during the growing period (ca 4 month) and the level of field
resistance to O. neolycopersici.
• In the end of experiment (110th day after inoculation of spread plants)
susceptible tomato cv. Amateur was heavily infested. However, some other
accessions (S. pennellii /LA 2560/, S. peruvianum /LA 445/, tomato line OR
4061) did not exceed 20% of the maximum infection degree (ID) and
expressed slower rate of diseases development, i.e. high level of field
resistance.
Field resistance in the interaction between wild
Solanum spp. and tomato powdery mildew
Solanum spp. accession
Σ%maxID
(leaf disc experiments)
S. lycopersicum cv. Amateur
100
S. lycopersicum OR 4061
12.5
S. lycopersicum OR 960008
50
S. chmielewskii LA 2663
36.66
S. habrochaites LA 1347
28.33
S. habrochaites LA 1738
3.33
S. habrochaites f. glabratum LA 2120 3.33
S. neorickii LA 1322
0c
S. pennellii LA 2560
14.44
S. peruvianum LA 445
63.33
ABC
5918.75
1328.00
2685.00
0
0
0
0
0
1440.00
1493.75
Physiology and biochemistry of host-pathogen interaction
•One of the first responses of host cells after beginning of the interaction
between plant and pathogen is the increased PRODUCTION OF REACTIVE
OXYGEN SPECIES (ROS).
•PEROXIDASES (POXS) represent one of the important groups of enzymes,
which participate in the metabolism of ROS in plants
•Reactive ROS are apparently involved in the INDUCTION OF
HYPERSENSITIVE RESPONSE and they function also as SIGNAL
MOLECULES in the programmed cell death (Lamb and Dixon, 1997;
Hückelhoven and Kogel, 2003).
•NITRIC OXIDE (NO), the ubiquitous intra- and extracellular messenger, has
a wide spectrum of regulatory functions in plant growth, ontogenesis and
responses to various stress stimuli. The key role of NO AS A SIGNAL
MOLECULE and in defense processes of plants was documented
Production of ROS in the interaction between
Lycopersicon spp. and Oidium neolycopersici
 Defence reactions occurring in tissue of three Lycopersicon spp. were
investigated during the first 120 hpi. Changes in accumulation of HYDROGEN
PEROXIDE and enzymes involved in its metabolism (CATALASE,
PEROXIDASES, SUPEROXIDE DISMUTASE) were monitored.
 A hypersensitive reaction was detected after 48 hpi in both resistant tomato
accessions.
 High production of SUPEROXIDE ANION was observed mainly in infected
leaves of highly susceptible Lycopersicon esculentum cv. ‘Amateur’ during
the first hours post inoculation (hpi).
 The production of HYDROGEN PEROXIDE as well as an INCREASE OF
PEROXIDASE (POX) activity were detected mainly in RESISTANT
ACCESSIONS at 4–12 hpi and at the second phase (20-48 hpi).
 INCREASED SOLUBLE POX AND CATALASE ACTIVITY in leaf extracts of
resistant accessions L. chmielewskii (LA 2663) and L. hirsutum (LA 2128) (20
hpi) CORRELATED with the % of NECROTIC CELLS in infection sites.
 The correlation between production of reactive oxygen species (ROS) and
activity of enzymes participating in their metabolism and hypersensitive
response was evident during plant defence response.
Time course of hydrogen peroxide concentration in leaf tissues of
Lycopersicon spp. accessions after inoculation by O.
neolycopersici. ■ - infected, □ - control plants.
Mlíčková, K., Luhová, L., Lebeda, A.,
Mieslerová, B., Peč, P. Plant Physiol.
Biochem. 42: 753-761, 2004.
Tománková, K., Luhová, L., Petřivalský, M., Peč, P.,
Lebeda, A. Physiol. Mol. Plant. Pathol. 68: 22–32,
2006.
Infected plants
Healthy plants
350
Peroxidase activity
(nkat/ml)
300
250
L. esculentum cv.
Amateur
L. chmielewskii
(LA 2663)
200
L. hirsutum f.
glabratum
(LA 2128)
150
100
50
0
Time (hpi)
6
24
50
120
6
24
50
120
6
24
50
120
Time course of peroxidase activity in leaves of Lycopersicon spp.
accessions after inoculation by O. neolycopersici
Mlíčková, K., Luhová, L., Lebeda, A.,
Mieslerová, B., Peč, P. Plant Physiol.
Biochem. 42: 753-761, 2004.
Tománková, K., Luhová, L., Petřivalský, M., Peč, P.,
Lebeda, A. Physiol. Mol. Plant. Pathol. 68: 22–32,
2006.
Infected plants
Catalase activity
(nkat/ml)
600
L. esculentum cv.
Amateur
L. chmielewskii
(LA 2663)
6
6
Healthy plants
L. hirsutum f.
glabratum
(LA 2128)
500
400
300
200
100
0
24
50
120
24
50
120
6
24
50
120
Time course of catalase activity in leaves of Lycopersicon spp.
accessions after inoculation by O. neolycopersici
Mlíčková, K., Luhová, L., Lebeda, A.,
Mieslerová, B., Peč, P. Plant Physiol.
Biochem. 42: 753-761, 2004.
Tománková, K., Luhová, L., Petřivalský, M., Peč, P.,
Lebeda, A. Physiol. Mol. Plant. Pathol. 68: 22–32,
2006.
Hypersensitive reaction (72 hpi)
Mean length of germ tube (um) 48 hpi
Changes of catalase activity nkat/ml (72 hpi)
Changes of peroxidase activity nkat/ml (72 hpi)
100
80
60
20
40
Changes of enzyme
activity (nkat/ml)
40
HR (%); length of germ tube
(um)
120
20
0
0
L. esculentum
Mlíčková, K., Luhová, L., Lebeda, A.,
Mieslerová, B., Peč, P. Plant Physiol.
Biochem. 42: 753-761, 2004.
L. chmielewskii
L. hirsutum
Tománková, K., Luhová, L., Petřivalský, M., Peč, P.,
Lebeda, A. Physiol. Mol. Plant. Pathol. 68: 22–32,
2006.
Local and systemic production of nitric oxide in tomato
responses to powdery mildew infection
 NO production was determined in PLANT LEAF EXTRACTS of L.
esculentum cv. Amateur (susceptible), L. chmielewskii (moderately resistant)
and L. hirsutum f. glabratum (highly resistant) by the oxyhaemoglobin
method during 216 h post-inoculation.
 In SUSCEPTIBLE GENOTYPE, elevated NO production was observed only
during the EARLY INTERVAL following inoculation, at 4-8 hpi.
A specific, TWO-PHASE INCREASE IN NO PRODUCTION was observed in
the extracts of infected leaves of MODERATELY AND HIGHLY RESISTANT
genotypes. Second phase started from 96 hpi and lasted up to end of the
studied interval at 216 hpi.
 Moreover, transmission of a SYSTEMIC RESPONSE THROUGHOUT THE
PLANT was observed as an increase in NO production within tissues of
uninoculated leaves.
 In resistant tomato genotypes, increased NO production was LOCALIZED IN
INFECTED TISSUES by confocal laser scanning microscopy using the
fluorescent probe 4-amino-5- methylamino-2′,7′-difluorofluorescein diacetate.
Piterková, J., Petřivalský, M., Luhová, L., Mieslerová,
B., Sedlářová, M., Lebeda, A. Mol. Plant Pathol. 10:
501-513, 2009.
Localization of nitric oxide (NO) at
later stages of Oidium
neolycopersici pathogenesis (168
hpi) on Lycopersicon chmielewskii
(LA 2663) - Confocal fluorescence
staining with DAF-FM DA (4-amino-5-(N-methylamino)-2`,7`-difluorofluorescein diacetate)
Piterková, J., Petřivalský, M., Luhová, L., Mieslerová, B.,
Sedlářová, M., Lebeda, A. Mol. Plant Pathol. 10: 501-513, 2009.
Increase of NO production in infected compared to control non-infected
plants 4, 8 and 216 hpi in the leaves under (brown column) and above (green
column) inoculated (red column) leaves of L. esculentum cv. Amateur
(susceptible genotype), L. hirsutum f. glabratum (LA 2128) (highly resistant)
and L. chmielewskii (LA 2663) (moderately resistant).
Changes in photosynthesis of Lycopersicon spp. plants
induced by tomato powdery mildew infection in
combination with heat shock pre-treatment
 Effect of POWDERY MILDEW Oidium neolycopersici ON PHOTOSYNTHESIS
in tomato leaves was investigated DURING 9 DAYS after inoculation using CO2
exchange measurement and chlorophyll fluorescence imaging.
 In both MODERATELY RESISTANT (Lycopersicon chmielewskii) and
SUSCEPTIBLE (Lycopersicon esculentum cv. Amateur) genotypes the
infection caused only minimal impairment of photosynthesis.
 Because in many host-pathogen interactions, PLANT RESISTANCE and/or
susceptibility is INFLUENCED BY TEMPERATURE, we studied effect of short
heat stimulus (40,5°C 2 h) on pathogen development and changes of
photosynthesis.
 When the plants were PRE-TREATED BY HEAT SHOCK (40.5° C, 2 H) before
inoculation, RESISTANCE RESPONSE OF L. chmielewskii was NOT
AFFECTED, whereas in L. esculentum CHLOROSES/NECROSES DEVELOPED
and rate of CO2 assimilation and maximal quantum yield of photosystem II
photochemistry (FV/FM) decreased in infected leaves.
 The HS-pretreatment did not change significantly the resistance in L.
chmielewskii and increase susceptibility in L. esculentum.
Photographs (A-D) of representative healthy and powdery mildew infected
leaflets of the SUSCEPTIBLE TOMATO (L. esculentum) with (HS-treated) or
without (non-treated) heat shock pre-treatment; the image of MAXIMAL
QUANTUM YIELD OF PHOTOSYSTEM II PHOTOCHEMISTRY (FV/FM; E-H) and
steady-state value of NON-PHOTOCHEMICAL FLUORESCENCE QUENCHING
(NPQ; I-L) in the same leaflets (9dpi).
Prokopová, J.,Mieslerová, B., Hlaváčková, V., Hlavinka, J., Lebeda, A., Nauš, J.,
Špundová, M. . Physiol. Mol. Plant Pathol. 2010 (in print).
Genetic basis of resistance
 Only few experiments tried to study the genetic background of resistance
to O. neolycopersici in wild Lycopersicon spp..
 The resistance in the pathosystem Lycopericon spp. - O. neolycopersici is
conferred by monogenic genes (Bai et al., 2005; Huang et l., 2000; Li et al.,
2007).
 DOMINANT RESISTANCE GENES (Ol -1, Ol- 3, Ol -4, Ol -5, Ol- 6) confer
race-specific resistance by hampering the fungal growth via Hypersensitive
response of the host rpidermal cells, whereas the RECESSIVE GENE ol-2
confers reistance via papilla formation. POLYGENIC RESISTANCE – locus
linked on Chr 6- L. hirsutum PI247087.
Resistance gene
Origin
Author
Ol -1
L. hirsutum G1.1560
Huang et al., 2000
ol-2
L. esculentum var.
cerasiforme
Ciccarese et al., 1998
Ol- 3
L. hirsutum G1. 1290
Huang et al., 2000
Ol -4
L. peruvianum LA2172
Bai et al., 2004
Ol -5
L. hirsutum PI247087
Bai et al., 2005
Ol- 6
ABLs
Bai et al., 2005
Ol-QTLs 1-3
L. parviflorum G1.1601
Bai et al., 2003
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