Available via license: CC BY-NC-ND 4.0
Content may be subject to copyright.
Grapevine phytoplasma disease in Georgia
N.M. Chkhaidze
a,*
, Mz.I. Lobjanidze
a
, I.I. Dzmanashvili
a
,
Sh.Z. Barjadze
a,b
, D.N. Maghradze
a
a
Agricultural University of Georgia, 240, David Aghmashenebeli Ave, Tbilisi 0159, Georgia
b
Institute of Zoology of Ilia State University, Giorgi Tsereteli 3, Tbilisi 0162, Georgia
article info
Article history:
Received 26 January 2016
Accepted 8 April 2016
Available online xxx
Keywords:
Grapevine
Phytoplasma
Insect vectors
Resistance
abstract
Results of grapevine yellows disease (GY) studies in 2005e2015 are reported. Based on
symptoms and Dienes'staining method the disease was detected in Kartli, Kakheti and
Guria regions on Vitis vinifera (L.) Rkatsiteli, Saperavi, Shavkapito, Tavkveri, Aladasturi,
Kachichi, Ganjuri, Chardonnay, Vitis labrusca (L.) cultivar Isabella, species hybrid cultivar
Noah. The phytoplasmas were also visualized by using electron microscopy. The disease
seriously modifies the structure of leaf the grapevine phloem, the chlorophyll content and
the functioning of sinkesource system. According to anatomical characters the studied
cultivars showed a decreasing resistance from Noah, to Aladasturi, Rkatsiteli, Kachichi and
Saperavi. In the areas of disease epidemic 12 leafhopper species were identified: Agalma-
tium grylloides (Fabricius, 1794), Cicadella viridis (Linnaeus, 1758), Dictyophara europaea (Lin-
naeus, 1767), Empoasca vitis (Gothe, 1875), Erythroneura imeretina Dekanoidze, 1962,
Hyalesthes mlokosieviczi Signoret, 1879, Hyalesthes obsoletus Signoret, 1865, Lepironia coleop-
trata (Linnaeus, 1758), Pentastiridius leporinus (Linnaeus, 1761), Philaenus spumarius (Lin-
naeus, 1758), Metcalfa pruinosa (Say, 1830), Ricania japonica (Melichar, 1898), which may be
possible vectors of grapevine phytoplasmas in Georgia.
©2016 Agricultural University of Georgia. Production and hosting by Elsevier B.V. This is an
open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/
by-nc-nd/4.0/).
Introduction
Phytoplasmas are very small bacteria without cell wall, which
cause severe and untreatable diseases of wild and cultivated
plants and also of grapevine [1e4]. Grapevine phytoplasma
diseases with the general name “grapevine yellows”(GY) are
widely spread in the regions of intensive vine-growing all over
the world and some of them are subject to quarantine [2,5e7].
Yellowing of grapevine leaves or chlorosis is known in
Georgia since older times. According to the causes it was
divided into infectious (caused by viruses, fungi, bacteria,
pests) and non-infectious (disorder of soil conditions for
grapevine nutrition) [8]. In the last century, nobody suggested
phytoplasma infection as one of possible causes of yellowing
of grapevine in Georgia, despite a disease ecurly leaf of
mulberry or mulberry dwarf disease has been detected in
Georgia in 1964, which mycoplasmic nature has been estab-
lished in 1967 [9]. Georgia was the center of study of myco-
plasmosis in the former Soviet Union: the diagnostic method
for mulberry dwarf disease has been elaborated for field
conditions in 1964e1999 [10], the indicator variety of mulberry
[11], mycoplasma strains [12,13], the vector insect Hishimonus
*Corresponding author.
E-mail address: no.chkhaidze@agruni.edu.ge (N.M. Chkhaidze).
Peer review under responsibility of Journal Annals of Agrarian Science.
Available online at www.sciencedirect.com
ScienceDirect
journal homepage: http://www.journals.elsevier.com/annals-of-
agrarian-science
annals of agrarian science xxx (2016) 1e10
http://dx.doi.org/10.1016/j.aasci.2016.04.001
1512-1887/©2016 Agricultural University of Georgia. Production and hosting by Elsevier B.V. This is an open access article under the CC
BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
sellatus (Uhler, 1896) have been reported [14] based on selec-
tion mulberry cultivars resistant to phytoplasma have been
obtained [15], and a unique anatomical method for forecasting
the possible resistance of mulberry to the disease was settled
[16,17].
Leaves of GY symptomatic grapevine were provided by
farmers from Sighnaghi district in 2002. As a result of the vi-
sual and cytochemical analyses (Dienes'method) [18] of
samples of the cultivars Rkatsiteli and Saperavi phytoplasma
were detected [19]. The existence of a disease associated with
possible phytoplasma presence in the cultivar Aleksandrouli
in Racha region [20] and Saperavi in Kakheti region [21] was
also reported. In 2014, by PCR method it has been established
that the phytoplasma disease in grapevine is associated with
“stolbur”group in Eastern Georgia [22,23].
Phytoplasmas are characterized by complicated life cycle
and the diseases are distributed by sap feeding insects
belonging to the families Cicadellidae, Cixiidae, Psyllidae,
Delphacidae and Derbidae [24], by parasitic plants (Cuscuta sp.)
[25], by seed [26,27], by grafting [5,28]. The systematics of
phytoplasmas [29,30], structure of genome [31], interaction
with the host organisms [1,2], plant resistance [32,33] are
intensively studied. Decreasing of losses due to phytoplasma
diseases is possible by selection and practical use of resistant
cultivars [2,3,11,34,35]. Despite intensive investigations, the
available knowledge about phytoplasma biology and mecha-
nisms of plant resistance is insufficient, rendering not
possible to manage them with eradication control methods.
Moreover, the areas of distribution of phytoplasma diseases
and the species affected are quickly widening.
Even more questions are still present about the grapevine
phytoplasma disease in Georgia. It is not established e
whether there are different groups of phytoplasmas and
different insect vectors in the various vine-growing regions
and what is the resistance of the Georgian cultivars against
the GY. The symptoms of the disease, pathological changes
(anatomical, physiological, biochemical, genetic) according to
the cultivars, the markers necessary for selection of resistant
individuals are also not studied. Study of these issues in the
homeland of cultivated grapevine eGeorgia, where more than
500 endemic cultivars of Vitis vinifera (L.) are described
ampelographically in various agri-environmental conditions
[36], is especially important from the theoretical and practical
points of view.
Results of the investigation carried out on phytoplasma
disease of grapevine in Georgia during last 10 years are
presented.
Objectives and methods
The study has been conducted on the Georgian cultivars of the
grapevine Vitis vinifera (L.): Rkatsiteli, Saperavi, Shavkapito,
Tavkveri, Aladasturi, Kachichi, and on the Azerbaijan cultivar
Ganjuri, on the French cultivar Chardonnay, Vitis labrusca (L.)
on the cultivar Isabella (synonym Odessa), on the interspecific
hybrid cultivar Noah. Visual assessment of the disease was
made in farmers'vineyards (Sighnaghi and Lanchkhuti dis-
tricts), in the ampelographic collection of the Agricultural
University of Georgia (Mtskheta district), in the national
center of production of saplings of grapevine and fruit trees
(Mtskheta district). Sighnaghi district is located in the eastern
part of Tsiv-Gombori Range at 500e800 m a.s.l. Dry conti-
nental climate dominates there. Winter is cold, summer hot
and drought-afflicted. The annual precipitation is
400e500 mm. The snow cover is rarely formed. The soils there
are chernozem and cinnamonic; many aboriginal varieties
grow there. The best quality wines are produced there. The
main industrial cultivars for wine production are Rkatsiteli,
Saperavi and Goruli mtsvane. Mtskheta district is located at
400e600 m a.s.l., is characterized by dry subtropical climate
with relatively cold winter, annual precipitation is ca.
500e600 mm. Alluvial-calcareous and meadow cinnamonic
soils are mainly present there. The industrial cultivars are:
Goruli mtsvane, Chinuri, Tavkveri. High quality wines are
produced. Lanchkhuti district is located in Western Georgia, at
height 50e100 m a.s.l. The humid subtropical climate domi-
nates there. Due to vicinity to Black Sea it is characterized by
warm winter and moist climate. Summer is hot. The annual
precipitation is ca. 2000 mm. Mainly yellow and red soils are
there. The widespread cultivars are Odessa, Noah, Aladasturi.
There are many other local cultivars. Original wines are pro-
duced there.
Grapevine is cultivated by trellis method in Eastern Georgia
and on pergola in Western Georgia. The plants were assessed
according to external symptoms: healthy (without visual
symptoms), weakly diseased (up to 25% of the plants are
symptomatic), moderately (up to 50% of the plants are
symptomatic) and severely diseased (more than 50% symp-
tomatic) [10]. Visually healthy and symptomatic material has
been fixed in ethanol and formalin. Temporary slides were
made from the fixed material for establishment of disease and
patho-anatomical disorders. Preparation of anatomical sec-
tions, staining and microscopic study of structure was made
by standard methods [37]. For determination of content of
starch, the J þJK solution was used [37]. The quantitative
content of plastid pigments in leaves was measured by spec-
trophotometric method [38]. Diagnostic of phytoplasmas in
petiole of visually healthy and diseased leaves has been car-
ried out by Dienes'cytochemical method [18]. The material for
the detection of quantity of plastid pigments was sampled in
the vineyards of the village Kvemo Bodbe, Sighnaghi district.
Cicadas were collected by insect net and placed in glass tubes
for species determination [39]. For study plant cells and tis-
sues and insects the transmission microscope TESLA BS-500;
the light microscope MБИ-3, stereomicroscope MБС-9 were
used. The microphotographs have been taken by digital
camera Sony (12.3 megapixels). The experiments were
repeated three times. The study has been carried out in
2005e2015.
Results and analysis
Spread of disease
In 2005e2015, epidemics of GY disease were detected in re-
gions differing in agri-environmental conditions: Kakheti re-
gion eSighnaghi district, Kartli region eTbilisi and Mtskheta
districts (Eastern Georgia) and Guria region eLanchkhuti
annals of agrarian science xxx (2016) 1e102
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
district (Western Georgia). The local cultivars are well adapted
to the region.
Visual diagnostics of the disease
The symptoms of the disease are variable according to
cultivar, region and intensity. The most obvious symptom is
yellowing of leaves (on white grapevine cultivars, Shardon-
nay, Ganjuri) or reddening (on red grapevine cultivars Saper-
avi, Shavkapito) (Fig. 1), deformation of leaves, necrosis,
inhibition of growth and drying of diseased plants in spring
and summer. It should be mentioned that red-grapevine cul-
tivars Aladasturi, Saperavi, Shavkapito, and Tavkveri may
have not only red coloring, but yellow as well. Aladasturi and
Chardonnay are characterized by similar symptoms of leaf
deformation. The leaf size is reduced in all symptomatic
cultivars.
Cytochemical detection of the phytoplasmas
By using Dienes'stain healthy and phytoplasma infected
cultivars of grapevine and other host plant species of the po-
tential phytoplasma vector cicadas were identified. The
diseased phloem is always being stained dark blue (Fig. 2). In
the epidemic areas of the disease the presence of healthy
grapevine leaf with plants not carrying the infection is very
rare (Table 1). In the examined material only Noah samples
collected in 2010 in Guria, resulted symptomless (Fig. 2). The
plant had no character of disease eneither externally not
cyto-chemically. In 2015 in the same area in healthy looking
leaves, from Noah the Dienes'reagent has shown positive
reaction. In general, intensifying of visual disease symptoms
is accompanied by intensive staining of the phloem in all the
studied varieties (Fig. 2 and Table 1).
Fig. 1 e1. Ganjuri, white. Mtskheta, Kartli; 2. Chardonnay, white. Mtskheta, Kartli; 3. Shavkapito, red. Mtskheta, Kartli; 4.
Saperavi, red. Sighnaghi, Kakheti; A. General view of the plant. B. Diseased leaves.
Fig. 2 eHand cut sections of visual healthy cultivar Noah (A) and phytoplasma-infected cultivar Saperavi (B) leaf petioles
stained with Dienes'stain. Arrows show healthy (A) and diseased (B) phloems. x40.
annals of agrarian science xxx (2016) 1e10 3
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
Detection by electron microscopy
Electron microscopic study carried out for the first time on
diseased leaf of cultivar Saperavi. Only yellow spots were
visible on the leaf, caused by sucking insects; it had not
external symptoms of phytoplasma disease. Dienes'reaction
shown the phytoplasma presence in the middle part of the
leaf petiole and the electron microscopy allow to visualize
their forms and sizes (Fig. 3). It has been determined that their
form is slightly round, sizes vary within 0.2e1.0 mm, mem-
brane is well visible. Phytoplasmas have been mentioned in
the sieve cells of phloem. Phytoplasma cells are light colored
(Fig. 3).
Infection-transmitting cicadas
In the infected areas of Eastern Georgia, 10 species of cicadas,
which fed on grapevine as well as on other species, were
collected and most of them resulted carrying phytoplasmas:
Agalmatium grylloides (Fabricius, 1794) edistributed all over
Georgia, especially in Eastern Georgia. Its ability to trans-
mit phytoplasmosis is not studied.
Cicadella viridis (Linnaeus, 1758) edistributed all over
Georgia is hygrophilous. Its bio-ecology and ability to
transmit phytoplasma are not studied.
Dictyophara europaea (Linnaeus, 1767) epolyphagous found
on grapevine in Eastern Georgia (Sighnaghi district) in
2014e2015. The insect is considered in Europe as one of the
vector of the Flavescence dor
ee phytoplasma.
Empoasca vitis (Gothe, 1875) edistributed all over Georgia is
hygrophilous. It feeds on herbaceous plants and shrubs. Its
ability to transmit phytoplasma is not studied.
Erythroneura imeretina Dekanoidze, 1962 efound with high
population density in Mtskheta district (Mukhrani) in 2013
on the cultivar Saperavi, phytoplasma infected. Its ability
to transmit phytoplasma is not studied.
Hyalesthes mlokosieviczi Signoret, 1879 emorphologically
very similar to Hyalesthes obsoletus. It is distributed in Kartli
and Kakheti regions. It was found in the 50-ies of the XX
century in Eastern Georgia. It is possibly one of the vectors
of phytoplasmas.
H. obsoletus Signoret, 1865 efound on grapevine (V.
vinifera), sunflower (Helianthus annuus), liquorice (Glycyr-
rhiza glabra) and bindweed (Convolvulus arvensis) in Sigh-
naghi district in 2014e2015. Its specimens were found in
June, July and August. It is a vector of Bois noir disease in
Europe.
Lepyronia coleoptrata (Linnaeus, 1758) efed on grapevine (V.
vinifera), small nettle (Urtica urens), blackberry (Rubus),
liquorice (G. glabra), sunflower (H. annuus), agrimony
(Agrimonia eupatoria) and goosefoot (Chenopodium album).
Pentastiridius leporinus (Linnaeus, 1761) efound in Sighna-
ghi district on diseased grapevine (V. vinifera), small nettle
(U. urens), blackberry (Rubus), black locust (Robinia pseu-
doacacia), liquorice (G. glabra), sunflower (H. annuus), agri-
mony (A. eupatoria) and goosefoot (C. album).
Philaenus spumarius (Linnaeus, 1758) edistributed all over
Georgia, it is hygrophilous. It feeds on herbaceous plants
Table 1 eStructure of leaf petiole in middle part of visual healthy and diseased grapevine cultivars.
Cultivar Degree of the disease Conductive veins, number Vessel, number Vessel, diameters Xylem
Main Additional Main Additional Main Additional Main Additional
Number % Number Number % Number % mk % mk % mk
2
%mk
2
%
1. Rkatsiteli Visual healthy 19.3 100.0 2e3 223.0 100.0 18.8 100.0 3.3 100.0 1.9 100.0 735.9 100.0 35.7 100.0
Very diseased 17.3 89.7 2 178.7 80.1 11.7 62.2 2.6 78.8 1.9 100.0 464.6 63.1 22.2 62.2
2. Saperavi Visual healthy 29.5 100.0 2 247.0 100.0 11.5 100.0 2.9 100.0 2.1 100.0 716.3 100.0 24.2 100.0
Very diseased 13.0 44.1 2 130.0 52.6 7.0 60.9 2.7 93.1 2.3 109.5 351.0 49.0 16.1 66.5
3. Aladasturi Visual healthy 26.3 100.0 2e3 236.6 100.0 28.5 100.0 3.3 100.0 3.2 100.0 780.8 100.0 91.2 100.0
Very diseased 24.8 94.3 2 225.0 95.1 21.5 75.4 2.7 81.8 2.3 71.9 607.5 77.8 49.5 54.3
4. Kachichi Visual healthy 18.0 100.0 2 246.0 100.0 18.0 100.0 4.2 100.0 2.4 100.0 1033.2 100.0 43.2 100.0
Very diseased 17.0 94.4 2 201.0 81.7 12.0 66.7 2.7 64.3 1.6 66.7 542.7 52.5 19.2 44.4
5. Noah Visual healthy 32.0 e2 317.0 e24.0 e4.6 e3.3 e1046.1 e79.2 e
Diseased ee e ee eeeeeeeeee
annals of agrarian science xxx (2016) 1e104
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
and shrubs. Its ability to transmit phytoplasma is not
studied.
In the diseases areas in Lanchkhuti district (Western
Georgia) in 2015 the two species of cicadas listed below, which
feed on diseased grapevine and other plant species were
collected.
Metcalfa pruinosa ewide polyphagous insect damaging
many subtropical woody plants and shrubs. Colonies were
found on the following species: grapevine (V. vinifera,V. lab-
rusca), medlar (Mespilus germanica), walnut-tree (Juglans),
blackberry (Rubus), mulberry (Morus), small nettle (U. urens),
male-fern (Dryopteris), black locust (R. pseudoacacia), tea
(Camellia sinensis), Chinese wood-oil tree (Aleurite scordata),
braken (Pteridium tauricum), agrimony (A. eupatoria), common
ragweed (Ambrosia artemisiifolia), hazelnut (Corylus colchica), or-
ange (Citrus sinensis var. washington navel), colchis ivy (Hedera
colchica), trifoliate orange (Poncirus trifoliata). The Dienes'reac-
tion has shown that except for Morus and M. germanica, all the
above mentioned plant species were carrying phytoplasmas.
Ricania japonica Melich eis widely distributed in Western
Georgia, it is a polyphagous species. It was collected together
with M. pruinosa on the above mentioned plant species. They
both may be carriers of phytoplasmas.
Pathoanatomical changes in grapevine infected by
phytoplasmas
It has been defined that phytoplasmas induce structural dis-
orders in the middle part of petiole of leaf, which extent de-
pends on cultivar and disease severity (Table 1). The number
of main conducting bundles in the middle parts of a petiole of
visually healthy leaves varied within 18e32. The number of
additional bundles was mainly 2, rarely 3 or 4. Diameter of
vessels and water conducting area is higher in the cultivars
growing in Lanchkhuti district eAladasturi, Kachichi and
Noah, than in Rkatsiteli and Saperavi, distributed in Sighnaghi
district. Drastic changes are observed in the structure of
middle part of petiole of symptomatic grapevine leaf. In
particular, the numbers of main conductive bundles are
decreased in Rkatsiteli eby 10.4%, in Saperavi eby 55.9%, and
in Aladasturi eby 5.7%, the number of additional bundles
decreased by unit only in Rkatsiteli, Aladasturi (Table 1) and
Goruli mtsvane. In all the studied cultivars the number of
vessels decreased in main and additional bundles. The num-
ber of vessels to the additional bundles decreased in all vari-
eties, and the diameter of vessels decreased only in Kachichi
and Aladasturi, in the cultivar Rkatsiteli it remained un-
changed, and in Saperavi eincreased by 9.5%. The changes in
number and sizes of vessels were reflected in the total area of
vessels, i.e. water conductive area of the petiole (Fig. 4). The
latter is reduced in all diseased cultivars, especially in the
cultivars of dry climate eRkatsiteli and Saperavi growing in
the conditions of dry climate (Kakheti) have less total area of
water transmitting system of middle part of leaf petiole (area
of main vascular system þarea of companion vascular sys-
tem) (772 mm
2
and 740 mm
2
, respectively), than in Aladasturi
(872 mm
2
), Kachichi (1072 mm
2
) and Noah (1125 mm
2
), growing
in the conditions of high moisture (Guria region) (Fig. 4).
Pathophysiological changes in grapevine phytoplasma
infected
At the end of September in the petiole of leaf of diseased
grapevine, in comparison with the visually healthy one, big
quantity of starch content is observed. The starch has been
accumulated mainly in the parenchyma cells adjacent to
conductive system of petiole.
The content of plastid pigments is disordered in the leaves of
phytoplasma infected grapevines. Rkatsiteli had small,
yellowish colored leaves and Saperavieinternally twisted, dark
red colored, also small leaves. By using of Dienes'staining phy-
toplasmas in a small quantity was revealed in visually healthy
leaves of both cultivars, so they may be considered as latently
Fig. 3 ePhytoplasmas (arrows) in the phloem cells (A) of the visual healthy leaf (B) of cultivar Saperavi. A: X39,000.
annals of agrarian science xxx (2016) 1e10 5
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
infected. The area of visually diseased leaves was very much
decreased, especiallyin the cultivar Saperavi. In particular,in the
diseased cultivar Rkatsiteli the area of leaf reduced approxi-
mately by 70%, while in Saperavi eby 39% (Fig. 5). In the visually
diseased leaves of the cultivar Saperavi chlorophylls “a”and “b”
are reduced by equal quantities eapproximately by 44%, in
comparison with visually healthy ones. In the visually diseased
leaves of the cultivar Rkatsiteli chlorophyll “a”is reduced by 8%
(Fig. 6) and chlorophyll “b”by 23% (Fig. 7).
Discussion
The laboratory and field studies carried out in 2005e2015 have
shown that the area of distribution of grapevine phytoplasma
diseases is more than it was known up to 2013. In particular,
the districts Mtskheta and Lanchkhuti have been added to
Telavi, Kvareli, Oni and Sighnaghi districts. The symptoms
Fig. 4 eTotal water conducting area in the middle part of
visual healthy and phytoplasma diseased grapevine leaf
petioles. Cultivar Noah did not have symptoms of disease.
Fig. 5 eAreas in visual healthy and diseased leaves blades
of grapevine infected by phytoplasmas.
Fig. 6 eContent of chlorophyll “a”in visual healthy and
diseased grapevine leaves.
Fig. 7 eContent of chlorophyll “b”in visual healthy and
diseased grapevine leaves.
annals of agrarian science xxx (2016) 1e106
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
vary according to the cultivars and intensity of disease.
Typical, as well as, specific symptoms are mentioned, e.g.
yellowing of leaves instead of reddening on red culti-
varseAladasturi, Isabella and Tavkveri, whereas in Shavka-
pito and Saperavi the external manifestation of the disease
begins directly with reddening of leaves. Yellowing of leaves
on the cultivar Saperavi instead of reddening was mentioned
by D. Giorgadze [20]. The definite causes of such modification
of external symptoms are not known for us. It may be caused
by different immunity of cultivars or existence of different
strains. It was reported that in Eastern Georgia (Mtskheta
district) on grapevine and bindweed two phytoplasma strains
are associated with grapevine yellows ‘Candidatus Phyto-
plasma solani’(subgroup 16SrXII-A) and ‘Са.P.a convolvuli’
(subgroup 16SrXII-H) [22,23] respectively. Phytoplasmas are
characterized by high degree of genetic differentiation [40]
and GY are associated with genetically different phyto-
plasmas, the most important in Europe are Flavescence dor
ee
(FD) and Bois noir (BN). There are two groups of FD e16SrV-C
and 16SrV-D, which differ from each other by geographic
distribution [5,29,40e44]. The versatility of external symptoms
of the disease suggests that in the endemic Georgian grape-
vine cultivars, except for the reported ‘Ca. P. solani’and ‘Ca. P.
convolvuli’(subgroup 16SrXII-H), other groups of phyto-
plasmas should exist. The fact that the phytoplasma diseases
in the main industrial cultivars in Georgia has not the char-
acter of epiphytoty [19,23], as for example, in France, Spain
and Northern Italy [41,45e47], is especially noteworthy. It
points out that the Georgian cultivars in general would have
higher resistance against phytoplasmas. It may be caused by
coevolution of endemic cultivars of grapevine and defined
strains of phytoplasmas in a restricted geographic area. As it is
known, the cultivars resistant to a disease are usually met in
the natural epidemic source of origin of the cultivated plants,
where evolution of parasite and its host-organism proceeds
simultaneously [47]. The South Caucasus, in particular Geor-
gia, is the oldest center of origin and domestication of grape-
vine [48].
The 13 species of cicadas registered in Georgia that are
feeding on grapevine [20,49e52] deserve special investigation.
This should be focused on the insect families Aphrophoridae,
Cicadellidae, Cixiidae, Delphacidae, Derbidae, Dictyophar-
idae, Flatidae, Issidae, Psyllidae, and Ricaniidae, detected in
the epidemic areas of grapevine phytoplasma diseases. The
species composition of phytoplasmas depends on the vector
insect that is the host organism for a phytoplasma [53,54].An
insect may transmit certain group of phytoplasmas. It has
been already established that the BN disease is present and
spread [19e23] in Eastern Georgia. H. obsoletus, found in large
quantities in one epidemic area in Eastern Georgia eSighna-
ghi district, must be considered the main insect vector
candidate of BN. This insect is widespread in other regions as
well [50e55], therefore H. mlokosieviczi is very interesting as
also the representative of the genus Hyalesthes and D. europaea,
known as grapevine phytoplasma vectors in Europe [56e59].
The existence of different groups of phytoplasmas adapted to
various vector insects in Georgia is assumed. This idea fully
agrees to the theory of coevolution of host and parasite. There
is symbiotic interaction between phytoplasma and insect
vectors [54e56].H. obsoletus and D. europaea were not detected
in Guria region, however out of the 14 feeding plant species of
M. pruinosa and R. japonica 12 gave positive reaction with Di-
enes'staining, i.e. phloem contained phytoplasmas so both
species of cicadas should be considered as potential vectors of
phytoplasma diseases.
An effective measure of phytoplasma disease control is the
selection of resistant genotypes and their propagation. Phy-
toplasmas are localized in the conductive system of a plant;
they alter the process of formation of conductive bundles and
leaf morphology on the early stage of differentiation [60,61].In
the visually diseased deformed and etiolated leaf the ratio of
spongy-like and palisade-like tissues is lost [62], chlorophyll
destroyed and chloroplasts are fragmented [33,62,63]; in the
conductive system the number of vessel-fiber bundles and
water-transmitting area is reduced [64,65]. The anatomical
structure of the middle part of leaf petiole is a cultivar-specific
character [65,66]. It was successfully used for selection of
mulberry resistant to phytoplasma disease. This study shown
that phytoplasma presence induces reduction of water-
transmitting area in the middle part of grapevine leaf
petiole. Such condition is accompanied by water deficit and
arising of physiological dryness in mesophyll. Phytoplasmas
cause disorders characteristic for water deficit in other spe-
cies, e.g., closing of leaf stomata [33,65], inducing plasmolysis
of chloroplasts, decay of chlorophylls, reduction of activity of
ribulose-1,5-bisphosphate carboxylase, destruction of pro-
teins in the membranes of thylakoids and water splitting
system, accompanied by inactivation of photosystem II. The
photosystem I is damaged only in severe diseases and only
partially [63,64,67e71].
Decay of chlorophyll is a typical symptom of phytoplasma
disease in many species, including grapevine [69,70,72].
Reduction of quantity of chlorophyll “a”per unit leaf area
calculated per one leaf causes decreasing of the intensity of
photosynthesis, generation of energy and mass, slowing of
growth and reducing of immunity. Plant becomes small, thin
and colorless, easily dies in winter. Photosynthesis in a leaf is
weakened and respiration is intensified [62,70]. Sugar trans-
portation from symptomatic leaves is hindered. Starch is
accumulated in the mesophyll [33,61] and in the petiole of
diseased leaf. Accumulation of starch is a signal of breaking
down of sinkesource system in the diseased grapevine [73].
Intensity of the disease depends on plant resistance. Ac-
cording to the percentage of damage in the leaves anatomy in
the conditions of Guria the cultivar Noah (visually undam-
aged) is highly resistant, Aladasturi is relatively resistant
(damage 25%) and Kachichi is moderately resistant (damage
50%). In the conditions of dry climate (Kakheti region) Rkat-
siteli (damage 40%) and Saperavi (damage 50%) are moder-
ately resistant. The higher ability of retention of plastid
pigments by Rkatsiteli confirms the higher resistance of this
cultivar in comparison with Saperavi.
Conclusion
The existence of the GY disease in Georgia is known from
2002. Nowadays this disease has been detected in four regions
of Georgia. The symptoms of phytoplasma disease have been
observed on 10 cultivars of grapevine, 6 of them eRkatsiteli,
annals of agrarian science xxx (2016) 1e10 7
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
Saperavi, Shavkapito, Tavkveri, Aladasturi and Goruli
mtsvane eare Georgian endemics, four cultivars eIsabella,
Ganjuri, Chardonnay and Noah eare introduced. The pres-
ence of diverse symptomatology suggests that different
strains of phytoplasmas should exist in different regions of
Georgia. Almost all studied asymptomatic cultivars are
showing phytoplasma presence. Despite of this, epiphytoty is
not present in Georgian industrial cultivars, that is the evi-
dence of resistance of Georgian cultivars. The idea is also
confirmed by the results these anatomical studies, according
to which the damage of structure in the studied cultivars is
less than 50%. We have recorded 12 species of cicadas on the
investigated areas: A. grylloides,C. viridis,D. europaea,E. vitis,E.
imeretina,H. obsoletus,H. mlokosieviczi,L. coleoptrata,M. prui-
nosa,P. leporinus,P. spumarius, and R. japonica. A number of
these species of cicadas with high probability may be vectors
of grapevine phytoplasma infection in Georgia.
The studied cultivars according to anatomical and physi-
ological characteristics showed the following descending se-
ries of resistance: Noah, Aladasturi, Rkatsiteli, Kachichi,
Saperavi. The analysis of results of study of the grapevine
phytoplasma disease in Georgia during the last 10 years shows
that it is necessary to continue comprehensive study of phy-
toplasma disease in all regions, in order to establish disease
distribution and effective methods of control.
Acknowledgments
We would like to express our gratitude to Mr. Sergei Osipian
(head of the laboratory of electron microscopy of the Agri-
cultural University of Georgia) for the assistance.
references
[1] Phytoplasmas and phytoplasma disease management: how
to reduce their economic impact, in: Assunta Bertaccini (Ed.),
Food and Agriculture COST Action FA0807 Integrated
Management of Phytoplasma Epidemics in Different Crop
Systems, Alma Mater Studiorum eUniversity of Bologna,
Italy, 2014, p. 288.
[2] A. Bertaccini, Current Status and Perspective of Phytoplasma
Disease Research and Management. COST Action FA0807.
Integrated Management of Phytoplasma Epidemics in
Different Crop Systems, Publishing House of University of
Bologna, Bologna, Italy, 2014.
[3] A. Bertaccini, B. Duduk, S. Paltrinieri, N. Contaldo,
Phytoplasmas and phytoplasma diseases: a severe threat to
agriculture, Am. J. Plant Sci. 5 (2014) 1763e1788.
[4] F. Quaglino, Y. Zhao, P. Casati, D. Bulgari, P.A. Bianco,
W. Wei, R.E. Davis, ‘Candidatus Phytoplasma solani’, a novel
taxon associated with stolbur- and bois noir-related diseases
of plants, Int. J. Syst. Evol. Microbiol. 63 (2013) 2879e2894.
[5] H.D. Mohr, Farbatlas Krankheiten, Schadlinge und Nutzlinge
an der Weinrebe, Verlag, Stuttgart, 2005 (in German).
[6] 1st European Bois noir Work shop, Book of Abstracts,
Weinsberg, Germany. 11.11e13.11, 2008, 33 pp..
[7] G. Belli, P.A. Bianco, M. Conti, Invited review grapevine
yellows in Italy: past, present and future, J. Plant Pathol. 92
(2010) 301e324.
[8] I.A. Nakaidze, Soil Condition and Chlorosis of Grapevine in
Georgia, Agricultural Institute of Georgia, Tbilisi, 1965 (in
Russian).
[9] Y. Doi, M. Teranaka, K. Yora, H. Asuyama, Mycoplasma or
PLT group like microorganisms found in the phloem
elements of plants infected with mulberry dwarf, potato
witches'broom, aster yellows or pawlownia witches'broom,
Ann. Phytopathol. Soc. 33 (1967) 259e266.
[10] M. Kakulia, I. Chotorlishvili, H. Zedginidze, Z. Putkaradze,
Mulberry Dwarf Disease, Methods of Diagnostics in Field,
Agricultural Institute of Georgia, Tbilisi, 1979 (in Russian).
[11] M. Kakulia, Diseases of Mulberry, Agricultural Institute of
Georgia, Tbilisi, 1983 (in Georgian).
[12] T.I. Zakarashvili, T.I. Skripal, N.I. Pavchenko,
N.I. Mashkovskiy, Physic-chemical characters DNA of
mycoplasmas-causative agents of mulberry dwarf disease,
Microbiol. J. 45 (1983) 76e79 (in Russian).
[13] T.I. Zakarashvili, V.I. Prima, N.I. Pavchenko, L.P. Skripal,
Genome size of mycoplasmas ecausative agents of mulberry
dwarf disease, Microbiol. J. 45 (1983) 49e52 (in Russian).
[14] A. Silvere, D. Giorgadze, Mycoplasma and virion like
structures in salivary gland cells of Hishimonus sellatus Uhler.,
diseased with mulberry dwarf disease, Izvestia AN Estonia
SSR, Biol. 23 (1978) 9e15 (in Russian).
[15] M. Kakulia, RecommendationeMaterials on Resistance of
Mulberry Varieties, Polyploids and Local Forms to Dwarf
Disease, Agricultural Institute of Georgia, Tbilisi, 1982 (in
Russian).
[16] D. Shalamberidze, N. Chkhaidze, Anatomical Method of
Resistance Mulberry to Dwarf Disease, Serificate
U1995000444, Tbilisi, Georgia, 1999, p. 14.
[17] N. Chkhaidze, Anatomical method for selection dwarf disease
resistant mulberry (Morus), in: Proceedings of the Reports
Presented at the International Jubilee Scientific Conference
Problemsof Maintenance and Utilizationof Mulberry Silkworm
Genetic Resources, September 25e29, Vratza, 2007, p. 101.
[18] N. Srinivasan, Simple diagnostic technique for plant disease
of mycoplasmal etiology, Curr. Sci. 51 (1982) 883e885.
[19] N. Chkhaidze, I. Dzmanashvili, Danger of grapevine
phytoplasma diseases in Georgia, Probl. Agric. Sci. 33 (2005)
71e73 (in Georgian).
[20] D. Giorgadze, New disease of grapevine in Georgia, Zas.
Karantin Ras. 4 (2005) 45 (in Russian).
[21] D. Giorgadze, N. Zurabishvili, M. Oshkhereli, G. Aleksidze,
Preliminary data for establish the etiology of grapevine
disease turn red of leaf in Georgia, Bull. Acad. Agric. Sci. Geo
23 (2009) 116e118 (in Georgian).
[22] F. Quaglino, D. Maghradze, N. Chkhaidze, P. Casati, O. Failla,
P.A. Bianco, First report of ‘Candidatus Phytoplasma solani’
and ‘Candidatus Phytoplasma convolvuli’associated
respectively with grapevine bois noir and bindweed yellows
in Georgia, Plant Dis. 98 (2014), 1,151.2e1,151.2.
[23] F. Quaglino, N. Chkhaidze, D. Magradze, P. Casati, A. Ravazio,
Surveys on Grapevine Yellows Incidence on Georgian
Grapevine Varieties, COST, Conference abstracts, Oct. 2014,
p. 43.
[24] A. Bertachinni, B. Duduk, Phytoplasma and phytoplasma
disease: a review of recent research, Phytopathol. Mediterr.
48 (2009) 355e378.
[25] P.G. Weintraub, L.A. Beanland, Insect vectors of
phytoplasmas, Annu. Rev. Entomol. 51 (2006) 91e111.
[26] I. Cordova, P. Jones, N.A. Harrison, C. Oropeza, In situ
detection of phytoplasma DNA in embryos from coconut
palms with lethal yellowing disease, Mol. Plant Pathol. 4
(2003) 99e108.
[27] A.J. Khan, S. Botti, A.M. Paltrinieri, A. Bertachinni,
Phytoplasmas in alfalfa seedlings: infected or contaminated
seeds?, in: 14th International Organization of
annals of agrarian science xxx (2016) 1e108
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
Mycoplasmology Conference, July 07e12, 2002, p. 6. Vienna,
Austria.
[28] M. Algaghi, S. Massart, S. Steyer, M. Lateur, M. Haissam
Jijakli, Study of diverse grafting techniques for their
capability in rapid and efficient transmission of apple
proliferation disease to different host plants, Bull.
Insectology 60 (2) (2007) 381e382.
[29] S. Botti, A. Bertaccini, Phytoplasma infection trough seed
transmission: further observations, in: 16th Congress IOM,
Cambridge, 9e14 July, 2006, 113 pp.
[30] I.M. Lee, D.E. Gundersen-Rindal, R.E. Davis, I.M. Bartoszyk,
Revised classification scheme of phytoplasmas based on
RFLP analysis of 16S rRNA and ribosomal protein gene
sequences, Int. J. Syst. Bacteriol. 48 (1998) 1153e1169.
[31] S.A. Hogenhout, K. Oshima, E.D. Ammar, S. Kakizawa,
H.N. Kingdomand, S. Namba, Phytoplasmas: bacteria that
manipulate plants and insects, Mol. Plant Pathol. 9 (2008)
403e423.
[32] I.M. Lee, R.E. Davis, T.A. Chen, L.N. Chiykowski, J. Fletcher,
C. Hiruki, D.A. Schaff, A genotype-base system for
identification and classification of mycoplasma like
organisms (MLOs) in the aster yellows MLO strain cluster,
Phytopathology 82 (1992) 977e986.
[33] N. Chkhaidze, Physiological mechanisms of resistance in
mulberry (Morus) diseased with phytoplasma disease, in:
International Scientific Conference “Genetical Resources of
Cultivated Plants and Their Application in Agriculture”.
Conference Papers. Gori, 2008, pp. 268e271 (in Georgian).
[34] S. Santi, F. De Marco, R. Polizzotto, S. Grisan, R. Musetti,
Recovery fromstolbur disease ingrapevine involves changes in
sugar transport and metabolism, Front. Plant Sci. 4 (2013) 1e12.
[35] N. Chkhaidze, Selection of dwarf disease resistant mulberry
(Morus) forms by means of anatomical method, in:
International Workshop on Silk Handcrafts Cottage
Industries and Silk Enterprises Development in Europe,
Central Asia and Near East, Bursa, Turkey, 6e10 March, 2006,
pp. 26e27.
[36] N. Ketskhoveli, M. Ramishvili, D. Tabidze, Ampelography of
Georgia, Publisher of the Georgian Academy of Sciences,
Tbilisi, 1960 (in Georgian).
[37] Q. Tskhakaia, E. Mirianashvili, Plant Anatomy, Practical
Course, Tbilisi State University, Tbilisi, 1957 (in Georgian).
[38] N.N. Tretijakov, Practicum in Plant Physiology,
Agropromizdat, Moscow, 1990 (in Russian).
[39] N. Elerdashvili, Collection and Fixation of Insects (Methods),
Agricultural Institute of Georgia, Tbilisi, 1975 (in Georgian).
[40] S.N. Borkhsenius, O.A. Chernova, V.M. Chernov,
M.S. Vonskiy, Mycoplasmas: Molecular and Cellular Biology,
Interaction with Immune System of Mammals,
Pathogenicity, Diagnostics, Nauka, Saint-Petersburg, 2002 (in
Russian).
[41] M. Martini, S. Botti, C. Marcone, C. Marzachı`, P. Casati,
P.A. Bianco, R. Benedetti, A. Bertaccini, Genetic variability
among Flavescence dor
ee phytoplasmas from different
origins in Italy and France, Mol. Cell. Probes 16 (2002) 197e208.
[42] B. Duduk, S. Botti, M. Ivanovi
c, B. Krsti
c, N. Duki
c,
A. Bertaccini, Identification of phytoplasmas associated with
grapevine yellows in Serbia, J. Phytopathol. 152 (2004)
575e579.
[43] A. Alma, R.E. Davis, M. Vibio, A. Danielli, D. Bosco, A. Arzone,
A. Bertaccini, Mixed infection of grapevines in Northern Italy
by phytoplasmas including 16S rRNA RFLP subgroup 16SrI-B
strains previously unreported in this host, Plant Dis. 80 (1996)
418e421.
[44] A. Gajardo, N. Fiore, S. Prodan, S. Paltrinieri, S. Botti,
A.M. Pino, A. Zamorano, J. Montealegre, A. Bertaccini,
Phytoplasmas associated with grapevine yellows disease in
Chile, Plant Dis. 93 (2009) 789e796.
[45] M. Engelbrecht, J. Joubert, T.J. Burger, First report of aster
yellows phytoplasma in grapevines in South Africa, Plant
Dis. 94 (2010) 373.
[46] E. Angelini, D. Clair, M. Borgo, A. Bertaccini, E. Boudon-
Padieu, Flavescence dor
ee in France and Italy doccurrence
of closely related phytoplasma isolates and their near
relationships to palatinate grapevine yellows and an alder
yellows phytoplasma, Vitis 40 (2001) 79e86.
[47] E. Torres, S. Botti, J. Rahola, M.P. Martin, A. Bertaccini,
Grapevine yellows diseases in Spain: eight years survey of
disease spread and molecular characterization of
phytoplasmas involved, An. Jard. Bot. Madr. 62 (2005)
127e133.
[48] N.I. Vavilov, in: P.M. Jukovskij, F.X. Bakhteev (Eds.), Selected
Works, vol. IV, Nauka, Moscow-Leningrad, 1964, pp. 314e435.
[49] S. Imazio, D. Maghradze, G. De Lorenzis, R. Bacilieri,
V. Laucou, P. This, A. Scienza, O. Failla, From the cradle of
grapevine domestication: molecular overview and
description of Georgian grapevine (Vitis vinifera L.)
germplasm, Tree Genet. Genomes 9 (2013) 641e665.
[50] Ir. Batiashvili, G. Dekanoidze, Entomology, Ganatleba, Tbilisi,
1974 (in Georgian).
[51] Mz.I. Lobjanidze, N.J. Robakidze, Carriers of disease of plants
in Georgia, actual problems of parasitology in Georgia, in:
Sh. Potskhveria (Ed.), Association of Parasitologists of
Georgia. Proceedings Scientific Works, 2009, pp. 175e180.
Sveti.
[52] N. Chkaidze, Mz Lobjanidze, Grapevine phytoplasma disease
and its potential carriers in Georgia, in: Science Works of the
International Conference, Kherson, Ukraine, 2012, pp.
149e152 (in Russian).
[53] H. Kawakita, T. Saiki, W. Wei, W. Mitsuhashi, K. Watanabe,
M. Sato, Identification of mulberry dwarf phytoplasmas in
the genital organs and eggs of leafhopper Hishimonoides
sellatiformis, Phytopathology 90 (8) (2000 Aug) 909e914.
[54] N.M. Christensen, K.B. Axelsen, M. Nicolaisen, A. Schultz,
Phytoplasmas and their interactions with their hosts, Trends
Plant Sci. 10 (2005) 526e535.
[55] E. Gonella, I. Negri, M. Marzorati, M. Mandrioli, L. Sacchi,
M. Pajoro, E. Crotti, A. Rizzi, E. Clementi, R. Tedeschi,
C. Bandi, A. Alma, D. Daffonchio, Bacterial endosymbiont
localization in Hyalesthes obsoletus, the insect vector of Bois
Noir in Vitis vinifera, Appl. Environ. Microbiol. 77 (2011)
1423e1435.
[56] F. Lessio, A. Alma, Host plants and seasonal presence of
Dictyophara europaea in the vineyard agro-ecosystem, Bull.
Insectology 61 (2008) 199e200.
[57] P.G. Ploalie, C. Chireceanu, Experimental proofs regarding
the association of cell wall deficient bacteria (mycoplasma
like organisms, phytoplasmas) with grapevine yellows
disease in Romania, Romanian Biotechnol. Lett. 17 (3) (2012)
7261e7269.
[58] C. Linder, M. Cavadini, Dictyophara europaea an alternative
host of Flavescence dor
ee in Switzerland, IOBC WPRS Bull.
105 (2014) 191e194.
[59] L. Filippin, J. Jovi
c, T. Cvrkovic, V. Forte, D. Clair, I. To
sevski,
E. Boudon-Padieu, M. Borgo, E. Angelini, Molecular
characteristics of phytoplasmas associated with Flavescence
dor
ee in clematis and grapevine and preliminary results on
the role of Dictyophara europaea as a vector, Plant Pathol. 58
(2009) 826e837.
[60] N. Chkhaidze, Mitosis in mulberry (Morus) diseased with
dwarf disease, Probl. Agric. Sci. 36 (2006) 54e55.
[61] N. Chkhaidze, N. Sichinava, Differentiation of conductive
system in mulberry shoot diseased with dwarf disease, Probl.
Agric. Sci. 37 (2006) 134e136.
[62] N. Kandelaki, Ratio of Palisade and Spongy Parenchima in
Mesophyll of Mulberry Leaf Diseased with Dwarf Disease,
annals of agrarian science xxx (2016) 1e10 9
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
Questions of Sericulture in Georgia, Scientific Works, Tbilisi,
1986, pp. 116e121 (in Georgian).
[63] T.I. Zakarashvili, Electron-microscopic researches of
mycoplasmas-causative agents of mulberry dwarf disease,
Microbiol. J. 45 (1983) 71e76 (in Russian).
[64] M. Bertamin, N. Nedunchenzian, F. Tomasi, M.S. Grando,
Phytoplasma [stolbur-subgroup (bois noir-BN)] infection
inhibits photosynthetic pigments, ribulose-1,4-bisphosphate
carboxylase snd photosynthetic activities in field grown
grapevine (Vitis vinifera L. cv. Chardonnay) leaves, Physiol. Mol.
Plant Pathol 61 (2002) 357e366.
[65] D. Shalamberidze, Selection of Mulberry Forms Resistance to
Dwarf Disease by Means of Anatomical Structure
(Dissertation), Tbilisi, 1998 (in Georgian).
[66] N. Chkhaidze, Leaf petiole structure of grapevine (Vitis
vinifera L.) diseased with phytoplasma, Probl. Agric. Sci. 40
(2007) 67e70.
[67] T.V. Vekua, Leaf petiole architecture of grapevine varieties
distributed in West Georgia, Sci. Works Georgian State Agric.
Inst. 1 (1940) 41e45.
[68] N. Chkhaidze, Mycoplasmal infection and water economy in
mulberry (Morus), Probl. Agric. Sci. (2001) 190e193 (in Russian).
[69] M. Bertamini, M.S. Grando, N. Nedunchezhian, Effects of
phytoplasma infection on pigments, chlorophyll-protein
complex and photosynthetic activities in field grown apple
leaves, Biol. Plant. 47 (2003) 237e242.
[70] M. Bertamini, N. Nedunchezhian, Effects of phytoplasma
[stolbur-subgroup (bois noir-BN)] on photosynthetic pigments,
saccharides, ribulose 1,5-bisphosphate carboxylase, nitrate
and nitrite reductases, and photosynthetic activities in field-
grown grapevine (Vitis vinifera L. cv. Chardonnay) leaves,
Photosynthetica 39 (2001) 119e122.
[71] Z. Khidesheli, Biochemical, physiological and ultrastructural
changes in tissues of tomato diseased with mycoplasma, Sci.
Works Acad. Agric. Sci. Georgia (1996) 191e194.
[72] N. Chkhaidze, CO
2
changes and chlorophyll content in
different resistant mulberry (Morus) leaves diseased with
phytoplasma, in: 5th BACSA International Conference
“Sericulture for Multiproducts eNew Prospects for
Development.”Seriprodev, Bucharest, Romania, April
11the15th, 2011, pp. 70e73.
[73] Yu.V. Gamalei, The nature of the trophic tract in vascular
plants, Cytology 51 (2009) 375e387.
annals of agrarian science xxx (2016) 1e1010
Please cite this article in press as: N.M. Chkhaidze et al., Grapevine phytoplasma disease in Georgia, Annals of Agrarian Science (2016),
http://dx.doi.org/10.1016/j.aasci.2016.04.001
