scholarly journals First Report of ‘Candidatus Phytoplasma solani’ Strains Associated with Grapevine Bois Noir in Jordan

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1505-1505 ◽  
Author(s):  
N. M. Salem ◽  
F. Quaglino ◽  
A. Abdeen ◽  
P. Casati ◽  
D. Bulgari ◽  
...  
Keyword(s):  
16S Rdna ◽  
Nucleotide Sequences ◽  
Pcr Analysis ◽  
Vitis Vinifera L ◽  
Insect Vector ◽  
Convolvulus Arvensis ◽  
Disease Etiology ◽  
Bois Noir ◽  
Negative Controls ◽  
Positive Controls

During a survey carried out in Jordanian vineyards in August and October 2012, grapevine (Vitis vinifera L.) plants showing typical grapevine yellows (GY) disease symptoms, including leaf discoloration and curling, berry shriveling, and irregular maturation of wood, were observed. In the same vineyards, bindweed (Convolvulus arvensis L.) plants showing stunting and leaf chromatic alteration were found, suggesting the involvement of phytoplasmas in the disease etiology. Using a CTAB method, total DNA was extracted from leaf veins of 25 symptomatic and two asymptomatic grapevines, and from five symptomatic and two asymptomatic bindweeds for PCR analysis. DNAs from periwinkle (Catharanthus roseus (L.) G. Don) plants infected by ‘Ca. Phytoplasma asteris’ strain SAY (group 16SrI), ‘Ca. Phytoplasma solani’ strain STOL (group 16SrXII), and ‘Ca. Phytoplasma ulmi’ strain EY1 (group 16SrV), were used as positive controls. DNAs from healthy periwinkle and reactions without template DNA were employed as negative controls. 16S rDNA nested PCRs, carried out using the primer pairs P1/P7, followed by R16F2n/R16R2 (1), yielded an amplicon of the expected size (1,250-bp) in three grapevine and in five bindweed samples, and in positive controls. Amplicons were not produced with DNA from 22 symptomatic grapevines (probably because samples were collected late in the growing season and phytoplasma distribution in plants was non-uniform [2]); nor from asymptomatic plants and negative controls. PCR products were sequenced by commercial services in Italy (Primm, Milan) and Korea (Macrogen Inc., Soul). Representative 16S rDNA nucleotide sequences were deposited in NCBI GenBank with accessions KC835139 (from grapevine) and KC835140 (from bindweed). The 16S rDNA nucleotide sequences of phytoplasmas identified in grapevine and bindweed in Jordan shared >99.5% sequence identity with ‘Ca. Phytoplasma solani’ reference strain STOL (AF248959), and carried identical STOL-unique signature sequences and distinguishing sequence blocks (3). Phylogenetic and in silico RFLP analyses confirmed the affiliation of phytoplasma strains identified in grapevine and bindweed in Jordan to the species ‘Ca. Phytoplasma solani’ (subgroup 16SrXII-A), opening an avenue to future studies on the dissemination and impact of Bois noir (BN) in Jordan. These studies may add new information about BN, previously reported in neighboring countries (4). Further studies will investigate the role of Hyalesthes obsoletus Signoret, a polyphagous Cixiidae responsible for the BN phytoplasma transmission in Europe, and other possible insect vector(s) in the BN spread in Jordan. References: (1) I.-M. Lee et al. Int. J. Syst. Bact. 48:1153, 1998. (2) F. E. Constable et al. Plant Pathol. 52:267, 2003. (3) F. Quaglino et al. Int. J. Syst. Evol. Microb. 63:2879. (4) E. Choueiri et al. Plant Dis. 86:697, 2002.

scholarly journals First Report of ‘Candidatus Phytoplasma solani’ and ‘Ca. P. convolvuli’ Associated with Grapevine Bois Noir and Bindweed Yellows, Respectively, in Georgia

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1151-1151 ◽  
Author(s):  
F. Quaglino ◽  
D. Maghradze ◽  
N. Chkhaidze ◽  
P. Casati ◽  
O. Failla ◽  
...  
Keyword(s):  
16S Rdna ◽  
Reference Strain ◽  
Phylogenetic Analyses ◽  
Nucleotide Sequences ◽  
Insect Vector ◽  
Disease Etiology ◽  
Bois Noir ◽  
Sequence Identity ◽  
Negative Controls ◽  
Positive Controls

A survey carried out in Georgian vineyards, located in the Khaketi region, in September 2013, showed the presence of vines of the cultivar Chardonnay with typical grapevine yellows (GY) symptoms including leaf discoloration and curling, berry shriveling, and irregular maturation of wood. In the same vineyards, bindweed (Convolvulus arvensis L.) plants showing shoot proliferation and leaf yellowing were found, suggesting the involvement of phytoplasmas in the disease etiology. Total DNA was extracted by a CTAB method from leaf veins of 18 symptomatic and two asymptomatic grapevines, and from four symptomatic and two asymptomatic bindweeds, and analyzed by PCR assays. Moreover, DNA extracted from ‘Candidatus Phytoplasma asteris’ strain SAY (group 16SrI), ‘Ca. P. solani’ strain STOL (group 16SrXII), and ‘Ca. P. ulmi’ strain EY1 (group 16SrV) were used as positive controls. DNA extracted from healthy periwinkle and a reaction mixture without template were employed as negative controls. Nested PCRs targeting the 16S rDNA, carried out using the primer pairs P1/P7 followed by R16F2n/R16R2 (1), produced a band of the expected size (1,250 nt) in all the symptomatic grapevine and bindweed plants, and in the positive controls. No amplification was observed with DNA from asymptomatic plants nor the negative controls. PCR products were sequenced by a commercial sequencing service (Primm, Milan, Italy). The 16S rDNA nucleotide sequences of phytoplasmas identified in all grapevines and in two bindweed samples shared >99.5% sequence identity with ‘Ca. P. solani’ reference strain STOL (GenBank Accession No. AF248959), and carried identical STOL-unique signature sequence and distinguishing sequence blocks (3). Moreover, nucleotide sequences of phytoplasmas identified in the other two bindweed samples shared >99.6% sequence identity with ‘Ca. P. convolvuli’ reference strain BY-S57/11 (JN833705) (2). RFLP and phylogenetic analyses confirmed the affiliation of the phytoplasma strains identified in grapevine and bindweed plants in Georgia to the species ‘Ca. P. solani’ (subgroup 16SrXII-A) and ‘Ca. P. convolvuli’ (subgroup 16SrXII-H). Representative 16S rDNA nucleotide sequences were deposited in NCBI GenBank website with accession nos. KF996535 and KF996536 (‘Ca. P. solani’ from grapevine and bindweed, respectively), and KF996537 (‘Ca. P. convolvuli’). Future studies will focus on investigating the spread and impact of ‘Ca. P. solani’-associated bois noir (BN) in Georgia. In particular, the identification of ‘Ca. P. solani’ in bindweeds suggested the presence of the insect Hyalesthes obsoletus, a polyphagous cixiidae responsible for BN phytoplasma transmission in vineyards in Europe. Accurate surveys and molecular analyses will be performed for identifying the insect vector(s) of the BN associated phytoplasma strains in Georgia. Additional studies will be performed to study the spread and impact of ‘Ca. P. convolvuli,’ identified only in Italy, Germany, Serbia, and Bosnia and Herzegovina (2), throughout the Caucasian countries. References: (1) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) M. Martini et al. Int. J. Syst. Evol. Microbiol. 62:2910, 2013. (3) F. Quaglino et al. Int. J. Syst. Evol. Microbiol. 63:2879, 2013.

scholarly journals First Report of 16S rDNA II Group Phytoplasma on Polygala mascatense, a Weed in Oman

Plant Disease ◽  
2006 ◽  
Vol 90 (2) ◽  
pp. 248-248 ◽  
Author(s):  
S. Livingston ◽  
M. O. Al-Azri ◽  
N. A. Al-Saady ◽  
A. M. Al-Subhi ◽  
A. J. Khan
Keyword(s):  
16S Rdna ◽  
Nested Pcr ◽  
Pcr Amplification ◽  
Perennial Herb ◽  
Direct Pcr ◽  
First Report ◽  
Palm Trees ◽  
National Botanic Garden ◽  
Negative Controls ◽  
Positive Controls

Polygala mascatense Boiss. (family Polygalaceae) is a common weed found in neglected farms, under date palm trees, and in stony locations throughout the Sultanate of Oman (1). It is a perennial herb approximately 30 to 40 cm tall, has slender branches, is woody at the base, and has linear leaves with purple flowers. Recently (November 2004), in the interior region of Oman (210 km south of Muscat), some polygala plants were found stunted with small leaves, bushy growth, and the floral parts were showing phyllody symptoms. Total genomic DNA extracted from asymptomatic and symptomatic plants with modified cetyltrimethylammoniumbromide (CTAB) buffer method (4) was used as a template for direct polymerase chain reaction (PCR) amplification of phytoplasma 16S rDNA with P1/P7 primers. Direct PCR product was used as template DNA for nested PCR with primers R16F2n/R16R2. DNA from plants infected with alfalfa and lime witches'-broom phytoplasma was used as positive controls, and DNA from healthy plants and water was used as negative controls. Products from nested PCR (1.2 kb) were analyzed by using single endonuclease enzyme digestion (restriction fragment length polymorphism [RFLP]) with Tru9I, HaeIII, HhaI, TaqI, AluI, and RsaI (3). The results showed the presence of a 1.8-kb product amplified with direct PCR and a 1.2-kb product of the nested PCR from infected polygala and the positive controls, whereas no PCR products were observed in the negative controls. The PCR assay confirmed the presence of phytoplasma causing witches'-broom disease in polygala. The RFLP results showed the polygala phyto-plasma to be most similar to the alfalfa phytoplasma, a member of 16SrII group (2). Infected polygala weeds may serve as a reservoir for alfalfa witches'-broom phytoplasma that causes annual losses over $25 million to alfalfa cultivation in Oman (2). A detailed investigation needs to be carried out to establish transmission of phytoplasma from polygala to alfalfa. To our knowledge, this is the first report of phytoplasma infecting polygala weeds in Oman. References: (1) S. A. Ghazanfar. Pages 95–96 in: An Annotated Catalogue of the Vascular Plants in Oman. Scripta Botanica Belgica Meise, National Botanic Garden of Belgium, 1992. (2) A. J. Khan et al. Phytopathology 92:1038, 2002. (3) I. M. Lee et al. Int. J. Syst. Bacteriol. 1153, 1998. (4) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA 81:8014, 1984.

scholarly journals Molecular Typing of ‘Candidatus Phytoplasma solani’ in Iranian Vineyards

Plant Disease ◽  
2019 ◽  
Vol 103 (9) ◽  
pp. 2412-2416 ◽  
Author(s):  
Elham Jamshidi ◽  
Sergio Murolo ◽  
Sareh Baghaee Ravari ◽  
Mohammad Salehi ◽  
Gianfranco Romanazzi
Keyword(s):  
Molecular Characterization ◽  
Control Strategies ◽  
Economic Losses ◽  
Vitis Vinifera L ◽  
Convolvulus Arvensis ◽  
Inoculum Sources ◽  
Bois Noir ◽  
Multiple Gene ◽  
Horticultural Crops

Grapevine (Vitis vinifera L.) is one of the most important horticultural crops in Iran, with >200,000 ha of cultivated area. Recently, outbreaks of the grapevine yellows Bois noir that is associated with phytoplasma strains related to ‘Candidatus Phytoplasma solani’ were recorded in several Iranian regions. This has resulted in severe economic losses. We carried out a survey in 2015, followed by collection of leaf samples from symptomatic grapevines and weeds. Because no information is available on the molecular epidemiology of ‘Ca. P. solani’ in Iran, multiple gene analyses were carried out here according to molecular characterization of the tuf and vmp1 genes. From the molecular characterization, all of the samples (i.e., grapevines, weeds) were infected with tuf b type. Detailed molecular characterization of the vmp1 gene (i.e., PCR–restriction fragment length polymorphism, sequence analysis) defined five molecular types: V1, V4, V10, V15, and V20. The abundance of Convolvulus arvensis in vineyards and detection of the same ‘Ca. P. solani’ molecular types in grapevines and weeds suggest that C. arvensis has a major role in Bois noir epidemiology of Iranian vineyards. Therefore, control strategies should be developed to manage these host plants to reduce inoculum sources of the phytoplasma in vineyards.

scholarly journals Nanocarriers of Miconazole or Fluconazole: Effects on Three-Species Candida Biofilms and Cytotoxic Effects In Vitro

2021 ◽  
Vol 7 (7) ◽  
pp. 500
Author(s):  
Anne Caroline Morais Caldeirão ◽  
Heitor Ceolin Araujo ◽  
Laís Salomão Arias ◽  
Wilmer Ramírez Carmona ◽  
Gustavo Porangaba Miranda ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Artificial Saliva ◽  
Cytotoxic Effects ◽  
Promising Alternative ◽  
Colony Forming Units ◽  
Mtt Reduction ◽  
Diphenyl Tetrazolium Bromide ◽  
Negative Controls ◽  
Positive Controls

The contribution of different Candida species in oral fungal infections has stimulated the search for more effective therapies. This study assessed the antibiofilm effects of nanocarriers of miconazole (MCZ) or fluconazole (FLZ) on Candida biofilms, and their cytotoxic effects on murine fibroblasts. Three-species biofilms (Candida albicans/Candida glabrata/Candida tropicalis) were formed on 96-well plates, and they were treated with nanocarriers (iron oxide nanoparticles coated with chitosan—“IONPs-CS”) of MCZ or FLZ at 39/78/156 µg/mL; antifungals alone at 156 µg/mL and artificial saliva were tested as positive and negative controls, respectively. Biofilms were analyzed by colony forming units (CFU), biomass, metabolic activity, and structure/viability. The cytotoxicity (L929 cells) of all treatments was determined via 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) reduction assay. Data were submitted to one- or two-way ANOVA, followed by Tukey’s or Fisher LSD’s tests (p < 0.05). IONPs-CS-MCZ at 78 µg/mL promoted similar antibiofilm and cytotoxic effects compared with MCZ at 156 µg/mL. In turn, IONPs-CS-FLZ at 156 µg/mL was overall the most effective FLZ antibiofilm treatment, surpassing the effects of FLZ alone; this nanocarrier was also less cytotoxic compared with FLZ alone. It can be concluded that both nanocarriers are more effective alternatives to fight Candida biofilms compared with their respective positive controls in vitro, being a promising alternative for the treatment of oral fungal infections.

scholarly journals Unraveling the Etiology of North American Grapevine Yellows (NAGY): Novel NAGY Phytoplasma Sequevars Related to ‘Candidatus Phytoplasma pruni’

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1087-1097 ◽  
Author(s):  
Robert E. Davis ◽  
Ellen L. Dally ◽  
Yan Zhao ◽  
Ing-Ming Lee ◽  
Wei Wei ◽  
...  
Keyword(s):  
16S Rdna ◽  
North American ◽  
Phylogenetic Analyses ◽  
New York State ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Vitis Vinifera L ◽  
Polymorphism Analysis ◽  
Ribosomal Protein Genes ◽  
Grapevine Yellows

North American grapevine yellows (NAGY) disease has sometimes been attributed to infection of Vitis vinifera L. by Prunus X-disease phytoplasma (‘Candidatus Phytoplasma pruni’) but this attribution may not be fully adequate. In this study, phytoplasma strains related to ‘Ca. Phytoplasma pruni’ were found in NAGY-diseased grapevines in Maryland, Pennsylvania, Virginia, Ohio, Missouri, and New York State. Based on restriction fragment length polymorphism analysis of 16S ribosomal RNA gene (16S rDNA) sequences, the strains (termed NAGYIII strains) were classified in group 16SrIII (X-disease group) but they contained a recognition site for the restriction endonuclease MseI that is not present in the 16S rDNA of ‘Ca. Phytoplasma pruni’. The 16S rDNA of the strains differed by three or four nucleotides from that of ‘Ca. Phytoplasma pruni’, indicating that they belonged to two novel 16S rDNA sequevars, designated NAGYIIIα and NAGYIIIβ. Both sequevars differed from ‘Ca. Phytoplasma pruni’ by a single base in each of three regions corresponding to species-unique (signature) sequences described for ‘Ca. Phytoplasma pruni’. Phylogenetic analyses of 16S rRNA genes and SecY proteins, and single-nucleotide polymorphism analyses of secY and ribosomal protein genes, further distinguished the two grapevine sequevar lineages from one another and from ‘Ca. Phytoplasma pruni’. The NAGYIIIα and NAGYIIIβ sequevars also differed from ‘Ca. Phytoplasma pruni’ in regions of the folded SecY protein that are predicted to be near or exposed at the outer surface of the phytoplasma membrane. No evidence indicated that diseased grapevines contained any phytoplasma strain conforming to ‘Ca. Phytoplasma pruni’ sensu stricto. Because the NAGYIII sequevars have not been reported in X-disease, a question is raised as to whether NAGYIII and Prunus X-disease are caused by different phytoplasma genotypes.

scholarly journals First Report of an Aster Yellows Phytoplasma Associated with Cabbage in Southern Texas

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 447-447 ◽  
Author(s):  
I.-M. Lee ◽  
R. A. Dane ◽  
M. C. Black ◽  
Noel Troxclair
Keyword(s):  
16S Rdna ◽  
Nested Pcr ◽  
Restriction Enzymes ◽  
Diagnostic Procedures ◽  
Acid Extraction ◽  
Insect Vector ◽  
Aster Yellows ◽  
First Report ◽  
Pcr Products ◽  
Aster Yellows Phytoplasma

In early spring 2000 carrot crops in southwestern Texas were severely infected by an outbreak of phyllody associated with aster yellows phytoplasma. Cabbage crops that had been planted adjacent to these carrot fields began to display previously unobserved symptoms characteristic of phytoplasma infection. Symptoms included purple discoloration in leaf veins and at the outer edges of leaves on cabbage heads. Proliferation of sprouts also occurred at the base of the stem and between leaf layers of some plants, and sprouts sometimes continued to proliferate on extended stems. About 5% of cabbage plants in the field exhibited these symptoms. Two symptomless and four symptomatic cabbage heads were collected in early April from one cabbage field. Veinal tissues were stripped from each sample and used for total nucleic acid extraction. To obtain specific and sufficient amount of PCR products for analysis, nested PCR was performed by using primer pairs (first with P1/P7 followed by R16F2n/R16R2) (1,2) universal for phytoplasma detection. A specific 16S rDNA fragment (about 1.2 kb) was strongly amplified from the four symptomatic but not from the two asymptomatic samples. The nested PCR products obtained from the four symptomatic samples were then analyzed by restriction fragment length polymorphism (RFLP) using the restriction enzymes MseI, HhaI, and HpaII, and the RFLP patterns were compared to the published patterns of known phytoplasmas (1). The resulting RFLP patterns were identical to those of a phytoplasma belonging to subgroup B of the aster yellows phytoplasma group (16SrI). These RFLP patterns were also evident in putative restriction sites observed in a 1.5 kbp nucleotide sequence of the 16S rDNA. This is the first report of aster yellows phytoplasma associated disease symptoms in cabbage in Texas. The occurrence of cabbage proliferation coincided with the presence of high populations of the insect vector, aster leafhopper. References: (1) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) B. Schneider et al. 1995. Molecular and Diagnostic Procedures in Mycoplasmology, Vol. I. Academic Press, San Diego, CA.

Evaluation of diagnostic accuracy of 10 serological assays for detection of SARS-CoV-2 antibodies.

2020 ◽  
Author(s):  
MD. ◽  
Sara Gómez de Frutos ◽  
Diego Domingo García PharmD ◽  
Eva Navarro Lara ◽  
Ayla Yarci Carrión ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Gold Standard ◽  
Epidemiological Studies ◽  
Antibody Detection ◽  
Diagnostic Tools ◽  
Sensitivity Range ◽  
Sensitivity Specificity ◽  
Negative Controls ◽  
Ig G ◽  
Positive Controls

Abstract BackgroundAntibody detection is essential to establish exposure, infection and immunity to SARS-CoV-2, as well as to perform epidemiological studies. The worlwide urge for new diagnostic tools to control the pandemic has led to a quick in- corporation in clinical practice of the recently developed serological assays.MethodsWe evaluated the diagnostic accuracy to detect Ig G, Ig M+A and/or IgA anti SARS-CoV-2 of 10 different assays: 3 Lateral Flow card inmunoassays, 4 en- zyme-linked inmunoabsorbent assay (ELISA) and 3 chemiluminescent particle immunoassays (CMIA). Using PCR for COVID-19 as gold standard, sensitivity, specificity, PPV, and NPV were determined. Each assay was tested in 2 groups: Positive Controls, formed by 50 sera from 50 patients with SARS-CoV-2 pneu- monia with positive PCR; Negative Controls, formed by 50 sera from 50 pa- tients with respiratory infection non-COVID-19.ResultsSensitivity range of the 10 assays evaluated for patients with positive COVID-19 PCR was 40-77% (65-81% considering IgG plus IgM). Specificity ranged 83-100%. VPP and VPN were respectively 81-100% and 61.6-81%.ConclusionsResults obtained varied widely among the assays evaluated.Highest diagnostic accuracy was obtained with ELISA and CMIAs, but they last much longer.

scholarly journals Serum Exosomal MicroRNAs as Potential Circulating Biomarkers for Endometriosis

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Lu Zhang ◽  
Huihui Li ◽  
Ming Yuan ◽  
Dong Li ◽  
Chang Sun ◽  
...  
Keyword(s):  
Area Under The Curve ◽  
Roc Curves ◽  
Diagnostic Value ◽  
Pcr Analysis ◽  
Go Annotation ◽  
Qrt Pcr ◽  
Noninvasive Biomarker ◽  
Novel Biomarkers ◽  
Negative Controls ◽  
Exosomal Mirna

Background. A reliable noninvasive biomarker is not yet available for endometriosis diagnosis. Novel biomarkers for the diagnosis of endometriosis are urgently needed. The molecular constituents of exosomes, especially exosomal microRNAs (miRNAs), have considerable potential as novel biomarkers for clinical diagnosis. This study is aimed at exploring aberrant exosomal miRNA profiles by using miRNA microarray and at providing more accurate molecular biomarkers of endometriosis. Methods. Exosomes were isolated from the serum of patients with endometriosis and negative controls and identified by electron microscopy, nanoparticle tracking analysis, and Western blot. Exosomal miRNAs were profiled by miRNA microarrays. The expression of selective serum exosomal miRNA was validated by qRT-PCR. Receiver operating characteristic (ROC) curves were established to explore the diagnostic value of selective miRNAs. Finally, GO annotation and KEGG pathway enrichment analyses were used to display possible functions associated with the two miRNAs. Results. A total of 24 miRNAs showed differential levels of enrichment with P<0.05 and log2 fold change>1 by miRNA microarrays. Among the six selective miRNAs (i.e., miR-134-5p, miR-197-5p, miR-22-3p, miR-320a, miR-494-3p, and miR-939-5p), qRT-PCR analysis revealed that miR-22-3p and miR-320a were significantly upregulated in serum exosomes from patients with endometriosis compared with negative individuals. ROC curve revealed that the serum exosomal miR-22-3p and miR-320a yielded the area under the curve values of 0.855 and 0.827, respectively. Conclusion. Our results demonstrated that exosomal miR-22-3p and miR-320a were significantly increased in the sera of patients with endometriosis. The two miRNAs may be useful potential biomarkers for endometriosis diagnosis.

scholarly journals Recovery of Vitis vinifera L. cv. ‘Kékfrankos’ from ‘bois noir’ disease

2019 ◽  
Vol 156 (3) ◽  
pp. 987-991
Author(s):  
Anikó Mátai ◽  
Péter Teszlák ◽  
Gábor Jakab
Keyword(s):  
Gas Exchange ◽  
Vitis Vinifera ◽  
Photosynthetic Performance ◽  
Photochemical Quenching ◽  
Vitis Vinifera L ◽  
Bois Noir ◽  
Flavescence Dorée ◽  
Exchange Performance ◽  
Concentration Changes ◽  
Non Photochemical Quenching

AbstractInvestigation of diseases caused by phytoplasmas, a group of cell-wall-less gram-positive bacteria has received significant attention in plant pathology. Grapevine is a host of two, genetically distinct phytoplasmas: Line Flavescence dorée (FD) phytoplasma associated to ‘flavescence dorée’ and ‘Candidatus Phytoplasma solani’ responsible for ‘bois noir’ (BN) disease. In the current study, we focused on BN diseased grapevines (Vitis vinifera L. cv. ‘Kékfrankos’), measured their photosynthetic performance and leaf hydrogen peroxide (H2O2) concentration. The latter is generally considered as a key molecule in the process of ‘recovery’ which is a spontaneous and unpredictable long-term remission of disease symptoms. This phenomenon also occurred during the time of our experiment. Infection resulted in reduced gas exchange performance and maximum quantum efficiency of PSII with an increased regulated non-photochemical quenching of PSII and H2O2 concentration. Changes in gas exchange seem to be a systemic response, while reduced photochemistry is a local response to ‘Ca. P. solani’ infection. H2O2 accumulation in BN phytoplasma infected plants, unlike in FD disease, was found to be a typical response to the appearance of a biotic stressor.

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