Institute for Plant Protection in Fruit Crops and Viticulture

Dossenheim, Germany

Institute for Plant Protection in Fruit Crops and Viticulture

Dossenheim, Germany

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Schuler H.,University of Natural Resources and Life Sciences, Vienna | Arthofer W.,University of Innsbruck | Riegler M.,University of Western Sydney | Bertheau C.,University of Natural Resources and Life Sciences, Vienna | And 5 more authors.
Entomologia Experimentalis et Applicata | Year: 2011

Rhagoletis pomonella Walsh (Diptera: Tephritidae) is a model species for sympatric speciation through host race formation on apple and hawthorn. The bacterial endosymbiont Wolbachia, a manipulator of arthropod reproduction, has been considered to contribute to speciation in several species. A potential role of Wolbachia in sympatric speciation of R. pomonella remains to be tested despite an earlier detection by PCR. In this study, we isolated Wolbachia from R. pomonella individuals from both host species using multi-locus sequence typing (MLST) and the surface protein wsp. By cloning and sequencing of 311 plasmids, we found sequence types of at least four wPom strains. A complete MLST profile was obtained only for wPom1, whereas MLST loci of the other putative strains were difficult to assign because of multiple infections and low sample numbers. wPom1 occurs in both host races, whereas different sequence types were found at low frequencies only in apple-infesting R. pomonella. This warrants further investigation as it cannot be excluded that Wolbachia plays a part in this model of sympatric speciation. © 2011 The Authors. Entomologia Experimentalis et Applicata © 2011 The Netherlands Entomological Society.


Lindner K.,Institute for Plant Protection in Field Crops and Grassland | Haase N.U.,Federal Research Institute of Nutrition and Food | Roman M.,Fangmeier Agro Impex | Seemuller E.,Institute for Plant Protection in Fruit Crops and Viticulture
Potato Research | Year: 2011

Potato stolbur is a phytoplasmal disease that seriously affects yield and tuber quality in South Eastern Europe, Russia and the Mediterranean areas. In 2007 and 2008, field experiments were carried out to determine stolbur resistance of processing potato cultivars at Sannicolau Mare (Romania) by determining consistency and concentration of reducing sugars (fructose and glucose), sucrose and phytoplasmas in potato tubers. In both years, non-symptomatic potato tubers showed sucrose levels in the range of 3,000 mg kg -1 fresh weight (FW). In contrast, sucrose concentrations were up to 11,820 mg kg -1 FW in 2007 and 19,560 mg kg -1 FW in 2008 in tubers showing severe symptoms. These high values severely affect suitability of tubers for processing as sucrose serves as substrate for the formation of reducing sugars that are the limiting factor in fried potato production for Maillard-related discolouration. The cultivars examined differed considerably in susceptibility to stolbur disease. Whereas cvs. 'Courage' and 'Lady Rosetta' showed high numbers of diseased tubers and high sucrose concentrations, 'Lady Claire' had a lower incidence of symptomatic tubers and lower sucrose concentrations. However, fully resistant cultivars were not observed. Across all cultivars examined, phytoplasmal concentration was significantly higher in symptomatic tubers than in non-symptomatic ones. © 2011 EAPR.


Kube M.,Max Planck Institute for Molecular Genetics | Kube M.,Humboldt University of Berlin | Luge T.,Max Planck Institute for Molecular Genetics | Seemuller E.,Institute for plant protection in Fruit Crops and Viticulture | And 2 more authors.
Bulletin of Insectology | Year: 2011

The protein content of Nicotiana occidentalis infected by the non-cultivable phytopathogenic mollicute 'Candidatus Phytoplasma mali' strain AT was determined by shotgun proteomics. 102 out of 497 predicted phytoplasma proteins were identified as expressed in shoot tissue. In addition, 940 proteins of N. occidentalis were detected. Results demonstrate the successful application of LTQ Orbitrap XL ETD™ mass spectrometer in detecting phytoplasma-specific proteins in protein mixtures. A high portion of proteins with unknown function was identified beside prominent proteins involved in translation. Several of the proteins with unknown function contain a signal peptide suggesting a potential pathogen-host interaction.


Kube M.,Humboldt University of Berlin | Kube M.,Max Planck Institute for Molecular Genetics | Mitrovic J.,Serbian Institute of Pesticides and Environmental Protection | Duduk B.,Serbian Institute of Pesticides and Environmental Protection | And 3 more authors.
The Scientific World Journal | Year: 2012

Phytoplasmas are specialised bacteria that are obligate parasites of plant phloem tissue and insects. These bacteria have resisted all attempts of cell-free cultivation. Genome research is of particular importance to analyse the genetic endowment of such bacteria. Here we review the gene content of the four completely sequenced Candidatus Phytoplasma genomes that include those of Ca. P. asteris strains OY-M and AY-WB, Ca. P. australiense, and Ca. P. mali. These genomes are characterized by chromosome condensation resulting in sizes below 900kb and a G + C content of less than 28%. Evolutionary adaption of the phytoplasmas to nutrient-rich environments resulted in losses of genetic modules and increased host dependency highlighted by the transport systems and limited metabolic repertoire. On the other hand, duplication and integration events enlarged the chromosomes and contribute to genome instability. Present differences in the content of membrane and secreted proteins reflect the host adaptation in the phytoplasma strains. General differences are obvious between different phylogenetic subgroups. Ca. P. mali is separated from the other strains by its deviating chromosome organization, the genetic repertoire for recombination and excision repair of nucleotides or the loss of the complete energy-yielding part of the glycolysis. Apart from these differences, comparative analysis exemplified that all four phytoplasmas are likely to encode an alternative pathway to generate pyruvate and ATP. © Copyright 2012 Michael Kube et al.


Johannesen J.,University of Mainz | Albert A.,University of Mainz | Imo M.,University of Mainz | Maixner M.,Institute for Plant Protection in Fruit Crops and Viticulture
Bulletin of Insectology | Year: 2011

The epidemiology of phytoplasma-induced plant diseases is significantly influenced by the interaction between phytoplasma and the vectoring insect. Infection with phytoplasma may increase or lower fitness, or change the behaviour of the vector. The cixiid Hyalesthes obsoletus vectors stolbur 16SrXII-A phytoplasma from bindweed and stinging nettle to grapevine, where it causes the yellows disease 'bois noir'. Here we present first experiments studying the effect of stolbur infection on longevity in H. obsoletus. Preliminary tests of female H. obsoletus sampled on bindweed and stinging nettle, respectively, showed that females survive significantly longer on the own plant, whereas no effect of stolbur infection was observed on other host plant.


Weintraub P.,Gilat Research Center | Gross J.,Institute for Plant Protection in Fruit Crops and Viticulture
Methods in Molecular Biology | Year: 2013

Insect vectors of phytoplasmas are limited to leafhoppers, planthoppers, and psyllids. While populations can be monitored by a number of passive techniques in the fi eld, the capture of live insects is necessary for manipulation and study. A number of physical methods for capturing these insects already exist, but more innovative traps equipped with infochemical lures for species-speci fi c monitoring and mass trapping are being developed. © Springer Science+Business Media, LLC 2013.


PubMed | Institute for plant protection in Fruit Crops and Viticulture
Type: Journal Article | Journal: Phytopathology | Year: 2010

Forty-eight apple trees infected by Candidatus Phytoplasma mali were examined using single-strand conformation polymorphism (SSCP) and sequence analysis of a variable hflB gene fragment and the immunodominant membrane protein-encoding imp gene. SSCP analysis of polymerase chain reaction-amplified hflB gene fragments revealed diverse profiles, differing in number and position of the bands. The Ca. P. mali content of a single infected apple tree was termed an accession. Cloning of fragments from accessions that yielded fewer bands resulted in clone populations showing uniform or moderately polymorphic SSCP patterns and largely homogenous nucleotide sequences. In contrast, inserts from accessions yielding more bands were heterogeneous and formed two to four distinct groups of profiles. DNA fragments from such accessions were diverse and clustered distantly when subjected to phylogenetic analysis, mostly as two homogenous groups plus one or a few other sequences. Similar results were obtained upon imp gene examination. The collective data indicate that accessions exhibiting more complex patterns were composed of two or three distinct Ca. P. mali strains. There is evidence that multiple infections are of pathological relevance due to strain interactions leading to shifts in the populations. In triply infected trees of one accession, no specific symptoms were induced by the presence of two of the strains. The rare appearance of pronounced symptoms was associated with a separate strain that possessed a unique SSCP profile and a unique hflB sequence. The two mild strains from this apple accession also induced only mild symptoms on periwinkle and tobacco and occurred specifically in one of these plants.

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