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Humboldt-Universität zu Berlin - Faculty of Life Sciences - Phytomedicine

Division Phytomedicine - Main Research

 

The division´s special focus lies on linking molecular and conventional methods with practical reference within the scope of the following research areas:

 

 

 

Characterization of plant pathogens[to the top]

 

Functional genomics of Cherry leaf roll virus (CLRV) and molecular analyses of Finnish virus variants

 

Cherry leaf roll virus (CLRV) is a subgroup C Nepovirus (family Comoviridae) with a bipartite ss (+)RNA genome, which we have recently completely sequenced. Apart from the viral coat protein, functional characterization of CLRV-encoded gene products or processing of the encoded polyprotein precursors (RNA1 encoded P1 and RNA2 encoded P2) by the putative viral proteinase (Pro) has never been achieved and is therefore a main research topic of this proposal. Furthermore, functional analyses of CLRV-encoded genes which exhibit no similarity to any characterized protein available in the databases are intended, in order to contribute to our general knowledge of nepovirus´ gene functions. The virus infects many woody and several herbaceous species and is widespread in temperate regions. The proposed study will include genetic and serological characterization of Finnish CLRV variants, which could be associated with a recent epidemic impairing several important birch species all over the country. In parallel, population structure of the virus infecting Finnish birch trees will be analyzed, because initial investigations showed that CLRV from Finnish origins represent atypical sequence variants. This will facilitate the correlation of the molecular traits with serological data and the disease symptoms observed in Finland which may contribute to the substantial evaluation of the severe disease situation.

Head of Project: Prof. Dr. agr. Carmen Büttner

carmen.buettner[ät]agrar.hu-berlin.de

Additional Member of Project: Prof. Dr. Hans-Peter Mühlbach
Duration of Project: 01/2011 - 01/2016
Funded by: DFG: Sachbeihilfe

Characterization of the non-structural protein p4 of the recently detected new virus European mountain ash ringspot-associated virus in European mountain ash (Sorbus aucuparia L.)

 

The European mountain ash ringspot-associated virus (EMARaV) infects the European mountain ash (Sorbus aucuparia L.) and is widespread throughout Northern- and Central Europe. It leads from degeneration up to die back of the plant. EMARaV has been associated with the ringspot disease of Sorbus aucuparia L.. So far, modes of virus transmission, possible host range and economic importance of EMARaV are unknown. We characterized EMARaV as a novel negative orientated single strand RNA virus that can be transmitted by grafting (Führling and Büttner, 1995). Each of the four identified viral RNAs contains one open reading frame. Sequence comparisons revealed a possible function of the RNA1, RNA2 and RNA3 encoded proteins as a RNA dependent RNA polymerase (p1), a glycoprotein precursor (p2) and a nucleocapsid protein (p3) respectively. So far, the function of the RNA4 encoded p4 protein is unknown. The open reading frame of this RNA shows no sequence homologies to known proteins. We hypothesize that this protein might act as a gene silencing suppressor and/or a movement protein. In plants, cell-to-cell spread as well as systemic distribution of EMARaV requires a viral movement protein. In this proposal we aim to investigate the possible movement function of the p4 protein. The localization of the p4 protein will be identified in p4-transfected protoplasts and in cross sections of EMARaV-infected European mountain ash leaves using a p4 specific antibody. We will investigate whether p4 colocalizes with cell walls taking advantage of specific plasmodesmal markers. EMARaV is presumably moving as nucleocapsid coated genomic RNA (ribonucleoprotein complex) along p4 tubular structures formed as a result of the aggregation of viral movement proteins. We will examine whether tubule formation takes place in p4-transfected protoplasts. The formation of tubuli and the transport of ribonucleoprotein complexes along those structures will be verified in protein-protein interaction experiments. We will analyze whether the p4 protein interacts with itself and nucleocapsid proteins using bimolecular fluorescence complementation (BIFC). The gall mite Phytoptus pyri has been identified as a potential vector of this virus and replication of EMARaV in this vector is likely. The detection of the non-structural protein p4 in the gall mite would further confirm virus transmission in a circulative propagative manner. The main objective of this study is to investigate and understand the function of the p4 protein of EMARaV and will thus deepen our much needed knowledge about spread and epidemiology of EMARaV.

Head of Project: Prof. Dr. agr. Carmen Büttner

carmen.buettner[ät]agrar.hu-berlin.de

Additional Member of Project: Prof. Dr. Hans-Peter Mühlbach
Duration of Project: 08/2013 - 07/2016
Funded by: DFG: Sachbeihilfe
 
Epidemiology[to the top]

 

Biotic and abiotic influences on pollen production and birch allergenicity and their effects on human health

 

 

Head of Project: Prof. Dr. agr. Carmen Büttner

carmen.buettner[ät]agrar.hu-berlin.de

Additional Member of Project: Dr. Maria Landgraf
Duration of Project: 04/2019 - 02/2022
Funded by: DFG, Bk 890|31-1

Exposure of city trees to pathogens with a focus on plant viruses - Survey of street and climate change trees in the Hamburg metropolitan region

 

 

Head of Project: Prof. Dr. agr. Carmen Büttner

carmen.buettner[ät]agrar.hu-berlin.de

Additional Member of Project: Dr. Matrina Bandte
Duration of Project: 08/2018 - 07/2021
Funded by: BWVI; 734.650-004/014

A novel Emaracirus in Populus tremula: Identification and epidemiology of the causal agent of the mosaic syndrome

 

 

Head of Project: Prof. Dr. agr. Carmen Büttner

carmen.buettner[ät]agrar.hu-berlin.de

Additional Member of Project: Dr. Rim Al Kubruski (guest scientist)
Duration of Project: 11/2018 - 12/2019
Funded by: Einstein-Stiftung EPG-2018_476

Modes of vector transmission of Cherry leaf roll virus (CLRV) - molecular basis and potential arthropod vector species

 

Cherry leaf roll virus (CLRV) is a plant pathogen of economic and ecologic importance. It is globally distributed in a wide range of forest, fruit, and ornamental trees and shrubs. In several areas of cherry and walnut production CLRV causes severe losses in yield and quality. With current reference to the rapid dissemination and strong symptom expression in Finnish birches and the Germany-wide distribution of CLRV in birches and elderberry, we continuously investigate and gradually reveal CLRV transmission pathways as by pollen, seeds or water. However, modes and interactions responsible for the wide intergeneric host transmission as well as for the exceptional CLRV epidemic in Fennoscandia still remain unknown. In this project systematic studies shall investigate biological vectors as a causal agent to finally derive control mechanisms and strategies to avoid new epidemics in different hosts and geographic regions. Detailed monitorings of the invertebrate fauna of birch stands/forests and elderberry plantations in Germany and Finland shall reveal potential vectors to subsequently study them in detail by approved virus detection methods and transmission experiments. Molecular analyses of the CLRV coat protein shall prove its role as a viral determinant for a virus/vector interaction. Consequently, this project essentially will contribute important answers on the CLRV epidemiology, and this will be a key element within the first network of research on plant viral pathogens in forest trees.

Head of Project: Prof. Dr. agr. Carmen Büttner

carmen.buettner[ät]agrar.hu-berlin.de

Additional Member of Project: Dr. Juliane Langer
Duration of Project: 06/2012 - 06/2016
Funded by: DFG: Sachbeihilfe

Development of a recirculating irrigation system with reduced phytosanitary risk in greenhouse

 

A new electrolytic disinfection procedure for sustainable water reuse with reduced phytosanitary risk in greenhouse should allow a customized water disinfection by means of sensor-dosed addition of effective disinfectants. These disinfectants are produced from the existing constituents of the water by anodic oxidation (AO), without using a membrane and without additional chemicals.

Head of Project: Prof. Dr. agr. Carmen Büttner

carmen.buettner[ät]agrar.hu-berlin.de

Additional Head of Project: Prof. Dr. Uwe Schmidt
Duration of Project: 03/2013 - 12/2018
Funded by: Bundesministerium für Verbraucherschutz, Ernährung und Landwirtschaft

 

Link: Research database

 

Additional:

Development and evaluation of prophylactical activities to combat of viral infection

Büttner, C., Koenig, R., 2014: Plant viruses in irrigation water. In: Biology, detection and management of plant pathogens in irrigation water. Hong C., Moorman GW., Wohanka W., Büttner C. (eds), APS Press, in press

Hong, Ch., Moormann, G., Wohanka, W., Büttner, C., 2014: Biology, Detection and Management of Plant Pathogens in Irrigation Water. APS Press, USA (in press).

 

  • Examination of packing wood on nematode infestation and determination of residual moisture content [various industrial partners]
  • Composts as potential source of plant pathogens [PDF]
  • Allergenic potential of Cherry leaf roll virus-infected birch pollen
  • Efficacy of desinfection against Synchytrium endobioticum in vitro