Pathogene und endophytische Interaktion zwischen Clavibacter michiganensis subsp. michiganensis und der Tomate
Zusammenfassung der Projektergebnisse
In this trilateral research initiative the pathogenic and endophytic interaction of the bacterium "Clavibacter michiganensis" subsp. "michiganensis (Cmm)" and the host plant tomato ("Solanum lycopersicum") was studied. It was found that besides the cell wall degrading cellulase CelA, no other hydrolase seems to be required for virulence. However, secreted serine proteases play an important role in the plant-microbe interaction, by leading to the disease (Pat-1, ChpF), affecting colonization of the host (ChpC, PpaA and PpaC) or inducing a hypersensitive reaction in non-host plants (ChpG). So far, quorum sensing could not be demonstrated for "Cmm", although growth in tomato xylem sap triggers biofilm and aggregate formation which indicates a quorum sensing control. The signal for this phenomenon remains to be identified. We succeeded in constructing a GFP-labeled plasmid which could be introduced into "Cmm" and allowed to follow the movement of "Cmm" in the plant by confocal laser scanning microscopy. The experiments suggest that virulence factors located on the "chp/tomA" pathogenicity island are required for an effective movement of "Cmm" in tomato. To obtain information on the population structure of Cmm in Israel pulse field gel electrophoresis (PFGE) and multi locus sequence typing (MLST) were employed. Both methods are useful for the differentiation of isolates from different locations and have provided some interesting data on the relationship of isolates and given indications of the sources of "Cmm" in outbreaks of the disease. In another line of experiments the response of tomato to "Cmm" infection has been studied. The aim of these efforts was to gain information on genes of tomato differentially expressed after infection by "Cmm". This information may eventually be useful in the generation of tomato plants resistant or tolerant to "Cmm" infection. Proteomic investigations using multidimensional protein identification technology (MudPIT) and mass spectrometry showed that "in planta" "Cmm" excretes a wide range of enzymes targeted at the tomato cell wall and defense proteins. On the other hand the plant perceives the invading pathogen and replies with an extensive defense response with strong expression of PR-proteins and ethylen production. There are indications that "loxA" of tomato is involved in the development of wilt symptoms upon "Cmm" infection, while the phytohormon jasmonate might contribute to the defense of tomato against "Cmm".
Projektbezogene Publikationen (Auswahl)
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2008. A family of serine proteases of Clavibacter michiganensis subsp. michiganensis: ChpC plays a role in colonization of the host plant tomato. Molec. Molecular Plant Pathology, Vol. 9. 2008, Issue 5, pp. 599–608.
Stork, I., A. Burger, K.-H. Gartemann and Eichenlaub, R.
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2010. Sequential expression of bacterial virulence and plant defense genes during infection of tomato with Clavibacter michiganensis subsp. michiganensis. Phytopathology, Vol. 100. 2010, Number 3, pp. 252-261.
Chalupowicz, L., Cohen-Kandli, M., Dror, O., Eichenlaub, R., Gartemann, K.-H., Sessa, G., Barash, I., Manulis-Sasson S.
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2011. The Clavibacter michiganensis subspecies, molecular investigation of Gram-positive bacterial plant pathogens.
Annual Review of Phytopathology, Vol. 49.2011, pp. 445-464.
Eichenlaub, R., Gartemann, K.-H.
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2012. Colonization and movement of GFP-labeled Clavibacter michiganensis subsp. michiganensis during tomato infection. Phytopathology, Vol. 102. 2012, Number 1, pp. 23-31.
Chalupowicz, L., Zellermann, E.-M., Fluegel, M., Dror, O., Eichenlaub, R., Gartemann, K.-H., Savidor, A., Sessa, G., Iraki, N., Barash, I. and Manulis-Sasson, S.
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2012. The Clavibacter michiganensis subsp. michiganensis-tomato interactome reveals perception of pathogen by host and suggests mechanisms of infection. Journal of Proteome Research, Vol. 11.2012, Issue 2, pp 736–750.
Savidor, A., Teper, D., Gartemann, K.-H., Eichenlaub, R., Chalupowicz, L., Manulis-Sasson S., Barash, I., Tews, H., Mayer, K., Giannone, R.J., Hettich, R.L., Sessa, G.
