Pathogenicity test

These type of test specially is used in the identification of plant bacterial pathogens (or fungi, viruses) as the last one to confirm of the detection process by the pathogen (e.g. it is required such test for Ralstonia solanacearum - bacteria which causes the quarantine potato disease named ring rot of potato (see also: http://www.aphis.usda.gov/ppq/ep/ralstonia and http://bioinfo.genopole-toulouse.prd.fr/annotation/iANT/bacteria/ralsto/), but the pathogencity tests are used e.g. in medical researches (see: Stelma et al.,1987)

The aims of the pathogenicity tests are to describe of ability to cause of disease symptoms by pathogens or to describe the level of conducting disease process by one bacteria species or subspecies e.g.: Pectobacterium carotovorum subsp. atrosepticum, Pectobacterium carotovorum subsp. carotovorum or Ralstonia solanacearum.

The different sorts (range) of plant species (e.g.: begonia, potato, tomato, carrot, ect.) are taken advantage depending on bacteria (or virus) used to the testing. It is possible to execute these tests on whole plants or their parts (e.g.: steams, flowers, leaves) (Phot. A,B).

Photo A Photo B
Photo APhoto B
Incubation of potato tuber slices infected by Pectobacterium carotovorum subsp. atrosepticum


The several factors has the influence on the finally results of pathogenicity tests. Except genetic differences between testing strains of bacteria (or fungi, viruses), there are the big role of test conditions (e.g. level of humidity in incubation chamber, illuminating exhibition, optimal temperature or time of incubation during the test) (Zimnoch-Guzowska and Lojkowska, 1993).


Links:

More information about pathogenicity test:
- http://www.fftc.agnet.org/library/article/bc45013.html
- http://www.actahort.org/members/showpdf?booknrarnr=668_15
- http://www.fundecitrus.com.br/english/pesquisas_us.html
- http://www.clas.ufl.edu/jur/0801/andersonpaper.html
- http://www.plantmanagementnetwork.org/pub/php/research/cottonseedling/
- http://www.herts.ac.uk/natsci/Env/Fungi/Blackspot/objective_2.htm


References:

    The publications below in the pdf. format are available via internet:
  1. Bertoni G., Mills D. (1987). A simple method to monitor growth of bacterial populations in leaf tissue. Phytopathology 77: 832-835
  2. Gans P. T., Jellis G. J., Little G., Logan C., Wastie R. L. (1991). A comparison of methods to evaluate the susceptibility of potato cultivars to blackleg (caused by Erwinia carotovora subsp. atroseptica) in the field at different sites. Plant Pathology 40: 238-248
  3. Lapwood D. H., Read P. J. (1986). The susceptibility of different potato cultivars to blackleg caused by Erwinia carotovora sunspecies atroseptica. Annual Applied of Biology 109: 555-560
  4. Lapwood D. H., Read P. J., Spokes J. (1984). Methods for assessing the susceptibility of potato tubers of different cultivar to rotting by Erwinia carotovora subspecies atroseptica and carotovora. Plant Pathology 33: 13-20
  5. Medina-Mora C.M., Hausbeck M.K., Fulbright D.W. (2001). Bird's Eye Lesions of Tomato Fruit Produced by Aerosol and Direct Application of Clavibacter michiganensis subsp. michiganensis. Plant Disease 1: 88-91Available in Acrobat reader format
  6. Perombelon M. C. M. (1972). The extent and survival of contamination of potato stocks in Scotland by Erwinia carotovora var. carotovora and E. carotovora var. atroseptica. Annual Applied of Biology 71: 111-117
  7. Stelma G.N., Reyes A.L., Peeler J.T., Francis D.W., Hunt J.M., Spaulding P.L., Johnson C.H., Lovett J. (1987). Pathogenicity test for Listeria monocytogenes using immunocompromised mice. Journal of Clinical Microbiology 11: 2085-2089 Available in Acrobat reader format
  8. Taylor R. J., Secor G. A. (1990). Potato protoplast-derived callus tissue challenged with Erwinia carotovora subsp. carotovora: survival, growth and identification of resistant callus lines. J. Phytopathology 129: 228-236
  9. Vikram S. B., Bains P. S., Letal J. R. (1993). A simple and efficient method to assess susceptibility of potato to stem rot by Erwinia carotovora subspecies. American Potato Journal 70: 611-616
  10. Xu G.-W., Gross D. G. (1986). Field evaluation of interactions among fluorescent Pseudomonas, Erwinia carotovora, and potato yields. Phytophatology 76: 423-430
  11. Zimnoch-Guzowska E., Lojkowska E. (1993). Resistance to Erwinia spp. in diploid potato with a high starch content. Potato Research 36: 177-182