CKTM medium

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Contents

Purpose

For isolation of Xanthomonas campestris pv. vesicatoria.

Ingredients

Ingredient 1 L 500 ml
Part 1
Distilled water 900 ml 400 ml
Pourite, anit-bubble agent 1 drop 0.5 drop (10μl)
Soy peptone1 2 g 1 g
Bacto tryptone 2 g 1 g
Dextrose 1 g 0.5 g
L-Glutamine 6 g 3 g
L-Histidine 1 g 0.5 g
(NH4)2HPO4 0.8 g 0.4 g
KH2PO4 1 g 0.5 g
MgSO4 • 7H2O 0.4 g 0.2 g
CaCl2 0.25 g 0.125 g
Bacto agar 12 g 6 g
Part 2
Tween 80 (tissue culture grade) 10 ml 5 ml
Part 3
Cycloheximide stock* 0.5 ml 0.25 ml
Bacitracin stock** 2 ml 1 ml
Neomycin sulfate stock † 0.5 ml 0.25 ml
Part 4
Cephalexin 0.065 g 0.0325 g
5-Fluorouracil 0.012 g 0.006 g
Tobramycin 0.0004 g 0.0002 g

Instructions

  1. Dissolve ingredients in part 1 separately to avoid precipitates:
  2. Autoclave ingredients in part 1in a flask with a stir bar. Also, autoclave ingredient in part 2 in a separate flask.
  3. Immediately after autoclaving, add the ingredient in part 2 to the hot medium and stir. Allow to cool to 45 °C, still using the stir plate. Then add the antibiotics from part 3.
  4. Also add, 100.0 ml of sterile distilled water containing the ingredients from part 4
  • 1 g in 5 ml ethanol
  • 1 g in 20 ml distilled water

† 0.4 g in 20 ml distilled water

Notes

  • Isolates of Xanthomonas campestris vesicatoria appear as circular, raised, yellow colonies surrounded by a clear ring. This clear ring forms as early as 1-2 days after spot inoculation onto the medium, or 3-4 days after dilutions are plated. Tan to white minute crystals form in the clear ring of pepper strains and dense white halos form around the colonies inside the clear ring of tomato strains. Other pathovars of Xanthomonas campestris and opportunistic Xanthomonads, except X. translucens, do not form a clear ring before forming a dense halo. Xanthomonas campestris pv. translucens will form a clear ring, but neither tomato nor pepper is considered to be a host of this pathovar2.


1Soy peptone is essential, source: Adam Scientific Inc., West Warwick, RI 02893, (401) 828-5250.

2Leyns, F., De Cleene, M., Swings, J-G., and De Ley, J. 1984. The host range of the Genus Xanthomonas. Bot. Rev. 50:308-365.

References

  • Sijam, K., Chang, C. J., and Gitaitis, R. D. 1991. An Agar Medium for the Isolation and Identification of Xanthomonas campestris pv. vesicatoria from seed. Phytopathology 81: 831-834.
  • Leyns, F., M. De Cleene, J. G. Swings, and J. De Ley. 1984. The host range of the genus Xanthomanas. Bot. Rev. 50:308 365.

Contributed by

From the Culture Media for Plant Pathogenic Fungi and Bacteria, University of Massachusetts: Contributed by Robert L. Wick

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