Ketolactose test medium

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Contents 1 Purpose 2 Ingredients 2.1 Medium 1 2.2 Medium 1 3 Instructions 4 Notes 5 References 6 Contributed by

Purpose

Diagnostic for Agrobacterium tumefaciens biovar 1.

Ingredients

Medium 1

Ingredient
dH2O	1 L
Yeast extract	10 g
Glucose	20 g
Calcium carbonate	20 g
Agar	15 g

Medium 1

Ingredient
dH2O	1 L
Lactose	10 g
Yest extract	1 g
Agar	20 g

Instructions

1. Melt Medium 1 over flame and pour slants.
2. Autoclave.
3. Autoclave Medium 2 and pour into plates.
4. Grow bacterium for 24 to 48 hours on Medium 1.
5. Transfer a loop of bacteria to Medium 2.
6. Allow to grow for 24-48 hours. Flood plate with Benedict's reagent.

Notes

• If 3-ketolactose is formed, a yellow ring becomes visible around the colony; this is diagnostic for A. tumefaciens biovar 1. Color becomes strongest after 1 hour.

References

• Schaad, N. W. 1980. Laboratory Guide for the Identification of Plant Pathogenic Bacteria. The American Phytopathological Society, St. Paul, MN. 72 pp. (pp. 19-21).

Contributed by

From the Virginia Tech Mediabook; Orignially created by Robert Wick; contributed by Mary Ann Hansen