High sucrose medium

From BugwoodWiki

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

Purpose

Diagnostic for Erwinia amylovora

Ingredients

Ingredient	1 L	500 mL
distilled water	760 mL	380 mL
sucrose	320 g	160 g
nutrient agar	24 g	12 g
0.1% crystal violet in absolute alcohol	1.6 mL	0.8 mL
0.1% cycloheximide	40 mL	20 mL

Instructions

1. Mix water and sucrose first, bringing it to a boil to dissolve, then add all other ingredients (except 0.1% cycloheximide) until they dissolve.
2. Autoclave and cool
3. Add 0.1% cycloheximide
4. pour plates and allow to dry for 2 hours prior to use or storage
5. Incubate cultures at 28°C for 60 hours. Examine for cratering of colony surface.

Notes

• Erwinia amylovora colonies will develop "craters" on the colony surface. Craters can be seen as soon as colonies are large enough for viewing, usually in 48 72 hr, but are most distinct after 60 hr. Colony surface should be viewed on a stereoscope using oblique light. Erwinia herbicola and some other saprophytic isolates can grow on this medium, but do not show cratering.

References

• Crosse, J. E. and R. N. Goodman. 1973. A selective medium for a definitive colony characteristic of Erwinia amylovora. Phytopathology 63: 1425 1426.

Contributed by

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