In response to Rich Glick's question:
You can infect Kalanchoe on either the stem or the leaf. Infections on
the leaf with a wildtype Agrobacterium tumefaciens strain will result in classicunorganized tumors. Infections on the stem will result in a tumor surrounded byroots. These roots are made up of normal cells that are responding to the
excess hormones produced by the tumor. For qualitative infections, use a
toothpick or needle to gently scrape the surface of the leaf or stem. You just
need to break through the epidermis. Use a toothpick to transfer a colony of
Agrobacterium onto the wound. You should see a clear tumor in 14-17 days.
For more quantitative infections, glue a piece of sandpaper onto the butt end
of a dowel rod and rotate a set number (I used 7 when I did this years ago) of
times at one place on the stem. To be even more controlled, choose the same
spot on each stem (e.g., the 3rd visible internode from the shoot apex). Pipet
onto the wound 5-10 microliters of water containing a known number of Agro.
You may want to use this method if you are looking at strains that differ in
virulence.
If I can be of more help, please let me know. I did hundreds of these
infections years ago as part of my Ph.D. project.
Brad Goodner
Biology, University of Richmond
