Kanamycin in media

[V. Polanski]

Cayetana Schluter wrote:
> 
> Hello all,
> 
> I'm trying to do plant (ginseng) transformations and I'm using kanamycin
> to select for the transformants. Does anybody know how long kanamycin can
> remain in solid MS media (50mg/L) at room temperature before it breaks
> down? Ginseng is rather slow in that it takes at least 3 weeks before the
> tissue starts to callus, so the fewer times I half to transfer my explants
> the better.
> 
> Cayetana

I routinely do plant tissue culture only in the presence of 20 mg/L of
kanamycin and I have found that transfers over 2 week intervals have
never been a problem in the selection process.  So I am guessing that at
50 mg/L you can at least go for 3 weeks at room temp. provided your
Agrobacterium does not start growing back due to a breakdown in the
antibiotic you use to select against that.  Good luck.
VP