Seeking explanation on transformation results

Alexander Kraev kraev at
Fri Mar 21 13:42:40 EST 1997

In article <333273DD.6317 at>, y-zhou at RSGIS4.TAMU.EDU
(Yuanxiang Zhou) wrote:

> Doing molecular analysis of R1 and R2 plants derived from R0 which
> survived antibiotic selection after Agrobacterium-mediated
> transformation, we detected GUS positive with histo-staining, PCR
> positive with primers amplifying GUS and selection marker.  But we did
> not get Southern positive.  Moreover, those showed positive with
> histochemical assay also showed PCR bands when amplifying VirG, which is
> not in the binary vector.  Can anyone give any explanation?

You have Agrobacterium growing around somewhere in the greenhouse or  its
DNA present
in the PCR reagents (or both).  Check  PCR reagents one by one and
replace. As for the greenhouse, it may
be necessary to clean it up as well :-(


Alexander Kraev, PhD
Biochemie III, ETHZ Zurich
Phone 41-1-632-31-47
Fax 41-1-632-12-13
e-mail kraev at

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