In order to decrease guard cell density, a construct
(pBinARHyg-AtSDD1) was transferred that causes the potato plants to
overexpress the SDD1 protein from Arabidopsis thaliana. AtSDD1 is
put under the control of the CaMV 35S promoter and the ocs
terminator. An hph gene cassette consisting of the nos promoter,
the hph gene, the polyadenylation signal of gene 7 from plasmid
pTiAch5 from Agrobacterium tumefaciens, and the nos terminator was
used as a selection marker system.