|Authors: ||C.B. Wegener, O. Olsen|
|Keywords: ||Erwinia carotovora, soft rot, resistance, plant defence, transgenic potatoes|
Pectate lyase (PL) isoenzymes cleave pectic polymers of plant cell walls.
End-products of enzyme action are unsaturated oligogalacturonates (OG) that elicit plant defence responses.
The gene encoding the isoenzyme PL1 was introduced into potatoes of cultivar ‘Désirée’ by means of Agrobacterium-mediated transformation, in order to study its effect on plant defence responses directed against bacterial soft rot.
Plant lines expressing the transgene under control of the potato patatin B33 promoter were grouped according to the PL activity measured in tuber tissue.
In addition to the resistance properties, these PL-expressing potatoes were analysed for the action of phenylanine ammonia-lyase (PAL) and peroxidase (POD), key enzymes in the biosynthesis of phenolics, suberin and lignin.
Compared with the non-transgenic counterparts, significantly enhanced activities of PAL and POD were found in tuber tissue of the PL1 expressers; the PL activities correlated well with those of PAL and POD. As an important factor related to potato quality, there was found an enhanced resistance of tuber tissue to Erwinia soft rot.
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