Transgenic potatoes that express an Erwinia pectate lyase isoenzyme

Abstract Pectate lyase isoenzyme 3 (PL3) from Erwinia carotovora subsp. atroseptica depolymerizes pectins of plant middle lamellae, leaving cells with intact primary and secondary cell walls. The sequence encoding mature PL3 was fused to the promoter of the potato patatin B33 gene and the CaMV 35S promoter, respectively, and inserted into the binary vector pBin19 for Agrobacterium -mediated transformation of potatoes, cultivar Desiree. While enzyme production in plant lines transformed with pB33-PL3 was confined to tuber tissue, those plants transformed with p35S-PL3 exhibited tissue-independent production. The transformants differed considerably with respect to accumulation of PL3. After wounding of tubers, liberated PL3 caused tissue maceration. Moreover, some transformants expressing PL3 were more resistant against maceration by externally applied Erwinia bacteria or enzymes thereof.