Pectic epitopes are differentially distributed in the cell walls of potato (Solanum tuberosum) tubers

except at corners and pit fields. In contrast, pectic side-chains Six monoclonal antibodies (mAbs) were used to map the were not detectable in the middle lamella of all parenchymal distribution of pectic epitopes in the cell walls of potato cell walls, except in the cortex where mAb LM6 (arabinan (Solanum tuberosum L. cvs Kardal and Karnico) tuber tissue epitope) labelled the entire wall. The galactan epitope (mAb in both light and electron microscopes. Unesterified (mAb JIM LM5) was localised to a zone very close to the plasmalemma 5 epitope) and methyl-esterified (mAb JIM 7 epitope) pectins in cortical cell walls and was also less abundant at pit fields were abundant and equally distributed in all parenchymal and and in vascular cell walls. MAb CCRC-M2 (rhamnogalacturvascular cell walls. Homogalacturonans (HGAs) involved in Ca-cross-linking (mAb 2F4 epitope) were localised to the onan I epitope) did not cross-react. Our results show that the cell walls of potato tubers are not homogeneous structures and middle lamella and abundant at cell corners. The tuber cortex was densely labelled, but parenchymal cell walls in the perthat the pectic composition of the walls is spatially regulated. imedullary region contained few epitopes of calcium pectate