Pectin in the primary plant cell wall is thought to be responsible for its porosity, charge density, and microfibril spacing and is the main component of the middle lamella. Plant-parasitic nematodes secrete a cocktail of cell wall degrading enzymes that macerate the plant tissue, facilitating the penetration and migration within the roots. In sedentary nematodes, these enzymes are released only during the migration of infective juveniles through the root. At later stages nematodes manipulate the expression of host plant genes including various cell wall enzymes in order to induce specific feeding sites. In this study we investigated pectin and pectate epitopes together with the expression of two Arabidopsis thaliana pectate lyase-like genes, PLL18 (At3g27400) and PLL19 (At4g24780), in both syncytia induced by the cyst nematode Heterodera schachtii and giant cells induced by the root-knot nematode Meloidogyne incognita. We analyzed their expression in both types of feeding sites and confirmed their upregulation based on our previous GeneChip and microarray results by qRT-PCR and in situ RT-PCR. Furthermore, the functional analysis of mutants demonstrated the important role of both PLLs in the development and maintenance of syncytia but not giant cells. Our results show that both enzymes play distinct roles in different infected root tissues as well as during parasitism of different nematodes.