Identification and Characterization of C-Type Lectin Genes From the Reniform Nematode

C-type lectins represent a large family of sugar-binding proteins which require calcium for their ligand-binding activity. C-type lectins play an important role in the innate immune response in all life forms when challenged by pathogens. Ligand binding occurs via conserved domain sequences which recognize specific carbohydrates on the cell surface resulting in cell-cell adhesion followed by inflammation and encapsulation. They comprise a large family of proteins with each member playing a specific role in innate immune response. The identification and characterization of C-type lectins expressed by plant-parasitic nematodes may help to elucidate the nature of the molecular interactions that occur at the host-parasite interface. We have characterized and studied the expression of multiple C-type lectins collected from different life stages of the reniform nematode Rotylenchulus reniformis. All C-type lectins identified have a conserved domain of 155 amino acids and a signal peptide of 20 amino acids at the N-terminus. Three C-type lectins were found that were expressed in all life-stages; whereas, an additional eleven other C-type lectins were expressed in individual life stages, four of which were expressed only in adult vermiform. The expression level of the conserved C-type lectin domain was predominantly higher in the sedentary female stage compared to the other life stages. The identified lectins are most similar to C-type lectins from other parasitic nematodes. We hypothesize that C-type lectins in reniform nematode may facilitate the recognition and establishment of the parasitic relationship with the host plant.