Identification of a high-affinity binding protein for N-acetylchitooligosaccharide elicitor in the plasma membrane from rice leaf and root cells

Presence of a high-affinity binding protein for N-acetylchitooligosaccharid e (fragments of chitin) elicitor in the plasma membrane from rice leaf and root cells was shown by affinity labeling experiments with an I-125-labeled N-acetylchitooligosaccharide derivative. Binding studies also showed that binding site in the leaf cells has a high affinity to highly elicitor-activ e, larger chitin fragments but much lower or no affinity to less elicitor-a ctive or elicitor-inactive oligosaccharides. The amount of the binding prot ein in the leaf cells was slightly smaller than that in the suspension-cult ured cells but much larger compared to that in the root cells. These result s indicate the possible- involvement of the elicitor binding protein in the perception of the elicitor signal in intact rice plant.