Localized Expression of Cathepsin B-like Sequences from Root Nodules of Pea (<i>Pisum sativum</i>)

Cathepsin B is an ancient family of eukaryotic cysteine proteases. We describe PsCat1, a plant cathepsin B-like transcript, identified as an expressed sequence in Rhizobium-induced, nitrogen-fixing root nodules of pea. In situ hybridization studies in root nodules showed strong, extremely localized expression of PsCat1 in individual cells associated with the central infected tissue. Restriction fragment polymorphism mapping of the PsCat1 locus in pea shows no correlation with existing mutant lines defective in symbiosis.