PLANT PHYSIOLOGY , Vol 111, Issue 1 49-60, Copyright © 1996 by American Society of Plant Biologists
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PLANT-MICROBE AND PLANT-INSECT INTERACTIONS |
Identification of a New Pea Gene, PsNlec1, Encoding a Lectin-like Glycoprotein Isolated from the Symbiosomes of Root Nodules
I. V. Kardailsky, D. J. Sherrier and N. J. Brewin
Department of Genetics, John Innes Centre, Norwich NR4 7UH, United Kingdom
A 27-kD glycoprotein antigen recognized by monoclonal antibody MAC266 was
purified from isolated symbiosomes derived from pea (Pisum sativum) root
nodules containing Rhizobium. The N-terminal amino acid sequence was
obtained, and the corresponding cDNA clone was isolated by a polymerase
chain reaction-based strategy. The clone contained a single open reading
frame, and the gene was termed PsNlec1. Phylogenetic analysis of 31 legume
sequences showed that the PsNlec1 protein is related to the legume lectin
family but belongs to a subgroup that is very different from pea seed
lectin. Expression of the PsNlec1 transcript was much stronger in nodules
than in other parts of the plant. It was found in both infected and
uninfected cells in the central tissue of the nodule and in the stele of
the root near the attachment point of the nodule. When uninfected pea
seedlings were grown on medium containing nitrate, weak transcription of
PsNlec1 was observed in the root system. The identification of PsNlec1
inside the symbiosome is consistent with the observation that legume
lectins are generally vacuolar proteins that may serve as transient storage
components.
