Localization of a Nod factor-binding protein in legume roots and factors influencing its distribution and expression.
The roots of the legume Dolichos biflorus contain a lectin/nucleotide phosphohydrolase (Db-LNP) that binds to the Nod factor signals produced by rhizobia that nodulate this plant. In this study we show that Db-LNP is differentially distributed along the surface of the root axis in a pattern that correlates with the zone of nodulation of the root. Db-LNP is present on the surface of young and emerging root hairs and redistributes to the tips of the root hairs in response to treatment of the roots with a rhizobial symbiont or with a carbohydrate ligand. This redistribution does not occur in response to a non-symbiotic rhizobial strain or a root pathogen. Db-LNP is also present in the root pericycle where its level decreases upon initiation of nodule formation. Maximum levels of Db-LNP are found in 2-d-old roots, and the expression of this root protein is increased when the plants are grown in the absence of NO(3)(-) and NH(4)(+). These results support the possibility that Db-LNP is involved in the initiation of the Rhizobium legume symbiosis.
Kalsi
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Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA.
Etzler
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ME
D020369:Bradyrhizobium / Q000378:metabolism* / Q000502:physiology; D007887:Fabaceae / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D018506:Gene Expression Regulation, Plant; D015151:Immunoblotting; D037102:Lectins / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism*; D018613:Microscopy, Confocal; D009708:Nucleotidases / Q000235:genetics / Q000378:metabolism*; D037121:Plant Lectins; D018517:Plant Roots / Q000033:anatomy & histology / Q000378:metabolism* / Q000382:microbiology; D010946:Plants, Medicinal; D013559:Symbiosis; D014018:Tissue Distribution
D037102:Lectins; D008070:Lipopolysaccharides; D037121:Plant Lectins; D009708:Nucleotidases; C030287:nucleotidase