Autoregulation of Root Nodule Formation: Signals of Both Symbiotic Partners Studied in a Split-Root System of Vicia sativa subsp. nigra
Autor: | Kees J. M. Boot, Jan W. Kijne, Teun Tak, Anton A. N. van Brussel |
---|---|
Rok vydání: | 2002 |
Předmět: |
Lipopolysaccharides
Cytokinins Time Factors Rhizobiaceae Root nodule Zeatin Physiology medicine.disease_cause Plant Roots Rhizobium leguminosarum Microbiology Rhizobia Nod factor chemistry.chemical_compound Plant Growth Regulators Botany medicine Symbiosis biology food and beverages Fabaceae General Medicine Hydrogen-Ion Concentration biology.organism_classification Culture Media chemistry Cytokinin Rhizobium Agronomy and Crop Science Signal Transduction |
Zdroj: | Molecular Plant-Microbe Interactions®. 15:341-349 |
ISSN: | 1943-7706 0894-0282 |
Popis: | Inhibition of root nodule formation on leguminous plants by already induced or existing root nodules is called autoregulation of root nodule formation (AUT). Optimal conditions for AUT were determined using a split-root technique newly developed for Vicia sativa subsp. nigra. Infection of a root A with nodulating Rhizobium leguminosarum bv. viciae bacteria systemically inhibited nodulation of a spatially separated root B inoculated 2 days later with the same bacteria. This treatment gives complete AUT (total absence of nodules on root B). Only partial AUT of root B was obtained by incubation of root A with mitogenic nodulation (Nod) factors or with a noninfective strain producing normal mitogenic Nod factors. Nonmitogenic Nod factors did not evoke AUT. We identified two systemic plant signals induced by Rhizobium bacteria. Signal 1 (at weak buffering) was correlated with sink formation in root A and induced acidification of B-root medium. This signal is induced by treatment of root A with (i) nodulating rhizobia, (ii) mitogenic Nod factors, (iii) nonmitogenic Nod factors, or (iv) the cytokinin zeatin. Signal 2 (at strong buffering) could only be evoked by treatment with nodulating rhizobia or with mitogenic Nod factors. Most probably, this signal represents the specific AUT signal. Induction of complete AUT appears to require actively dividing nodule cells in nodule primordia, nodule meristems, or both of root A. |
Databáze: | OpenAIRE |
Externí odkaz: |