Induction of actinorhizal nodules on Datisca glomerata
Rogalla von Bieberstein, U.1, van de Sande, K.2, Berry, A.M.3, Bisseling, T.4, Pawlowski, K.1,4
1Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Untere Karspüle 2, D-37073 Göttingen, Germany
2Dept. of Biology, University of York, York Y01 5YW, U.K.
3Dept. of Environmental Horticulture, University of California, Davis CA 95616, U.S.A.
4Dept. of Molecular Biology, Agricultural University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
Actinomycetes of the genus Frankia induce the formation of nitrogen fixing nodules on the roots of plants from eight different families, summarily called "actinorhizal plants". Dependent on the host plant family, bacteria enter the plant intracellularly via root hair deformation and infection thread formation, similarly to the mechanism in legumes, or via intercellular penetration of the epidermis and colonization of the root cortex. In both cases, Frankia induces the formation of a nodule meristem in the root pericycle.
During legume nodule formation, nodule meristem formation involves the induction of the early nodulin gene ENOD40 by bacterial signal molecules. ENOD40 encodes a short peptide that modulates plant hormone response as analysed in a tobacco protoplast system (van de Sande et al., 1996). An ENOD40 homolog has been found in the intracellularly infected actinorhizal plant Alnus glutinosa. In the intercellularly infected actinorhizal plant Datisca glomerata, a nodule-specific gene was characterized which has an ENOD40-like effect when expressed in the tobacco protoplast system.
Thus, induction of nodule meristem formation by both Frankia and rhizobia seems to involve the induction of plant genes whose products modulate phytohormone response.
van de Sande et al. (1996) Modification of phytohormone response by a peptide encoded by ENOD40 of legumes and a nonlegume. Science 273, 370-273.
| LOCATION |
DATE |
TIME |
| Lecture Hall II |
Thursday, April 9 |
05:10 pm |