Root nodulation: a paradigm for how plant-microbe symbiosis influences host developmental pathways.
Legume plants have an exceptional capacity for association with microorganisms, ranging from largely nonspecific to very specific interactions. Legume-rhizobial symbiosis results in major developmental and metabolic changes for both the microorganism and host, while providing the plant with fixed nitrogen. A complex signal exchange leads to the selective rhizobial colonization of plant cells within nodules, new organs that develop on the roots of host plants. Although the nodulation mechanism is highly specific, it involves the same subset of plant phytohormones, namely auxin, cytokinin, and ethylene, which are required for root development. In addition, nodulation triggered by the rhizobia affects the development of the host root system, indicating that the microorganism can alter host developmental pathways. Nodulation by rhizobia is a prime example of how microorganisms and plants have coevolved and exemplifies how microbial colonization may affect plant developmental pathways.
Laboratory of Mediterranean and Tropical Symbiosis (LSTM) CC002, Université Montpellier 2, Place E. Bataillon, F-34095 Montpellier Cedex 05, France.
Guilhem J
GJ
Desbrosses
Jens
J
Stougaard
D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism*; D003583:Cytokinins / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D007887:Fabaceae / Q000382:microbiology / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism; D055170:Plant Root Nodulation; D018517:Plant Roots / Q000382:microbiology* / Q000502:physiology*; D013559:Symbiosis
D003583:Cytokinins; D005030:Ethylenes; D007210:Indoleacetic Acids; C036216:ethylene