Legume nodule senescence: roles for redox and hormone signalling in the orchestration of the natural aging process.
Research on legume nodule development has contributed greatly to our current understanding of plant-microbe interactions. However, the factors that orchestrate root nodule senescence have received relatively little attention. Accumulating evidence suggests that redox signals contribute to the establishment of symbiosis and senescence. Although degenerative in nature, nodule senescence is an active process programmed in development in which reactive oxygen species (ROS), antioxidants, hormones and proteinases have key roles. Nodules have high levels of the redox buffers, ascorbate and glutathione, which are important in the nodulation process and in senescence. These metabolites decline with N-fixation as the nodule ages but the resultant decrease in redox buffering capacity does not necessarily lead to enhanced ROS or oxidative stress. We propose models by which ROS and antioxidants interact with hormones such as abscisic acid in the orchestration of nodule senescence.
Puppo
Alain
A
UMR CNRS-UNSA-INRA IPMSV 400, Route des Chappes, BP167 06903 Sophia-Antipolis Cedex, France.
Groten
Karin
K
Bastian
Fabiola
F
Carzaniga
Raffaella
R
Soussi
Mariam
M
Lucas
M Mercedes
MM
de Felipe
Maria Rosario
MR
Harrison
Judith
J
Vanacker
Hélène
H
Foyer
Christine H
CH
D000975:Antioxidants; D017209:Apoptosis; D007887:Fabaceae / Q000502:physiology*; D010084:Oxidation-Reduction; D010937:Plant Growth Regulators / Q000502:physiology*; D018517:Plant Roots / Q000382:microbiology / Q000502:physiology* / Q000648:ultrastructure; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D013997:Time Factors
D000975:Antioxidants; D010937:Plant Growth Regulators; D017382:Reactive Oxygen Species