The influence of ethylene, gibberellins and brassinosteroids on energy and nitrogen-fixation metabolites in nodule tissue.

Abstract

Legume nodules are a unique plant organ that contain nitrogen-fixing rhizobial bacteria. For this interaction to be mutually beneficial, plant and bacterial metabolism must be precisely co-ordinated. Plant hormones are known to play essential roles during the establishment of legume-rhizobial symbioses but their role in subsequent nodule metabolism has not been explored in any depth. The plant hormones brassinosteroids, ethylene and gibberellins influence legume infection, nodule number and in some cases nodule function. In this paper, the influence of these hormones on nodule metabolism was examined in a series of well characterised pea mutants with altered hormone biosynthesis or response. A targeted set of metabolites involved in nutrient exchange and nitrogen fixation was examined in nodule tissue of mutant and wild type plants. Gibberellin-deficiency had a major negative impact on the level of several major dicarboxylates supplied to rhizobia by the plant and also led to a significant deficit in the amino acids involved in glutamine-aspartate transamination, consistent with the limited bacteroid development and low fixation rate of gibberellin-deficient na mutant nodules. In contrast, no major effects of brassinosteroid-deficiency or ethylene-insensitivity on the key metabolites in these pathways were found. Therefore, although all three hormones influence infection and nodule number, only gibberellin is important for the establishment of a functional nodule metabolome.

• Authors: Peter N McGuiness, James B Reid, Eloise Foo
• Journal: Plant science : an international journal of experimental plant biology (Plant Sci) Vol. 305 Pg. 110846 (Apr 2021) ISSN: 1873-2259 [Electronic] Ireland
• PMID: 33691972 (Publication Type: Comparative Study, Journal Article)
• Copyright: Crown Copyright © 2021. Published by Elsevier B.V. All rights reserved.

Chemical References

• Brassinosteroids
• Ethylenes
• Gibberellins
• Plant Growth Regulators
• ethylene

Topics

• Brassinosteroids (metabolism)
• Energy Metabolism (drug effects)
• Ethylenes (metabolism)
• Gene Expression Regulation, Plant
• Genes, Plant
• Genetic Variation
• Genotype
• Gibberellins (metabolism)
• Mutation
• Nitrogen Fixation (drug effects)
• Pisum sativum (genetics, metabolism, microbiology)
• Plant Growth Regulators (metabolism)
• Plant Root Nodulation (drug effects)
• Rhizobium (physiology)
• Root Nodules, Plant (metabolism)
• Symbiosis (drug effects)