title: Molecular mechanisms controlling legume autoregulation of nodulation.
abstract: BACKGROUND
  High input costs and environmental pressures to reduce nitrogen use in agriculture have increased the competitive advantage of legume crops. The symbiotic relationship that legumes form with nitrogen-fixing soil bacteria in root nodules is central to this advantage.
  
  
  METHODS
  Understanding how legume plants maintain control of nodulation to balance the nitrogen gains with their energy needs and developmental costs will assist in increasing their productivity and relative advantage. For this reason, the regulation of nodulation has been extensively studied since the first mutants exhibiting increased nodulation were isolated almost three decades ago.
  
  
  CONCLUSIONS
  Nodulation is regulated primarily via a systemic mechanism known as the autoregulation of nodulation (AON), which is controlled by a CLAVATA1-like receptor kinase. Multiple components sharing homology with the CLAVATA signalling pathway that maintains control of the shoot apical meristem in arabidopsis have now been identified in AON. This includes the recent identification of several CLE peptides capable of activating nodule inhibition responses, a low molecular weight shoot signal and a role for CLAVATA2 in AON. Efforts are now being focused on directly identifying the interactions of these components and to identify the form that long-distance transport molecules take.
authors.affiliation: ARC Centre of Excellence for Integrative Legume Research, School of Agriculture and Food Sciences, University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: Dugald E
authors.initials: DE
authors.lastname: Reid
authors.forename: Brett J
authors.initials: BJ
authors.lastname: Ferguson
authors.forename: Satomi
authors.initials: S
authors.lastname: Hayashi
authors.forename: Yu-Hsiang
authors.initials: YH
authors.lastname: Lin
authors.forename: Peter M
authors.initials: PM
authors.lastname: Gresshoff
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D007887:Fabaceae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006706:Homeostasis; D009586:Nitrogen Fixation; D011494:Protein Kinases / Q000378:metabolism; D053204:Root Nodules, Plant / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D015398:Signal Transduction; D013559:Symbiosis
chemical_list: D011494:Protein Kinases