title: Organogenic nodule development in hop (Humulus lupulus L.): transcript and metabolic responses.
abstract: BACKGROUND
  Hop (Humulus lupulus L.) is an economically important plant forming organogenic nodules which can be used for genetic transformation and micropropagation. We are interested in the mechanisms underlying reprogramming of cells through stress and hormone treatments.
  
  
  RESULTS
  An integrated molecular and metabolomic approach was used to investigate global gene expression and metabolic responses during development of hop's organogenic nodules. Transcript profiling using a 3,324-cDNA clone array revealed differential regulation of 133 unigenes, classified into 11 functional categories. Several pathways seem to be determinant in organogenic nodule formation, namely defense and stress response, sugar and lipid metabolism, synthesis of secondary metabolites and hormone signaling. Metabolic profiling using 1H NMR spectroscopy associated to two-dimensional techniques showed the importance of metabolites related to oxidative stress response, lipid and sugar metabolism and secondary metabolism in organogenic nodule formation.
  
  
  CONCLUSIONS
  The expression profile of genes pivotal for energy metabolism, together with metabolites profile, suggested that these morphogenic structures gain energy through a heterotrophic, transport-dependent and sugar-degrading anaerobic metabolism. Polyamines and auxins are likely to be involved in the regulation of expression of many genes related to organogenic nodule formation. These results represent substantial progress toward a better understanding of this complex developmental program and reveal novel information regarding morphogenesis in plants.
authors.affiliation: ICAT, FCUL, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal. margafortes@yahoo.com
authors.forename: Ana M
authors.initials: AM
authors.lastname: Fortes
authors.forename: Filipa
authors.initials: F
authors.lastname: Santos
authors.forename: Young H
authors.initials: YH
authors.lastname: Choi
authors.forename: Marta S
authors.initials: MS
authors.lastname: Silva
authors.forename: Andreia
authors.initials: A
authors.lastname: Figueiredo
authors.forename: Lisete
authors.initials: L
authors.lastname: Sousa
authors.forename: Fernando
authors.initials: F
authors.lastname: Pessoa
authors.forename: Bartolomeu A
authors.initials: BA
authors.lastname: Santos
authors.forename: Mónica
authors.initials: M
authors.lastname: Sebastiana
authors.forename: Klaus
authors.initials: K
authors.lastname: Palme
authors.forename: Rui
authors.initials: R
authors.lastname: Malhó
authors.forename: Rob
authors.initials: R
authors.lastname: Verpoorte
authors.forename: Maria S
authors.initials: MS
authors.lastname: Pais
mesh_terms: D020869:Gene Expression Profiling; D017343:Genes, Plant; D027582:Humulus / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D020411:Oligonucleotide Array Sequence Analysis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D010940:Plant Proteins