title: Flavonoid supplementation affects the expression of genes involved in cell wall formation and lignification metabolism and increases sugar content and saccharification in the fast-growing eucalyptus hybrid E. urophylla x E. grandis.
abstract: BACKGROUND
  Eucalyptus species are the most widely planted hardwood species in the world and are renowned for their rapid growth and adaptability. In Brazil, one of the most widely grown Eucalyptus cultivars is the fast-growing Eucalyptus urophylla x Eucalyptus grandis hybrid. In a previous study, we described a chemical characterization of these hybrids when subjected to flavonoid supplementation on 2 distinct timetables, and our results revealed marked differences between the wood composition of the treated and untreated trees.
  
  
  RESULTS
  In this work, we report the transcriptional responses occurring in these trees that may be related to the observed chemical differences. Gene expression was analysed through mRNA-sequencing, and notably, compared to control trees, the treated trees display differential down-regulation of cell wall formation pathways such as phenylpropanoid metabolism as well as differential expression of genes involved in sucrose, starch and minor CHO metabolism and genes that play a role in several stress and environmental responses. We also performed enzymatic hydrolysis of wood samples from the different treatments, and the results indicated higher sugar contents and glucose yields in the flavonoid-treated plants.
  
  
  CONCLUSIONS
  Our results further illustrate the potential use of flavonoids as a nutritional complement for modifying Eucalyptus wood, since, supplementation with flavonoids alters its chemical composition, gene expression and increases saccharification probably as part of a stress response.
authors.forename: Jorge
authors.initials: J
authors.lastname: Lepikson-Neto
authors.forename: Leandro C
authors.initials: LC
authors.lastname: Nascimento
authors.forename: Marcela M
authors.initials: MM
authors.lastname: Salazar
authors.forename: Eduardo L O
authors.initials: EL
authors.lastname: Camargo
authors.forename: João P F
authors.initials: JP
authors.lastname: Cairo
authors.forename: Paulo J
authors.initials: PJ
authors.lastname: Teixeira
authors.forename: Wesley L
authors.initials: WL
authors.lastname: Marques
authors.forename: Fabio M
authors.initials: FM
authors.lastname: Squina
authors.forename: Piotr
authors.initials: P
authors.lastname: Mieczkowski
authors.forename: Ana C
authors.initials: AC
authors.lastname: Deckmann
authors.forename: Gonçalo A G
authors.initials: GA
authors.lastname: Pereira
mesh_terms: D050260:Carbohydrate Metabolism / Q000187:drug effects; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D015536:Down-Regulation; D005052:Eucalyptus / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D008031:Lignin / Q000737:chemistry / Q000378:metabolism; D014197:Trees; D014934:Wood / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
chemical_list: D005419:Flavonoids; D008031:Lignin