title: Lignification in sugarcane: biochemical characterization, gene discovery, and expression analysis in two genotypes contrasting for lignin content.
abstract: Sugarcane (Saccharum spp.) is currently one of the most efficient crops in the production of first-generation biofuels. However, the bagasse represents an additional abundant lignocellulosic resource that has the potential to increase the ethanol production per plant. To achieve a more efficient conversion of bagasse into ethanol, a better understanding of the main factors affecting biomass recalcitrance is needed. Because several studies have shown a negative effect of lignin on saccharification yield, the characterization of lignin biosynthesis, structure, and deposition in sugarcane is an important goal. Here, we present, to our knowledge, the first systematic study of lignin deposition during sugarcane stem development, using histological, biochemical, and transcriptional data derived from two sugarcane genotypes with contrasting lignin contents. Lignin amount and composition were determined in rind (outer) and pith (inner) tissues throughout stem development. In addition, the phenolic metabolome was analyzed by ultra-high-performance liquid chromatography-mass spectrometry, which allowed the identification of 35 compounds related to the phenylpropanoid pathway and monolignol biosynthesis. Furthermore, the Sugarcane EST Database was extensively surveyed to identify lignin biosynthetic gene homologs, and the expression of all identified genes during stem development was determined by quantitative reverse transcription-polymerase chain reaction. Our data provide, to our knowledge, the first in-depth characterization of lignin biosynthesis in sugarcane and form the baseline for the rational metabolic engineering of sugarcane feedstock for bioenergy purposes.
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, 13083-970 Campinas, São Paulo, Brazil.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Bottcher
authors.forename: Igor
authors.initials: I
authors.lastname: Cesarino
authors.forename: Adriana Brombini dos
authors.initials: AB
authors.lastname: Santos
authors.forename: Renato
authors.initials: R
authors.lastname: Vicentini
authors.forename: Juliana Lischka Sampaio
authors.initials: JL
authors.lastname: Mayer
authors.forename: Ruben
authors.initials: R
authors.lastname: Vanholme
authors.forename: Kris
authors.initials: K
authors.lastname: Morreel
authors.forename: Geert
authors.initials: G
authors.lastname: Goeminne
authors.forename: Jullyana Cristina Magalhães Silva
authors.initials: JC
authors.lastname: Moura
authors.forename: Paula Macedo
authors.initials: PM
authors.lastname: Nobile
authors.forename: Sandra Maria
authors.initials: SM
authors.lastname: Carmello-Guerreiro
authors.forename: Ivan Antonio dos
authors.initials: IA
authors.lastname: Anjos
authors.forename: Silvana
authors.initials: S
authors.lastname: Creste
authors.forename: Wout
authors.initials: W
authors.lastname: Boerjan
authors.forename: Marcos Guimarães de Andrade
authors.initials: MG
authors.lastname: Landell
authors.forename: Paulo
authors.initials: P
authors.lastname: Mazzafera
mesh_terms: D001499:Bayes Theorem; D053898:Biosynthetic Pathways / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D056726:Genetic Association Studies; D005838:Genotype; D008031:Lignin / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism; D018547:Plant Stems / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D025341:Principal Component Analysis; D031786:Saccharum / Q000235:genetics* / Q000378:metabolism*; D012995:Solubility
chemical_list: D010636:Phenols; D008031:Lignin