A model system to study the lignification process in Eucalyptus globulus.
Recalcitrance of plant biomass is closely related to the presence of the phenolic heteropolymer lignin in secondary cell walls, which has a negative effect on forage digestibility, biomass-to-biofuels conversion and chemical pulping. The genus Eucalyptus is the main source of wood for pulp and paper industry. However, when compared to model plants such as Arabidopsis thaliana and poplar, relatively little is known about lignin biosynthesis in Eucalyptus and only a few genes were functionally characterized. An efficient, fast and inexpensive in vitro system was developed to study lignification in Eucalyptus globulus and to evaluate the potential role of candidate genes in this biological process. Seedlings were grown in four different conditions, in the presence or absence of light and with or without sucrose in the growth medium, and several aspects of lignin metabolism were evaluated. Our results showed that light and, to a lesser extent, sucrose induced lignin biosynthesis, which was followed by changes in S/G ratio, lignin oligomers accumulation and gene expression. In addition, higher total peroxidase activity and differential isoperoxidase profile were observed when seedlings were grown in the presence of light and sucrose. Peptide sequencing allowed the identification of differentially expressed peroxidases, which can be considered potential candidate class III peroxidases involved in lignin polymerization in E. globulus.
Departamento de Biologia Vegetal, Instituto de Biologia, CP 6109, Universidade Estadual de Campinas, 13083-970 Campinas, SP, Brazil.
Pedro
P
Araújo
Igor
I
Cesarino
Juliana Lischka Sampaio
JL
Mayer
Ilse Fernanda
IF
Ferrari
Eduardo
E
Kiyota
Alexandra Christine Helena Frankland
AC
Sawaya
Adriana Franco
AF
Paes Leme
Paulo
P
Mazzafera
D002473:Cell Wall / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D005052:Eucalyptus / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant; D008027:Light; D008031:Lignin / Q000378:metabolism*; D008954:Models, Biological; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D013395:Sucrose / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
D010940:Plant Proteins; D013395:Sucrose; D008031:Lignin; D010544:Peroxidases