Comprehensive genetic dissection of wood properties in a widely-grown tropical tree: Eucalyptus

Background: Eucalyptus is an important genus in industrial plantations throughout the world and is grown for use as timber, pulp, paper and charcoal. Several breeding programmes have been launched worldwide to concomitantly improve growth performance and wood properties (WPs). In this study, an interspecific cross between Eucalyptus urophylla and E. grandis was used to identify major genomic regions (Quantitative Trait Loci, QTL) controlling the variability of WPs. Results: Linkage maps were generated for both parent species. A total of 117 QTLs were detected for a series of wood and end-use related traits, including chemical, technological, physical, mechanical and anatomical properties. The QTLs were mainly clustered into five linkage groups. In terms of distribution of QTL effects, our result agrees with the typical L-shape reported in most QTL studies, i.e. most WP QTLs had limited effects and only a few (13) had major effects (phenotypic variance explained > 15%). The co-locations of QTLs for different WPs as well as QTLs and candidate genes are discussed in terms of phenotypic correlations between traits, and of the function of the candidate genes. The major wood property QTL harbours a gene encoding a Cinnamoyl CoA reductase (CCR), a structural enzyme of the monolignol-specific biosynthesis pathway. Conclusions: Given the number of traits analysed, this study provides a comprehensive understanding of the genetic architecture of wood properties in this Eucalyptus full-sib pedigree. At the dawn of Eucalyptus genome sequence, it will provide a framework to identify the nature of genes underlying these important quantitative traits. (Résumé d'auteur

Lignin synthesis, transcriptional regulation and potential for useful modification in plants

Lignin, the second most abundant plant polymer on earth, has always been of great interest for research with regard to its biological roles and potential for useful modification. Over the last few decades, numerous studies have considerably enriched our knowledge of lignin biosynthesis. In the first part, a revision of lignin composition and synthesis is described, highlighting the key genes shown to be implicated in the lignification process occurring during secondary cell wall (SCW) formation in plants. Availability of genome sequencing data has brought about useful information concerning the different gene families of the lignin biosynthesis pathway. These data can be exploited to isolate the members that are more specific to the SCW formation process through combination of sequence homology or specific transcript-profiling techniques. This review also summarizes our current knowledge on the transcriptional regulation of lignin biosynthesis, particularly the R2R3-MYB and NAC transcription factor (TF) families. Strategies of lignin modification for the production of second-generation biofuels are also discussed

Lignin synthesis, transcriptional regulation and potential for useful modification in plants

Lignin, the second most abundant plant polymer on earth, has always been of great interest for research with regard to its biological roles and potential for useful modification. Over the last few decades, numerous studies have considerably enriched our knowledge of lignin biosynthesis. In the first part, a revision of lignin composition and synthesis is described, highlighting the key genes shown to be implicated in the lignification process occurring during secondary cell wall (SCW) formation in plants. Availability of genome sequencing data has brought about useful information concerning the different gene families of the lignin biosynthesis pathway. These data can be exploited to isolate the members that are more specific to the SCW formation process through combination of sequence homology or specific transcript-profiling techniques. This review also summarizes our current knowledge on the transcriptional regulation of lignin biosynthesis, particularly the R2R3-MYB and NAC transcription factor (TF) families. Strategies of lignin modification for the production of second-generation biofuels are also discussed

Solutions de phytoremédiation pour une gestion durables de sites contaminés

National audienc

Interaction between environmental factors affects the accumulation of root proteins in hydroponically grown Eucalyptus globulus (Labill.)

Eucalyptus globulus (Labill.) is used for pulp and paper production worldwide. In this report we studied changes in protein expression in one osmotically stressed elite clone widely used in industrial plantations in Spain. High molecular weight polyethylene glycol (PEG) was used as an osmoticum in the growing medium. Roots of rooted cuttings were sampled after 3 and 36 h of treatment. Water potential and abscissic acid content were measured in shoot and root apices to characterize the physiological states of the plants. Total soluble proteins from roots were extracted and separated using two-dimensional gel electrophoresis (2-DE). Gels were stained with Coomassie brillant blue for quantitative analysis of protein accumulation. From a total of 406 reproducible spots, 34 were found to be differentially expressed depending on treatment (osmotic versus control condition) and/or stress duration (3 h versus 36 h), and were further characterized by tandem mass spectrometry. Several proteins were reliably identified including adenosine kinase, actin, stress-related proteins as well as proteins associated to cellular processes, among which some residents of the endoplasmic reticulum. This study constitutes the first investigation of the root proteome in this important forest tree genus

Proteomic characterization of phenotypic plasticity between metallicolous and non-metallicolous populations of Agrostis capillaris L. exposed to Cu

International audienc