文献类型： 会议论文

第一作者： Deborah Goffner

作者： Deborah Goffner ¹ ; Taku Demura ¹ ; Hiroo Fukuda ¹ ; Alain M. Boudet ¹ ; Alain Jauneau ¹ ; Catherine Digonnet ¹ ; Philippe Ranocha ¹ ; Christophe Pineau ¹ ; Magalie Pichon ¹ ; Edouard Pesquet ¹ ;

作者机构： 1.UMR -CNRS-UPS 5546 "Signaux et Messages Cellulaires chez le Vegetaux" Pole de Biotechnologie Vegetale, Chemin de Borde Rouge 31326 Castanet Tolosan, France

关键词： lignin;arabidopsis mutants;zinnia subtractive library;antisense poplar;laccase

会议名称： Molecular Breeding of Woody Plants

主办单位：

页码： 11-18

摘要： Laccases (EC 1.10.3.2) are blue copper oxidases that are found in a large variety of living organisms including bacteria, fungi, insects and plants. To date their role in these organisms has not yet been clearly established. In higher plants, based on their capacity to oxidize monolignols in vitro and localization at the cell wall, laccases are considered candidate enzymes in the ultimate step in lignification. In order to provide functional evidence to support or refute this hypothesis, four lines of antisense poplars, each corresponding to a different gene, were obtained. Although none of the lines exhibited significant differences in either lignin content or composition, one line, lac3AS, is characterized by a two to three-fold increase in soluble phenolics and perturbations in cell adhesion of xylem fibers. The fact that several laccases from Zinnia (8 out of the 9 obtained) are heavily induced at the onset of lignification during the formation of tracheary elements (TEs) further suggest then involvement of laccases in secondary cell wall formation. In order to make a quantitative leap in our understanding of lignification and vascular development, we are currently developing two strategies that will lead to the identification of new genes involved in these plant-specific processes. Firstly, we have constructed a "late xylogenesis" cDNA library by suppression subtractive hybridization (SSH) from differentiating TEs of Zinnia. Approximately 75% of the 800 clones obtained appear to be differentially expressed during TE formation. A limited number of differentially expressed clones were randomly chosen and sequenced. Among them, known molecular markers of late xylogenesis including a cysteine protease and an endonuclease were identified, demonstrating the quality of the library. Massive sequencing and the determination of detailed expression profiles of these cDNAs are now underway. Secondly, we have screened T-DNA tagged Arabidopsis mutants (Versailles collection) for atypical vascular patterns in floral stems. One of these mutants, hca, for high cambial activity, is characterized by the formation of a continuous ring of vascular tissue as opposed to the discrete vascular bundles typically observed in Arabidopsis. The identification of the gene responsible for this phenotype is now underway.

分类号： Q9