Sunday, April 29, 2007

Characterization of lignocellulosic O-acylation and deacetylation to facilitate cell wall biomass degradation

Chang-Jun Liu, Biology, Brookhaven National Laboratory, 50 Bell Avenue, Upton, NY 11973

Acyl-CoA dependent O-acylation and its reverse process deacylation are prevalent modification reactions involved in biogenesis of cell wall components hemicelluloses, pectin, and lignin, as well as in the biosynthesis of a wide variety of wood-forming required secondary metabolites, primarily polyphenolics, in tree species.  The degree of acylation influences the chemical and physical properties of cell wall lignocelluloses, and negatively affects the degradation of plant biomass for bioethanol production.  Characterization of O-acylation and de-acetylation in cell wall biogenesis implicates a great potential for genetic modification of lignocelluloses to produce better quality and easier degradable biomass feedstock. Toward this end, we conducted comprehensive sequence searching and data mining based upon poplar genomic sequences using the highly conserved sequence motifs of plant acyltransferase superfamily members. A total of 81 putative O-acyltransferase and 10 deacetylase gene models were identified from poplar genome. Followed by the comprehensive bioinformatics analyses, extensive gene expression profiling has been conducted by the solid RT-PCR using mRNAs that were prepared from poplar leaf, root, developing stem, apical bud, cortex of bark, phloem, developing wood and lignified wood, and by “in silico” northern analysis based upon the public available EST and cell wall biogenesis microarray databases. The wood tissue expressing genes potentially involved in either acylation or deacetylation have been selected for producing recombinant proteins in either E.coli or yeast. The biochemical analyses are undertaking, and the transgenes in model experimental plants are been making in order to dissect the gene functions in vivo. The progresses will be discussed.

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