Thammannagowda, Shiv , Fei, Zhangjun , Crasta, Oswald , Joshi, Chandrashekhar P. .
Use of Affymetrix poplar whole genome arrays for global transcriptome analysis of tension wood formation in aspen trees.
Angiosperm trees respond to mechanical bending stress by developing cellulose-laden tension wood (TW) on the upper side of their bent trunks. TW fibers contain a thick, unlignified, and gelatinous (G) innermost layer that is almost entirely made up of cellulose (98.5%). The wood formed on the lower side of the bent tree contains less amount of cellulose as compared to vertical wood (VW) and is designated as opposite wood (OW). Thus comparative study of VW/TW/OW offers a novel systems-based approach to unravel mechanism of cellulose biosynthesis in angiosperm trees. To investigate the differential expression patterns of cell wall-related genes during VW/TW/OW formation, Affymetrix poplar whole genome microarrays covering over 45,000 poplar genes were used to compare the gene expression profiles from VW and 7 and 21-days stressed TW and OW samples from aspen (Populus tremuloides). Clear distinctions of VW, TW and OW gene expression profiles suggested that a massive metabolic reprogramming occurs in response to mechanical stress in these tissues. As compared to OW, several cellulose synthesis related genes were upregulated in TW while several lignin biosynthesis genes were down-regulated suggesting a tension-stress responsive compensatory regulation of xylem’s two major structural building blocks. Several transcription factors and phytohormone genes were also differentially expressed in TW leading to major reorganization of carbon allocation in woody tissues.
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1 - Michigan Technological University, School of Forest Resources and Environmental Sciences, Houghton, MI, 49931, USA
2 - Cornell University, Boyce Thompson Institute
3 - Virginia Bioinformatics Institute, Cyberinfrastructure Group
4 - Michigan Technological University, School of Forest Resources and Environmental Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM