Poster: Cell Walls
Abs #
1260: Coordinate expression of three cellulose synthase genes orchestrate cellulose biosynthesis during the wood formation in aspen trees
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Presenter: |
Joshi, Chandrashekhar P., cpjoshi@mtu.edu |
Authors | Joshi, Chandrashekhar P. (A) Liang, Xiaoe (A) Samuga, Anita (A) Kalluri, Udaya (A) | | Affiliations: |
(A): School of Forest Resources and Environmental Science, Michigan Technological University
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| Web Site: | http://forestry.mtu.edu/faculty/joshi/ | |
Secondary cell walls of woody trees provide valuable resources for a variety of forest products. Biotechnological improvement of cell wall components of forest trees, therefore, holds an enormous promise for forest product industries. Our long-term goal is to decipher the biosynthetic mechanisms of major cell wall polymers in trees in order to genetically improve them for better wood utilization. Recent molecular genetic evidence strongly suggests that plant genomes host a rather large family of cellulose synthase (CesA) genes and multiple but distinct CesAs are involved in primary and secondary cell wall formation in Arabidopsis. In order to evaluate whether the mechanism of cellulose biosynthesis is conserved between Arabidopsis and trees, we isolated three distinct secondary wall-related CesA genes from aspen namely, PtrCesA1, PtrCesA2 and PtrCesA3 where encoded proteins share a high degree of similarity (>85%) with Arabidopsis AtCesA8, AtCesA7 and AtCesA4 gene products implicated in secondary cell wall formation. In situ mRNA hybridization experiments exclusively localized PtrCesA1-PtrCesA3 transcripts in the same developing xylem and phloem fiber cells of aspen stems suggesting that their coordinate expression is germane for proper cellulose deposition during wood formation. Moreover, PtrCesA1-PtrCesA3 genes are simultaneously upregulated in tension stress-responsive manner on upper side of bent stem and coordinately downregulated on lower side of bent stem mimicking the tension wood formation in angiosperm trees during which large quantities of highly crystalline cellulose are produced in tension wood fibers. These results imply that genetic manipulation of three types of CesAs may be required to obtain a desired outcome for forest product industries.
