Poster: Cell walls

Abs # 618: Large scale identification of genes that are preferentially expressed during cotton fiber secondary wall deposition

Presenter:	Zhang, Deshui , dzhang3@ncsu.edu
Authors	Zhang, Deshui  (A)   Wilkerson, Curt  (B)   Haigler, Candace H. (A)
Affiliations:	(A): North Carolina State University (B): Michigan State University

Cotton fiber secondary walls are composed of nearly 100% cellulose, which is deposited at a high rate over a prolonged period. The thickness and physical properties of the secondary wall have a major impact on cotton fiber yield and textile properties. Manipulating cellulose deposition using diverse strategies requires more understanding of how the process is controlled. Cotton fibers are ideal targets for genomic approaches because primary and secondary wall deposition are separated in time and the fibers can be completely separated from other cell types using minimally disruptive procedures. To identify on a large scale genes that are preferentially expressed in secondary-wall-stage cotton fibers, a cDNA library was made using suppression subtractive hybridization with cDNA from 20 days post anthesis (DPA) fiber as tester and cDNA from 6 DPA fiber as driver. We randomly sequenced about 11,000 clones and derived a putative unigene set composed of more than 3,000 sequences. The utility of the library was demonstrated by its inclusion of genes associated with secondary wall cellulose synthesis such as cellulose synthases, sucrose synthase, katanin, and a chitin binding protein. Also included were other genes encoding proteins that are required for cellulose synthesis, such as kobito 1, korrigan, and enzymes involved in glycoprotein synthesis. Initial efforts in characterizing the data set, verifying patterns of gene expression, and using the library as a tool for functional genomics will be described.