title: Expression profiling and integrative analysis of the CESA/CSL superfamily in rice.
abstract: BACKGROUND
  The cellulose synthase and cellulose synthase-like gene superfamily (CESA/CSL) is proposed to encode enzymes for cellulose and non-cellulosic matrix polysaccharide synthesis in plants. Although the rice (Oryza sativa L.) genome has been sequenced for a few years, the global expression profiling patterns and functions of the OsCESA/CSL superfamily remain largely unknown.
  
  
  RESULTS
  A total of 45 identified members of OsCESA/CSL were classified into two clusters based on phylogeny and motif constitution. Duplication events contributed largely to the expansion of this superfamily, with Cluster I and II mainly attributed to tandem and segmental duplication, respectively. With microarray data of 33 tissue samples covering the entire life cycle of rice, fairly high OsCESA gene expression and rather variable OsCSL expression were observed. While some members from each CSL family (A1, C9, D2, E1, F6 and H1) were expressed in all tissues examined, many of OsCSL genes were expressed in specific tissues (stamen and radicles). The expression pattern of OsCESA/CSL and OsBC1L which extensively co-expressed with OsCESA/CSL can be divided into three major groups with ten subgroups, each showing a distinct co-expression in tissues representing typically distinct cell wall constitutions. In particular, OsCESA1, -3 & -8 and OsCESA4, -7 & -9 were strongly co-expressed in tissues typical of primary and secondary cell walls, suggesting that they form as a cellulose synthase complex; these results are similar to the findings in Arabidopsis. OsCESA5/OsCESA6 is likely partially redundant with OsCESA3 for OsCESA complex organization in the specific tissues (plumule and radicle). Moreover, the phylogenetic comparison in rice, Arabidopsis and other species can provide clues for the prediction of orthologous gene expression patterns.
  
  
  CONCLUSIONS
  The study characterized the CESA/CSL of rice using an integrated approach comprised of phylogeny, transcriptional profiling and co-expression analyses. These investigations revealed very useful clues on the major roles of CESA/CSL, their potentially functional complement and their associations for appropriate cell wall synthesis in higher plants.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors.forename: Lingqiang
authors.initials: L
authors.lastname: Wang
authors.forename: Kai
authors.initials: K
authors.lastname: Guo
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Tu
authors.forename: Huizhen
authors.initials: H
authors.lastname: Hu
authors.forename: Bingrui
authors.initials: B
authors.lastname: Wang
authors.forename: Xiaocan
authors.initials: X
authors.lastname: Cui
authors.forename: Liangcai
authors.initials: L
authors.lastname: Peng
mesh_terms: D000595:Amino Acid Sequence; D016000:Cluster Analysis; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005964:Glucosyltransferases / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D010940:Plant Proteins; D005964:Glucosyltransferases; C478648:cellulose synthase