Full Length Research Paper

Expression of the C-terminal family 22 carbohydrate-binding module of xylanase 10B of Clostridium themocellum in tobacco plant

Olawole O. Obembe^{1, 2}

¹Laboratory of Plant Breeding, Wageningen University, Box 386 6700AJ Wageningen, The Netherlands

²Department of Biological Sciences, Covenant University, PMB 1023 Ota, Ogun State, Nigeria.

E-mail: obembe@covenantuniversity.com. Tel: +234-8060164341.

Accepted 12 June, 2008

   Abstract

Carbohydrate-binding modules have been shown to alter plant cell wall structural architecture.  Hence, they have the potential application of being used to engineer the plant to produce tailor-made natural fibers in the cell wall. The Clostridium thermocellum xylanase, Xyn10B, contains two CBMs that belong to family 22 (CBM22). The C-terminal CBM22-2 of the glycoside hydrolase (GH) 10 had been characterized to interact with xylan, a major hemicellulosic component in the secondary cell wall of plants. In this work, the expression of the CBM22-2 in transgenic tobacco plants was evaluated. Histological examinations of the transgenic stems did not reveal marked cell wall phenotype. In addition, there were no observable changes in the height or the appearance of the transgenic plants expressing the CBM22-2 module. The results indicate that the family 22 carbohydrate binding module is not a potential candidate for use in in planta modification of the cell wall.

Key words: Carbohydrate binding module, xylan binding protein, cell wall modification, cellulose-hemicellulose network, Nicotiana tabacum.