Finding genes related with cell wall proteins in sugar cane

• Grant number: 00/07436-9
• Support Opportunities: Genome Research Grants
• Start date: August 01, 2000
• End date: August 31, 2002
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Marcos Silveira Buckeridge
• Grantee: Marcos Silveira Buckeridge
• Host Institution: Instituto de Botânica. Secretaria de Meio Ambiente, Infraestrutura e Logística (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

The plant cell wall is composed of a number of different carbohydrate polymers which form an extracellular liquid crystal-like composite. This composite has a number of functions associated with plant development and morphogenesis. On the other hand, cell wall polymers are a source of food and fiber, and may be also related to industrial problems such as interference of sucrose crystallization. Besides cellulose, monocots such as sugar cane contain mixed linkage glucan, glucuronoarabinoxylan and some xyloglucan as the principal hemicelluloses and rhamnogalacturonan branched with different types of arabinogalactan as pectins. The celI wall proteins can be divided into three groups: structural, enzymes and expansins. The structural proteins are named extensins and are glycine and hydroxyproline rich proteins. Cell wall hydrolases are a major class of cell wall proteins and include endo-β-glucanases, xyloglucan endo-β-transglycosilases, β-(1-3),(1,4)-glucanases, β-xylanases, endo-β-mannanases, α-galactosidases, α-arabinosidases amongst the hemicellulases and endo-polygalacturonases, exo-β-galactosidases and alfa-arabinosidases as pectinases. A third group is the expansins which are polysaccharide binding proteins with no enzymatic activity, but extremely important for cell expansion. These groups of extracellular carbohydrates and proteins are somehow related with all developmental processes within the plant (since virtually all plant cells have a cell wall) and knowing that these genes are present in sugar cane tissues will certainly be a valuable tool to be used in future studies of cell wall related gene expression during development and senescence and also to be used in conjunction with other gene sequences that are under current investigation at DATA MINING, to understand key processes of sugar cane plant development. We are currently studying the composition of the ceII polysaccharides present in sugar cane juices and its correlation with problems in industrial sucrose precipitation. Also, in a tissue printing experiment, we used a purified antibody raised against β-galactosidase from lupin (a dicot) and found cross reactions into sugar cane stem. On this basis, this proposal has the aim of searching for the genes that code for cell wall related proteins within the three groups mentioned above. To perform the annotations we intend have the help of the undergraduate students Fabio Daile Molle and Tatiana Cotelesse, who have been trained in our lab for six months on cell wall hydrolases purification and action on cell wall polysaccharides. Other PhD and MSc students whose theses themes are related to cell wall proteins in Brazilian native trees, will also help with the interpretation of the results. (AU)