PRIMARY STEM DEVELOPMENT IN Arabidopsis thaliana: A COMBINED TRANSCRIPTOME AND PROTEOME LEVEL ANALYSIS

¹ Biotechnology Laboratory, UBC, Vancouver, B.C., Canada

² Dept. of Biochemistry, Univ. of Victoria, B.C., Canada

³ Dept. of Forest Sciences, UBC, Vancouver, B.C., Canada

⁴ Dept. of Botany, UBC, Vancouver, B.C., Canada

Arabidopsis thaliana has been shown to undergo secondary growth and to develop a vascular cambium with structural and ultrastructural characteristics similar to those found in angiosperm trees. It is clear from these studies that the genes required for wood formation are present and functional in Arabidopsis, and as such, Arabidopsis is being used as a model for understanding wood formation by our group. Fibre differentiation is also pronounced in developing bolting stems (rachis) and the different stages of vascular and interfascicular fibre differentiation can be separated along the axis of the rachis. To understand the metabolic, developmental, and regulatory events that occur along this axis in Arabidiopsis, sections from bolting stems, representing different developmental stages of vascular bundle and interfascicular fibre differentiation, were used for global transcript and protein profiling. We have developed an Arabidopsis near full genome longmer microarray that represents most Arabidopsis genes (more than 26,000 oligos). This microarray was used to investigate differential gene expression patterns during stem/fibre differentiation and data was analyzed by cluster analysis. 2D-gel analyses of proteins from the same material revealed significant differential display of several proteins. Subsequent protein identification by MALDI and correlation between transcript and protein profiling will be discussed in detail. We anticipate that results from these studies will lead to candidate gene mining for wood formation and xylem differentiation in poplar and spruce.