Abstract
In Arabidopsis, the root vasculature contains two files of protoxylem and of protophloem elements, which are alternately located on the opposite sides of the vascular cylinder. Metaxylem develops centripetally from the protoxylem poles, creating the continuous xylem plate. Consequently, phloem is separated into two regions by the xylem plate. In order to clarify the mechanism of vascular development and the xylem-phloem patterning, genes involved in the formation of the procambium, precursor tissue of vascular elements, should be identified. We screened for enhancer-trap lines expressing reporter GFP in the procambium and obtained 376 procambium/vasculature lines. So far, three novel genes expressed in the root procambium in the cell-type-specific manner were identified. They are expressed in xylem and protophloem cell files, in metaxylem cell files, and in phloem and adjacent pericycle cell files, respectively. Expression patterns of GFP in the aforementioned lines, and of the isolated genes will be presented.
