Tracheary Element Differentiation Simon Turner, Patrick Gallois, and David Brown University of Manchester, Faculty of Life Sciences, Manchester M13 9PT, United Kingdom; email: simon.turner@manchester.ac.uk Annu. Rev. Plant Biol. 2007. 58:407–33 The Annual Review of Plant Biology is online at plant.annualreviews.org This article’s doi: 10.1146/annurev.arplant.57.032905.105236 Copyright c  2007 by Annual Reviews. All rights reserved 1543-5008/07/0602-0407$20.00 Key Words xylem, secondary cell wall, programmed cell death, microtubules Abstract Tracheary elements (TEs) are cells in the xylem that are highly spe- cialized for transporting water and solutes up the plant. TEs undergo a very well-defined process of differentiation that involves specifica- tion, enlargement, patterned cell wall deposition, programmed cell death and cell wall removal. This process is coordinated such that adjacent TEs are joined together to form a continuous network. Ex- pression studies on model systems as diverse as trees and cell cultures have contributed to providing a flood of candidate genes with po- tential roles in TE differentiation. Analysis of some of these genes has yielded important information on processes such as patterned secondary cell wall deposition. The current challenge is to continue this functional analysis and to use these data and build an integrated model of TE development. 407 Annu. Rev. Plant Biol. 2007.58:407-433. Downloaded from arjournals.annualreviews.org by Swedish University of Agricultural Sciences on 09/03/07. For personal use only.