A genomic approach to investigate developmental cell death in woody tissues of Populus trees

Charleen Moreau,Maribel García Lorenzo,Peter Nilsson,Bo Segerman,Stefan Jansson,Christiane Funk,Nikolay Aksenov,Hannele Tuominen

doi:10.1186/gb-2005-6-4-r34

Abstract

A Populus EST dataset was used for in silico transcript profiling of the programmed death of the xylem fibres in woody tissues of Populus stem. The analysis suggests the involvement of two novel extracellular serine proteases, nodulin-like proteins and an AtOST1 (Arabidopsis thaliana OPEN STOMATA 1) homolog in signaling fiber-cell death.

Highlights

Poplar (Populus sp.) has emerged as the main model system for molecular and genetic studies of forest trees
The programmed cell death (PCD) of xylem has been analyzed in detail in an in vitro system of Zinnia elegans, in which mesophyll cells of Zinnia transdifferentiate into xylem vessels commonly called as tracheary elements in a semi-synchronized manner [3]
Xylem fibers are formed in Arabidopsis only after two to three months of growth, which is equivalent to the time required to grow Populus trees to a size that allows collection of large amounts of woody tissues from the stem

Summary

Introduction

Poplar (Populus sp.) has emerged as the main model system for molecular and genetic studies of forest trees. A Populus expressed sequence tag (EST) database (POPULUSDB) was previously created from 19 cDNA libraries each originating from different Populus tree tissues, and opened to the public in September 2004. We used this dataset for in silico transcript profiling of a particular process in the woody tissues of the Populus stem: the programmed death of xylem fibers. In Zinnia cells, irreversible differentiation into tracheary elements is marked by the accumulation of hydrolytic enzymes in the vacuole and deposition of the secondary cell walls, followed by tonoplast disruption, release of the vacuolar proteases and nucleases into the cytoplasm, and the autolytic loss of cell contents [2,4]. The Zinnia system has not allowed analysis of the different cell types of the xylem, such as the fibers

Methods

Results

Conclusion