Poster: Vegetative Development

Abs # 437: Analysis of a lipase gene that is expressed during the programmed cell death of tracheary elements

Presenter:	Kuriyama, Hideo , h-kuri@postman.riken.go.jp
Authors	Kuriyama, Hideo  (A)   Horiguchi, Gorou  (A)   Sassa, Naomi  (A)   Endo, Satoshi  (A)   Fukuda, Hiroo  (A) (B)  Demura, Taku  (A)
Affiliations:	(A): Plant Science Center, RIKEN (The Institute of Physical and Chemical Research) (B): Department of Biological Sciences, Graduate School of Science, University of Tokyo

Xylem vessels and tracheides in vascular plants consist of tracheary elements (TEs). Differentiating TEs undergo programmed cell death and autolysis to function as hollow tubular cell corpses. We are analyzing mechanisms of this TE PCD/autolysis using a culture system by which very efficient TE differentiation can be induced from newly isolated Zinnia elegans L. mesophyll cells. We prepared ca. 9000 ESTs from mRNAs of Zinnia cells cultured for 48 and 60 hours, which include many differentiating TEs, and subjected them to an expression analysis by cDNA microarray. These experiments identified a clone encoding a homologous sequence of lipase genes. To date, little is known about lipid degradation during plant PCD. Thus, we are planning to perform a series of molecular biological analyses to reveal functions of the corresponding gene. RNA gel-blot analysis confirms its transient and differentiation-specific expression patterns in cultures. In situ hybridization analysis indicates that the corresponding gene is expressed only in living TEs of shoot apical tissues of Zinnia seedlings. We speculate that this gene is involved in lipid hydrolysis during TE PCD/autolysis.