OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 149/2/775    most recent pp.108.132720v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Senatore, A. Articles by Greenwood, J. S. Search for Related Content PubMed PubMed Citation Articles by Senatore, A. Articles by Greenwood, J. S. Agricola Articles by Senatore, A. Articles by Greenwood, J. S.

CELL BIOLOGY AND SIGNAL TRANSDUCTION

Ricinosomes Predict Programmed Cell Death Leading to Anther Dehiscence in Tomato^{1,[C],[W],[OA]}

Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1

Successful development and dehiscence of the anther and release of pollen are dependent upon the programmed cell death (PCD) of the tapetum and other sporophytic tissues. Ultrastructural examination of the developing and dehiscing anther of tomato (Solanum lycopersicum) revealed that cells of the interlocular septum, the connective tissue, the middle layer/endothecium, and the epidermal cells surrounding the stomium all exhibit features consistent with progression through PCD. Ricinosomes, a subset of precursor protease vesicles that are unique to some incidents of plant PCD, were also present in all of these cell types. These novel organelles are known to harbor KDEL-tailed cysteine proteinases that act in the final stages of corpse processing following cell death. Indeed, a tomato KDEL-tailed cysteine proteinase, SlCysEP, was identified and its gene was cloned, sequenced, and characterized. SlCysEP transcript and protein were restricted to the anthers of the senescing tomato flower. Present in the interlocular septum and in the epidermal cells surrounding the stomium relatively early in development, SlCysEP accumulates later in the sporophytic tissues surrounding the locules as dehiscence ensues. At the ultrastuctural level, immunogold labeling localized SlCysEP to the ricinosomes within the cells of these tissues, but not in the tapetum. It is suggested that the accumulation of SlCysEP and the appearance of ricinosomes act as very early predictors of cell death in the tomato anther.

² Present address: B1-173, Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: John S. Greenwood (jgreenwo{at}uoguelph.ca).

^[C] Some figures in this article are displayed in color online but in black and white in the print edition.

^[W] The online version of this article contains Web-only data.

^[OA] Open Access articles can be viewed online without a subscription.

www.plantphysiol.org/cgi/doi/10.1104/pp.108.132720

^* Corresponding author; e-mail jgreenwo{at}uoguelph.ca.

Received November 19, 2008; accepted December 15, 2008; published December 19, 2008.

This article has been cited by other articles:

				J. Mukoko Bopopi, O. M. Vandeputte, K. Himanen, A. Mol, Q. Vaessen, M. El Jaziri, and M. Baucher Ectopic expression of PtaRHE1, encoding a poplar RING-H2 protein with E3 ligase activity, alters plant development and induces defence-related responses J. Exp. Bot., November 5, 2009; (2009) erp305v1. [Abstract] [Full Text] [PDF]