Imaging plant cell death: GFP-Nit1 aggregation marks an early step of wound and herbicide induced cell death

Journal Article · 29 March 2005 · BMC Plant Biology

DOI: https://doi.org/10.1186/1471-2229-5-4 · OSTI ID:1626505

Cutler, Sean R. ^[1]; Somerville, Chris R. ^[2]

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1. Univ. of Toronto, ON (Canada). Dept. of Botany; DOE/OSTI
2. Carnegie Inst., Stanford, CA (United States). Dept. of Plant Biology

Background: A great deal is known about the morphological endpoints of plant cell death, but relatively little is known about its sequence of events and / or its execution at the biochemical level. Live cell imaging using GFP-tagged markers is a powerful way to provide dynamic portraits of a cellular process that can in turn provide a descriptive foundation valuable for future biochemical and genetic investigations. Results: While characterizing a collection of random GFP-protein fusion markers we discovered that mechanical wounding induces rapid aggregation of a GFP-Nitrilase 1 fusion protein in Arabidopsis cells directly abutting wound sites. Time-lapse imaging of this response shows that the aggregation occurs in cells that subsequently die 30 – 60 minutes post-wounding, indicating that GFP-Nit1 aggregation is an early marker of cell death at wound sites. Time-lapse confocal imaging was used to characterize wound-induced cell death using GFP-Nit1 and markers of the nucleus and endoplasmic reticulum. These analyses provide dynamic portraits of well-known death-associated responses such as nuclear contraction and cellular collapse and reveal novel features such as nuclear envelope separation, ER vesiculation and loss of nuclear-lumen contents. As a parallel system for imaging cell death, we developed a chemical method for rapidly triggering cell death using the herbicides bromoxynil or chloroxynil which cause rapid GFP-Nit1 aggregation, loss of nuclear contents and cellular collapse, but not nuclear contraction, separating this response from others during plant cell death. Conclusion: Our observations place aggregation of Nitrilase 1 as one of the earliest events associated with wound and herbicide-induced cell death and highlight several novel cellular events that occur as plant cells die. Our data create a detailed descriptive framework for future investigations of plant cell death and provide new tools for both its cellular and biochemical analysis.

• Research Organization: Carnegie Inst. of Science, Stanford, CA (United States); Univ. of Toronto, ON (Canada)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER). Biological Systems Science Division
• OSTI ID: 1626505
• Journal Information: BMC Plant Biology, Journal Name: BMC Plant Biology Journal Issue: 1 Vol. 5; ISSN 1471-2229
• Publisher: BioMed CentralCopyright Statement
• Country of Publication: United States
• Language: English