A nitric oxide burst precedes apoptosis in angiosperm and gymnosperm callus cells and foliar tissues

Abstract

Leaves and callus of Kalanchoë daigremontiana and Taxus brevifolia were used to investigate nitric oxide-induced apoptosis in plant cells. The effect of nitric oxide (NO) was studied by using a NO donor, sodium nitroprusside (SNP), a nitric oxide-synthase (NOS) inhibitor, N:(G)-monomethyl-L-arginine (NMMA), and centrifugation (an apoptosis-inducing treatment in these species). NO production was visualized in cells and tissues with a specific probe, diaminofluorescein diacetate (DAF-2 DA). DNA fragmentation was detected in situ by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) method. In both species, NO was detected diffused in the cytosol of epidermal cells and in chloroplasts of guard cells and leaf parenchyma cells. Centrifugation increased NO production, DNA fragmentation and subsequent cell death by apoptosis. SNP mimicked centrifugation results. NMMA significantly decreased NO production and apoptosis in both species. The inhibitory effect of NMMA on NO production suggests that a putative NOS is present in Kalanchoë and Taxus cells. The present results demonstrated the involvement of NO on DNA damage leading to cell death, and point to a potential role of NO as a signal molecule in these plants.

An extensive microarray analysis of AAL-toxin-induced cell death in Arabidopsis thaliana brings new insights into the complexity of programmed cell death in plants

“…All these results together suggest that genes regulated by ethylene and ROS are important modulators of plant PCD. In recent years, NO has emerged as a versatile signalling molecule regulating a myriad of biological processes in plants, including cell death responses [31,32]. We showed that generation of NO is important for the enhancement of AAL-toxin-induced cell death as plants unable to synthesize NO were significantly compromised in the PCD response.…”

Nitric oxide: promoter or suppressor of programmed cell death?

“…1B): non-enzymatic conversion of nitrite to NO in the apoplast, nitrate reductase (NR)-dependent NO formation, and NOS-like activity that is arginine-dependent (Leitner et al, 2009). Decreased NO synthesis and PCD in the presence of NOS inhibitor suggested the involvement of an NOS-like enzyme in plants, but this enzyme remains enigmatic (Pedroso et al, 2000). One potential candidate for a plant NOS, AtNOA1/RIF1, was subsequently demonstrated not to exhibit NOS activity.…”

Regulation of Plant Glycine Decarboxylase byS-Nitrosylation and Glutathionylation

“…Fluorescence was visualized by confocal laser microscopy ( Fig. 1) as described (Foissner et al, 2000;Pedroso et al, 2000;Beligni et al, 2002;Yao et al, 2002). As a control, we applied carboxy-2-phenyl-4,4,5,5-tetramethylimidazolinone-3-oxide-1-oxyl (cPTIO), an NO scavenger that does not react with any ROS (Barchowsky et al, 1999).…”