Short-term salinity stress in tobacco plants leads to the onset of animal-like PCD hallmarks in planta in contrast to long-term stress

Abstract

Recent results have identified mitochondria as centers of stress-induced generation of reactive oxygen species in plants. Depolarization of plant mitochondrial membrane during stress results the release of programmed cell death (PCD)-inducing factors in the cytosol in a fashion similar to the onset of animal-like PCD. Herein, we report significant similarities of animal-like PCD and salinity stress-induced plant PCD. Short-term salinity stress (3 h) led to depolarization of the mitochondrial membrane, release of cytochrome c (CYT-c), which was visualized using a contemporary molecular technique, activation of caspase-3 type proteases and the onset of PCD in wild type tobacco plants, Nicotiana tabacum cv. Petit Havana. However, PCD was not manifested during long-term salinity stress (24 h). Interestingly long-term salinity stress led to necrotic-like features, which were accompanied by collapse of respiration, reduction of key components of the respiratory chain, such as CYT-c and alternative oxidase, ATP depletion and high proteolytic activity. The results suggest that salinity stress of tobacco plants in planta leads to the onset of animal-like PCD only during the early stages post-stress, while long-term stress leads to necrotic-like features.

High Yields of Hydrogen Production Induced by Meta-Substituted Dichlorophenols Biodegradation from the Green Alga Scenedesmus obliquus

“…Measurements for COX capacity were carried out using the inhibitors SHAM and PG, for AOX capacity using KCN and PG, while for PTOX activity using KCN and SHAM, as described by Andronis and Roubelakis-Angelakis [33]. Alternatively, PTOX activity can be measured using SHAM for AOX inhibition followed by PG insertion for estimating the residual PTOX activity, according to Cournac et al [34], [35].…”

Alternative Oxidase: A Mitochondrial Respiratory Pathway to Maintain Metabolic and Signaling Homeostasis during Abiotic and Biotic Stress in Plants

“…In tobacco, it was shown that short-term salt stress resulted in a strong elevation of leaf O 2 − , with only a more moderate increase in H 2 O 2 [184]. …”

“…The induction of AOX transcript and protein by salt stress has been shown in a number of plant species including Arabidopsis [185,186], pea [187], tobacco [184] and poplar [188]. In a callus culture of Arabidopsis , evidence supports a role for ethylene in the induction of AOX capacity by salt stress [189].…”

Polyamines as redox homeostasis regulators during salt stress in plants

“…Salt stress led to high cytosolic [Ca 2+ ] which promoted the opening of mitochondrial permeability transition pore (MPTP) and PCD induction in tobacco protoplasts (Lin et al, 2005). Mitochondrial depolarization and cytochrome-c release is a hallmark event during the PCD (Logan, 2008;Andronis and Roubelakis-Angelakis, 2010). Takahashi's group showed that 0.5 mM Spm pretreatment of tobacco leaf discs induced expression of the Salicylic acid (SA)-induced Protein Kinase Frontiers in Environmental Science | www.frontiersin.org(SIPK) and Wound-Induced Protein Kinase (WIPK) and caused mitochondrial dysfunction similar to the one observed during PCD in tobacco leaves (Takahashi et al, 2003).…”