Cell death associated release of volatile organic sulphur compounds with antioxidant properties in chemical-challenged tobacco BY-2 suspension cultured cells

Elena T Iakimova,Zhenia P Yordanova,Simona M Cristescu,Frans F.M Harren,Ernst J Woltering

doi:10.1016/j.jplph.2020.153223

Abstract

The production of volatile organic compounds (VOCs) during programmed cell death (PCD) is still insufficiently studied and their implication in the process is not well understood. The present study demonstrates that the release of VOSCs with presumed antioxidant capacity (methanethiol, dimethylsulfide and dimethyldisulfide) accompanies the cell death in chemical-stressed tobacco BY-2 suspension cultured cells. The cells were exposed to cell death inducers of biotic nature mastoparan (MP, wasp venom) and camptothecin (CPT, alkaloid), and to the abiotic stress agent CdSO4. The VOCs emission was monitored by proton-transfer reaction mass spectrometry (PTR-MS). The three chemicals induced PCD expressing apoptotic-like phenotype. The identified VOSCs were emitted in response to MP and CPT but not in presence of Cd. The VOSCs production occurred within few hours after the administration of the elicitors, peaked up when 20–50 % of the cells were dead and further levelled off with cell death advancement. This suggests that VOSCs with antioxidant activity may contribute to alleviation of cell death-associated oxidative stress at medium severity of cell death in response to the stress factors of biotic origin. The findings provide novel information about cell death defence mechanisms in chemical-challenged BY-2 cells and show that PCD related VOSCs synthesis depends on the type of inducer.

Highlights

Volatile organic compounds (VOCs) represent a diversity of bio generated low molecular mass metabolites with high vapor pressure
The living cells appeared fluorescein diacetate (FDA) positive with intact (FDA negative) vacuole and diffuse nucleus (Fig. 2 A); the dead cells were with propidium iodide (PI) positive condensed nucleus (Fig. 2 B) and shrunken protoplast retracted from cell wall (Fig. 2 C)
The present study demonstrates that programmed cell death (PCD) in tobacco Bright Yellow -2 (BY-2) suspension cultured cells exposed to the cell death elicitors of biotic origin MP and CPT is accompanied by the emission of volatile organic sulphur compounds (VOSCs) with presumed antioxidant capacity, identified as MT, DMS and DMDS

Summary

Introduction

Volatile organic compounds (VOCs) represent a diversity of bio generated low molecular mass metabolites with high vapor pressure. Among them dimethylsulfoniopropionate (DMSP), dimethylsulfide (DMS), dimethyldisulfide (DMDS) and methanethiol (MT) are suggested to effectively scavenge reactive oxygen species (ROS) and under conditions of severe physiological stress to potentiate the survival rate of algal and other plant cells (Sunda et al, 2002). The formation of these VOCs is interconnected.

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Conclusion