Allyl isothiocyanate affects the cell cycle of Arabidopsis thaliana.

Signe E Ã…Sberg,Anders Ã˜Verby,Atle M Bones

doi:10.3389/fpls.2015.00364

Signe E Ã…Sberg, Anders Ã˜Verby + Show 1 more

Open Access

https://doi.org/10.3389/fpls.2015.00364

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Abstract

Isothiocyanates (ITCs) are degradation products of glucosinolates present in members of the Brassicaceae family acting as herbivore repellents and antimicrobial compounds. Recent results indicate that allyl ITC (AITC) has a role in defense responses such as glutathione depletion, ROS generation and stomatal closure. In this study we show that exposure to non-lethal concentrations of AITC causes a shift in the cell cycle distribution of Arabidopsis thaliana leading to accumulation of cells in S-phases and a reduced number of cells in non-replicating phases. Furthermore, transcriptional analysis revealed an AITC-induced up-regulation of the gene encoding cyclin-dependent kinase A while several genes encoding mitotic proteins were down-regulated, suggesting an inhibition of mitotic processes. Interestingly, visualization of DNA synthesis indicated that exposure to AITC reduced the rate of DNA replication. Taken together, these results indicate that non-lethal concentrations of AITC induce cells of A. thaliana to enter the cell cycle and accumulate in S-phases, presumably as a part of a defensive response. Thus, this study suggests that AITC has several roles in plant defense and add evidence to the growing data supporting a multifunctional role of glucosinolates and their degradation products in plants.

Highlights

Glucosinolates are a group of secondary metabolites commonly found in members of the Brassicaceae family, including the cruciferous vegetables that have been part of the human diet for thousands of years (Halkier and Gershenzon, 2006)
We investigated the effect of non-lethal, growth inhibiting concentrations of vapor phase of allyl ITC (AITC) on the cell cycle of A. thaliana
As cells of A. thaliana can take up to 48 h to progress through the cell cycle, seedlings were exposed to AITC for 36, 48, and 60 h, ensuring enough time for all cells to go through the cell cycle at least once (Beemster et al, 2002)

Summary

Introduction

Glucosinolates are a group of secondary metabolites commonly found in members of the Brassicaceae family, including the cruciferous vegetables that have been part of the human diet for thousands of years (Halkier and Gershenzon, 2006). To prevent constitutive production and potential damage to the plant cells, myrosinase is stored separately from its substrates in specialized cells called myrosin cells (Bones and Iversen, 1985; Bones and Rossiter, 1996; Halkier and Gershenzon, 2006; Kissen et al, 2009b; Wittstock and Burow, 2010). The hydrolysis products are produced upon attack by herbivores or pathogens when damage to the plant tissue and disruption of the cells causes myrosinase to come into contact with glucosinolates (Bones and Rossiter, 1996, 2006; Halkier and Gershenzon, 2006; Kissen et al, 2009b; Wittstock and Burow, 2010). The small sulfur-containing isothiocyanates (ITCs) are among the biodegradation

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