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Mechanisms of thaxtomin A-induced root toxicity revealed by a thaxtomin A sensitive Arabidopsis mutant (ucu2-2/gi-2)


Tegg, RS and Shabala, S and Cuin, TA and Wilson, CR, Mechanisms of thaxtomin A-induced root toxicity revealed by a thaxtomin A sensitive Arabidopsis mutant (ucu2-2/gi-2), Plant Cell Reports, 35, (2) pp. 347-356. ISSN 0721-7714 (2016) [Refereed Article]

Copyright Statement

Copyright 2015 Springer-Verlag Berlin Heidelberg

DOI: doi:10.1007/s00299-015-1888-4


Thaxtomin A (TA) is a cellulose biosynthetic inhibitor (CBI) that promotes plant cell hypertrophy and cell death. Electrophysiological analysis of steady-state K+ and Ca2+ fluxes in Arabidopsis thaliana roots pretreated with TA for 24 h indicated a disturbance in the regulation of ion movement across the plant cell membrane. The observed inability to control solute movement, recorded in rapidly growing meristematic and elongation root zones, may partly explain typical root toxicity responses to TA treatment. Of note, the TA-sensitive mutant (ucu2-2/gi-2) was more susceptible with K+ and Ca2+ fluxes altered between 1.3 and eightfold compared to the wild-type control where fluxes altered between 1.2 and threefold. Root growth inhibition assays showed that the ucu2-2/gi-2 mutant had an increased sensitivity to the auxin 2,4-D, but not IAA or NAA; it also had increased sensitivity to the auxin efflux transport inhibitor, 1-naphthylphthalamic acid (NPA), but not 2,3,5- Triiodobenzoic acid (TIBA), when compared to the WT. The NPA sensitivity data were supported by electrophysiological analysis of H+ fluxes in the mature (but not elongation) root zone. Increased sensitivity to the CBI, isoxaben (IXB), but not dichlobenil was recorded. Increased sensitivity to both TA and IXB corresponded with higher levels of accumulation of these toxins in the root tissue, compared to the WT. Further root growth inhibition assays showed no altered sensitivity of ucu2-2/gi-2 to two other plant pathogen toxins, alternariol and fusaric acid. Identification of a TA-sensitive Arabidopsis mutant provides further insight into how this CBI toxin interacts with plant cells.

Item Details

Item Type:Refereed Article
Keywords:thaxtomin A, auxin transport inhibitors, NPA, TIBA, isoxaben, cellulose biosynthetic inhibitor, ion fluxes, plasma membrane
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Horticultural production
Research Field:Horticultural crop protection (incl. pests, diseases and weeds)
Objective Division:Plant Production and Plant Primary Products
Objective Group:Horticultural crops
Objective Field:Field grown vegetable crops
UTAS Author:Tegg, RS (Dr Robert Tegg)
UTAS Author:Shabala, S (Professor Sergey Shabala)
UTAS Author:Cuin, TA (Dr Tracey Cuin)
UTAS Author:Wilson, CR (Professor Calum Wilson)
ID Code:104140
Year Published:2016
Web of Science® Times Cited:2
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2015-11-03
Last Modified:2018-07-09

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