Tegg, RS and Shabala, SN and Cuin, TA and Davies, NW and Wilson, CR, Enhanced resistance to the cellulose biosynthetic inhibitors, thaxtomin A and isoxaben in Arabidopsis thaliana mutants, also provides specific co-resistance to the auxin transport inhibitor, 1-NPA, BMC Plant Biology, 13 Article 76. ISSN 1471-2229 (2013) [Refereed Article]
Copyright 2013 Tegg et al; licensee Biomed Central Ltd.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Official URL: http://www.biomedcentral.com/1471-2229/13/76
Background: Thaxtomin A (TA) is a phytotoxin produced by plant pathogenic Streptomyces spp. responsible for potato common scab. TA inhibits cellulose biosynthesis in expanding plant tissues and is essential for disease induction. Auxin treatment of various plant tissues has been repeatedly demonstrated to inhibit TA toxicity and to reduce common scab. This work utilises Arabidopsis thaliana mutants with resistance to cellulose biosynthesis inhibitors (CBIs) to investigate the interaction between TA, other CBIs and auxins.
Results: Three CBI resistant A. thaliana mutants; txr1-1 (tolerance to TA), ixr1-1 (tolerance to isoxaben - IXB) and KOR1 (cellulose deficiency), showed no altered root growth response to treatment with natural or synthetic auxins, nor with the auxin efflux transport inhibitor 2,3,5-Triiodobenzoic acid (TIBA). However, all mutants had significantly enhanced tolerance to 1-napthylphthalamic acid (NPA), another auxin efflux transport inhibitor, which blocks polar auxin transport at a site distinct from TIBA. NPA tolerance of txr1-1 and ixr1-1 was further supported by electrophysiological analysis of net H+ fluxes in the mature, but not elongation zone of roots. All three mutants showed increased tolerance to IXB, but only txr1-1 showed tolerance to TA. No mutant showed enhanced tolerance to a third CBI, dichlobenil (DCB).
Conclusions: We have demonstrated that plant tolerance to TA and IXB, as well as cell wall synthesis modifications in roots, have resulted in specific co-resistance to NPA but not TIBA. This suggests that CBI resistance has an impact on polar auxin efflux transport processes associated with the NPA binding protein. We also show that NPA inhibitory response in roots occurs in the mature root zone but not the elongation zone. Responses of mutants to CBIs indicate a similar, but not identical mode of action of TA and IXB, in contrast to DCB.
|Item Type:||Refereed Article|
|Keywords:||1-napthylphthalamic acid - NPA, 2,3,5-triiodobenzoic acid - TIBA, thaxtomin A, Iisoxaben, dichlobenil, cellulose biosynthetic inhibitor, common scab, ion fluxes, plasma membrane|
|Research Division:||Agricultural and Veterinary Sciences|
|Research Group:||Crop and Pasture Production|
|Research Field:||Crop and Pasture Improvement (Selection and Breeding)|
|Objective Division:||Plant Production and Plant Primary Products|
|Objective Group:||Other Plant Production and Plant Primary Products|
|Objective Field:||Plant Production and Plant Primary Products not elsewhere classified|
|Author:||Tegg, RS (Dr Robert Tegg)|
|Author:||Shabala, SN (Professor Sergey Shabala)|
|Author:||Cuin, TA (Dr Tracey Cuin)|
|Author:||Davies, NW (Associate Professor Noel Davies)|
|Author:||Wilson, CR (Associate Professor Calum Wilson)|
|Web of Science® Times Cited:||9|
|Deposited By:||Tasmanian Institute of Agriculture|
|Downloads:||257 View Download Statistics|
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