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Conditioning of roots with hypoxia increases aluminum and acid stress tolerance by mitigating activation of K+ efflux channels by ROS in barley: insights into cross-tolerance mechanisms

Citation

Ma, Y and Zhu, M and Shabala, L and Zhou, M and Shabala, S, Conditioning of roots with hypoxia increases aluminum and acid stress tolerance by mitigating activation of K+ efflux channels by ROS in barley: insights into cross-tolerance mechanisms, Plant and Cell Physiology, 57, (1) pp. 160-173. ISSN 0032-0781 (2016) [Refereed Article]

Copyright Statement

Copyright The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved.

DOI: doi:10.1093/pcp/pcv175

Abstract

Aluminum (Al) is prevalent in soils, but Al toxicity is manifested only under acid conditions. It causes severe damages to the root system. Short-term waterlogging stress can occur simultaneously with Al toxicity in areas with high rainfall or an inappropriate irrigation pattern. Barley (Hordeum vulgare L.) is one of the most Al-sensitive small-grained cereals. In this work, we have investigated effects of short-term treatments with hypoxia and phenolic acid (two major constraints in waterlogged soils) on root sensitivity to low-pH and Al stresses. We showed that hypoxia-primed roots maintained higher cell viability when exposed to low-pH/Al stress, in both elongation and mature root zones, and possessed superior ability to retain K+ in response to low-pH/Al stresses. These priming effects were not related to higher H+-ATPase activity and better membrane potential maintenance, and could not be explained by the increased expression levels of HvHAK1, which mediates high-affinity K+ uptake in roots. Instead, hypoxia-conditioned roots were significantly less sensitive to H2O2 treatment, indicated by the 10-fold reduction in the magnitude of K+ efflux changes. This suggested that roots pre-treated with hypoxia desensitized reactive oxygen species (ROS)-inducible K+ efflux channels in root epidermis, most probably via enhanced antioxidative capacity. A possible role for Ca2+ in stress-induced ROS signaling pathways is also discussed. Overall, our results report, for the first time, the phenomenon of cross-protection between hypoxia and low-pH/Al stresses, and causally link it to the cellís ability to maintain cytosolic K+ homeostasis.

Item Details

Item Type:Refereed Article
Keywords:barley, Al tolerance, ROS, aluminum toxicity, calcium, cross-tolerance, hypoxia, potassium, reactive oxygen species
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:Winter Grains and Oilseeds
Objective Field:Barley
Author:Ma, Y (Ms Yanling Ma)
Author:Zhu, M (Ms Min Zhu)
Author:Shabala, L (Dr Lana Shabala)
Author:Zhou, M (Associate Professor Meixue Zhou)
Author:Shabala, S (Professor Sergey Shabala)
ID Code:106564
Year Published:2016
Web of Science® Times Cited:1
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2016-02-14
Last Modified:2017-11-06
Downloads:0

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