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Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species

Citation

Chakraborty, K and Bose, J and Shabala, L and Shabala, S, Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species, Journal of Experimental Botany, 67, (15) pp. 4611-4625. ISSN 0022-0957 (2016) [Refereed Article]


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The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. Licensed under Creative Commons Attribution 3.0 unported (CC BY 3.0) https://creativecommons.org/licenses/by/3.0/

DOI: doi:10.1093/jxb/erw236

Abstract

Brassica species are known to possess significant inter and intraspecies variability in salinity stress tolerance, but the cell-specific mechanisms conferring this difference remain elusive. In this work, the role and relative contribution of several key plasma membrane transporters to salinity stress tolerance were evaluated in three Brassica species (B. napus , B. juncea , and B. oleracea) using a range of electrophysiological assays. Initial root growth assay and viability staining revealed that B. napus was most tolerant amongst the three species, followed by B. juncea and B. oleracea . At the mechanistic level, this difference was conferred by at least three complementary physiological mechanisms: (i) higher Na+ extrusion ability from roots resulting from increased expression and activity of plasma membrane SOS1-like Na+/H+ exchangers; (ii) better root K+ retention ability resulting from stress-inducible activation of H+-ATPase and ability to maintain more negative membrane potential under saline conditions; and (iii) reduced sensitivity of B. napus root K+-permeable channels to reactive oxygen species (ROS). The last two mechanisms played the dominant role and conferred most of the differential salt sensitivity between species. Brassica napus plants were also more efficient in preventing the stress-induced increase in GORK transcript levels and up-regulation of expression of AKT1 , HAK5, and HKT1 transporter genes. Taken together, our data provide the mechanistic explanation for differential salt stress sensitivity amongst these species and shed light on transcriptional and post-translational regulation of key ion transport systems involved in the maintenance of the root plasma membrane potential and cytosolic K/Na ratio as a key attribute for salt tolerance in Brassica species.

Item Details

Item Type:Refereed Article
Keywords:ROS, potassium retention, salinity tolerance, ion homeostasis, membrane potential, potassium retention
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Horticultural Crops
Objective Field:Vegetables
Author:Chakraborty, K (Dr Koushik Chakraborty)
Author:Bose, J (Dr Jayakumar Bose)
Author:Shabala, L (Dr Lana Shabala)
Author:Shabala, S (Professor Sergey Shabala)
ID Code:113388
Year Published:2016
Web of Science® Times Cited:9
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2016-12-22
Last Modified:2017-11-02
Downloads:47 View Download Statistics

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