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Type: Journal article
Title: 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
Other Titles: 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
Author: Chakraborty, K.
Bose, J.
Shabala, L.
Shabala, S.
Citation: Journal of Experimental Botany, 2016; 67(15):4611-4625
Publisher: Oxford University Press
Issue Date: 2016
ISSN: 0022-0957
Statement of
Koushik Chakraborty, Jayakumar Bose, Lana Shabala and Sergey Shabala
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.
Keywords: H⁺-ATPase
ion homeostasis
membrane potential
potassium retention
ROS detoxification
sodium exclusion
tissue tolerance
Description: Advance Access publication 23 June 2016
Rights: © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
DOI: 10.1093/jxb/erw236
Grant ID: ARC
Appears in Collections:Agriculture, Food and Wine publications
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