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Tissue-specific regulation of Na+ and K+ transporters explains genotypic differences in salinity stress tolerance in rice

Citation

Liu, J and Shabala, SN and Shabala, L and Zhou, M and Meinke, H and Venkataraman, G and Chen, Z and Zeng, F and Zhao, Q, Tissue-specific regulation of Na+ and K+ transporters explains genotypic differences in salinity stress tolerance in rice, Frontiers in Plant Science, 10 Article 1361. ISSN 1664-462X (2019) [Refereed Article]


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DOI: doi:10.3389/fpls.2019.01361

Abstract

Rice (Oryza sativa) is a staple food that feeds more than half the world population. As rice is highly sensitive to soil salinity, current trends in soil salinization threaten global food security. To better understand the mechanistic basis of salinity tolerance in rice, three contrasting rice cultivars - Reiziq (tolerant), Doongara (moderately tolerant), and Koshihikari (sensitive) - were examined and the differences in operation of key ion transporters mediating ionic homeostasis in these genotypes were evaluated. Tolerant varieties had reduced Na+ translocation from roots to shoots. Electrophysiological and quantitative reverse transcription PCR experiments showed that tolerant genotypes possessed 2-fold higher net Na+ efflux capacity in the root elongation zone. Interestingly, this efflux was only partially mediated by the plasma membrane Na+/H+ antiporter (OsSOS1), suggesting involvement of some other exclusion mechanisms. No significant difference in Na+ exclusion from the mature root zones was found between cultivars, and the transcriptional changes in the salt overly sensitive signaling pathway genes in the elongation zone were not correlated with the genetic variability in salinity tolerance amongst genotypes. The most important hallmark of differential salinity tolerance was in the ability of the plant to retain K+ in both root zones. This trait was conferred by at least three complementary mechanisms: (1) its superior ability to activate H+-ATPase pump operation, both at transcriptional and functional levels; (2) reduced sensitivity of K+ efflux channels to reactive oxygen species; and (3) smaller upregulation in OsGORK and higher upregulation of OsAKT1 in tolerant cultivars in response to salt stress. These traits should be targeted in breeding programs aimed to improve salinity tolerance in commercial rice cultivars.

Item Details

Item Type:Refereed Article
Keywords:root, H+-ATPase, potassium, sodium, Na+, H+ exchanger, reactive oxygen species
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Summer Grains and Oilseeds
Objective Field:Rice
UTAS Author:Liu, J (Ms Juan Liu)
UTAS Author:Shabala, SN (Professor Sergey Shabala)
UTAS Author:Shabala, L (Associate Professor Lana Shabala)
UTAS Author:Zhou, M (Professor Meixue Zhou)
UTAS Author:Meinke, H (Professor Holger Meinke)
ID Code:136641
Year Published:2019
Deposited By:Agriculture and Food Systems
Deposited On:2020-01-11
Last Modified:2020-01-14
Downloads:0

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