Lotus tenuis tolerates combined salinity and waterlogging: maintaining O2 transport to roots and expression of an NHX1-like gene contribute to regulation of Na+ transport

Teakle, N.L., Amtmann, A. , Real, D. and Colmer, T.D. (2010) Lotus tenuis tolerates combined salinity and waterlogging: maintaining O2 transport to roots and expression of an NHX1-like gene contribute to regulation of Na+ transport. Physiologia Plantarum, 139(4), pp. 358-374. (doi: 10.1111/j.1399-3054.2010.01373.x)

Abstract

Salinity and waterlogging interact to reduce growth for most crop and pasture species. The combination of these stresses often cause a large increase in the rate of Na+ and Cl− transport to shoots; however, the mechanisms responsible for this are largely unknown. To identify mechanisms contributing to the adverse interaction between salinity and waterlogging, we compared two Lotus species with contrasting tolerances when grown under saline (200 mM NaCl) and O2-deficient (stagnant) treatments. Measurements of radial O2 loss (ROL) under stagnant conditions indicated that more O2 reaches root tips of Lotus tenuis, compared with Lotus corniculatus. Better internal aeration would contribute to maintaining Na+ and Cl− transport processes in roots of L. tenuis exposed to stagnant-plus-NaCl treatments. L. tenuis root Na+ concentrations after stagnant-plus-NaCl treatment (200 mM) were 17% higher than L. corniculatus, with 55% of the total plant Na+ being accumulated in roots, compared with only 39% for L. corniculatus. L. tenuis accumulated more Na+ in roots, presumably in vacuoles, thereby reducing transport to the shoot (25% lower than L. corniculatus). A candidate gene for vacuole Na+ accumulation, an NHX1-like gene, was cloned from L. tenuis and identity established via sequencing and yeast complementation. Transcript levels of NHX1 in L. tenuis roots under stagnant-plus-NaCl treatment were the same as for aerated NaCl, whereas L. corniculatus roots had reduced transcript levels. Enhanced O2 transport to roots enables regulation of Na+ transport processes in L. tenuis roots, contributing to tolerance to combined salinity and waterlogging stresses.

• Item Type: Articles
• Additional Information: The definitive version is available at www3.interscience.wiley.com
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Amtmann, Professor Anna
• Authors: Teakle, N.L., Amtmann, A., Real, D., and Colmer, T.D.
• Subjects: Q Science > QK Botany
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Physiologia Plantarum
• Publisher: Wiley-Blackwell
• ISSN: 0031-9317
• ISSN (Online): 1399-3054
• Published Online: 23 April 2010
• Copyright Holders: Copyright © 2010 Wiley-Blackwell
• First Published: First published in Physiologia Plantarum 139(4):358-374
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher