|SADE, NIR - University Of California, Davis
|RUBIO-WILHELMI, MARIA - University Of California
|KE, XIAOJUAN - University Of California, Davis
|BROTMAN, YARIV - Ben Gurion University Of Negev
|WRIGHT, MATTHEW - University Of California, Davis
|KHAN, IMRAN - University Of California, Davis
|DE SOUZA, WAGNER - University Of California, Davis
|BASSIL, ELIAS - University Of California, Davis
|VOGEL, JOHN - Department Of Energy Joint Genome
|BLUMWALD, EDUARDO - University Of California, Davis
Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2017
Publication Date: 1/10/2018
Citation: Sade, N., del Mar Rubio-Wilhelmi, M., Ke, X., Brotman, Y., Wright, M., Khan, I., De Souza, W., Bassil, E., Tobias, C.M., Thilmony, R.L., Vogel, J.P., Blumwald, E. 2018. Salt tolerance of two perennial grass Brachypodium sylvaticum accessions. Plant Molecular Biology. 96(3):305-314. https://doi.org/10.1007/s11103-017-0696-3.
Interpretive Summary: We studied the salt stress tolerance of two Brachypodium sylvaticum accessions isolated from different areas of the world (Norway and Tunisia) and characterized the mechanism(s) regulating salt stress. Higher expresson of K+/Na+ transporters and Na+/H+ antiporters in the isolate from Norway is likely to be one mechanism that increases salt tolerance in this isolate relative to the isolate from Tunisia. This finding is important due to its implications for growing perennial biomass crops in areas with marginal, salinized soils, or excessive nutrient runoff.
Technical Abstract: Perennial grasses are widely grown in different parts of the world as an important feedstock for renewable energy. Their perennial nature that reduces management practices and use of energy and agrochemicals give these biomass crops advantages when dealing with modern agriculture challenges such as soil erosion, increase in salinized marginal lands and the runoff of nutrients. Brachypodium sylvaticum is a perennial grass that was recently suggested as a suitable model for the study of biomass plant production and renewable energy. However, its plasticity to abiotic stress is not yet clear. We studied the salt stress tolerance of two accessions isolated from different areas of the world and characterized the mechanism(s) regulating salt stress in B. sylvaticum Osl1 originated from Oslo, Norway and Ain1 originated from Ain-Durham, Tunisia. Osl1 limited sodium transport from root to shoot, maintaining a better K/Na homeostasis and preventing toxicity damage in the shoot. This was accompanied by higher expression of HKT8 transporter in Osl1 as compared to Ain1. In addition, Osl1 salt tolerance was accompanied by higher abundance of the vacuolar proton pump pyrophosphatase and Na+/H+ antiporters (NHXs) leading to a better vacuolar pH homeostasis, efficient compartmentation of Na+ in the root vacuoles and salt tolerance. Although preliminary, our results further support previous results highlighting the role of Na+ transport systems in plant salt tolerance. The identification of salt tolerant and sensitive accessions can provide an experimental system for the study of the mechanisms and regulatory networks associated with stress tolerance in perennial grasses.