Balancing Ions: Insights into how plants cope with salinity from high-resolution cryo-elemental imaging

Abstract:

Salinity is a major environmental stress that affects plant growth and development. Most plants avoid salt (primarily sodium) toxicity through subcellular compartmentation or intricate strategies with high elemental interdependence. While we do not fully understand why plants avoid salt, we know that saline soil has physiological impacts on the plants. There are major gaps in our understanding of how sodium toxicity plays out at the cellular level and affects organelle functionality. A challenge has been to reliably visualize where these ions sit within the cells to help us meaningfully interpret their impact on cellular processes. Towards this, I will describe a newly developed cryo-elemental imaging approach, which allows high-resolution subcellular mapping of elements in vitrified plant samples. We used this approach to examine the root meristems of Arabidopsis and rice, revealing how key physiologically important ions are distributed during salinity stress. Our initial findings show a concentration-dependent switch in sodium accumulation in the root meristem, and scenarios of sodium detoxification within cells. I will present our efforts to map and compare these responses with salt-tolerant halophyte species to understand differences in cellular salinity tolerance strategies, and discuss future perspectives.

Articles:

1. Ramakrishna et al., (2025) Nature, 637, 1228–1233. https://doi.org/10.1038/s41586-024-08403-y