Alternative routes to deal with salinity

• Applicant: Dr. Jennifer Saile
• Subject Area: Plant Physiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 557398876

Salt stress is a major abiotic stress that severely affects plant growth and development and represents one of the most prevalent causes of crop losses worldwide. Rising sea levels and irrigation cause an increase in salinization of soils. In order to ensure food security, we need to develop strategies to increase plant stress resilience. Therefore, it is of utmost importance to understand the molecular mechanisms of how plants perceive and adjust to high salinity. When plants are exposed to salt, different signaling pathways are activated, with developmental plasticity as a critical response. Initially, salt stress decreases root growth rates, but at later stages growth rates are partially recovered. These changes in root morphology are accompanied by dynamic transcriptional responses. An additional layer of gene regulation is alternative splicing, a mechanism that is increasingly recognized as highly relevant for plant responses to salinity. Alternative splicing describes the processing of a precursor mRNA into two or more variants by removing different intron segments. However, the key regulators involved in salt-regulated alternative splicing, their target genes and their contribution to local developmental plasticity and salt stress tolerance remain largely unknown. Using a phospho-proteomic approach, we identified four serine/arginine-rich (SR) splicing regulators (RS40, RS41, RS2Z32 and RS2Z33) that are specifically phosphorylated in response to either NaCl, Na+ (NaCl and NaNO3) or osmotic stress (sorbitol). These four proteins act as prime candidates for controlling salt-regulated alternative splicing. Therefore, this project aims to unravel the importance of alternative splicing for salt tolerance by studying the role of RS40, RS41, RS2Z32 and RS2Z33. First, I will characterize the role of these SR proteins in salt- and osmotic-stress tolerance using corresponding Arabidopsis knockout mutants. To study the specificity and timing of salt-regulated alternative splicing responses in roots, I will re-analyze RNA-seq data sets of the host laboratory. I will then proceed to identify global transcriptomic effects of selected SR candidates under control and salt stress conditions. Lastly, I will study how salt/osmotic-stress induced phosphorylation affect SR localization, splicing activity, and overall salt tolerance. Altogether, the goal is to gain new insights into salt-regulated alternative splicing by deciphering the molecular mechanisms and physiological functions of SR proteins.

• DFG Programme: WBP Fellowship
• International Connection: Netherlands
• Host: Professorin Dr. Christa Testerink