New Insights into Salinity Sensing, Signaling and Adaptation in Plants

Being predominantly sessile organisms, plants have evolved complex mechanisms to survive the changing and sometimes challenging environmental conditions. In response to salinity stress, plants adjust morphologically, anatomically, physiologically and biochemically. However, to date, the identity of Na⁺ sensors in plants and the perception of salinity stress are still unclear. During salt stress, intracellular organelles and compartments (nucleus, endoplasmic reticulum, mitochondria, chloroplasts, peroxisomes, plasma membrane, cell wall and apoplast) play an important role in salinity responses. Despite all the progress made over the past years, we still lack a complete understanding of how signals generated from the different organelles in response to environmental stresses are integrated and coordinated. Moreover, plant scientists have long tried to understand the mechanisms underlying the salt stress responses, with particular interest in the identification of specific genomic regions, genes, proteins, and metabolites that play a role in salt tolerance. With the advent of high-throughput transcriptomics, proteomics and metabolomics as functional genomics tools, it is now possible to further elucidate and integrate cellular networks of stress perception, signal transduction and metabolic responses in plants under salt stress.

Individual plant species show great differences in salinity tolerance. Glycophytic plant species experience growth inhibition at relatively low salt concentrations, whereas halophyte plant species tolerate high salt concentrations. Most crop plants, including cereal grasses, are glycophytes. A better understanding of stress responses and tolerance mechanisms would greatly assist plant breeders in developing stress tolerant varieties, and thereby contribute to improve crop yield.

With this Research Topic, we aim to create a cohesive collection of current knowledge on the response and adaptation mechanisms of salinity stress that may help breed better crops with enhanced tolerance to salinity stress in the future. We welcome Original Research, Review and Methods falling under (but not limited to) the following categories:

I. Plant salinity stress responses and tolerance mechanisms.

- Mechanistic insights of plant responses to salinity.
- Chemical genetic screening of key components in plant salinity stress responses.
- New methods for high-throughput plant salinity stress phenotyping.
- Ionic and molecular mechanisms related to salt tolerance:
1. Osmotic tolerance - The ability to maintain growth under osmotic stress;
2. Na⁺ exclusion - The ability to exclude Na⁺from tissue;
3. Vacuolar Na⁺ sequestration - The ability to sequestrate Na+ into the vacuole;
4. K⁺ retention - The ability to maintain K⁺ in the cytosol.

II. The role of intracellular organelles and compartments in salinity stress sensing and responses (sensing, signaling, ion transport and compartmentalization).

- Cellular partitioning of Na⁺ ions.
- Role of secondary messengers such as cytosolic Ca²⁺, ROS, abscisic acid (ABA) and phosphatidic acid (PA).
- Role of Na⁺ transport processes and transporters.
- Role of signal transduction and signaling cascades in response to salinity.

III. Plant breeding towards stress tolerant crop varieties.

- Identify salinity stress related QTLs.
- Develop molecular markers.
- Develop high-throughput screening methods for breeding programs.
- Learning from halophytes towards breeding salt tolerant crops.

Note for authors: Before preparing your manuscript, please check the Scope of the Plant Abiotic Stress section that describes the requirements for reporting experimental studies and acceptance of manuscripts.