About this Research Topic
The ability to respond to osmotic stress is conserved in plants and it has been suggested to be a critical trait for the successful land colonization in the Paleozoic by the common ancestor of living land plants, allowing them to survive in an environment with limited water availability. Although the mechanisms of osmostress sensing and signal transduction are largely unknown, one major component of this signaling is abscisic acid (ABA), which accumulates in a phylogenetically diverse array of prokaryotic and eukaryotic organisms. Interestingly, land plants show specifically high ABA sensitivity during osmostress response compared to other organisms.
The finding of soluble receptors for ABA in Arabidopsis revealed the fundamental mechanism that triggers the ABA signaling pathway. The subsequent studies demonstrated that there is a signaling module core, consisting of ABA receptors (PYR/PYL/RCAR proteins), Group A protein phosphatases (PP2CAs), and subclass III SnRK2 protein kinases which is evolutionarily conserved among land plants. Bryophytes, often considered as “basal” land plants, have shown to use this core ABA signaling module to establish cellular desiccation tolerance, suggesting that the origin of plant ABA signaling was as an adaptation to the water-limited environment. On the other hand, recent research also reveals diverse roles for ABA and novel regulatory components for osmostress signaling and responses. Recent reports further imply a role for other plant hormones, such as ethylene and brassinosteroids (BR), in the regulation of SnRK2 activity. Therefore, in this Research Topic, we highlight recent advances in ABA signaling beyond the “ABA core module” to capture a comprehensive view of ABA signaling across the plant kingdom.
We welcome submission of all types of articles, with a preference for Original Research, Reviews, and Opinions, focusing on the following topics regarding plant adaptation to terrestrial abiotic stress conditions:
- Novel regulators of ABA signaling pathways
- Role of ABA signaling in non-angiosperms
- ABA signaling cross-talk with other regulatory players in plant abiotic stress
- Evolutionary analyses of ABA signaling in plants
- Improvement of plant drought tolerance via modulation of ABA signaling
Keywords: Abiotic stress, Abscisic acid, Osmostress, Land Plant Evolution
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