Adaptation to unfavorable abiotic stresses is one of the key processes in the evolution of plants. Calcium (Ca²⁺) signaling is characterized by the spatiotemporal pattern of Ca²⁺ distribution and the activities of multi-domain proteins in integrating environmental stimuli and cellular responses, which are crucial early events in abiotic stress responses in plants. However, a comprehensive summary and explanation for evolutionary and functional synergies in Ca²⁺ signaling remains elusive in green plants. We review mechanisms of Ca²⁺ membrane transporters and intracellular Ca²⁺ sensors with evolutionary imprinting and structural clues. These may provide molecular and bioinformatics insights for the functional analysis of some non-model species in the evolutionarily important green plant lineages. We summarize the chronological order, spatial location, and characteristics of Ca²⁺ functional proteins. Furthermore, we highlight the integral functions of calcium-signaling components in various nodes of the Ca²⁺ signaling pathway through conserved or variant evolutionary processes. These ultimately bridge the Ca²⁺ cascade reactions into regulatory networks, particularly in the hormonal signaling pathways. In summary, this review provides new perspectives towards a better understanding of the evolution, interaction and integration of Ca²⁺ signaling components in green plants, which is likely to benefit future research in agriculture, evolutionary biology, ecology and the environment.

The recent advances in plant biology have significantly improved our understanding of reactive oxygen species (ROS) as signaling molecules in the redox regulation of complex cellular processes. In plants, free radicals and non-radicals are prevalent intra- and inter-cellular ROS, catalyzing complex metabolic processes such as photosynthesis. Photosynthesis homeostasis is maintained by thiol-based systems and antioxidative enzymes, which belong to some of the evolutionarily conserved protein families. The molecular and biological functions of redox regulation in photosynthesis are usually to balance the electron transport chain, photosystem II, photosystem I, mesophyll and bundle sheath signaling, and photo-protection regulating plant growth and productivity. Here, we review the recent progress of ROS signaling in photosynthesis. We present a comprehensive comparative bioinformatic analysis of redox regulation in evolutionary distinct photosynthetic cells. Gene expression, phylogenies, sequence alignments, and 3D protein structures in representative algal and plant species revealed conserved key features including functional domains catalyzing oxidation and reduction reactions. We then discuss the antioxidant-related ROS signaling and important pathways for achieving homeostasis of photosynthesis. Finally, we highlight the importance of plant responses to stress cues and genetic manipulation of disturbed redox status for balanced and enhanced photosynthetic efficiency and plant productivity.

Reactive oxygen species (ROS) serve as crucial signaling molecules in plants, enabling rapid responses to environmental stresses such as abiotic factors. ROS production primarily stems from the activation of enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and peroxidases, as well as disruptions in the respiratory and photosynthetic electron transport chains. This oxidative stress triggers signaling pathways that involve in calcium ion (Ca²⁺) influx across cell membranes, altering ionic conductance. ROS encompass hydroxyl radicals (OH•) and hydrogen peroxide (H₂O₂), which activate hyperpolarization‐activated Ca²⁺ channels and influence ion transport dynamics. Our review focuses on the mechanisms driving ROS generation and ion transport during plant responses to abiotic stress. We explore the regulation, characteristics, and potential structures of ROS‐activated ion channels in plants. Specifically, we examine the molecular responses and evolutionary adaptations of Shaker‐type K⁺ channels (AKT/KAT/GORK/SKOR) under stress conditions. Comparative genetic analyses highlight the conservation of these channels and other ROS‐regulated proteins (e.g., MDHAR, POX, and RBOH), suggesting their essential roles in plant to adapt to diverse stresses. This study underscores the significance of ROS‐regulated proteins in plant stress responses, advocating for further research to elucidate their fundamental roles.