Understanding the salt overly sensitive pathway in Prunus: Identification and characterization of NHX, CIPK, and CBL genes.

Authors: ACHARYA, BISWA - University Of California, Riverside; Zhao, Chaoyang; REYES, LORENSO - University Of California, Riverside; Ferreira, Jorge; Sandhu, Devinder

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2023
Publication Date: 2/21/2024
Citation: Acharya, B., Zhao, C., Reyes, L., Ferreira, J.F., Sandhu, D. 2024. Understanding the salt overly sensitive pathway in Prunus: Identification and characterization of NHX, CIPK, and CBL genes.. The Plant Genome. 17(1): e20371. https://doi.org/10.1002/tpg2.20371.
DOI: https://doi.org/10.1002/tpg2.20371

Interpretive Summary: To maintain ion balance and survive in their environment, organisms must regulate various factors including temperature, pH, and ion concentrations. When exposed to stressors such as high levels of salt, the balance of molecules within an organism can be disrupted, leading to negative impacts on growth and survival. One way plants cope with salt stress is through the Salt Overly Sensitive (SOS) pathway, which helps regulate the concentration of sodium ions inside plant cells. This study aimed to understand the role of the SOS pathway in regulating sodium concentration in peach, a plant species belonging to the Rosaceae family. We analyzed the genes involved in the SOS signaling pathway in five different plant species from the Rosaceae family and found that many of the genes in the Rosaceae species were similar, or "orthologous," to those in Arabidopsis. Some genes were specific to the Rosaceae species and not present in Arabidopsis. We identified one corresponding gene to each of the SOS1, SOS2, and SOS3 genes in peach and showed that there is a direct interaction between SOS3 and SOS2; and between SOS2 and SOS1 proteins, as observed in Arabidopsis. Overall, the results of this study suggest that the SOS pathway is important for salt tolerance in peach. The findings of this study could be useful for breeding and genetic studies aimed at developing salt-tolerant peach and almond varieties. This could help farmers increase crop yield in areas with poor water or soil quality, where traditional peach and almond varieties may not thrive. By developing more resilient varieties, breeders and geneticists could contribute to global food security by increasing peach and almond production in a wider range of growing conditions.

Technical Abstract: Salinity is a major abiotic stress factor that can significantly impact crop growth,and productivity. In response to salt stress, the plant Salt Overly Sensitive (SOS) signaling pathway regulates the homeostasis of intracellular sodium ion concentration. The SOS1, SOS2, and SOS3 genes play critical roles in the SOS pathway, which belongs to the members of Na+/H+ exchanger (NHX), CBL-interacting protein kinase (CIPK), and calcineurin B-like (CBL) gene families, respectively. In this study, we performed genome-wide identifications and phylogenetic analyses of NHX,CIPK, and CBL genes in six Rosaceae species: Prunus persica, Prunus dulcis, Prunus mume, Prunus armeniaca, Pyrus ussuriensis × Pyrus communis, and Rosa chinensis.NHX, CIPK, and CBL genes of Arabidopsis thaliana were used as controls for phylogenetic analyses. Our analysis revealed the lineage-specific and adaptive evolutions of Rosaceae genes. Our observations indicated the existence of two primary classes of CIPK genes: those that are intron-rich and those that are intron-less. Intronrich CIPKs in Rosaceae and Arabidopsis can be traced back to algae CIPKs and CIPKs found in early plants, suggesting that intron-less CIPKs evolved from their intron-rich counterparts. This study identified one gene for each member of the SOS signaling pathway in P.persica: PpSOS1, PpSOS2, and PpSOS3. Gene expression analyses indicated that all three genes of P. persicawere expressed in roots and leaves. Yeast two-hybrid-based protein–protein interaction analyses revealed a direct interaction between PpSOS3 and PpSOS2; and between PpSOS2 and PpSOS1C-terminus region. Our findings indicate that the SOS signaling pathway is highly conserved in P. persica.