The quinoa inbred lines (Yasui et al., 2016; Mizuno et al., 2020; Ogata et al., 2021) used in this study are listed in Supplementary Table 1 . For salt stress tests, quinoa seeds were sown and grown in vermiculite-filled cell trays in 8.2-L trays containing reverse osmosis (RO) water for 10 days in a growth chamber set at 22 ± 2°C under a 12-h-light/12-h-dark photoperiod, with light supplied at a 75 ± 25 µmol photons/m²/s. Ten days after sowing, these cell trays were transferred to trays containing 0 or 600 mM NaCl RO water. After the salt or control treatment, individual plants were pulled from their cells at the designated time and cut into roots, hypocotyls, and cotyledons for sampling. For VIGS analysis, quinoa Kd seeds were sown in a peat moss mixture (Jiffy Mix, Sakata Seeds, Yokohama, Japan) in a cell tray. After 7 days, the seedlings were transferred to a standard potting mix (Tsuchitaro, Sumitomo Forestry, Tokyo, Japan) in 0.11-L pots and grown in a temperature-controlled phytotron set at 22 ± 2°C under a 12-h-light/12-h-dark photoperiod for 7 days.

The Na⁺ and K⁺ measurements were performed as previously described (Cataldi et al., 2003), with slight modifications. Cotyledon, hypocotyl, and root tissues of quinoa seedlings were collected after salt treatment and oven-dried at 60°C for 2 days. Tissue extracts were prepared by adding 1 mL ultrapure water to ground tissue using a ShakeMaster (BMS, Japan) and 2-mm zirconia beads (1,100 rpm, 2min). The suspensions were heated at 90°C for 20 min and centrifuged at 21,500 g for 15 min at 4°C. The ionic contents were analyzed using a high-performance liquid chromatography (HPLC) system (Jasco, Japan, PU-4185 pump, CO-4060 column oven, AS-4150 autosampler) with a CD-200 conductivity detector (Shodex, Japan). Na⁺ and K⁺ were separated using a Shim-pack IC-C4 with Shim-pack IC-C4 guard column (Shimadzu, Japan) and eluted with 2.5 mM oxalic acid. The peak area and concentration of the ions were calculated using ChromNAV Ver.2 software (Jasco, Japan).

Quinoa Kd, J075, and J100 seeds were sown on mesh floating in a modified Molecular Genetics Research Laboratory (MGRL) solution (Kobayashi et al., 2013) containing 0.175 mM sodium phosphate buffer, 0.4 mM NaNO₃, 0.3 mM KNO₃, 0.2 mM CaCl₂, 0.15 mM MgSO₄, 3 μM H₃BO₃, 0.86 μM Fe(III)-EDTA, 1.03 μM MnSO₄, 0.1 μM CuSO₄, 0.1 μM ZnSO₄, 0.24 nM (NH₄)₆Mo₇O₂₄ 4H₂O, 1.3 nM CoCl₂, and 2 mM MES (pH 5.6). After 6 days, the seedlings were transferred to the MGRL solution containing 21.7 pM ²²Na (1 kBq/mL, Chiyoda Technol Co. Japan). The seedlings were collected at 1 and 24 h after the onset of ²²Na treatment. After the seedling roots were rinsed with the modified MGRL solution, ²²Na activity was measured using imaging plates (BAS-IP MS, FUJIFILM, Tokyo, Japan) and a Typhoon FLA-7000 image reader (Cytiva, Tokyo, Japan). The ²²Na content of the aerial parts of each quinoa line was calculated from the photostimulated luminescence value using a calibration curve generated from spotted samples.

Total RNA extraction and reverse transcription quantitative PCR (RT-qPCR) analysis were generally performed as previously described (Nagatoshi et al., 2023). Cotyledons, hypocotyls, and roots of seedlings treated as described for Na⁺ and K⁺ ion content measurements were rapidly frozen in liquid nitrogen. RNA was extracted from tissues using RNAiso plus (Takara). First-strand cDNA was synthesized from half a volume of total RNA (1 μg) treated for 30 min at 37°C with RQ1 RNase-free DNase (Promega) using a SuperScript III First-Strand Synthesis System (Invitrogen). Gene expression was quantified on a QuantStudio 7 Frex real-time PCR system (Applied Biosystems) using GoTaq qPCR Master Mix (Promega). The primers used in this study are described in Supplementary Table 2 .

Three quinoa inbred lines (Kd, J075, and J100) grown in vermiculite culture for 10 d were treated with 0 or 600 mM NaCl solution for 0, 6, and 24 h. Total RNA was extracted from cotyledons and roots and treated with DNase as described above. The libraries were prepared and sequenced at Macrogen Japan. The integrity of the total RNA was evaluated using an Agilent 2100 Bioanalyzer (Agilent). Paired-end sequencing (151-bp) of the mRNA library prepared using a TruSeq standard mRNA library Prep was performed on a NovaSeq 6000. All paired-end reads were trimmed using a Trimmomatic (v.0.38) (Bolger et al., 2014) to remove adapter sequence (ILLUMINACLIP:2:20:10) and low-quality reads (SLIDINGWINDOW:4:20, MINLEN:40). The filter-passed reads were mapped on reference sequence from CoGe database (id60716) (Rey et al., 2023) using Hisat2 (v2.1.0) (Kim et al., 2019). Reads mapped to transcript regions were counted and transcripts per million (TPM) values of transcripts were calculated for each sample.

Differentially expressed genes (DEGs) were identified by organ-specific comparison of cotyledons and roots for 6 and 24 h of salt treatment. We performed quantitative analyses using three biological replicates. The statistical difference of read count data between the 0 and 600 mM NaCl treatments in each line was calculated using the edgeR package (Chen et al., 2016). Gene expression was considered significant if the false discovery rate (FDR) was less than 0.01 and |log₂(fold change (FC))| was greater than 1 in at least one comparison. The resulting gene expression level data obtained were then imported into R software for hierarchical clustering. Prior to the clustering analysis, the TPM values were converted to z-scores for each gene using the “genescale” function included in the “genefilter” package obtained from bioconductor.org. Hierarchical clustering analysis and drawing of heat maps with dendrograms were performed using the heatmap.2 function of the “gplots” package (Warnes et al., 2024).

Gene ontology (GO) enrichment analysis was performed with topGO using the classical algorithm with Fisher’s test (Alexa and Rahnenführer, 2009). GO annotations were also assigned to the quinoa reference genomes using the Trinotate pipeline (Bryant et al., 2017). The top 50 biological process GO terms significantly enriched in the gene list for each cluster were filtered by applying a 0.05 cutoff to Fisher’s weighted P-values.

The three-dimensional (3D) structures of the HKT1 and SOS1 transporter proteins were determined using AlphaFold 2 on Google Colab’s Notebook (Mirdita et al., 2022). Predictions were performed using the default LocalColabFold settings with 3 prediction cycles and no template mode. Output PDB files, predicted local difference distance (pLDDT) confidence scores, and predicted alignment error (PAE) were visually inspected individually for each transporter prediction. For each transporter, AlphaFold generated five atomic models, ranked in order of predicted accuracy. For simplicity, only the top-ranked model is shown in this manuscript.

We used total genomic DNA from 17 quinoa inbred lines for whole-genome resequencing (Mizuno et al., 2020). DNA libraries were prepared using an Illumina TruSeq DNA PCR-Free Kit and sequenced as 151-bp paired-end reads on an Illumina NovaSeq 6000 system at Macrogen Japan. Low-quality reads and adapters were trimmed using Trimmomatic (v.0.38) (Bolger et al., 2014) with the options ‘SLIDINGWINDOW:4:25’ and ‘MINLEN:40’. The trimmed paired-end reads were aligned to the quinoa reference genome (QQ74, v2, id60716) from CoGe (https://genomevolution.org/coge/) using BWA 0.7.17 (Li, 2013). Samtools (v1.8) (Danecek et al., 2021) was used to convert the alignment SAM files to BAM files and prepare the alignment file for viewing in the Integrative Genomics Viewer (IGV) (Robinson et al., 2011).

Based on the coding sequences (CDSs) for putative CqHKT1;1, CqHKT1;2 and CqSOS1 genes obtained from the NCBI database of Chenopodium quinoa, which the amino acid sequences of Arabidopsis thaliana AtHKT1 (AT4G10310) and AtSOS1 (AT2G01980) were used as queries in the BLASTP program, we designed PCR primers ( Supplementary Table 2 ) to amplify trigger regions for VIGS in the CDSs. Apple latent spherical virus (ALSV)-RNA2 vectors for VIGS analyses were constructed as previously described (Ogata et al., 2021), with minor modifications. The amplified DNA fragments containing trigger sequences of quinoa genes for VIGS were cloned in-frame into the XhoI/BamHI site of pEALSR2 to generate pEALSR2-CqHKT1;1, pEALSR2-CqHKT1;2 and pEALSR2-CqSOS1, respectively.

ALSV inoculations were performed as previously described (Ogata et al., 2021). The plasmids for the ALSV-RNA1 (pEALSR1) and ALSV-RNA2 constructs were mixed in equal amounts, and the DNA solution was mechanically inoculated onto the true leaves of 14-day-old quinoa plants (Iw inbred line) using carborundum (Li et al., 2004). The inoculated quinoa plants were grown for 2 to 3 weeks and the uninoculated upper leaves showing chlorotic spots symptoms were harvested. The detached leaves were ground using the ShakeMaster and 3-mm stainless steel beads and suspended in extraction buffer (0.1 M Tris-HCl, pH 8.0, 0.1 M NaCl, 5 mM MgCl₂) (Igarashi et al., 2009). Debris was precipitated by centrifugation at 18,800 g for 10 min at 4°C, and the supernatants were used to inoculate quinoa Kd lines grown in the temperature-controlled phytotron as described above. Infected leaves or the inocula were stored at −80°C prior to use. ALSV derived from quinoa Iw plants inoculated with a mixture of pEALSR1 and pEALSR2 was used as a control (ALSV-WT). Seedlings (14-day-old) of quinoa Kd lines were mechanically inoculated with the inocula using carborundum. Kd plants at 10 days post inoculation were treated with 0.5 L of 300 mM NaCl solution once a week for 3 weeks. For Na⁺ content measurements, the lower leaves above the ALSV-inoculated leaves were collected and oven-dried at 60°C for 2 days. In the same plants, other leaves at similar positions were collected for gene expression analysis. Na⁺ content measurement and gene expression analysis were performed as described above.

All data are presented as mean ± standard deviation. Significant differences in data for physiological and morphological indices were determined by one-way analysis of variance and Tukey’s honestly significant difference (HSD) test or Student’s t-test using R version 4.3.0. The data were visualized using the “ggplot2” packages in R.

In this analysis, we used Kd, a sequenced model quinoa line that exhibits uniform growth among individuals and is suitable for molecular biology experiments (Yasui et al., 2016; Mizuno et al., 2020; Ogata et al., 2021) ( Figures 1 , 2 ). Although there is research supporting the notion that epidermal bladder cells are not involved in quinoa salt tolerance (Moog et al., 2022), to further confirm this notion, this study focused on the salt tolerance mechanism of quinoa plants at the seedling stage, which lack epidermal bladder cells ( Figure 1A ). In the quinoa plants examined in this study, no epidermal bladder cells were present on the cotyledons ( Figures 1B, C ), but epidermal bladder cells form on the first true leaves and all subsequent leaves that emerge ( Figure 1D ). In addition, in our previous research (Mizuno et al., 2020), the germination of quinoa in 600 mM NaCl showed clear differences depending on the genotype, in contrast to the case of 300 mM NaCl, so in this study we used 600 mM NaCl for the salt treatment.

We determined the dry weight and Na⁺ and K⁺ accumulations of various tissues of quinoa seedlings up to 4 days after treatment with or without 600 mM NaCl. Notably, salt treatment did not appear to inhibit biomass increase at most time points up to after 96 h of the salt treatment ( Figures 2A–C ). For all plants examined, the dry weight of the cotyledons increased in a time-dependent manner, whereas the dry weight of the hypocotyls and roots remained mostly unchanged ( Figures 2A–C ). In the salt-treated plants, the cotyledons and hypocotyls showed a time-dependent increase in Na⁺ accumulation, whereas there was no increase in Na⁺ accumulation in control plants ( Figures 2D, E ). Additionally, the Na⁺ accumulation in the roots plateaued after 24 h of salt treatment, all but the earliest time points were higher than in the control plants ( Figure 2F ). No difference in K⁺ accumulation was observed between the cotyledons of the salt-treated and control plants ( Figure 2G ); however, the K⁺ accumulation was lower in the roots of the salt-treated plants than in those of the control plants after 2 h of salt treatment ( Figure 2I ). By contrast, K⁺ accumulation in the hypocotyls increased in salt-treated plants but decreased in control plants up to after 6 h of salt treatment ( Figure 2H ). After 12 to 48 h of the salt treatment, there was no difference in K⁺ accumulation between the salt-treated and control plants, but after this time point, K⁺ increased in the control seedlings and decreased in the salt-treated plants ( Figure 2H ). Thus, the biomass increase of the model quinoa line Kd was not affected by treatment with 600 mM NaCl, but high salinity resulted in the accumulation of Na⁺, mainly in the aerial parts of the plants.

Next, we investigated the physiological responses of all three subpopulations, as well as the quinoa model line Kd, which belongs to the lowland subpopulation, to high seawater salinity. Based on the results of our previous genetic structure analysis of quinoa inbred lines (Mizuno et al., 2020), we selected six inbred lines containing 100% of the genetic background of each subpopulation from each subpopulation for this experiment ( Supplementary Table 1 ). For all three genotypes examined, there was no significant difference in the dry weights of cotyledons, hypocotyls, and roots between seedlings treated or not with 600 mM NaCl at either 24 or 48 h after the salt treatment ( Figures 3 , 4 ; Supplementary Figure 1 ), indicating that this treatment did not affect the initial growth of quinoa seedlings of any of the three genotypes. Interestingly, although the 600 mM NaCl treatment did not affect the growth of young Kd seedlings, it caused a rapid upward (hyponastic) leaf movement ( Figure 3 ), suggesting that these plants have a physiological response to salt stress.

We then examined tissue-specific Na⁺ accumulation in young quinoa seedlings treated or not with 600 mM NaCl for 24 and 48 h using six representative inbred lines of each of the three genotypes ( Figure 5A ; Supplementary Figure 2 ; Supplementary Table 1 ). In all salt-treated lines, Na⁺ accumulation tended to be highest in the cotyledons, at intermediate levels in the hypocotyls, and lowest in the roots ( Figure 5A ), indicating that young quinoa seedlings grown in a high-salinity environment accumulate more Na⁺ in the aerial parts than in the roots ( Figure 5A ; Supplementary Figure 2 ). Na⁺ accumulation in aerial parts, especially in the cotyledons, tended to be higher in the lowland lines and lower in the southern highland lines ( Figure 5A ).

To determine whether this difference in Na⁺ accumulation in aerial parts by genotype was due to differences in growth or Na⁺ uptake by genotype, we performed uptake experiments with radiolabeled ²²Na using Kd, J075, and J100 as three lines with each genotype background ( Figure 5B ). At 24 h after transferring the young seedlings to the ²²Na-containing medium, we observed significantly higher ²²Na signals in the aerial parts in the order of Kd, J075, and J100 ( Figures 5B, C ). Thus, Na⁺ uptake in the aerial parts of quinoa was higher in the lowland line (Kd), followed by the northern highland line (J075) and the southern highland line (J100), demonstrating that Na⁺ uptake in the aerial parts of quinoa is determined by the genotype. In addition, it did not induce rapid hyponastic leaf movement at low Na concentrations such as those used in this experiment ( Figure 5B ), supporting the hypothesis that hyponastic leaf movement may play a physiological role in response to high salinity.

We further assessed tissue-specific K⁺ accumulation in young quinoa seedlings treated or not with 600 mM NaCl for 24 and 48 h using six representative inbred lines of each of the three genotypes ( Figure 6 ; Supplementary Figure 3 ; Supplementary Table 1 ). In cotyledons and hypocotyls, salt treatment tended to slightly reduce K⁺ accumulation in many of the lines ( Figure 6 ). Regardless of the salinity conditions, K⁺ accumulation tended to be slightly lower in the aerial parts of southern highland lines than in those of the lowland and northern highland lines ( Figure 6 ). By contrast, in roots, salt treatment significantly reduced K⁺ accumulation in all lines examined, and K⁺ accumulation differed little among genotypes ( Figure 6 ). The results obtained so far showed that Na⁺ accumulation in the cotyledons of the salt-treated young seedlings is different among the genotypes but that there is no clear difference in Na⁺ and K⁺ accumulation in the roots among the genotypes ( Figures 5 , 6 ). We therefore concluded that salt treatment generally increases Na⁺ accumulation and decreases K⁺ accumulation in whole seedlings across all genotypes ( Figures 5 , 6 ).

To investigate the effect of high salinity on gene expression in young quinoa seedlings, we analyzed the gene expression profiles of cotyledons and roots after 0, 6, and 24 h of treatment with or without 600 mM NaCl ( Figure 7 ). We used Kd (Yasui et al., 2016) as a genome-sequenced representative lowland inbred line, J075 (Kobayashi et al., 2024) as a genome-sequenced representative northern highland inbred line, and J100 (Kobayashi et al., 2024) as a genome-sequenced representative southern highland inbred line ( Figure 7 ). In the RNA-seq experiment, we identified 8,303 and 4,121 DEGs (|log₂(FC)| ≥ 1, TPM value > 0, FDR < 0.01) in response to high salinity in at least one sampling in cotyledons and roots of each line, respectively ( Figure 7 ; Supplementary Table 3 ). We then performed hierarchical clustering and GO enrichment analysis of these genes. In cotyledons, one gene set, designated cluster A, was enriched in genes involved in biological processes related to cell wall organization ( Figure 7A ; Supplementary Figure 4 ; Supplementary Table 4 ). Two other gene sets, designated clusters B and C, were enriched in genes involved in biological processes related to photosynthesis and cellular response to hypoxia ( Figure 7A ; Supplementary Figures 5 , 6 ; Supplementary Table 4 ). These results indicate that, in cotyledons of the salt-stressed lowland Kd line, the expression of genes related to cell wall composition is up-regulated, while the expression of genes related to photosynthesis and oxygen deprivation response is down-regulated. In roots, one gene set, designated cluster D, was enriched in genes involved in biological processes related to responses to water deprivation and ABA ( Figure 7B ; Supplementary Figure 7 ; Supplementary Table 5 ). Two additional gene sets, designated clusters E and F, were enriched in genes involved in biological processes related to cellular response to hypoxia, defense response to bacteria, and hydrogen peroxide catabolic process ( Figure 7B ; Supplementary Figures 8 , 9 ; Supplementary Table 5 ). To validate the RNA-seq expression data, we performed RT-qPCR analyses on 18 inbred lines−six from each genotype−under the same conditions. We analyzed a putative quinoa xyloglucan endotransglucosylase/hydrolase 23 (CqXTH23) and a putative quinoa cellulose synthase 1 (CqCESA1) genes included in cluster A and a putative quinoa chaperon protein ClpB1 (CqCLPB1), a putative quinoa zinc finger protein ZAT12 (CqZAT12), and a putative quinoa peroxidase PER4 (CqPER4) genes included in clusters E and F, and verified the results of these RNA-seq analyses ( Supplementary Figures 10 , 11 ). This consistency supports the reliability of the expression patterns identified across these genotypes and conditions. Taken together, these results indicate that all lines tested, regardless of the genotype, showed increased expression of genes involved in responses to water deprivation and ABA in their roots under high salinity conditions. Interestingly, in the roots of the highland lines J075 and J100, salt application specifically resulted in a significant increase in the expression of genes related to the hypoxia response, defense response against bacteria, and reactive oxygen species (ROS) pathways.

So far, we have analyzed gene expression responses to high salinity, but salt stress–tolerant plants often do not show significant changes in the expression of key genes involved in the salt stress response due to constitutive expression of key genes such as HKT1 and SOS1 (Taji et al., 2004; Katschnig et al., 2015). The quinoa sodium transporter CqHKT1 gene has been reported to have a root-expressed CqHKT1;1 and a shoot-expressed CqHKT1;2 (Böhm et al., 2018). CqSOS1 is also conserved in the quinoa genome and is mainly expressed in roots (Maughan et al., 2009). The expression of these genes remained unchanged in quinoa subjected to salt stress treatment (Maughan et al., 2009; Böhm et al., 2018). The results of these reports are largely consistent with those of our RNA-seq analysis ( Supplementary Figure 12 ). To date, in vitro functional analysis has been performed for CqHKT1;1 and CqHKT1;2 (Böhm et al., 2018), but no functional analysis results have been reported for CqSOS1. However, a comparison of the predicted three-dimensional structures shows that CqHKT1 and CqSOS1, which are homologs of quinoa HKT1 and SOS1, both have high homology with the Arabidopsis homologous proteins, suggesting functional similarity ( Supplementary Figure 13 ).

To explore the genetic variation in the quinoa inbred lines examined in this study, we employed resequencing to analyze 18 of the quinoa inbred lines ( Supplementary Table 1 ). Genomic analysis showed that the CqHKT1;1 gene in lines J072, J073, and J075 had a single nucleotide insertion in the first exon, which shifted the reading frame ( Supplementary Figure 14 ). Expression of this disrupted gene was completely undetectable ( Supplementary Figure 15 ). In lines J064 and J071, a 6.9-kb deletion was found in the 5′ flanking region of the CqSOS1 gene ( Supplementary Figure 16 ), and almost no gene expression was observed ( Supplementary Figure 15 ). By contrast, the other lines examined showed full-length gene expression with no mutations in or near the CqHKT1;1 or CqSOS1 genes ( Supplementary Figures 17 – 19 ).

RT-qPCR analysis revealed that CqHKT1;2 in cotyledons and CqHKT1;1 and CqSOS1 in roots did not show significant changes in gene expression in response to high salinity in many of the lines examined, but there were significant differences in expression levels among genotypes with and without salt treatment ( Figure 8 ; Supplementary Figure 15 ). However, the expression levels of these genes tended to be more genotype-dependent in CqHKT1;2 and CqSOS1, and less so in CqHKT1;1 ( Figure 8 ; Supplementary Figure 15 ). In most cases, CqHKT1;1 and CqHKT1;2 were expressed higher in lowland lines than in highland lines, whereas CqSOS1 was expressed higher in southern and northern highland lines than in lowland lines ( Figure 8 ; Supplementary Figure 15 ). By contrast, it appears that genotype-dependent gene expression pattern was not clearly observed for the expression of K⁺ transporter genes ( Supplementary Figures 20 , 21 ), consistent with the property of maintaining high K⁺ concentrations in the aerial part even under high salinity conditions, regardless of genotype ( Figure 6 ). In addition, many sequence polymorphisms were observed around the promoter regions of the CqHKT1;1, CqHKT1;2, and CqSOS1 genes between lowland and highland quinoa lines ( Supplementary Figures 17 – 19 ), strengthening the hypothesis that the expression levels of these transporter genes are genotype dependent. Given that constitutive gene expression levels of transporters are associated with Na⁺ accumulation and salt tolerance (Oh et al., 2009; Jha et al., 2010), these results support the notion that the function and activity of the transporters are defined by genotype in quinoa.

To determine whether the CqHKT1 and CqSOS1 transporters are involved in Na⁺ transport in quinoa, we suppressed the gene expression of these transporters using the VIGS method with an ALSV vector, the only method currently available to analyze endogenous gene function in quinoa (Ogata et al., 2021) ( Figure 9 ). Because this ALSV-VIGS experimental system requires virus inoculation of leaves with epidermal bladder cells and sampling of uninoculated upper leaves with epidermal bladder cells, the transport ability of the transporters was analyzed in older quinoa plants, which have true leaves with epidermal bladder cells, rather than in seedlings, which lack epidermal bladder cells. In addition, a model quinoa line, the lowland line Kd, was used in this experiment. This is because lowland lines tend to accumulate more Na⁺ in the aerial parts under high salinity conditions, unlike southern highland lines, and are therefore more suitable for analyzing the function of these transporters. RT-qPCR analysis revealed that CqHKT1;1, CqHKT1;2, and CqSOS1 expression was significantly down-regulated in the uninoculated upper leaves of the plants inoculated with ALSV-CqHKT1;1, ALSV-CqHKT1;2, and ALSV-CqSOS1, respectively, compared with those inoculated with ALSV-WT in each experiment ( Figure 9B ). Knockdown of CqHKT1;1, CqHKT1;2, and CqSOS1 had no significant effect on plant height ( Figures 9B, C ) but increased the Na⁺ content in the uninoculated upper leaves of salt-treated plants by 56%, 47%, and 55%, respectively, indicating that reduced expression of these transporter genes results in increased salt accumulation in plants ( Figure 9D ). Considering that these transporters generally function to control Na⁺ homeostasis through long-distance transport of Na⁺ in a variety of plants (Ali et al., 2021; Gámez-Arjona et al., 2024), these results demonstrate that CqHKT1;1, CqHKT1;2, and CqSOS1 function in Na⁺ exclusion in the long-distance transport system under high salinity conditions in quinoa.