Nuclear factor Y subunit GmNFYA competes with GmHDA13 for interaction with GmFVE to positively regulate salt tolerance in soybean

A small peptide miPEP172b encoded by primary transcript of miR172b regulates salt tolerance in rice

Recent studies have demonstrated that the primary transcript of miRNAs (pri-miRNAs) are able to encode small peptides influencing plant growth and development, as well as responses to various environmental cues. However, their role in plant responses to salt stress is not fully comprehended. Here, we characterized a short peptide encoded by miR172b (miPEP172b) in rice (Oryza sativa L.). By applying synthetic miPEP172b, we observed a significant increase in miR172b abundance and a decrease in the expression of its target gene IDS1. Consequently, plants treated with miPEP172b exhibited enhanced tolerance to salinity stress. Furthermore, we found that miPEP172b was efficiently absorbed by roots and transported to the aerial parts of the plant, thus conferring salt tolerance in the aboveground organs. Overexpression of miPEP172b resulted in reduced levels of reactive oxygen species (ROS), leading to improved performance of rice seedlings under salinity conditions. This was consistent with the observations in miR172-overexpressing plants. Conversely, miPEP172b mutants showed increased sensitivity to salt stress. Further analysis revealed that miPEP172b-miR172-IDS1 improved rice salt tolerance by integrating the ROS scavenging pathway and plant hormone signaling. Our findings highlight the significant role of miPEP172b in regulating miR172 activity and salt tolerance, providing a useful agent for improving crop salt tolerance.

The soybean NUCLEAR FACTOR-Y C4 and α-EXPANSIN 7 module influences phosphorus uptake by regulating root morphology

Soybean (Glycine max) is a globally important crop; however, its productivity is severely impacted by phosphorus (P) deficiency. Understanding the transcriptional regulation of low P (LP) response mechanisms is essential for enhancing soybean P use efficiency. In this study, we found that the Nuclear Factor-Y (NF-Y) transcription factor GmNF-YC4, in addition to its previously discovered role in regulating flowering time, possesses other functions in modulating root morphology and P uptake. Knockout of GmNF-YC4 notably boosted root proliferation and P uptake while also influencing the expression of genes related to LP stress. GmNF-YC4 acts as a specific DNA-binding transcriptional repressor, modulating the expression of the soybean α-EXPANSIN 7 (GmEXPA7) gene, which encodes a cell-wall-loosening factor, through direct binding to its promoter region. Further investigation revealed that GmEXPA7 expression is predominantly root-specific and induced by LP. Moreover, overexpression of GmEXPA7 in soybean hairy roots enhanced LP tolerance by stimulating root growth and P uptake. We further screened and obtained more potential target genes of GmNF-YC4 via DNA affinity purification sequencing, including those related to LP stress. These findings underscore the pivotal role of the GmNF-YC4-GmEXPA7 module as a key regulator in mitigating LP stress in soybeans.

Functional Characterisation of GmGASA1-like Gene in Glycine max (L.) Merr.: Overexpression Promotes Growth, Development and Stress Responses

The presence of Gibberellic Acid-Stimulated Arabidopsis, GASA, gene family has been reported in many important plants, playing roles in various aspects of plant biology but little has been uncovered in soybeans. Soybean is one of the major plants providing nutrition for humans and livestock globally. In this study, we overexpressed a novel GASA gene (GmGASA1-like) in Glycine max and conducted bioinformatic analyses, evaluated the T2 transgenic line in an open field, and applied major stressors along with the growth promoter GA3 to investigate the potential functions of the GmGASA1-like gene. The results of bioinformatics implied that the GmGASA1-like gene is regulated by GA3, and its protein has the potential to influence key processes of plant growth and development. The transgenic plants (JN74-OE) were significantly taller and had a larger canopy in the field trial at the R1-growth stage and demonstrated superiority in some seed quantity and quality traits after harvesting. Under abiotic stresses (including cold, heat, and drought) and spraying of GA3, the level of GmGASA1-like gene expression in JN74-OE exceeded the levels measured before the treatments. Notably, the highest expression level was observed during the drought stress treatment. Photosynthesis pigments levels in both the overexpressed lines and the control group showed no significant differences. In summary, this study sheds light on the multifaceted roles of the GmGASA1-like gene, impacting soybean plant architecture, seed traits, and stress responses. Ultimately, this research paves the way for a more productive and sustainable soybean industry.

Promoting γ-aminobutyric acid accumulation to enhances saline-alkali tolerance in tomato

Saline-alkali stress is a widely distributed abiotic stress that severely limits plant growth. γ-Aminobutyric acid (GABA) accumulates rapidly in plants under saline-alkali stress, but the underlying molecular mechanisms and associated regulatory networks remain unclear. Here, we report a MYB-like protein, I-box binding factor (SlMYBI), which positively regulates saline-alkali tolerance through induced GABA accumulation by directly modulating the glutamate decarboxylase (GAD) gene SlGAD1 in tomato (Solanum lycopersicum L.). Overexpression of SlGAD1 increased GABA levels and decreased reactive oxygen species accumulation under saline-alkali stress, while silencing of SlGAD1 further suggested that SlGAD1 plays an active role in GABA synthesis and saline-alkali tolerance of tomato. In addition, we found that SlMYBI activates SlGAD1 transcription. Both overexpression of SlMYBI and editing of SlMYBI using CRISPR-Cas9 showed that SlMYBI regulates GABA synthesis by modulating SlGAD1 expression. Furthermore, the interaction of SlNF-YC1 with SlMYBI enhanced the transcriptional activity of SlMYBI on SlGAD1 to further improve saline-alkali tolerance in tomato. Interestingly, we found that ethylene signaling was involved in the GABA response to saline-alkali stress by RNA-seq analysis of SlGAD1-overexpressing lines. This study elucidates the involvement of SlMYBI in GABA synthesis regulation. Specifically, the SlMYBI-SlNF-YC1 module is involved in GABA accumulation in response to saline-alkali stress.

Comparative Analysis of Two Soybean Cultivars Revealed Tolerance Mechanisms Underlying Soybean Adaptation to Flooding

Flooding stress poses a significant challenge to soybean cultivation, impacting plant growth, development, and ultimately yield. In this study, we investigated the responses of two distinct soybean cultivars: flooding-tolerant Nanxiadou 38 (ND38) and flooding-sensitive Nanxiadou 45 (ND45). To achieve this, healthy seedlings were cultivated with the water surface consistently maintained at 5 cm above the soil surface. Our objective was to elucidate the physiological and molecular adaptations of the two cultivars. Under flooding stress, seedlings of both cultivars exhibited significant dwarfing and a notable decrease in root length. While there were no significant differences in the dry weight of aboveground shoots, the dry weight of underground shoots in ND38 was strikingly decreased following flooding. Additionally, total chlorophyll content decreased significantly following flooding stress, indicating impaired photosynthetic performance of the cultivars. Moreover, malondialdehyde (MDA) levels increased significantly after flooding, particularly in the ND45 cultivar, suggesting heightened oxidative stress. Expression analysis of methylation and demethylation genes indicated that MET1 and DME play crucial roles in response to flooding stress in soybeans. Meanwhile, analysis of the hemoglobin family (GLBs), aquaporin family (AQPs), glycolytic pathway-related genes, and NAC transcription factor-related genes identified GLB1-1 and GLB1-2, GLB2-2, PIP2-6, PIP2-7, TIP2-2, TIP4-1, TIP5-1, Gm02G222400 (fructose-bisphosphate aldolase), Gm19G017200 (glucose-6-phosphate isomerase), and Gm04G213900 (alcohol dehydrogenase 1) as key contributors to flooding tolerance in both soybean cultivars. These findings provide crucial insights into the physiological and molecular mechanisms underlying flooding tolerance in soybeans, which could guide future molecular breeding strategies for the development of flooding-tolerant soybean cultivars.

Salt Tolerance in Sugar Beet: From Impact Analysis to Adaptive Mechanisms and Future Research

The continuous global escalation of soil salinization areas presents severe challenges to the stability and growth of agricultural development across the world. In-depth research on sugar beet (Beta vulgaris L.), an important economic and sugar crop with salt tolerance characteristics, is crucial for to determine its salt-tolerance mechanisms, which has important practical implications for production. This review summarizes the multifaceted effects of salt stress on sugar beet, ranging from individual plant responses to cellular and molecular adaptations. Sugar beet exhibits robust salt-tolerance mechanisms, including osmotic regulation, ion balance management, and the compartmentalization of toxic ions. Omics technologies, including genomics, transcriptomics, proteomics, post-translational modification omics and metabolomics, have played crucial roles in elucidating these mechanisms. Key genes and pathways involved in salt tolerance in sugar beet have been identified, paving the way for targeted breeding strategies and biotechnological advancements. Understanding these mechanisms not only enhances our knowledge of sugar beet's adaptation strategies but also provides insights for improving salt tolerance in other crops. Future studies should focus on analyzing gene expression changes in sugar beet under salt stress to gain insight into the molecular aspects of its salt-tolerance mechanisms. Meanwhile, the effects of different environmental conditions on sugar beet adaptation strategies should also be investigated to improve their growth potential in salinized soils.

Harnessing Multi-Omics Strategies and Bioinformatics Innovations for Advancing Soybean Improvement: A Comprehensive Review

Soybean improvement has entered a new era with the advent of multi-omics strategies and bioinformatics innovations, enabling more precise and efficient breeding practices. This comprehensive review examines the application of multi-omics approaches in soybean-encompassing genomics, transcriptomics, proteomics, metabolomics, epigenomics, and phenomics. We first explore pre-breeding and genomic selection as tools that have laid the groundwork for advanced trait improvement. Subsequently, we dig into the specific contributions of each -omics field, highlighting how bioinformatics tools and resources have facilitated the generation and integration of multifaceted data. The review emphasizes the power of integrating multi-omics datasets to elucidate complex traits and drive the development of superior soybean cultivars. Emerging trends, including novel computational techniques and high-throughput technologies, are discussed in the context of their potential to revolutionize soybean breeding. Finally, we address the challenges associated with multi-omics integration and propose future directions to overcome these hurdles, aiming to accelerate the pace of soybean improvement. This review serves as a crucial resource for researchers and breeders seeking to leverage multi-omics strategies for enhanced soybean productivity and resilience.

Epigenetic control of plant abiotic stress responses

On top of genetic information, organisms have evolved complex and sophisticated epigenetic regulation to adjust gene expression in response to developmental and environmental signals. Key epigenetic mechanisms include DNA methylation, histone modifications and variants, chromatin remodeling, and chemical modifications of RNAs. Epigenetic control of environmental responses is particularly important for plants, which are sessile and unable to move away from adverse environments. Besides enabling plants to rapidly respond to environmental stresses, some stress-induced epigenetic changes can be maintained, providing plants with a pre-adapted state to recurring stresses. Understanding these epigenetic mechanisms offers valuable insights for developing crop varieties with enhanced stress tolerance. Here, we focus on abiotic stresses and summarize recent progress in characterizing stress-induced epigenetic changes and their regulatory mechanisms and roles in plant abiotic stress resistance.

CRISPR-Cas9-mediated editing of GmARM improves resistance to multiple stresses in soybean

The growth and development of soybean plants can be affected by both abiotic and biotic stressors, such as saline-alkali stress and Phytophthora root rot. In this study, we identified a stress-related gene-GmARM-whose promoter contained several hormone-response and stress-regulatory elements, including ABRE, TCA element, STRE, and MBS. qRT-PCR analysis showed that the expression of GmARM was the highest in seeds at 55 days after flowering. Furthermore, this gene was upregulated after exposure to saline-alkali stress and Phytophthora root rot infection at the seedling stage. Thus, we generated GmARM mutants using the CRISPR-Cas9 system to understand the role of this gene in stress response. T3 plants showed significantly improved salt tolerance, alkali resistance, and disease resistance, with a significantly higher survival rate than the wildtype plants. Moreover, mutations in GmARM affected the expression of related stress-resistance genes, indicating that GmARM mutants achieved multiple stress tolerance. Therefore, this study provides a foundation for further exploration of the genes involved in resistance to multiple stresses in soybean that can be used for breeding multiple stress-resistance soybean varieties.

NF-YC15 transcription factor activates ethylene biosynthesis and improves cassava disease resistance

The nuclear factor Y (NF-Y) transcription factors play important roles in plant development and physiological responses. However, the relationship between NF-Y, plant hormone and plant stress resistance in tropical crops remains unclear. In this study, we identified MeNF-YC15 gene in the NF-Y family that significantly responded to Xanthomonas axonopodis pv. manihotis (Xam) treatment. Using MeNF-YC15-silenced and -overexpressed cassava plants, we elucidated that MeNF-YC15 positively regulated disease resistance to cassava bacterial blight (CBB). Notably, we illustrated MeNF-YC15 downstream genes and revealed the direct genetic relationship between MeNF-YC15 and 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (MeACO1)-ethylene module in disease resistance, as evidenced by the rescued disease susceptibility of MeNF-YC15 silenced cassava plants with ethylene treatment or overexpressing MeACO1. In addition, the physical interaction between 2C-type protein phosphatase 1 (MePP2C1) and MeNF-YC15 inhibited the transcriptional activation of MeACO1 by MeNF-YC15. In summary, MePP2C1-MeNF-YC15 interaction modulates ethylene biosynthesis and cassava disease resistance, providing gene network for cassava genetic improvement.

Plant responses to abiotic stress regulated by histone acetylation

In eukaryotes, histone acetylation and deacetylation play an important role in the regulation of gene expression. Histone acetylation levels are reversibly regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Increasing evidence highlights histone acetylation plays essential roles in the regulation of gene expression in plant response to environmental stress. In this review, we discussed the recent advance of histone acetylation in the regulation of abiotic stress responses including temperature, light, salt and drought stress. This information will contribute to our understanding of how plants adapt to environmental changes. As the mechanisms of epigenetic regulation are conserved in many plants, research in this field has potential applications in improvement of agricultural productivity.

GmNF-YC4 delays soybean flowering and maturation by directly repressing GmFT2a and GmFT5a expression

Flowering time and growth period are key agronomic traits which directly affect soybean (Glycine max (L.) Merr.) adaptation to diverse latitudes and farming systems. The FLOWERING LOCUS T (FT) homologs GmFT2a and GmFT5a integrate multiple flowering regulation pathways and significantly advance flowering and maturity in soybean. Pinpointing the genes responsible for regulating GmFT2a and GmFT5a will improve our understanding of the molecular mechanisms governing growth period in soybean. In this study, we identified the Nuclear Factor Y-C (NFY-C) protein GmNF-YC4 as a novel flowering suppressor in soybean under long-day (LD) conditions. GmNF-YC4 delays flowering and maturation by directly repressing the expression of GmFT2a and GmFT5a. In addition, we found that a strong selective sweep event occurred in the chromosomal region harboring the GmNF-YC4 gene during soybean domestication. The GmNF-YC4Hap3 allele was mainly found in wild soybean (Glycine soja Siebold & Zucc.) and has been eliminated from G. max landraces and improved cultivars, which predominantly contain the GmNF-YC4Hap1 allele. Furthermore, the Gmnf-yc4 mutants displayed notably accelerated flowering and maturation under LD conditions. These alleles may prove to be valuable genetic resources for enhancing soybean adaptability to higher latitudes.

Integrative analysis of metabolome and transcriptome reveals regulatory mechanisms of flavonoid biosynthesis in soybean under salt stress

Introduction

Salt stress is a major environmental factor that constrains soybean growth, development, and productivity. Flavonoids are key secondary metabolites that play a crucial role in enhancing plant resistance to both biotic and abiotic stress. However, a comprehensive understanding of the regulatory mechanisms underlying flavonoid biosynthesis under salt stress in soybean is lacking.

Methods

In this study, an integrative analysis of soybean metabolome and transcriptome was conducted using two soybean lines, FQ03 (salt-sensitive, SS) and FQ07 (salt-tolerant, ST).

Results

A total of 650 significantly changed metabolites were identified in SS and ST after salt stress treatment. Among them, 151 flavonoids were categorized into nine classes, with flavones and flavonols being the predominant flavonoid types in soybean. Heatmap analysis showed higher contents of most flavonoid metabolites in ST than in SS under salt stress, and the total flavonoid content in ST was significantly higher than that in SS. In addition, transcriptome analysis revealed a higher number of differentially expressed genes (DEGs) in ST than in SS under salt stress. KEGG enrichment analysis revealed that DEGs were mainly enriched in pathways related to phenylpropanoid biosynthesis, isoflavonoid biosynthesis, flavonoid biosynthesis, as well as flavone and flavonol biosynthesis. Notably, 55 DEGs that were mapped to the flavonoid biosynthetic pathway were identified, with most showing higher expression levels in ST than in SS. Weighted gene correlation network analysis identified eight structural genes and six transcription factor genes as key regulators of flavonoid biosynthesis within the blue module. Furthermore, qRT-PCR results confirmed the accuracy of the transcriptomic data and reliability of the identified candidate genes.

Discussion

This study provides insights into the regulatory mechanisms underlying salt stress responses in soybean and highlights hub genes as potential targets for developing salt-tolerant soybean varieties.

MicroRNA-encoded regulatory peptides modulate cadmium tolerance and accumulation in rice

MicroRNAs (miRNAs) are small noncoding RNAs that play a vital role in plant responses to abiotic and biotic stresses. Recently, it has been discovered that some primary miRNAs (pri-miRNAs) encode regulatory short peptides called miPEPs. However, the presence of miPEPs in rice, and their functions in response to abiotic stresses, particularly stress induced by heavy metals, remain poorly understood. Here, we identified a functional small peptide (miPEP156e) encoded by pri-miR156e that regulates the expression of miR156 and its target SPL genes, thereby affecting miR156-mediated cadmium (Cd) tolerance in rice. Overexpression of miPEP156e led to decreased uptake and accumulation of Cd and reactive oxygen species (ROS) levels in plants under Cd stress, resulting in improved rice Cd tolerance, as observed in miR156-overexpressing lines. Conversely, miPEP156e mutants displayed sensitivity to Cd stress due to the elevated accumulation of Cd and ROS. Transcriptome analysis further revealed that miPEP156e improved rice Cd tolerance by modulating Cd transporter genes and ROS scavenging genes. Our study provides insights into the regulatory mechanism of miPEP156e in rice response to Cd stress and demonstrates the potential of miPEPs as an effective tool for improving crop abiotic stress tolerance.

Identification of QTNs, QTN-by-environment interactions, and their candidate genes for salt tolerance related traits in soybean

BACKGROUND

Salt stress significantly reduces soybean yield. To improve salt tolerance in soybean, it is important to mine the genes associated with salt tolerance traits.

RESULTS

Salt tolerance traits of 286 soybean accessions were measured four times between 2009 and 2015. The results were associated with 740,754 single nucleotide polymorphisms (SNPs) to identify quantitative trait nucleotides (QTNs) and QTN-by-environment interactions (QEIs) using three-variance-component multi-locus random-SNP-effect mixed linear model (3VmrMLM). As a result, eight salt tolerance genes (GmCHX1, GsPRX9, Gm5PTase8, GmWRKY, GmCHX20a, GmNHX1, GmSK1, and GmLEA2-1) near 179 significant and 79 suggested QTNs and two salt tolerance genes (GmWRKY49 and GmSK1) near 45 significant and 14 suggested QEIs were associated with salt tolerance index traits in previous studies. Six candidate genes and three gene-by-environment interactions (GEIs) were predicted to be associated with these index traits. Analysis of four salt tolerance related traits under control and salt treatments revealed six genes associated with salt tolerance (GmHDA13, GmPHO1, GmERF5, GmNAC06, GmbZIP132, and GmHsp90s) around 166 QEIs were verified in previous studies. Five candidate GEIs were confirmed to be associated with salt stress by at least one haplotype analysis. The elite molecular modules of seven candidate genes with selection signs were extracted from wild soybean, and these genes could be applied to soybean molecular breeding. Two of these genes, Glyma06g04840 and Glyma07g18150, were confirmed by qRT-PCR and are expected to be key players in responding to salt stress.

CONCLUSIONS

Around the QTNs and QEIs identified in this study, 16 known genes, 6 candidate genes, and 8 candidate GEIs were found to be associated with soybean salt tolerance, of which Glyma07g18150 was further confirmed by qRT-PCR.

GhWRKY4 binds to the histone deacetylase GhHDA8 promoter to regulate drought and salt tolerance in Gossypium hirsutum

Soil drought and salinization, caused by water deficiency, have become the greatest concerns limiting crop production. Up to now, the WRKY transcription factor and histone deacetylase have been shown to be involved in drought and salt responses. However, the molecular mechanism underlying their interaction remains unclear in cotton. Herein, we identified GhWRKY4, a member of WRKY gene family, which is induced by drought and salt stress and is located in the nucleus. The ectopic expression of GhWRKY4 in Arabidopsis enhanced drought and salt tolerance, and suppressing GhWRKY4 in cotton increased susceptibility to drought and salinity. Subsequently, DAP-seq analysis revealed that the W box element in the promoter of stress-induced genes could potentially be the binding target for GhWRKY4 protein. GhWRKY4 binds to the promoters of GhHDA8 and GhNHX7 via W box element, and the expression level of GhHDA8 was increased in GhWRKY4-silenced plants. In addition, GhHDA8-overexpressed Arabidopsis were found to be hypersensitive to drought and salt stress, while silencing of GhHDA8 enhanced drought and salt tolerance in cotton. The stress-related genes, such as GhDREB2A, GhRD22, GhP5CS, and GhNHX7, were induced in GhHDA8-silenced plants. Our findings indicate that the GhWRKY4-GhHDA8 module regulates drought and salt tolerance in cotton. Collectively, the results provide new insights into the coordination of transcription factors and histone deacetylases in regulating drought and salt stress responses in plants.

A novel miR160a-GmARF16-GmMYC2 module determines soybean salt tolerance and adaptation

Salt stress is a major challenge that has a negative impact on soybean growth and productivity. Therefore, it is important to understand the regulatory mechanism of salt response to ensure soybean yield under such conditions. In this study, we identified and characterized a miR160a-GmARF16-GmMYC2 module and its regulation during the salt-stress response in soybean. miR160a promotes salt tolerance by cleaving GmARF16 transcripts, members of the Auxin Response Factor (ARF) family, which negatively regulates salt tolerance. In turn, GmARF16 activates GmMYC2, encoding a bHLH transcription factor that reduces salinity tolerance by down-regulating proline biosynthesis. Genomic analysis among wild and cultivated soybean accessions identified four distinct GmARF16 haplotypes. Among them, the GmARF16H3 haplotype is preferentially enriched in localities with relatively saline soils, suggesting GmARF16H3 was artificially selected to improve salt tolerance. Our findings therefore provide insights into the molecular mechanisms underlying salt response in soybean and provide valuable genetic targets for the molecular breeding of salt tolerance.

Stress salinity in plants: New strategies to cope with in the foreseeable scenario

The excess of salts in soils causes stress in most plants, except for some halophytes that can tolerate higher levels of salinity. The excess of Na+ generates an ionic imbalance, reducing the K+ content and altering cellular metabolism, thus impacting in plant growth and development. Additionally, salinity in soil induces water stress due to osmotic effects and increments the production of reactive oxygen species (ROS) that affect the cellular structure, damaging membranes and proteins, and altering the electrochemical potential of H+, which directly affects nutrient absorption by membrane transporters. However, plants possess mechanisms to overcome the toxicity of the sodium ions, such as internalization into the vacuole or exclusion from the cell, synthesis of enzymes or protective compounds against ROS, and the synthesis of metabolites that help to regulate the osmotic potential of plants. Physiologic and molecular mechanisms of salinity tolerance in plants will be addressed in this review. Furthermore, a revision of strategies taken by researchers to confer salt stress tolerance on agriculturally important species are discussed. These strategies include conventional breeding and genetic engineering as transgenesis and genome editing by CRISPR/Cas9.

A novel natural variation in the promoter of GmCHX1 regulates conditional gene expression to improve salt tolerance in soybean

Identification and characterization of soybean germplasm and gene(s)/allele(s) for salt tolerance is an effective way to develop improved varieties for saline soils. Previous studies identified GmCHX1 (Glyma03g32900) as a major salt tolerance gene in soybean, and two main functional variations were found in the promoter region (148/150 bp insertion) and the third exon with a retrotransposon insertion (3.78 kb). In the current study, we identified four salt-tolerant soybean lines, including PI 483460B (Glycine soja), carrying the previously identified salt-sensitive variations at GmCHX1, suggesting new gene(s) or new functional allele(s) of GmCHX1 in these soybean lines. Subsequently, we conducted quantitative trait locus (QTL) mapping in a recombinant-inbred line population (Williams 82 (salt-sensitive) × PI 483460B) to identify the new salt tolerance loci/alleles. A new locus, qSalt_Gm18, was mapped on chromosome 18 associated with leaf scorch score. Another major QTL, qSalt_Gm03, was identified to be associated with chlorophyll content ratio and leaf scorch score in the same chromosomal region of GmCHX1 on chromosome 3. Novel variations in a STRE (stress response element) cis-element in the promoter region of GmCHX1 were found to regulate the salt-inducible expression of the gene in these four newly identified salt-tolerant lines including PI 483460B. This new allele of GmCHX1 with salt-inducible expression pattern provides an energy cost efficient (conditional gene expression) strategy to protect soybean yield in saline soils without yield penalty under non-stress conditions. Our results suggest that there might be no other major salt tolerance locus similar to GmCHX1 in soybean germplasm, and further improvement of salt tolerance in soybean may rely on gene-editing techniques instead of looking for natural variations.

Long noncoding RNA TRABA suppresses β-glucosidase-encoding BGLU24 to promote salt tolerance in cotton

Salt stress severely damages the growth and yield of crops. Recently, long noncoding RNAs (lncRNAs) were demonstrated to regulate various biological processes and responses to environmental stresses. However, the regulatory mechanisms of lncRNAs in cotton (Gossypium hirsutum) response to salt stress are still poorly understood. Here, we observed that a lncRNA, trans acting of BGLU24 by lncRNA (TRABA), was highly expressed while GhBGLU24-A was weakly expressed in a salt-tolerant cotton accession (DM37) compared to a salt-sensitive accession (TM-1). Using TRABA as an effector and proGhBGLU24-A-driven GUS as a reporter, we showed that TRABA suppressed GhBGLU24-A promoter activity in double transgenic Arabidopsis (Arabidopsis thaliana), which explained why GhBGLU24-A was weakly expressed in the salt-tolerant accession compared to the salt-sensitive accession. GhBGLU24-A encodes an endoplasmic reticulum (ER)-localized β-glucosidase that responds to salt stress. Further investigation revealed that GhBGLU24-A interacted with RING-type E3 ubiquitin ligase (GhRUBL). Virus-induced gene silencing (VIGS) and transgenic Arabidopsis studies revealed that both GhBGLU24-A and GhRUBL diminish plant tolerance to salt stress and ER stress. Based on its substantial effect on ER-related degradation (ERAD)-associated gene expression, GhBGLU24-A mediates ER stress likely through the ERAD pathway. These findings provide insights into the regulatory role of the lncRNA TRABA in modulating salt and ER stresses in cotton and have potential implications for developing more resilient crops.

The first released available genome of the common ice plant ( Mesembryanthemum crystallinum L.) extended the research region on salt tolerance, C 3-CAM photosynthetic conversion, and halophilism

Background

The common ice plant ( Mesembryanthemum crystallinum L.) is an annual herb belonging to the genus Mesembryanthemum of the family Aizoaceae, native to Southern Africa.

Methods

We performed shotgun genome paired-end sequencing using the Illumina platform to determine the genome sequence of the ice plants. We assembled the whole genome sequences using the genome assembler "ALGA" and "Redundans", then released them as available genomic information. Finally, we mainly estimated the potential genomic function by the homology search method.

Results

A draft genome was generated with a total length of 286 Mb corresponding to 79.2% of the estimated genome size (361 Mb), consisting of 49,782 contigs. It encompassed 93.49% of the genes of terrestrial higher plants, 99.5% of the ice plant transcriptome, and 100% of known DNA sequences. In addition, 110.9 Mb (38.8%) of repetitive sequences and untranslated regions, 971 tRNA, and 100 miRNA loci were identified, and their effects on stress tolerance and photosynthesis were investigated. Molecular phylogenetic analysis based on ribosomal DNA among 26 kinds of plant species revealed genetic similarity between the ice plant and poplar, which have salt tolerance. Overall, 35,702 protein-coding regions were identified in the genome, of which 56.05% to 82.59% were annotated and submitted to domain searches and gene ontology (GO) analyses, which found that eighteen GO terms stood out among five plant species. These terms were related to biological defense, growth, reproduction, transcription, post-transcription, and intermembrane transportation, regarded as one of the fundamental results of using the utilized ice plant genome.

Conclusions

The information that we characterized is useful for elucidation of the mechanism of growth promotion under salinity and reversible conversion of the photosynthetic type from C3 to Crassulacean Acid Metabolism (CAM).

Salt Tolerance in Soybeans: Focus on Screening Methods and Genetics

Salinity greatly affects the production of soybeans in arid and semi-arid lands around the world. The responses of soybeans to salt stress at germination, emergence, and other seedling stages have been evaluated in multitudes of studies over the past decades. Considerable salt-tolerant accessions have been identified. The association between salt tolerance responses during early and later growth stages may not be as significant as expected. Genetic analysis has confirmed that salt tolerance is distinctly tied to specific soybean developmental stages. Our understanding of salt tolerance mechanisms in soybeans is increasing due to the identification of key salt tolerance genes. In this review, we focus on the methods of soybean salt tolerance screening, progress in forward genetics, potential mechanisms involved in salt tolerance, and the importance of translating laboratory findings into field experiments via marker-assisted pyramiding or genetic engineering approaches, and ultimately developing salt-tolerant soybean varieties that produce high and stable yields. Progress has been made in the past decades, and new technologies will help mine novel salt tolerance genes and translate the mechanism of salt tolerance into new varieties via effective routes.

Regulation of seed traits in soybean

Soybean (Glycine max) is an essential economic crop that provides vegetative oil and protein for humans, worldwide. Increasing soybean yield as well as improving seed quality is of great importance. Seed weight/size, oil and protein content are the three major traits determining seed quality, and seed weight also influences soybean yield. In recent years, the availability of soybean omics data and the development of related techniques have paved the way for better research on soybean functional genomics, providing a comprehensive understanding of gene functions. This review summarizes the regulatory genes that influence seed size/weight, oil content and protein content in soybean. We also provided a general overview of the pleiotropic effect for the genes in controlling seed traits and environmental stresses. Ultimately, it is expected that this review will be beneficial in breeding improved traits in soybean.

Epigenetic silencing of callose synthase by VIL1 promotes bud-growth transition in lily bulbs

In plants, restoring intercellular communication is required for cell activity in buds during the growth transition from slow to fast growth after dormancy release. However, the epigenetic regulation of this phenomenon is far from understood. Here we demonstrate that lily VERNALIZATION INSENSITIVE 3-LIKE 1 (LoVIL1) confers growth transition by mediating plasmodesmata opening via epigenetic repression of CALLOSE SYNTHASE 3 (LoCALS3). Moreover, we found that a novel transcription factor, NUCLEAR FACTOR Y, SUBUNIT A7 (LoNFYA7), is capable of recruiting the LoVIL1-Polycomb Repressive Complex 2 (PRC2) and enhancing H3K27me3 at the LoCALS3 locus by recognizing the CCAAT cis-element (Cce) of its promoter. The LoNFYA7-LoVIL1 module serves as a key player in orchestrating the phase transition from slow to fast growth in lily bulbs. These studies also indicate that LoVIL1 is a suitable marker for the bud-growth-transition trait following dormancy release in lily cultivars.

Subcellular Proteomics to Elucidate Soybean Response to Abiotic Stress

Climate change jeopardizes soybean production by declining seed yield and quality. In this review, the morphophysiological alterations of soybean in response to abiotic stress are summarized, followed by illustrations of cellular metabolisms and regulatory mechanisms to organellar stress based on subcellular proteomics. This highlights the communications associated with reactive oxygen species scavenging, molecular chaperones, and phytohormone signals among subcellular compartments. Given the complexity of climate change and the limitations of plants in coping with multiple abiotic stresses, a generic response to environmental constraints is proposed between calcium and abscisic acid signals in subcellular organelles. This review summarizes the findings of subcellular proteomics in stressed soybean and discusses the future prospects of subcellular proteomics for promoting the improvement of climate-tolerant crops.

Genome-Wide Identification and Analysis of the Plant Cysteine Oxidase (PCO) Gene Family in Brassica napus and Its Role in Abiotic Stress Response

Plant Cysteine Oxidase (PCO) is a plant O₂-sensing enzyme catalyzing the oxidation of cysteine to Cys-sulfinic acid at the N-termini of target proteins. To better understand the Brassica napus PCO gene family, PCO genes in B. napus and related species were analyzed. In this study, 20, 7 and 8 PCO genes were identified in Brassica napus, Brassica rapa and Brassica oleracea, respectively. According to phylogenetic analysis, the PCOs were divided into five groups: PCO1, PCO2, PCO3, PCO4 and PCO5. Gene organization and motif distribution analysis suggested that the PCO gene family was relatively conserved during evolution. According to the public expression data, PCO genes were expressed in different tissues at different developmental stages. Moreover, qRT-PCR data showed that most of the Bna/Bra/BoPCO5 members were expressed in leaves, roots, flowers and siliques, suggesting an important role in both vegetative and reproductive development. Expression of BnaPCO was induced by various abiotic stress, especially waterlogging stress, which was consistent with the result of cis-element analysis. In this study, the PCO gene family of Brassicaceae was analyzed for the first time, which contributes to a comprehensive understanding of the origin and evolution of PCO genes in Brassicaceae and the function of BnaPCO in abiotic stress responses.

Twenty years of mining salt tolerance genes in soybean

Current combined challenges of rising food demand, climate change and farmland degradation exert enormous pressure on agricultural production. Worldwide soil salinization, in particular, necessitates the development of salt-tolerant crops. Soybean, being a globally important produce, has its genetic resources increasingly examined to facilitate crop improvement based on functional genomics. In response to the multifaceted physiological challenge that salt stress imposes, soybean has evolved an array of defences against salinity. These include maintaining cell homeostasis by ion transportation, osmoregulation, and restoring oxidative balance. Other adaptations include cell wall alterations, transcriptomic reprogramming, and efficient signal transduction for detecting and responding to salt stress. Here, we reviewed functionally verified genes that underly different salt tolerance mechanisms employed by soybean in the past two decades, and discussed the strategy in selecting salt tolerance genes for crop improvement. Future studies could adopt an integrated multi-omic approach in characterizing soybean salt tolerance adaptations and put our existing knowledge into practice via omic-assisted breeding and gene editing. This review serves as a guide and inspiration for crop developers in enhancing soybean tolerance against abiotic stresses, thereby fulfilling the role of science in solving real-life problems.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11032-023-01383-3.

Overexpression of OsNF-YB4 leads to flowering early, improving photosynthesis and better grain yield in hybrid rice

For cereal crops, such as rice, the grain yield mainly comes from the accumulation of carbohydrates in the seed, which depends ultimately on photosynthesis during the growth period. To create early ripen variety, higher efficiency of photosynthesis is thus necessary to get higher grain yield with shorter growth period. In this study, flowering early was observed in the hybrid rice with overexpression of OsNF-YB4. Along with the flowering early, the hybrid rice also was shorter in plant height with less of leaves and internodes, but no changes of panicle length and leaf emergence. The grain yield was kept or even increased in the hybrid rice with shorter growth period. Transcription analysis revealed that Ghd7-Ehd1-Hd3a/RFT1 was activated early to promote the flowering transition in the overexpression hybrids. RNA-Seq study further showed that carbohydrate-related pathways were significantly altered in addition to circadian pathway. Notably, up-regulation of three pathways related to plant photosynthesis was observed, as well. Increased carbon assimilation with alteration of chlorophyll contents was subsequently detected in the following physiological experiments. All these results demonstrate that overexpression of OsNF-YB4 in the hybrid rice activates flowering early and improves photosynthesis resulting in better grain yield with shorter growth period.

New Genes Identified as Modulating Salt Tolerance in Maize Seedlings Using the Combination of Transcriptome Analysis and BSA

(1) Background: Salt stress is an abiotic factor that limits maize yield and quality. A highly salt-tolerance inbred AS5 and a salt-sensitive inbred NX420 collected from Ningxia Province, China, were used to identify new genes for modulating salt resistance in maize. (2) Methods: To understand the different molecular bases of salt tolerance in AS5 and NX420, we performed BSA-seq using an F2 population for two extreme bulks derived from the cross between AS5 and NX420. Transcriptomic analysis was also conducted for AS5 and NX420 at the seedling stage after treatment with 150 mM of NaCl for 14 days. (3) Results: AS5 had a higher biomass and lower Na⁺ content than NX420 in the seedling stage after treatment with 150 mM NaCl for 14 days. One hundred and six candidate regions for salt tolerance were mapped on all of the chromosomes through BSA-seq using F2 in an extreme population. Based on the polymorphisms identified between both parents, we detected 77 genes. A large number of differentially expressed genes (DEGs) at the seedling stage under salt stress between these two inbred lines were detected using transcriptome sequencing. GO analysis indicated that 925 and 686 genes were significantly enriched in the integral component of the membrane of AS5 and NX420, respectively. Among these results, two and four DEGs were identified as overlapping in these two inbred lines using BSA-seq and transcriptomic analysis, respectively. Two genes (Zm00001d053925 and Zm00001d037181) were detected in both AS5 and NX420; the transcription level of Zm00001d053925 was induced to be significantly higher in AS5 than in NX420 (41.99 times versus 6.06 times after 150 mM of NaCl treatment for 48 h), while the expression of Zm00001d037181 showed no significant difference upon salt treatment in both lines. The functional annotation of the new candidate genes showed that it was an unknown function protein. (4) Conclusions: Zm00001d053925 is a new functional gene responding to salt stress in the seedling stage, which provides an important genetic resource for salt-tolerant maize breeding.

Zinc-finger protein GmZF351 improves both salt and drought stress tolerance in soybean

Abiotic stress is one of the most important factors reducing soybean yield. It is essential to identify regulatory factors contributing to stress responses. A previous study found that the tandem CCCH zinc-finger protein GmZF351 is an oil level regulator. In this study, we discovered that the GmZF351 gene is induced by stress and that the overexpression of GmZF351 confers stress tolerance to transgenic soybean. GmZF351 directly regulates the expression of GmCIPK9 and GmSnRK, leading to stomata closing, by binding to their promoter regions, which carry two CT(G/C)(T/A)AA elements. Stress induction of GmZF351 is mediated through reduction in the H3K27me3 level at the GmZF351 locus. Two JMJ30-demethylase-like genes, GmJMJ30-1 and GmJMJ30-2, are involved in this demethylation process. Overexpression of GmJMJ30-1/2 in transgenic hairy roots enhances GmZF351 expression mediated by histone demethylation and confers stress tolerance to soybean. Yield-related agronomic traits were evaluated in stable GmZF351-transgenic plants under mild drought stress conditions. Our study reveals a new mode of GmJMJ30-GmZF351 action in stress tolerance, in addition to that of GmZF351 in oil accumulation. Manipulation of the components in this pathway is expected to improve soybean traits and adaptation under unfavorable environments.

Crucial Abiotic Stress Regulatory Network of NF-Y Transcription Factor in Plants

Nuclear Factor-Y (NF-Y), composed of three subunits NF-YA, NF-YB and NF-YC, exists in most of the eukaryotes and is relatively conservative in evolution. As compared to animals and fungi, the number of NF-Y subunits has significantly expanded in higher plants. The NF-Y complex regulates the expression of target genes by directly binding the promoter CCAAT box or by physical interaction and mediating the binding of a transcriptional activator or inhibitor. NF-Y plays an important role at various stages of plant growth and development, especially in response to stress, which attracted many researchers to explore. Herein, we have reviewed the structural characteristics and mechanism of function of NF-Y subunits, summarized the latest research on NF-Y involved in the response to abiotic stresses, including drought, salt, nutrient and temperature, and elaborated the critical role of NF-Y in these different abiotic stresses. Based on the summary above, we have prospected the potential research on NF-Y in response to plant abiotic stresses and discussed the difficulties that may be faced in order to provide a reference for the in-depth analysis of the function of NF-Y transcription factors and an in-depth study of plant responses to abiotic stress.

Beyond transcription factors: more regulatory layers affecting soybean gene expression under abiotic stress

Abiotic stresses such as nutritional imbalance, salt, light intensity, and high and low temperatures negatively affect plant growth and development. Through the course of evolution, plants developed multiple mechanisms to cope with environmental variations, such as physiological, morphological, and molecular adaptations. Epigenetic regulation, transcription factor activity, and post-transcriptional regulation operated by RNA molecules are mechanisms associated with gene expression regulation under stress. Epigenetic regulation, including histone and DNA covalent modifications, triggers chromatin remodeling and changes the accessibility of transcription machinery leading to alterations in gene activity and plant homeostasis responses. Soybean is a legume widely produced and whose productivity is deeply affected by abiotic stresses. Many studies explored how soybean faces stress to identify key elements and improve productivity through breeding and genetic engineering. This review summarizes recent progress in soybean gene expression regulation through epigenetic modifications and circRNAs pathways, and points out the knowledge gaps that are important to study by the scientific community. It focuses on epigenetic factors participating in soybean abiotic stress responses, and chromatin modifications in response to stressful environments and draws attention to the regulatory potential of circular RNA in post-transcriptional processing.

Unfolding molecular switches for salt stress resilience in soybean: recent advances and prospects for salt-tolerant smart plant production

The increasing sodium salts (NaCl, NaHCO3, NaSO4 etc.) in agricultural soil is a serious global concern for sustainable agricultural production and food security. Soybean is an important food crop, and their cultivation is severely challenged by high salt concentration in soils. Classical transgenic and innovative breeding technologies are immediately needed to engineer salt tolerant soybean plants. Additionally, unfolding the molecular switches and the key components of the soybean salt tolerance network are crucial for soybean salt tolerance improvement. Here we review our understandings of the core salt stress response mechanism in soybean. Recent findings described that salt stress sensing, signalling, ionic homeostasis (Na⁺/K⁺) and osmotic stress adjustment might be important in regulating the soybean salinity stress response. We also evaluated the importance of antiporters and transporters such as Arabidopsis K⁺ Transporter 1 (AKT1) potassium channel and the impact of epigenetic modification on soybean salt tolerance. We also review key phytohormones, and osmo-protectants and their role in salt tolerance in soybean. In addition, we discuss the progress of omics technologies for identifying salt stress responsive molecular switches and their targeted engineering for salt tolerance in soybean. This review summarizes recent progress in soybean salt stress functional genomics and way forward for molecular breeding for developing salt-tolerant soybean plant.

Natural and induced epigenetic variation for crop improvement

Maintaining global food security is a major challenge that requires novel strategies for crop improvement. Epigenetic regulation of plant responses to adverse environmental conditions provides a tunable mechanism to optimize plant growth, adaptation and ultimately yield. Epibreeding employs agricultural practices that rely on key epigenetic features as a means of engineering favorable phenotypic traits in target crops. This review summarizes recent findings on the role of epigenetic marks such as DNA methylation and histone modifications, in controlling phenotypic variation in crop species in response to environmental factors. The potential use of natural and induced epigenetic features as platforms for crop improvement via epibreeding, is discussed.

Agronomical selection on loss-of-function of GIGANTEA simultaneously facilitates soybean salt tolerance and early maturity

Salt stress and flowering time are major factors limiting geographic adaptation and yield productivity in soybean (Glycine max). Although improving crop salt tolerance and latitude adaptation are essential for efficient agricultural production, whether and how these two traits are integrated remains largely unknown. Here, we used a genome-wide association study to identify a major salt-tolerance locus controlled by E2, an ortholog of Arabidopsis thaliana GIGANTEA (GI). Loss of E2 function not only shortened flowering time and maturity, but also enhanced salt-tolerance in soybean. E2 delayed soybean flowering by enhancing the transcription of the core flowering suppressor gene E1, thereby repressing Flowering Locus T (FT) expression. An E2 knockout mutant e2^CR displayed reduced accumulation of reactive oxygen species (ROS) during the response to salt stress by releasing peroxidase, which functions in ROS scavenging to avoid cytotoxicity. Evolutionary and population genetic analyses also suggested that loss-of-function e2 alleles have been artificially selected during breeding for soybean adaptation to high-latitude regions with greater salt stress. Our findings provide insights into the coupled selection for adaptation to both latitude and salt stress in soybean; and offer an ideal target for molecular breeding of early-maturing and salt-tolerant cultivars.

Molecular Tools and Their Applications in Developing Salt-Tolerant Soybean (Glycine max L.) Cultivars

Abiotic stresses are one of the significant threats to soybean (Glycine max L.) growth and yields worldwide. Soybean has a crucial role in the global food supply chain and food security and contributes the main protein share compared to other crops. Hence, there is a vast scientific saddle on soybean researchers to develop tolerant genotypes to meet the growing need of food for the huge population. A large portion of cultivated land is damaged by salinity stress, and the situation worsens yearly. In past years, many attempts have increased soybean resilience to salinity stress. Different molecular techniques such as quantitative trait loci mapping (QTL), genetic engineering, transcriptome, transcription factor analysis (TFs), CRISPR/Cas9, as well as other conventional methods are used for the breeding of salt-tolerant cultivars of soybean to safeguard its yield under changing environments. These powerful genetic tools ensure sustainable soybean yields, preserving genetic variability for future use. Only a few reports about a detailed overview of soybean salinity tolerance have been published. Therefore, this review focuses on a detailed overview of several molecular techniques for soybean salinity tolerance and draws a future research direction. Thus, the updated review will provide complete guidelines for researchers working on the genetic mechanism of salinity tolerance in soybean.

Expression patterns of the poplar NF-Y gene family in response to Alternaria alternata and hormone treatment and the role of PdbNF-YA11 in disease resistance

Plant nuclear factor-Y (NF-Y) transcription factors (TFs) are key regulators of growth and stress resistance. However, the role of NF-Y TFs in poplar in response to biotic stress is still unclear. In this study, we cloned 26 PdbNF-Y encoding genes in the hybrid poplar P. davidiana × P. bollena, including 12 PdbNF-YAs, six PdbNF-YBs, and eight PdbNF-YCs. Their physical and chemical parameters, conserved domains, and phylogeny were subsequently analyzed. The protein–protein interaction (PPI) network showed that the three PdbNF-Y subunits may interact with NF-Y proteins belonging to two other subfamilies and other TFs. Tissue expression analysis revealed that PdbNF-Ys exhibited three distinct expression patterns in three tissues. Cis-elements related to stress-responsiveness were found in the promoters of PdbNF-Ys, and most PdbNF-Ys were shown to be differentially expressed under Alternaria alternata and hormone treatments. Compared with the PdbNF-YB and PdbNF-YC subfamilies, more PdbNF-YAs were significantly induced under the two treatments. Moreover, loss- and gain-of-function analyses showed that PdbNF-YA11 plays a positive role in poplar resistance to A. alternata. Additionally, RT‒qPCR analyses showed that overexpression and silencing PdbNF-YA11 altered the transcript levels of JA-related genes, including LOX, AOS, AOC, COI, JAZ, ORCA, and MYC, suggesting that PdbNF-YA11-mediated disease resistance is related to activation of the JA pathway. Our findings will contribute to functional analysis of NF-Y genes in woody plants, especially their roles in response to biotic stress.

Time-series transcriptome comparison reveals the gene regulation network under salt stress in soybean (Glycine max) roots

BACKGROUND

Soil salinity is a primary factor limiting soybean (Glycine max) productivity. Breeding soybean for tolerance to high salt conditions is therefore critical for increasing yield. To explore the molecular mechanism of soybean responses to salt stress, we performed a comparative transcriptome time-series analysis of root samples collected from two soybean cultivars with contrasting salt sensitivity.

RESULTS

The salt-tolerant cultivar 'Qi Huang No.34' (QH34) showed more differential expression of genes than the salt-sensitive cultivar 'Dong Nong No.50' (DN50). We identified 17,477 genes responsive to salt stress, of which 6644 exhibited distinct expression differences between the two soybean cultivars. We constructed the corresponding co-expression network and performed Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The results suggested that phytohormone signaling, oxidoreduction, phenylpropanoid biosynthesis, the mitogen-activated protein kinase pathway and ribosome metabolism may play crucial roles in response to salt stress.

CONCLUSIONS

Our comparative analysis offers a comprehensive understanding of the genes involved in responding to salt stress and maintaining cell homeostasis in soybean. The regulatory gene networks constructed here also provide valuable molecular resources for future functional studies and breeding of soybean with improved tolerance to salinity.

Genome-wide Identification, Expression, and Functional Analysis of MdMSI Genes in Apples (Malus domestica Borkh.)

The multicopy suppressor of IRA (MSI) is a subfamily of WD40 repeat proteins, which is widely involved in plant growth and development. In order to explore the function of MdMSI members in abiotic stress, we identified eight MSI gene family members from the Malus × domestica reference genome. They were distributed on six chromosomes, and they had similar secondary and tertiary structures. We found a variety of regulatory elements in response to hormones and abiotic stress in MdMSI promoters. Through qRT-PCR analysis, it was revealed that MdMSIs were expressed in all tissues, especially in roots. The analysis results also revealed that the expression of MdMSIs was induced in varying degrees under salt, drought stress, and ABA treatments. Furthermore, we obtained the overexpression of MdMSI1-1 transgenic apple calli and Arabidopsis. The overexpression of MdMSI1-1 in calli and Arabidopsis played a negative regulatory role in salt stress response. Our work laid a foundation for further verifying the function of MSI genes under abiotic stress in apples.