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Aegilops tauschii Coss. (2n = 2x = 14, DD) is a problematic weed and a rich source of genetic material for wheat crop improvement programs. We used physiological traits (plant height, dry weight biomass, Na+ and K+ concentration) and 14 microsatellite markers to evaluate the genetic diversity and salinity tolerance in 40 Ae. tauschii populations. The molecular marker allied with salinity stress showed polymorphisms, and a cluster analysis divided the populations into different groups, which indicated diversity among populations. Results showed that the expression level of AeHKT1;4 and AeNHX1 were significantly induced during salinity stress treatments (50 and 200 mM), while AeHKT1;4 showed relative expression in roots, and AeNHX1 was expressed in leaves under the control conditions. Compared with the control conditions, the expression level of AeHKT1;4 significantly increased 1.7-fold under 50 mM salinity stress and 4.7-fold under 200 mM salinity stress in the roots of Ae. tauschii. AeNHX1 showed a relative expression level of 1.6-fold under 50 mM salinity stress and 4.6-fold under 200 mM salinity stress compared with the control conditions. The results provide strong evidence that, under salinity stress conditions, AeHKT1;4 and AeNHX1 synergistically regulate the Na+ homeostasis through regulating Na+ transport in Ae. tauschii. AeNHX1 sequestrated the Na+ into vacuoles, which control the regulation of Na+ transport from roots to leaves under salinity stress conditions in Ae. tauschii.

Soybean is an important oilseed crop that provides high-quality protein and vegetable oil. Salinity constitutes a negative abiotic factor that reduces soybean plant growth, production, and quality. The adsorption of Na+ by chitosan-modified biochar (CMB) has a significant effect on salinity but the application of CMB is limited in soybean. In the current study, CMB was used for characterization of physiological, biochemical, and molecular responses of soybean under salt stress. Comparison of CMB and unmodified (as-is) biochar (BR) demonstrated a significant difference between them shown by using Fourier transform infrared spectroscopy (FTIR), scan electron microscopy (SEM), Brunauer–Emmett–Teller (BET), elemental analysis and z-potential measurement. Pseudo-first and second-order better suited for the analysis of Na+ adsorption kinetics. The salt-stress reduced the soybean plants growth, root architecture characteristics, biomass yield, nutrients acquisition, chlorophyll contents, soluble protein, and sugar contents, while CMB with salt-stress significantly increased the above parameters. Moreover, CMB also reduced the salinity-induced increase in the Na+, glycine betaine (GB), proline, hydrogen peroxide (H2O2), and malondialdehyde (MDA) levels in plants. The antioxidant activity and gene expression levels triggered by salinity but with the application of CMB significantly further boosted the expression profile of four genes (CAT, APX, POD and SOD) encoding antioxidant enzyme and two salt-tolerant conferring genes (GmSALT3 and CHS). Overall, these findings demonstrate the crucial role of CMB in minimizing the adverse effects of high salinity on soybean growth and efficiency of the mechanisms enabling plant protection from salinity through a shift of the architecture of the root system and enhancing the antioxidant defense systems and stress-responsive genes for achieving sustainable crop production.

Biostimulants such as seaweed extracts are widely used to stimulate plant growth and crop productivity under optimal or stressful conditions, constituting a sustainable strategy to mitigate the impacts of abiotic stress on plant performance. In this study, a growth experiment was conducted to evaluate the effects of an aqueous extract from the seaweed Padina gymnospora on the physiological, biochemical, and molecular characteristics of Solanum lycopersicum under salt stress. The experiment included four treatments: 1) control plants, 2) plants irrigated with 300 mM NaCl solution, 3) plants treated with the P. gymnospora extract, and 4) plants treated with the P. gymnospora extract and irrigated with 300 mM NaCl solution. Salt stress increased the activity of antioxidant enzymes (catalase and superoxide dismutase) and resulted in the overaccumulation of the osmolyte proline and flavonoids while enhancing photosynthetic performance and chlorophyll content. In addition, treatment with P. gymnospora extract increased total reducing sugars and phenols in salt-stressed plants, which was correlated with DPPH and ABTS antioxidant activity. The induction of stress-responsive genes, such as SlHB7, SlSOD1, SlRD29 , and SlHKT, appears to be a major factor modulating the responses to P. gymnospora extract application in tomato plants. The results of this study demonstrate that the application of P. gymnospora to tomato plants attenuated the damage caused by salt stress. It is essential to continue studying the potential of seaweed extracts to mitigate stress in plants, given the promising agricultural applications of these novel biostimulants.

Abiotic stress plays a substantial role in morphological and physiological changes of plants leading to yield loss. Drought and salinity tolerance ( DST ) is a zinc finger protein serving an indispensable function in stress resilience through modulation of stomatal closure. Yet, no known report of their roles in sugarcane exists. This research presents a comprehensive study on isolation, characterization and identification of ShDST genes by employing a combination of in silico and experimental methods. The isolated full-length coding region of the ShDST gene transcribed a single open reading frame of 810 base pairs encoding 269 amino acids possessing a molecular weight of 27.7 kilo Daltons and an isoelectric point (Pi) of 7.70. Subcellular localization studies highlighted the presence of ShDST within the nucleus. A molecular docking study revealed a significant affinity between ShDST and Hydrogen peroxide suggesting a potential interaction and implication for oxidative stress response. In the course of this investigation, a total of 21 genes were identified utilizing Hidden Markov Models, for comprehensive genome-wide identification, contributing to a deeper understanding of genetic diversity and variation within the Saccharum species. Comparative evolutionary analysis, including phylogeny, collinearity, and synteny analysis was employed to compare the Saccharum DST gene families with various crops under Poaceae family. A heat map representation of Cis-element occurrence further elucidated the distribution and abundance of the regulatory elements, providing a valuable tool for assessing potential transcriptional activity and regulatory significance. This first systematic analysis of DST families in sugarcane provides a basis for further functional study and provides valuable insights into the potential to enhance crop breeding practices for improved sustainability and adaptability to challenging environmental conditions in sugarcane.

Biochar application is a promising sustainable strategy for enhancing soil properties thus crop production. However, biochar application to soil certainly alters its biological and physical properties, and could require extra costs. Therefore, biochar suitability to agroecosystems must be proactively estimated. The advantage of biochar addition to poor fertile or weathered soils has been well studies, however, its feasibility to fertile soil under low quality (saline) irrigation water was not frequently studied. Consequently, this work investigates the hypothesis of whether the application of biochar at a rate of 4.8 tons/ha to fertile soil (Nile Valley, Giza, Egypt) would ameliorate the negative effects of saline irrigation regime (3000 ppm) on tomato crop and soil. The results of two seasons experiments showed that saline irrigation significantly reduced tomato crop yield by an average reduction ratio of 51%, and biochar addition could not compensate such reduction. Furthermore, biochar did not reduce accumulated Na+ in fruits or roots. Tomato fruits produced from biochar-added soil were lower in TSS levels (41.7% reduction ratio) yet larger in diameter by approximately 1.5-fold increase. Interestingly, biochar addition into soil greatly promotes the length of stem-borne lateral roots and elevates the expression of LeNR (encodes nitrate reductase enzyme) in leaves yet under fresh irrigation regime. For soil properties, biochar application enhanced the soil properties under either saline or fresh water irrigation conditions. Collectively, it is assumed that biochar application to fertile soil in Nile Valley of Egypt could not alleviate tomato fruits yield reduction affected by applied saline irrigation regime.

Plant growth promoting rhizobacteria such as Azospirillum brasilense are agronomically important as they are frequently used for crop inoculation. But adverse factors such as increasing soil salinity limit their survival, multiplication and phytostimulatory effect. In order to understand the role of the genes involved in the adaptation of A. brasilense Sp7 to salt stress, a mutant library (6,800 mutants) was constructed after random integration of a mini-Transposon Tn5 derivative containing a promoterless gusA and oriV. The library was screened for salt stress inducible Gus activity on minimal malate agar medium containing NaCl and 5-bromo-4-chloro-3-indolyl-β-d-glucuronide. Salt stress responsiveness of the promoters was estimated by quantifying GusA activity in the presence and absence of NaCl stress using p-nitrophenyl-β-d-glucuronide as a substrate. In 11 mutants showing high levels of gusA expression in the presence of salt-stress, the partial nucleotide sequence of the DNA region flanking the site of Tn5 insertion was determined and analysed using the NCBI-BLAST programs. Similarity searches revealed that 10 out of the 11 genes sequenced showed notable similarity with genes involved in functions related to modulation in the composition of exopolysaccharides, capsular polysaccharides, lipopolysaccharides, peptidoglycan and lipid bilayer of the cell envelope. Induction of cell envelope related genes in response to salt stress and salt sensitive phenotype of several mutants in A. brasilense indicate a prominent role of cell envelope in salt-stress adaptation.

This study was designed to determine ZmHKT1; 5 gene expression in relatively salt tolerant using four maize genotypes (Alfajr and Almaha and medium-tolerant ones T1 and T6) within cellular level. Three salinity levels (2, 8, and 16 ds / m. Were used immature seeds were surface sterilized and embryos were dissected under full sterilization conditions. Callus was initiated from immature embryos of the above four genotypes on Skoog and Murashige (MS) medium supplemented with the required growth regulators (3 mg/L 2, 4-D +0.5 mg/L kinetin) and recultured for three times and transferred to the stress medium containing NaCl. K+/Na+ and Ca+ / Na+ were measured and ZmHKT1; 5 gene expression was estimated using Real-time PCR in callus cultures after tree cultures. Results indicated that a significant decrease in calcium and potassium ion concentrations with increasing NaCl level. The highest concentration was recorded in the genotype Almaha, while the lowest was in Alfajr. The highest concentration of gene ZmHKT1; 5 expression was achieved in the Alfajr genotype reached 5.59 at 16 ds/m. تهدف هذه الدراسة لتشخيص الجين المتحمل للملوحة ZmHKT1; 5 و دراسة تعبيره الجيني باستخدام أربعة تراكيب وراثية من الذرة الصفراء (الفجر و المها المتحملة للملوحة و المتوسطة التحمل للملوحة T1 و T6) ضمن ثلاث مستويات من الملوحة (2، 8، 16) ديسيسمنز/م). عقمت البذور الغير ناضجة سطحيا و من ثم تم استئصال الأجنة تحت ظروف التعقيم الكاملة. تم زراعة الأجنة و تحفيز الكالس عن طريق زراعتها في الوسط الغذائي (MS) الحاوية على منظمات النمو (3 2، 4-D ملغم/لتر + الكاينتين 5 ملغم/لتر) و من ثم إعادة زراعتها ثلاث مرات و نقلها إلى وسط ملحي حاوي على كلوريد الصوديوم. تم قياس نسبة الصوديوم / الكالسيوم و نسبة الصوديوم / البوتاسيوم و دراسة التعبير الجيني للجين ZmHKT1; 5 بواسطة تقنيةReal-time PCR. أشارت النتائج حدوث انخفاض معنوي في أيون البوتاسيوم و الكالسيوم بزيادة مستويات الملوحة. سجل التركيب الوراثي المها أعلى تركيز و أقل منه الفجر. الجين ZmHKT1; 5 أعطى تعبير جيني في التراكيز العالية من الملح حيث أعطى التركيب الوراثي الفجر تعبيرا 5.59 في المستوى الملحي 16 ديسسمنز/م).

Soil salinity is becoming a growing issue nowadays, severely affecting the world’s most productive agricultural landscapes. With intersecting and competitive challenges of shrinking agricultural lands and increasing demand for food, there is an emerging need to build resilience for adaptation to anticipated climate change and land degradation. This necessitates the deep decoding of a gene pool of crop plant wild relatives which can be accomplished through salt-tolerant species, such as halophytes, in order to reveal the underlying regulatory mechanisms. Halophytes are generally defined as plants able to survive and complete their life cycle in highly saline environments of at least 200-500 mM of salt solution. The primary criterion for identifying salt-tolerant grasses (STGs) includes the presence of salt glands on the leaf surface and the Na + exclusion mechanism since the interaction and replacement of Na + and K + greatly determines the survivability of STGs in saline environments. During the last decades or so, various salt-tolerant grasses/halophytes have been explored for the mining of salt-tolerant genes and testing their efficacy to improve the limit of salt tolerance in crop plants. Still, the utility of halophytes is limited due to the non-availability of any model halophytic plant system as well as the lack of complete genomic information. To date, although Arabidopsis ( Arabidopsis thaliana ) and salt cress ( Thellungiella halophila ) are being used as model plants in most salt tolerance studies, these plants are short-lived and can tolerate salinity for a shorter duration only. Thus, identifying the unique genes for salt tolerance pathways in halophytes and their introgression in a related cereal genome for better tolerance to salinity is the need of the hour. Modern technologies including RNA sequencing and genome-wide mapping along with advanced bioinformatics programs have advanced the decoding of the whole genetic information of plants and the development of probable algorithms to correlate stress tolerance limit and yield potential. Hence, this article has been compiled to explore the naturally occurring halophytes as potential model plant species for abiotic stress tolerance and to further breed crop plants to enhance salt tolerance through genomic and molecular tools.

Improper use of water resources in irrigation that contain a significant amount of salts, faulty agronomic practices such as improper fertilization, climate change etc. are gradually increasing soil salinity of arable lands across the globe. It is one of the major abiotic factors that inhibits overall plant growth through ionic imbalance, osmotic stress, oxidative stress, and reduced nutrient uptake. Plants have evolved with several adaptation strategies at morphological and molecular levels to withstand salinity stress. Among various approaches, harnessing the crop genetic variability across different genepools and developing salinity tolerant crop plants offer the most sustainable way of salt stress mitigation. Some important major genetic determinants controlling salinity tolerance have been uncovered using classical genetic approaches. However, its complex inheritance pattern makes breeding for salinity tolerance challenging. Subsequently, advances in sequence based breeding approaches and functional genomics have greatly assisted in underpinning novel genetic variants controlling salinity tolerance in plants at the whole genome level. This current review aims to shed light on physiological, biochemical, and molecular responses under salt stress, defense mechanisms of plants, underlying genetics of salt tolerance through bi-parental QTL mapping and Genome Wide Association Studies, and implication of Genomic Selection to breed salt tolerant lines.

Main conclusion There is a need to integrate conceptual framework based on the current understanding of salt stress responses with different approaches for manipulating and improving salt tolerance in crop plants. Soil salinity exerts significant constraints on global crop production, posing a serious challenge for plant breeders and biotechnologists. The classical transgenic approach for enhancing salinity tolerance in plants revolves by boosting endogenous defence mechanisms, often via a single-gene approach, and usually involves the enhanced synthesis of compatible osmolytes, antioxidants, polyamines, maintenance of hormone homeostasis, modification of transporters and/or regulatory proteins, including transcription factors and alternative splicing events. Occasionally, genetic manipulation of regulatory proteins or phytohormone levels confers salinity tolerance, but all these may cause undesired reduction in plant growth and/or yields. In this review, we present and evaluate novel and cutting-edge approaches for engineering salt tolerance in crop plants. First, we cover recent findings regarding the importance of regulatory proteins and transporters, and how they can be used to enhance salt tolerance in crop plants. We also evaluate the importance of halobiomes as a reservoir of genes that can be used for engineering salt tolerance in glycophytic crops. Additionally, the role of microRNAs as critical post-transcriptional regulators in plant adaptive responses to salt stress is reviewed and their use for engineering salt-tolerant crop plants is critically assessed. The potentials of alternative splicing mechanisms and targeted gene-editing technologies in understanding plant salt stress responses and developing salt-tolerant crop plants are also discussed.