Salinity Tolerance Of Crops Research Articles

RNA-Seq and WGCNA Analyses Reveal Key Regulatory Modules and Genes for Salt Tolerance in Cotton.

The problem of soil salinization has seriously hindered agricultural development. Cotton is a pioneering salinity-tolerant crop, so harvesting its key salinity-tolerant genes is important for improving crop salt tolerance. In this study, we analyzed changes in the transcriptome expression profiles of the salt-tolerant cultivar Lu Mian 28 (LM) and the salt-sensitive cultivar Zhong Mian Suo 12 (ZMS) after applying salt stress, and we constructed weighted gene co-expression networks (WGCNA). The results indicated that photosynthesis, amino acid biosynthesis, membrane lipid remodeling, autophagy, and ROS scavenging are key pathways in the salt stress response. Plant-pathogen interactions, plant hormone signal transduction, the mitogen-activated protein kinase (MAPK) signaling pathway, and carotenoid biosynthesis are the regulatory networks associated with these metabolic pathways that confer cotton salt tolerance. The gene-weighted co-expression network was used to screen four modules closely related to traits, identifying 114 transcription factors, including WRKYs, ERFs, NACs, bHLHs, bZIPs, and MYBs, and 11 hub genes. This study provides a reference for acquiring salt-tolerant cotton and abundant genetic resources for molecular breeding.

Role of iron oxide nanoparticles in maize (Zea mays L.) to enhance salinity stress tolerance

Soils have been getting worse over time, which has led to lower crop yields and nutritional value. This is because of too many conventional fertilizers, anthropogenic activities, and climate change. Soil salinity is also a big problem and challenge for agricultural scientists. To address this issue, nanoparticles are gaining a reputation in agriculture that can enhance salinity tolerance in crops, especially at early growth stages. A pot experiment was conducted at Post Agricultural Research Station (PARS), Faisalabad to assess the impact of iron oxide nanoparticles (0, 15, and 30 ppm) and four levels of salinity (0, 50, 100 and 150 mM) on morphological, physiological and yield traits of maize (Zea mays L.) in salinity stress. Salinity stress significantly negatively affected the growth attributes, photosynthetic pigments, ion content (Na+, K+, and Ca2+) of maize plants. Salinity has also increased the levels of MDA, H2O2, and Na+ ions. The application of iron oxide nanoparticles through foliar spray had a notable impact in enhancing the growth and yield of the tested maize variety. It was achieved by promoting the activities of antioxidant enzymes, increasing photosynthetic pigments, and elevating K+ and Ca2+ ion levels under both normal and salinity-stressed conditions. Additionally, iron oxide nanoparticles mitigated the adverse effects of salinity stress by effectively reducing Na+ ion concentration, MDA levels, and H2O2 concentration. Among the different concentrations tested, 30 ppm of iron oxide nanoparticles proved best in alleviating the negative impacts of salinity stress in maize. Thus, field use of 30 ppm iron oxide nanoparticles as foliar spray could effectively mitigate salinity stress in maize.

Regulation of nitro-oxidative homeostasis: an effective approach to enhance salinity tolerance in plants.

Soil salinity is a major constraint for sustainable agricultural productivity, which together with the incessant climate change may be transformed into a severe threat to the global food security. It is, therefore, a serious concern that needs to be addressed expeditiously. The overproduction and accumulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the key events occurring during salt stress, consequently employing nitro-oxidative stress and programmed cell death in plants. However, very sporadic studies have been performed concerning different aspects of nitro-oxidative stress in plants under salinity stress. The ability of plants to tolerate salinity is associated with their ability to maintain the cellular redox equilibrium mediated by both non-enzymatic and enzymatic antioxidant defense mechanisms. The present review emphasizes the mechanisms of ROS and RNS generation in plants, providing a detailed evaluation of how redox homeostasis is conserved through their effective removal. The uniqueness of this article stems from its incorporation of expression analyses of candidate genes for different antioxidant enzymes involved in ROS and RNS detoxification across various developmental stages and tissues of rice, utilizing publicly available microarray data. It underscores the utilization of modern biotechnological methods to improve salinity tolerance in crops, employing different antioxidants as markers. The review also explores how various transcription factors contribute to plants' ability to tolerate salinity by either activating or repressing the expression of stress-responsive genes. In summary, the review offers a thorough insight into the nitro-oxidative homeostasis strategy for extenuating salinity stress in plants.

From swamp to field: how genes from mangroves and its associates can enhance crop salinity tolerance.

Salinity stress is a critical challenge in crop production and requires innovative strategies to enhance the salt tolerance of plants. Insights from mangrove species, which are renowned for their adaptability to high-salinity environments, provides valuable genetic targets and resources for improving crops. A significant hurdle in salinity stress is the excessive uptake of sodium ions (Na+) by plant roots, causing disruptions in cellular balance, nutrient deficiencies, and hampered growth. Specific ion transporters and channels play crucial roles in maintaining a low Na+/K+ ratio in root cells which is pivotal for salt tolerance. The family of high-affinity potassium transporters, recently characterized in Avicennia officinalis, contributes to K+ homeostasis in transgenic Arabidopsis plants even under high-salt conditions. The salt overly sensitive pathway and genes related to vacuolar-type H+-ATPases hold promise for expelling cytosolic Na+ and sequestering Na+ in transgenic plants, respectively. Aquaporins contribute to mangroves' adaptation to saline environments by regulating water uptake, transpiration, and osmotic balance. Antioxidant enzymes mitigate oxidative damage, whereas genes regulating osmolytes, such as glycine betaine and proline, provide osmoprotection. Mangroves exhibit increased expression of stress-responsive transcription factors such as MYB, NAC, and CBFs under high salinity. Moreover, genes involved in various metabolic pathways, including jasmonate synthesis, triterpenoid production, and protein stability under salt stress, have been identified. This review highlights the potential of mangrove genes to enhance salt tolerance of crops. Further research is imperative to fully comprehend and apply these genes to crop breeding to improve salinity resilience.

Quinoa–Olive Agroforestry System Assessment in Semi-Arid Environments: Performance of an Innovative System

Agroforestry is a promising way to sustain land use efficiency in semi-arid areas. In this study, we introduce quinoa as a drought- and salinity-tolerant crop in olive-based agroforestry. We investigated how the microclimate created by olive trees affects agronomic and biochemical traits in quinoa and evaluated the performance of this new olive-based agroforestry system in terms of land equivalent ratio (LER). Field experiments were carried out under two pedoclimatic conditions (S1) and (S2) using a randomized complete block design with two cropping systems (sole crop (SCS) and agroforestry (AFS) systems), four quinoa cultivars (Puno, Titicaca, ICBA-Q5, and ICBA-Q4) and one olive orchard as a control (OR) in each block. Our results show that AFS had lower grain yield (−45%), dry biomass (−49%), and crop water productivity (−44%), but higher plant height (12%), grain protein (4%), saponin (26%), total polyphenol (12%), and DPPH (9%) contents compared to SCS. The highest grain yield was recorded for Titicaca and ICBA-Q5 (1.6 t ha−1). The LER ranged from 1.57 to 2.07, indicating that the overall productivity was 57% to 107% higher in the agroforestry system compared with the monoculture. We suggest that quinoa–olive tree intercropping could be a promising agroecological practice under semi-arid conditions.

Characterization of a Novel Polysaccharide Derived from Rhizospheric Paecilomyces vaniformisi and Its Mechanism for Enhancing Salinity Resistance in Rice Seedlings.

Soil salinity is an important limiting factor in agricultural production. Rhizospheric fungi can potentially enhance crop salinity tolerance, but the precise role of signaling substances is still to be systematically elucidated. A rhizospheric fungus identified as Paecilomyces vaniformisi was found to enhance the salinity tolerance of rice seedlings. In this study, a novel polysaccharide (PPL2b) was isolated from P. vaniformisi and identified as consisting of Manp, Glcp, GalpA, and Galp. In a further study, PPL2b showed significant activity in alleviating salinity stress-induced growth inhibition in rice seedlings. The results indicated that under salinity stress, PPL2b enhances seed germination, plant growth (height and biomass), and biochemical parameters (soluble sugar and protein contents). Additionally, PPL2b regulates genes such as SOS1 and SKOR to decrease K+ efflux and increase Na+ efflux. PPL2b increased the expression and activity of genes related to antioxidant enzymes and nonenzyme substances in salinity-induced oxidative stress. Further study indicated that PPL2b plays a crucial role in regulating osmotic substances, such as proline and betaine, in maintaining the osmotic balance. It also modulates plant hormones to promote rice seedling growth and enhance their tolerance to soil salinity. The variables interacted and were divided into two groups (PC1 77.39% and PC2 18.77%) based on their relative values. Therefore, these findings indicate that PPL2b from P. vaniformisi can alleviate the inhibitory effects of salinity stress on root development, osmotic adjustment, ion balance, oxidative stress balance, and growth of rice seedlings. Furthermore, it suggests that polysaccharides produced by rhizospheric fungi could be utilized to enhance crop tolerance to salinity.

Nano-silicone and Ascophyllum nodosum-based biostimulant down-regulates the negative effect of in vitro induced-salinity in Rosa damascena

BackgroundRosa damascena is extensively cultivated in various regions of Iran due to its aesthetic attributes, medicinal qualities, and essential oil production. This study investigated the efficacy of Ascophyllum nodosum extract (AnE) at concentrations of 0, 2, and 3 g L− 1 and Nano-silicon (nSiO2) at concentrations of 0, 50, and 100 mg L− 1 in ameliorating the impact of salinity on two genotypes of Damask rose (‘Chaharfasl’ and ‘Kashan’) under in vitro culture conditions. Additionally, various physio-chemical characteristics of R. damascena explants were assessed.ResultsThe findings revealed that exposure to 100 mM NaCl resulted in a substantial reduction in the Relative Water Content (RWC), Membrane Stability Index (MSI), leaf pigments (Chlorophyll b, Chlorophyll a, total Chlorophyll, and carotenoids), chlorophyll fluorescence parameters, and protein content in both genotypes when compared to control conditions. Salinity induced a significant increase in the parameter F0 and a decrease in the parameter Fv/Fm compared to the control conditions in both genotypes. Nonetheless, the genotype Kashan treated with 3 g L− 1 AnE + 100 mg L− 1 nSiO2 exhibited the maximum Fm value under control conditions, with a significant difference compared to other treatments. Furthermore, salinity caused a considerable reduction in Fm in both ‘Kashan’ and ‘Chaharfasl’ by 22% and 17%, respectively, when compared to the control condition. ‘Kashan’ displayed the maximum Fv/Fm compared to the other genotype. The maximum levels of Malondialdehyde (MAD) and hydrogen peroxide (H2O2) were also observed in explants affected by salinity. The combination of 3 g L− 1 AnE + 100 mg L− 1 nSiO2, followed by 2 g L− 1 AnE + 100 mg L− 1 nSiO2, exhibited substantial positive effects. Salinity also led to an increase in proline content and the activity of peroxidase (POD), superoxide dismutase (SOD), guaiacol peroxidase (GPX), and catalase (CAT) in both genotypes. The activity of these enzymes was further enhanced when AnE was applied at concentrations of 2 and 3 g L− 1 in combination with 100 mg L− 1 nSiO2.ConclusionsThe ‘Kashan’ genotype displayed greater tolerance to salinity by enhancing water balance, maintaining membrane integrity, and augmenting the activity of antioxidant enzymes compared to ‘Chaharfasl’. The utilization of nSiO2 and AnE biostimulants demonstrated potential benefits for R. damascena, both under salinity and control conditions. These findings hold substantial importance for researchers, policymakers, and farmers, offering valuable insights into the development of salinity-tolerant crop varieties.

Morphological and biochemical variations caused by salinity stress in some varieties of Pennisetum glaucum L.

The salinity of the soil is a severe challenge to the sustainability of agricultural production. It causes significant loss in the productivity of crop plants. To overcome this problem, one of the possible solutions could be the identification and cultivation of salinity tolerant crop plants in salt affected land. Therefore, this study was designed to screen some varieties of Pearl Millet (Pennisetum glaucum L. Family Poaceae), an equally important cereal crop for food and forage, for salinity tolerance in a pot experiment. Some eighteen varieties of Pearl Millet were utilized to investigate the morphometric and biochemical variations induced by saline stress. The plants were grown for three weeks under normal conditions in sand culture in disposable PVP cups with three inches diameter. Afterwards, the plants were challenged with salinity stress (aqueous solution of NaCl applied in successive steps of 50, 100, 150 and 200 mM with Hoagland’s nutrients). The plants adopted salinity stress after one week and harvested for various physio-biochemical attributes. The results showed that the varieties YBS-93, YBS-94, YBS-95 and YDR-8-1 exhibited tolerance toward salinity stress as their shoot length, root length, biomass production and K+ was maintained under salt stress. The levels of proline contents and free amino acids in their leaves were relatively higher under salt stress as compared with other varieties. The accumulation of Na+ in theses varieties was lower as compared to other varieties under saline stress. These findings indicated their potential strategy to cope with salinity stress. While theYBS-83, YBS-98, YCMP-19 and YCMP-34 varieties among the subjected eighteen varieties of Pearl Millet were screened as most sensitive varieties to salinity stress in these experimental conditions. Because these varieties had reduction in shoot length, root length biomass production and K+. Other varieties did not show any significant success in salinity stress management. This study has provided significant preliminary screening data of morphological and biochemical aspects of eighteen varieties of Pearl Millet for their capability of salinity tolerance. Further molecular investigations are underway which will be helpful in revealing insights of the salt tolerance mechanism and signaling pathways in the screened salt tolerant varieties.

Plant growth-promoting endophytic fungi of the wild halophytic rice Oryza coarctata

BackgroundPlant growth-promoting endophytic fungi (PGPEF) that are associated with halophytes have the potential to boost crop salinity tolerance and productivity. This in turn has the potential of enabling and improving cultivation practices in coastal lands affected by salt stress.MethodsEndophytic fungi from the wild halophytic rice Oryza coarctata were isolated, characterized, identified, and studied for their effects on all developing stages of rice plant growth and their yields both with and without salt stress.Key resultsIn this study, three different fungal endophytes were isolated from the halophytic wild rice Oryza coarctata. Two isolates were identified as Talaromyces adpressus (OPCRE2) and Talaromyces argentinensis (OPCRh1) by ITS region sequencing. The remaining isolate NPCRE2 was confirmed as a novel strain named Aspergillus welwitschiae Ocstreb1 (AwOcstreb1) by whole genome sequencing. These endophytes showed various plant growth-promoting (PGP) abilities in vitro (e.g., IAA, ACC-deaminase and siderophore production, phosphate, and zinc solubilization as well as nitrogen fixation), where AwOcstreb1 was significantly more efficient compared to the other two isolates at high salinity (900 mm). Independent application of these fungi in commercial rice (Oryza sativa) showed significant elevation in plant growth, especially in the case of the AwOcstreb1 inoculants, which had enhanced metabolite and chlorophyll content at the seedling stage in both no-salt control and 100-mm salt-stressed plants. At the same time, AwOcstreb1-treated plants had a significantly lower level of H2O2, electrolyte leakage, and Na+/K+ ratio under saline conditions. Higher expression (1.6 folds) of the SOS1 (salt overly sensitive 1) gene was also observed in these plants under salinity stress. This strain also improved percent fertility, tillering, panicle number, and filled grain number in both no-salt control and 45-mm salt-stressed inoculated plants at the reproductive stage. Consequently, the differences in their yield was 125.16% and 203.96% (p < 0.05) in colonized plants in normal and saline conditions, respectively, compared to uninoculated controls.ConclusionsWe propose that AwOcstreb1 is a potential candidate for an eco-friendly biofertilizer formula to improve the cultivation and yield of rice or any other crop in the highly saline coastal regions of Bangladesh.

Computational and experimental analysis of foxtail millet under salt stress and selenium supplementation.

Salinity stress is a major threat to crop growth and productivity. Millets are stress-tolerant crops that can withstand the environmental constraints. Foxtail millet is widely recognized as a drought and salinity-tolerant crop owing to its efficient ROS scavenging mechanism. Ascorbate peroxidase (APX) is one of the reactive oxygen species (ROS) scavenging enzymes that leads to hydrogen peroxide (H2O2) detoxification and stabilization of the internal biochemical state of the cell under stress. This inherent capacity of the APX enzyme can further be enhanced by the application of an external mitigant. This study focuses on the impact of salt (NaCl) and selenium (Se) application on the APX enzyme activity of foxtail millet using in silico and in-vitro techniques and mRNA expression studies. The NaCl was applied in the concentrations, i.e., 150mM and 200mM, while the Se was applied in 1μM, 5μM, and 10μM concentrations. The in silico studies involved three-dimensional structure modeling and molecular docking. The in vitro studies comprised the morphological and biochemical parameters, alongside mRNA expression studies in foxtail millet under NaCl stress and Se applications. The in silico studies revealed that the APX enzyme showed better interaction with Se as compared to NaCl, thus suggesting the enzyme-modulating role of Se. The morphological and biochemical analysis indicated that Se alleviated the NaCl (150mM and 200mM) and induced symptoms at 1µM as compared to 5 and 10µM by enhancing the morphological parameters, upregulating the gene expression and enzyme activity of APX, and ultimately reducing the H2O2 content significantly. The transcriptomic studies confirmed the upregulation of chloroplastic APX in response to salt stress and selenium supplementation. Hence, it can be concluded that Se as a mitigant at lower concentrations can alleviate NaCl stress in foxtail millet.

Impacts of salinity stress on crop plants: improving salt tolerance through genetic and molecular dissection.

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.

Salinity hazard drives the alteration of occupation, land use and ecosystem service in the coastal areas: Evidence from the south-western coastal region of Bangladesh

Understanding the salinity effects on the rural livelihood and ecosystems services are essential for policy implications and mitigations. Salinity-driven modulation in land use and land cover, community traditional occupations, and ecosystem service have been elucidated in the present investigation. The study was carried out in the south-western region of Bangladesh as a representative case using focus group discussions, questionnaire survey, and remote sensing techniques. The findings showed that salinity-induced land use changes seriously threatened ecosystem services, employment and livelihoods. Shrimp farming was found to have replaced the majority of agricultural and bare lands, which led to the poor locals losing their land. The increasing land transformation to shrimp ponds as a coping strategy with salinity was not reported to be a viable option as maximum marginal poor people were unable to run the capital-intensive shrimp aquaculture. Eventually, many rich people occupied the cropland for shrimp farming which forced the traditional farmers and fishermen to leave their job and sell their labor. Many of the traditional services derived from the ecosystems were drastically reduced or got lost. The ultimate effect on the traditional livelihoods of the communities increased vulnerability and reduced resilience. The findings could aid in formulating realistic policies and action for ensuring the future resilience of the community through an appropriate adaptation strategy, such as introducing salinity-tolerant crops and integrated farming to safeguard the interest of the poor farmers. Despite the geographical locality of the study, its implications are global given the identical salinity concerns in other emerging nations' coastal regions.

Salicylic Acid and α-Tocopherol Ameliorate Salinity Impact on Wheat.

Background: Soil salinity negatively impacts agricultural productivity. Consequently, strategies should be developed to inculcate a salinity tolerance in crops for sustainable food production. Growth regulators play a vital role in regulating salinity stress tolerance. Methods: Thus, we examined the effect of exogenous salicylic acid (SA) and alpha-tocopherol (TP) (100 mg/L) on the morphophysio-biochemical responses of two wheat cultivars (Pirsabak-15 and Shankar) to salinity stress (0 and 40 mM). Results: Both Pirsabak-15 and Shankar cultivars were negatively affected by salinity stress. For instance, salinity reduced growth attributes (i.e., leaf fresh and dry weight, leaf moisture content, leaf area ratio, shoot and root dry weight, shoot and root length, as well as root-shoot ratio), pigments (chlorophyll a, chlorophyll a, and carotenoids) but increased hydrogen peroxide (H2O2), malondialdehyde (MDA), and endogenous TP in both cultivars. Among the antioxidant enzymes, salinity enhanced the activity of peroxidase (POD) and polyphenol oxidase (PPO) in Pirsabak-15; glutathione reductase (GR) and PPO in Shankar, while ascorbate peroxidase (APOX) was present in both cultivars. SA and TP could improve the salinity tolerance by improving growth and photosynthetic pigments and reducing MDA and H2O2. In general, the exogenous application did not have a positive effect on antioxidant enzymes; however, it increased PPO in Pirsabak-15 and SOD in the Shankar cultivar. Conclusions: Consequently, we suggest that SA and TP could have enhanced the salinity tolerance of our selected wheat cultivars by modulating their physiological mechanisms in a manner that resulted in improved growth. Future molecular studies can contribute to a better understanding of the mechanisms by which SA and TP regulate the selected wheat cultivars underlying salinity tolerance mechanisms.

Worldwide development of agronomic management practices for quinoa cultivation: a systematic review

Quinoa (Chenopodium quinoa Wild.) is a drought and salinity-tolerant crop that originated in the Andes over 7000 years ago. It is adapted to different agroecological areas and can be grown from sea level to an altitude of 4000 m. The outstanding nutritional status of quinoa, with its high content of proteins, vitamins, and minerals, makes it a promising crop able to combat hunger and malnutrition in different countries in the 21st century. Quinoa cultivation has expanded from South America to Africa, Europe, Asia, and North America. Reviewing quinoa cropping practices will provide farmers with adequate recommendations for improving the agronomic and environmental sustainability of quinoa cultivation worldwide. For this reason, we conducted a systematic review of agronomic management practices in 148 field experiments conducted worldwide from 2000 to 2022. The collected data from the literature were analyzed and presented by location to determine high-performing genotypes, optimal planting dates, and other adequate cropping practices affecting quinoa performance and yield. Results showed that quinoa could be successfully cultivated in the new farming areas. Quinoa yields were higher than those reported in its place of origin, ranging from 108 kg ha-1, obtained by KU-2 in Washington State, to 9667 kg ha-1, obtained by Longli in China. Although quinoa is considered a crop with low input requirements, positive grain yield response was observed following increasing fertilization rates. Quinoa needs 2 to 4.6 kg of nitrogen to produce 1q of grain yield. In terms of phosphorus and potassium, quinoa needs 3.7 kg P2O5 and 4.3 kg K2O to produce 1 ton of total biomass. Quinoa has low water requirements (300-400 mm). However, a positive response was recorded with water quantities up to 866 mm. During our investigation, weed control in quinoa crop is still undeveloped and usually done manually. Research addressing this issue can increase quinoa yields and decrease the production cost. Downey mildew and birds’ attack are the major phytosanitary problems affecting quinoa grain yield. Other pests such as miners and aphids can also affect the health of quinoa, but their injury is not a serious problem. After the harvest, saponins found in the out layer of the seed can be removed through washing and mechanical pearling process, but the latter technic was found to be efficient and cost effective to reduce the saponin content. Our results constitute the first recommendation base for the adequate worldwide agronomic practices of quinoa crop.

Developmental Fruit Quality Based Clustered Normalized Maturity Index Can Ensure Proper Harvesting Time of Ber

ABSTRACT Ziziphus mauritiana is a drought and salinity-tolerant crop and one of India’s most crucial arid fruit trees. The present study evaluated the fruit development of ber based on durational advancement in eight different cultivars, viz. Chhuhara, Chinese, Kalagola, Nazuk, Sanaur-2, Sanaur-4, Umran, and ZG-2. The developmental stages were chosen based on the number of days after full bloom: these stages included 28, 42, 56, 70, 84, 98, 112, 126, 140, 154, and 168 days after full bloom. With the advancement in fruit development, fruit firmness continued to decline till 168 days after full bloom. Total carotenoid content and flavonoid content were observed to increase as maturity progressed, but phenolic content decreased. The total antioxidant activity was also found to increase over time. Significant varietal differences were observed in the developmental changes in the quality attributes. To find optimized maturity time, varieties were grouped into four similar clusters. A normalized average maturity index was developed for each cluster. Depending upon the developed maturity index, a harvesting duration of 154 days after full bloom was found suitable for all tested varieties except ZG-2, for which 140 days after full bloom was found ideal as time for commercial harvest. The current experiment simplifies the complex maturity indices to a single harvesting time for each varietal cluster to act as ready recommendations to fruit growers.

Membrane Proteins in Plant Salinity Stress Perception, Sensing, and Response.

Plants have several mechanisms to endure salinity stress. The degree of salt tolerance varies significantly among different terrestrial crops. Proteins at the plant's cell wall and membrane mediate different physiological roles owing to their critical positioning between two distinct environments. A specific membrane protein is responsible for a single type of activity, such as a specific group of ion transport or a similar group of small molecule binding to exert multiple cellular effects. During salinity stress in plants, membrane protein functions: ion homeostasis, signal transduction, redox homeostasis, and solute transport are essential for stress perception, signaling, and recovery. Therefore, comprehensive knowledge about plant membrane proteins is essential to modulate crop salinity tolerance. This review gives a detailed overview of the membrane proteins involved in plant salinity stress highlighting the recent findings. Also, it discusses the role of solute transporters, accessory polypeptides, and proteins in salinity tolerance. Finally, some aspects of membrane proteins are discussed with potential applications to developing salt tolerance in crops.

The epidermal bladder cell-free mutant of the salt-tolerant quinoa challenges our understanding of halophyte crop salinity tolerance.

Halophytes tolerate high salinity levels that would kill conventional crops. Understanding salt tolerance mechanisms will provide clues for breeding salt-tolerant plants. Many halophytes, such as quinoa (Chenopodium quinoa), are covered by a layer of epidermal bladder cells (EBCs) that are thought to mediate salt tolerance by serving as salt dumps. We isolated an epidermal bladder cell-free (ebcf) quinoa mutant that completely lacked EBCs and was mutated in REBC and REBC-like1. This mutant showed no loss of salt stress tolerance. When wild-type quinoa plants were exposed to saline soil, EBCs accumulated potassium (K+ ) as the major cation, in quantities far exceeding those of sodium (Na+ ). Emerging leaves densely packed with EBCs had the lowest Na+ content, whereas old leaves with deflated EBCs served as Na+ sinks. When the leaves expanded, K+ was recycled from EBCs, resulting in turgor loss that led to a progressive deflation of EBCs. Our findings suggest that EBCs in young leaves serve as a K+ -powered hydrodynamic system that functions as a water sink for solute storage. Sodium ions accumulate within old leaves that subsequently wilt and are shed. This mechanism improves the survival of quinoa under high salinity conditions.

Transcriptome Analyses in a Selected Gene Set Indicate Alternative Oxidase (AOX) and Early Enhanced Fermentation as Critical for Salinity Tolerance in Rice.

Plants subjected to stress need to respond rapidly and efficiently to acclimatize and survive. In this paper, we investigated a selected gene set potentially involved in early cell reprogramming in two rice genotypes with contrasting salinity tolerance (Pokkali tolerant and IR29 susceptible) in order to advance knowledge of early molecular mechanisms of rice in dealing with salt stress. Selected genes were evaluated in available transcriptomic data over a short period of 24 h and involved enzymes that avoid ROS formation (AOX, UCP and PTOX), impact ATP production (PFK, ADH and COX) or relate to the antioxidant system. Higher transcript accumulation of AOX (ROS balancing), PFK and ADH (alcohol fermentation) was detected in the tolerant genotype, while the sensitive genotype revealed higher UCP and PTOX transcript levels, indicating a predominant role for early transcription of AOX and fermentation in conferring salt stress tolerance to rice. Antioxidant gene analyses supported higher oxidative stress in IR29, with transcript increases of cytosolic CAT and SOD from all cell compartments (cytoplasm, peroxisome, chloroplast and mitochondria). In contrast, Pokkali increased mRNA levels from the AsA-GSH cycle as cytosolic/mitochondrial DHAR was involved in ascorbate recovery. In addition, these responses occurred from 2 h in IR29 and 10 h in Pokkali, indicating early but ineffective antioxidant activity in the susceptible genotype. Overall, our data suggest that AOX and ADH can play a critical role during early cell reprogramming for improving salt stress tolerance by efficiently controlling ROS formation in mitochondria. We discuss our results in relation to gene engineering and editing approaches to develop salinity-tolerant crops.

Screening Blackgram (Vigna mungo (L.) Hepper) Genotypes for Salt Tolerance at Germination and Seedling Stages

Aim: Salt stress negatively affects the growth and development of plants. An effective and important strategy to develop salinity tolerant crops is to harness the genetic diversity within the crop germplasm by identification of salinity tolerant genotype. The present study was carried out with an objective to screen blackgram genotypes (A31, DPU 968, KU 7720, LBG 787, PLU 621, TMV 1, Tutiminimum, VBG 18028, VBG 18032, and VBN 2) for salt tolerance at germination and seedlings stage and identification of saline tolerant blackgram genotype based on salt stress tolerance indices.&#x0D; Study Design: Factorial and arranged in a completely randomized design.&#x0D; Place and Duration of Study: Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore; May-June 2022.&#x0D; Methodology: Using petriplate and roll towel techniques, blackgram seed germination indices and seedling growth indices such as germination percentage, germination index, mean germination time, seedling vigour index, shoot and root length, fresh and dry seedling weight, and stress tolerance indices were recorded. Two-way ANOVA, Principle Component Analysis (PCA) and Cluster Heat-map Analysis were used to analyze the data.&#x0D; Results: PCA indicates that salinity stress accounted for 86.2 percent of the variation, whereas the individual genotype contributes only 5.4 percent of the variation observed in germination and growth parameters that were studied in blackgram under control and 130mM NaCl salt stress conditions. Among the ten blackgram genotypes, stress tolerance index was highest for LBG 787 (0.831) followed by KU7720 (0.722). On the other side, the stress susceptible index was found to be lower for the blackgram genotype KU7720 (0.335) followed by LBG 787 (0.592), as compared to other genotypes screened. Cluster heat-map analysis for all the measured parameters revealed that blackgram genotype LBG 787 was clustered with PLU 621 and VBG 18028 and found to tolerate the salt stress level (130mM NaCl stress) compared to other blackgram genotypes.&#x0D; Conclusion: Observations indicate that the blackgram genotypes KU 7720, LBG 787, PLU 621 and VBG 18028 exhibit greater tolerance towards salinity during the germination and seedling growth stages.

Salinity impacts on irrigation water-scarcity in food bowl regions of the US and Australia

Irrigation water use and crop production may be severely limited by both water shortages and increased salinity levels. However, impacts of crop-specific salinity limitations on irrigation water scarcity are largely unknown. We develop a salinity-inclusive water scarcity framework for the irrigation sector, accounting for crop-specific irrigation water demands and salinity tolerance levels and apply it to 29 sub-basins within two food bowl regions; the Central Valley (CV) (California) and the Murray–Darling basin (MDB) (Australia). Our results show that severe water scarcity (levels >0.4) occurs in 23% and 66% of all instances (from >17 000 monthly crop-specific estimates) for the CV and MDB, respectively. The highest water scarcity levels for both regions occurred during their summer seasons. Including salinity and crop-specific salinity tolerance levels further increased water scarcity levels, compared to estimations based on water quantity only, particularly at local sub-basin scales. We further investigate the potential of alleviating water scarcity through diluting surface water with lower saline groundwater resources, at instances where crop salinity tolerance levels are exceeded (conjunctive water use). Results from the CV highlights that conjunctive water use can reduce severe water scarcity levels by up to 67% (from 946 monthly instances where surface water salinity tolerance levels were exceeded). However, groundwater dilution requirements frequently exceed renewable groundwater rates, posing additional risks for groundwater depletion in several sub-basins. By capturing the dynamics of both crops, salinity and conjunctive water use, our framework can support local-regional agricultural and water management impacts, on water scarcity levels.