Higher Proline Research Articles

The relationship between COMT, proline, and negative symptoms in clinical high risk and recent psychosis onset

Individuals at clinical high-risk (CHR) of developing psychosis, as well as patients with recent psychosis onset (RO), experience significant negative symptoms that detrimentally impact daily-life functioning and are associated with poor outcomes, even in those who do not convert to psychosis. Targeting negative symptoms may thus hold promise for the treatment of CHR and RO patients. Building from previous findings we examined whether the catechol-O-methyltransferase (COMT) Val158Met functional polymorphism and fasting peripheral proline concentration predicts the severity of negative symptoms experienced by adolescents and young adults at CHR or those with RO. As hypothesized, the interaction between fasting plasma proline and COMT predicted negative symptoms, as measured via the Scale for the Assessment of Negative Symptoms (SANS) total (n = 50, β = 0.066, adjusted p = 0.007) and global severity scores (n = 50, coefficient = 0.026, adjusted p = 0.003): Higher proline was beneficial for Val/Val subjects, but detrimental to those with the Met allele. In a secondary analysis, the COMT x proline interaction also predicted symptoms measured via the Clinical Assessment Interview for Negative Symptoms (CAINS) total scores (n = 50, β-coefficient = 0.035, adjusted p = 0.044), although this result did not reach the Benjamini-Hochberg’s threshold for significance. Further, there was a trend towards significance for an association with social and interpersonal function (Global Functioning-Social, coefficient = −0.005, adjusted p = 0.055). Negative symptoms are intractable and largely unaddressed by current medications. This study further supports a relationship between peripheral proline and COMT influencing negative symptoms such as anhedonia, in young CHR individuals and those with RO. That higher proline has converse effects on symptoms by COMT may have implications for the development of therapeutics to intervene early and specifically target the interaction pathway.

The Efficiency of Seed Priming with Dead Sea Water for Improving Germination and Early Seedling Growth of Wheat (Triticum aestivum L.) under Salinity

<p>Salinity is considered the most critical environmental factor which negatively affects the germination and growth of plants. In this study, the potential of using Dead Sea water (DS) as a seed priming agent for the mitigation of the adverse effects of salinity on seed germination and growth performance of wheat (<em>Triticum aestivum</em> L.) was investigated. Germination of wheat seeds primed with different doses of DS; 0%, 5%, 10%, 15%, and 20% were evaluated under different saline conditions (0, 100, 200, and 300 mM NaCl). High salinity (300 mM NaCl) remarkably inhibited germination attributes and reduced seedling length. However, seeds primed with DS exhibited improved germination parameters and seedling growth. Among the different DS concentrations used, the 10% DS priming achieved the highest increase in final germination percentage tolerance, germination index, relative germination salt tolerance, and seedling length. The increased tolerance to salinity was associated with improved water imbibition, α-amylase activity, antioxidant capacity and osmotic homeostasis correlated with high proline and soluble sugar levels. In addition, DS priming increased the membrane stability index, and reduced malondialdehyde content and K<sup>+</sup> leakage besides lowering Na<sup>+</sup>/K<sup>+</sup> ratio. Overall, priming with DS could be a promising strategy for minimizing the damaging effects of salinity in wheat.</p>

Integrated analysis of yield response and early stage biochemical, molecular, and gene expression profiles of pre-breeding rice lines under water deficit stress

Breeding high yielding water-deficit tolerant rice is considered a primary goal for achieving the objectives of the sustainable development goals, 2030. However, evaluating the performance of the pre-breeding-promising parental-lines for water deficit tolerance prior to their incorporation in the breeding program is crucial for the success of the breeding programs. The aim of the current investigation is to assess the performance of a set of pre-breeding lines compared with their parents. To achieve this goal a set of 7 pre-breeding rice lines along with their parents (5 genotypes) were field evaluated under well-irrigated and water-stress conditions. Water stress was applied by flush irrigation every 12 days without keeping standing water after irrigation. Based on the field evaluation results, a pre-breeding line was selected to conduct physiological and expression analysis of drought related genes at the green house. Furthermore, a greenhouse trial was conducted in pots, where the genotypes were grown under well and stress irrigation conditions at seedling stage for physiological analysis and expression profiling of the genotypes. Results indicated that the pre-breeding lines which were high yielding under water shortage stress showed low drought susceptibility index. Those lines exhibited high proline, SOD, TSS content along with low levels of MDA content in their leaves. Moreover, the genotypes grain yield positively correlated with proline, SOD, TSS content in their leaves. The SSR markers RM22, RM525, RM324 and RM3805 were able to discriminate the tolerant parents from the sensitive one. Expression levels of the tested drought responsive genes revealed the upregulation of OsLEA3, OsAPX2, OsNAC1, OSDREB2A, OsDREB1C, OsZIP23, OsP5CS, OsAHL1 and OsCATA genes in response to water deficit stress as compared to their expression under normal irrigated condition. Taken together among the tested pre-breeding lines the RBL112 pre-breeding line is high yielding under water-deficit and could be used as donor for high yielding genes in the breeding for water deficit resistance. This investigation withdraws attention to evaluate the promising pre-breeding lines before their incorporation in the water deficit stress breeding program.

Tetragonal crystalline MnO nanoparticles alleviate Pb stress in wheat by modulating antioxidant enzymes in leaves.

Agriculture ecosystems are seriously threatened by lead (Pb) contamination, which impacts plant growth and productivity. In this study, green synthesized manganese oxide nanoparticles (MnO NPs) using citrus peel were used for priming of wheat seeds. For the synthesis of MnO nanoparticles, peel extract of Citrus paradisi and 1mM solution of manganese acetate were stirred and calcinated at 500°C. Successful synthesis of MnO NPs was determined using advanced techniques. In Fourier-transform infrared spectroscopy (FTIR), the presence of amines, alkanes, aldehydes, and alcohol molecules, on the surface of MnO NPs, confirmed their stability. X-ray diffraction analysis described their average size (22nm), while scanning electron microscopy showed tetragonal crystalline shape and nano-flowers structure of MnO NPs. Sharp peaks of energy dispersive x-ray analysis described the presence of oxygen (28.81%) and manganese (71.19%) on MnO NPs. Priming of wheat seeds with synthesized MnO NPs significantly improved the growth attributes of wheat seedlings including the size of leaf, root length, size of shoots, chlorophyll and carotenoid contents, relative water content, decreased relative electrolyte leakage, high proline accumulation and decreased concentration of malondialdehyde. Application of MnO NPs also helped plants to accumulate antioxidant enzymes in their leaves. These results proved that the priming of MnO NPs can greatly reduce lead-induced stress in wheat seedlings and these NPs can alsobe used for the priming of other crops.

Revealing the effects of amino acid, organic acid, and phytohormones on the germination of tomato seeds under salinity stress.

Salinity accumulation poses a threat to the production and productivity of economically important crops such as tomatoes (Solanum lycopersicum L.). Currently, salt tolerance breeding programs have been limited by insufficient genetic and physiological knowledge of tolerance-related traits and a lack of an efficient selection domain. For that purpose, we aimed to determine the ability of tomato cultivars to tolerate salt based on seed traits by multiple biochemical pathways. First, we tested three tomato cultivars according to their response to different sodium chloride (NaCl) concentrations (0, 6.3, 9.8, 13.0, and 15.8 dS m-1) and then we analysed their amino acids, organic acids, and phytohormones. Considering the results of germination traits, it is possible to conclude that cultivar H-2274 was more tolerant to salt stress than others. As a result, multivariate discriminant analysis including principal component analysis and two-way hierarchical clustering analyses were constructed and demonstrated that tomato cultivars were separated from each other by the amino acid, organic acid, and phytohormone contents. Considering germination traits of tomato seeds, cv. 'H-2274' was more tolerant to salinity than others depending on high proline (29 pmol µl-1) and citric acid (568 ng µl-1) assays. Biochemical variability offers a valuable tool for investigating salt tolerance mechanisms in tomatoes, and it will be appreciated to find high-tolerant tomato cultivar(s) to saline conditions. Also, the findings of this study have significant potential for practical applications in agriculture, particularly in developing salt-tolerant tomato cultivars to enhance productivity in saline environments and address socio-economic challenges.

A CHEAPLY NON-DESTRUCTIVE TECHNIQUE TO ESTIMATE HONEY QUALITY: THERMAL IMAGING AND MACHINE LEARNING

The aim of this study was to estimate honey quality based on proline and Brix content using a thermal imaging and machine learning algorithm. The proline, Brix and color properties of twenty honey samples were determined. Proline and Brix values were classified and estimated using the classification and regression tree (CART) algorithm. The mean proline and Brix content in honey samples was 678.83±192.16 mg/kg and 83.2±0.79%, respectively. CART analysis revealed that high proline honey samples had L values above 48.143 and b* values below 35.416. In contrast, honey samples with low Brix values were characterized by L and a* values below 55.860 and 53.660, respectively, and were identified as freshly harvested. The CART algorithm classified the proline and Brix values with an accuracy of 95% and 100%, respectively (p< 0.001). As a result, whitish, bluish, blackish and greenish honeys are of higher quality due to high proline and low Brix content. However, to accurately assess honey quality based on its color traits, comprehensive studies with more honey samples and origin, are required.

Assessment of biochemical and physiological responses of several grape varieties under water deficit stress

Grapes (Vitis vinifera L.) are a crucial crop globally, particularly in arid regions where water scarcity is a concern. This study investigated the physiological and biochemical responses of several grape varieties to water deficit stress. The research was conducted within the controlled environment in a factorial experiment with a completely randomized setup comprising three replicates. The first variable, irrigation, consisted of two levels: a 15-day water stress and a control group receiving irrigation maintained at field capacity. The second variable was the grape variety, encompassing a total of 15 commercial varieties. Water deficit stress reduced chlorophyll content in all varieties. ‘Bidaneh Sefid’ variety had the highest chlorophyll content (8.76 µg.g-1 FW). Furthermore, this variety demonstrated superior relative water content under stress (79.22%), whereas ‘Keshmesh’ variety exhibited such performance under normal conditions. The results illustrated a proline content range spanning from 48.48 to 61.01 µmol.g-1 FW. Notably, water deficit stress resulted in elevated proline content, with the highest mean observed in the ‘Khalili’ variety under such stress conditions. Water scarcity impacted grape traits significantly: reduced chlorophyll, relative water content, increased leakage, higher proline, carbohydrate, anthocyanin, and phenols, with varying antioxidants. ‘Bidaneh Sefid’ variety had most chlorophyll, ‘Khalili’ highest proline under stress, ‘Maskeh’ variety excelled in carbohydrate. ‘Fakhri’, ‘Filam Seedless’, ‘Shiregi’ varieties topped anthocyanins; ‘Khalili’ variety showed best antioxidant activity. The findings highlight specific grape varieties that exhibit desirable traits under water deficit stress, such as higher chlorophyll content, proline accumulation, and carbohydrate accumulation. These varieties could serve as valuable genetic resources for breeding programs aimed at developing drought-tolerant grape cultivars. Additionally, the identification of varieties with enhanced antioxidant capacity and anthocyanin levels holds potential for the development of grape-based products with possible health benefits.

Inhibition of postharvest browning of white Hypsizygus marmoreus by LVEF-Vac: Evidence from phenolic metabolism and enzyme expression

A study was conducted to examine the effects of postharvest anti-browning of white Hypsizygus marmoreus and the enzymes related to it, utilizing the Low Voltage Electrostatic Field-Vacuum (LVEF-Vac, 150 V, 100 Hz, 26–36 kPa) treatment technology. The findings indicated that the application of LVEF-Vac treatment significantly extended the storage time of white Hypsizygus marmoreus to 14 d as compared to the control groups. Additionally, it successfully prevented the rise in color difference and browning degree, reduce them by 21.23 % and 36.62 %, respectively, while also inhibiting water loss and migration. Furthermore, it can impede the increase in total amino acid, tyrosine, and lysine content while maintaining a high proline and total phenols content of white Hypsizygus marmoreus during storage. At 9 d of storage, LVEF-vac treated laccase activity was reduced by 32.56 %, tyrosinase activity was reduced by 40.35 %, and gene expression of laccase and tyrosinase was reduced by 93.67 % and 48.77 %, respectively. Therefore, the discoloration of white Hypsizygus marmoreus during storage is slowed down, which improves its quality over time.

Multi-omics analysis provides insight into the genetic basis of proline-derived milk microbiota in buffalo

Understanding the intricate relationship between genetics, metabolites, and microbiota is paramount for unraveling the complexities that define buffalo milk composition. In this study, we employed a multi-omics approach to dissect the genetic and metabolic determinants of buffalo milk traits. Metabolomics analysis of 100 buffalo milk samples revealed a rich profile of 446 metabolites, with a particular emphasis on those associated with amino acid biosynthesis. Metabolite-based Genome-Wide Association Studies (mGWAS) uncovered 13 significant genetic variants, with a pronounced focus on l-Proline. Notably, single nucleotide polymorphisms (SNPs) within the ATG16L1 gene implicated its role in proline production. Concurrently, an in-depth exploration of milk microbiota dynamics highlighted marked differences between buffaloes with high and low proline groups. High proline abundance correlated with increased microbial diversity, dominated by Firmicutes and Proteobacteria. Distinct genera, such as Acinetobacter and Corynebacterium, characterized low and high proline groups, respectively. Functional changes in milk microbiota, especially in amino acid biosynthesis pathways, underscored proline's pivotal role in shaping microbial functions. Correlations between milk microbiota abundance and proline levels emphasized the intricate relationship between host physiology and microbial composition. These findings not only advance our understanding of the genetic basis of metabolic traits in buffalo milk but also present potential biomarkers for targeted breeding strategies. This integrated approach provides a nuanced perspective on milk composition, offering implications for dairy quality and nutritional enhancement.

Does aluminum induce high proline concentration in Pinus sylvestris, an Al-tolerant species?

Does aluminum induce high proline concentration in Pinus sylvestris, an Al-tolerant species?

Analysis of Morpho-physiological and Biochemical Responses in Brassica Varieties under Salt Stress

Abiotic stresses like salinity, water stress, high light intensity, heavy metals, etc. have a significant influence on the morphology, biochemical characteristics, and crop productivity, of Brassica species. Among these numerous abiotic stresses, stress from salinity is a significant issue, that demands immediate attention and resolution. Therefore, in this study, the tolerance of Brassica carinata and five different varieties of Brassica campestris including Agrani, Shafal, BINA Sharisha-6, BARI Sharisha-15 and Tori-7 were examined at varying concentrations of NaCl (0, 50, 100, 150, 200 mM). Different morpho-physiological and biochemical properties including seed germination parameters, root/shoot ratio, proline content, H2O2 and MDA level, photosynthetic pigments, and Na+/K+ ion accumulation were measured and showed varying responses to the inhibitory impacts of NaCl. B. carinata, BINA Sharisha-6, Tori-7 and Shafal, with increasing NaCl concentrations resulted in the loss of germination percentages, root/shoot ratio, levels of photosynthetic pigments, proline, levels of H2O2 and MDA and the Na+/K+ ion accumulation in comparison to the other Brassica varieties. Among these varieties, Shafal, showed the lowest values of the salt tolerant indicators. In contrast, variety Agrani and BARI Sharisha-15 exhibited high proline content, a good level of H2O2 and MDA and photosynthetic pigments, in response to salt stress, which enhanced their hydration status, enzyme activities and cellular functions. Plant Tissue Cult. & Biotech. 33(2): 167-180, 2023 (December)

Mitigating Salinity Stress in Quinoa (Chenopodium quinoa Willd.) with Biochar and Superabsorber Polymer Amendments.

In agriculture, soil amendments are applied to improve soil quality by increasing the water retention capacity and regulating the pH and ion exchange. Our study was carried out to investigate the impact of a commercial biochar (Bc) and a superabsorbent polymer (SAP) on the physiological and biochemical processes and the growth performance of Chenopodium quinoa (variety ICBA-5) when exposed to high salinity. Plants were grown for 25 days under controlled greenhouse conditions in pots filled with a soil mixture with or without 3% Bc or 0.2% SAP by volume before the initiation of 27 days of growth in hypersaline conditions, following the addition of 300 mM NaCl. Without the Bc or soil amendments, multiple negative effects of hypersalinity were detected on photosynthetic CO2 assimilation (Anet minus 70%) and on the production of fresh matter from the whole plant, leaves, stems and roots (respectively, 55, 46, 64 and 66%). Moreover, increased generation of reactive oxygen species (ROS) was indicated by higher levels of MDA (plus 142%), antioxidant activities and high proline levels (plus 311%). In the pots treated with 300 mM NaCl, the amendments Bc or SAP improved the plant growth parameters, including fresh matter production (by 10 and 17%), an increased chlorophyll content by 9 and 13% and Anet in plants (by 98 and 115%). Both amendments (Bc and SAP) resulted in significant salinity mitigation effects, decreasing proline and malondialdehyde (MDA) levels whilst increasing both the activity of enzymatic antioxidants and non-enzymatic antioxidants that reduce the levels of ROS. This study confirms how soil amendments can help to improve plant performance and expand the productive range into saline areas.

Cell-Penetrating Peptide Delivery of Nucleic Acid Cargo to Emiliania huxleyi, a Calcifying Marine Coccolithophore.

Coccolithophores are a group of unicellular marine phytoplankton that exhibit a prolific capacity for carbon conversion and are critical to ocean biogeochemistry. A fundamental understanding of coccolithophore biomineralization has been limited, in part, by the lack of genetic and molecular tools to investigate the organisms. In particular, it has proven to be difficult to deliver macromolecules across the coccosphere-membrane complex. To overcome this barrier, we employed cell-penetrating peptides (CPP) in the Emiliania huxleyi coccolithophores. We evaluated three established CPPs (TAT, R9, and KFF) and designed a CPP that incorporates a high proline content identified in the protein transduction domain of EhV060, an E. huxleyi virus lectin protein. To measure the delivery performance, we covalently linked CPPs to synthetic peptide nucleic acids (PNA) and attached a fluorescein marker. CPP-PNA-FITC complexes were efficiently delivered across the coccosphere-membrane complex to the cytoplasm of E. huxleyi cells. Characterization of E. huxleyi demonstrates that CPP-PNA are nontoxic and reveals specific effects of CPP-PNA on cell biology and calcification. Direct delivery and characterization of synthetic nucleic acids represent a step forward in synthetic biology to explore coccolithophore biomineralization.

Ultrastructural, Secondary Metabolite, and Antioxidant Modulation in Response to Salt-Affected Habitats Induced Oxidative Stress and Their Accumulation in Malva parviflora L. and Rumex dentatus L.

Salinity stress is a major abiotic factor that affects medicinal plant growth, performance, and secondary compounds. Malva parviflora L. and Rumex dentatus L. plants were collected from three habitats in the northeastern Nile Delta governorates of Damietta and El-Dakahlia. Conductivity (salinity) classified the habitats as mesophytic, moderately saline, and saline. Chemical and physical soil characteristics varied by habitat. Results show that M. parviflora L. and R. dentatus L. had high soluble sugars, total carbohydrates, electrolyte leakage, and proline in the saline habitat. In contrast, mesophytic habitats showed low content. In addition, R. dentatus L. had more antioxidant enzymes and elements in saline habitats than in mesophytic habitats. In saline habitats, M. parviflora L. and R. dentatus L. were characterized by more calcium and sodium increase than mesophytic habitats. Moreover, R. dentatus L. had more phenols, alkaloids, flavonoids, anthocyanin, and tannins under saline conditions than M. parviflora. Meanwhile, in the saline habitat, plant hormones, i.e., indole acetic acid and gibberellic acid, decreased significantly in both M. parviflora and R. dentatus than in the mesophytic habitat. Scanning Electron Microscopy (SEM) of the tested plants showed the highest stomatal frequency and area on the lower surface of mesophytic plant leaves compared to either its upper surface or both leaf surfaces in saline habitat. Hence, it can be concluded that R. dentatus plant can mitigate the negative effects of salinity by improving the qualitative and quantitative performance under salinity stress more than M. parviflora plant.

Physiological characteristics of IRR 400 series rubber clones (Hevea brasiliensis Muell. Arg.) under drought stress

Background Drought stress is one of the main causes of plant death. Strategies for plants survival are morphological adaptations, specific signaling pathways, and tolerance mechanisms. Rubber plantations have many uses, such as foreign exchange sources, job sources, forest revitalization, and a source of alternative wood for building materials and furniture. The rubber plant’s response to drought stress is a complex biological process. A tolerant rubber clone in a dry area is the right approach. The present study aimed to identify drought tolerant traits in order to select or identify drought-tolerant clones at juvenile stage. Methods The first factor examined for this work was clones (IRR 425, IRR 428, IRR 429, IRR 434, IRR 440, RRIC 100, and BPM 24) and the second factor was water content (30%, 60%, and 90%). The study was arranged on a factorial randomized block design and repeated three times. Characteristics observed were total sugar (µM), proline (mg/L), chlorophyll a, b, total (µg/mL), hydrogen peroxidase (µmol/g), ascorbate peroxidase (unit/mg), superoxide dismutase (unit/mg), and peroxide dismutase (unit/mg). Results The tolerance ability of the IRR 400 series rubber clones to drought stress was determined by observing the characteristics of sugar total and proline. The concentration of total sugar and proline were higher when the plant was treated with a lower water content. The selected clones tolerant to drought stress are RR 425 and IR 434 with high total sugar content and proline. Other characteristics, namely chlorophyll a, b, and total, as well as hydrogen peroxidase, ascorbate peroxidase, super oxide dismutase, peroxide dismutase, cannot be used as selection characteristics for this study. Conclusions This drought study of IRR 400 clones with varying water content percentages illustrated that the total sugar and proline characteristics could be used to distinguish tolerance levels from other observed characteristics.

Light pre-conditioning at the seedling stage affected root growth behavior and enhanced the thermotolerance of Petunia × hybrida

An investigation studied the impact of spectral composition on plant responses to heat stress. Petunia × hybrida seedlings were grown under nine different light qualities, including the modifying and constant compositions of blue and red LEDs light, as well as Fluorescent and white LED lamps. After 28 days, the seedlings were exposed to hyperthermia (40 °C / 35 °C, 4 days). The results showed that the highest survival rate (100 %), and the lowest leaf chlorotic area (14 %) were observed among seedlings grown under modifying spectral compositions with a gradual increase in red light, which also showed the highest change rate of increased Chl a/ b ratio (262 %) and lowest change rate of increased total Chl/ Car ratio (45 %). Furthermore, seedlings grown under a gradual increase in red light showed the highest relative water content (82 %) and the lowest change rate of root water content (1.2 %). Moreover, the highest proline and lignin contents, along with the lowest electrolyte leakage, 7.22 µg g−1 FW, 104 mg g−1 FW, and 25 %, respectively, were observed in seedlings exposed to a gradual increase in red light after heat stress compared to other lighting treatments. Also, after heat stress, seedlings grown under a gradual increase in red light showed the highest contents of studied enzymatic antioxidants. Our investigation highlighted a link between spectral composition during the seedling stage and heat stress tolerance of examined plants. This method can potentially prepare plant material during the propagation stage against extreme temperatures.

Biochemical Responses to Salt Stress and Biostimulant Action in Tomato Plants Grown in Two Different Soil Types

Soil salinity is one of the major causes of losses in agricultural production, which is accentuated by global warming. A sustainable strategy to mitigate the effects of the increasing soil salinisation is the use of biostimulants. In this study, the effect of a plant-based biostimulant was tested on tomato plants exposed to different salinity levels in loamy and sandy soils. Salinity in the soils reached a maximum value of 14.35 dS m−1. The treatments included a control (tap water) and a dose of 0.4 mL L−1 of the commercial biostimulant BALOX®, containing polyphenols and glycine betaine. After 60 days of treatment, several growth and biochemical parameters were evaluated in the plants, and different responses were found depending on the type of soil texture. Salt stress inhibited plant growth, mainly affecting the roots of plants not treated with the biostimulant, in both soil texture types. It also caused a reduction of total chlorophyll and carotenoid levels by 44% and 38%, respectively, under severe salinity conditions. High salinity induced a significant increase in ionic, osmotic and oxidative stress in plants, as indicated by the accumulation of toxic Na+ and Cl− ions, higher proline and MDA levels, and increased antioxidant enzyme activities. However, the application of BALOX® stimulated plant growth and root system development in all experimental conditions. The areas of roots and leaves and the stem length and diameter showed higher mean values in biostimulant-treated plants on both soil types, with more pronounced differences with the controls in sandy soils. The total fresh weight showed maximum increases of 54% and 93% on loamy and sandy soils, respectively. In addition, BALOX® significantly improved the active transport of nutrients such as K+ and Ca2+, and the concentration of photosynthetic pigments by up to 64% over control values; it also allowed greater protection against salt stress as shown by a significant reduction of proline levels, by up to 36%, and MDA by 51% under strongly saline conditions. The application of BALOX® generally decreased the level of stress in the tomato plants, promoting plant growth and enhancing their biochemical responses, even on strongly salinised soils.

Wheat WRKY transcription factor TaWRKY24 confers drought and salt tolerance in transgenic plants

Drought and salt stress are major environmental conditions that severely limit plant growth and productivity. WRKY transcription factors play a vital role in the responses against biotic or abiotic stress. In this study, TaWRKY24, a gene of the IIe WRKY family identified in wheat, was cloned and characterized. TaWRKY24 was mainly expressed in wheat leaf and stem and induced by treatment with PEG6000, salt, H2O2, ABA, MeJA, and ethrel. TaWRKY24 transient expression in onion epidermal cells suggested its nuclear localization and its transcriptional activation capability characteristics. Overexpression of TaWRKY24 in tobacco improved the seed germination rate and root growth of seedlings in transgenic lines when subjected to higher mannitol and NaCl concentrations. Further research showed that transgenic lines had higher proline and soluble sugars and lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Moreover, compared to normal and negative control plants, TaWRKY24 silenced wheat seedlings had reduced growth under salt and drought stress. This study shows that wheat TaWRKY24 is crucial to plant stress, providing an excellent candidate gene for wheat resistance breeding.

Analysis of Morphological, Physiological, and Biochemical Traits of Salt Stress Tolerance in Asian Rice Cultivars at Seedling and Early Vegetative Stages

Rice (Oryza sativa L.) is a primary energy food for the Asian population. One of the greatest constraints in rice production is soil salinity because rice is very susceptible to salt. Meanwhile, many agricultural lands in Asia are in saline areas. It is important to identify and develop salt-tolerant rice varieties that highly adapt to Asian climates. By combining morphological, physiological, and biochemical assessments for screening the salt tolerance of 116 Asian rice cultivars, we were able to classify them into tolerant, moderate, and sensitive rice cultivars under salinity stress conditions and also understand salt tolerance mechanisms. The rice cultivars that are salt-tolerant include Pokkali from India, TCCP 266 and IR 45427 from the Philippines, and Namyang 7 from Republic of Korea. However, salt-sensitive rice varieties like IR29 and IR58 are from the Philippines, and Daegudo and Guweoldo are from Korea. The salt-tolerant varieties showed signs of tolerance, including a lower percent reduction in germination percentage, root length, root fresh weight, shoot length, plant biomass, and chlorophyll content. In order to maintain the cellular osmotic balance under saline conditions, the salt-tolerant varieties exhibited less membrane damage, a lower Na/K ratio, high proline and sugar accumulation, and lower levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2). Pokkali from India, TCCP 266 and IR 45427 from the Philippines, and Namyang 7 from Republic of Korea are recommended as valuable germplasm resources for Asian rice breeding programs in saline agricultural areas.

Physiological characteristics of IRR 400 series rubber clones (Hevea brasiliensis Muell. Arg.) under drought stress

Background: Drought stress is one of the main causes of plant death. Strategies for plants survival are morphological adaptations, specific signaling pathways, and tolerance mechanisms. Rubber plantations have many uses, such as foreign exchange sources, job sources, forest revitalization, and a source of alternative wood for building materials and furniture. The rubber plant’s response to drought stress is a complex biological process. A tolerant rubber clone in a dry area is the right approach. The present study aimed to determine the mechanism of drought-tolerant clones, based on physiological characteristics, to obtain character selection and drought-tolerant clones early. Methods: The first factor examined for this work was clones (IRR 425, IRR 428, IRR 429, IRR 434, IRR 440, RRIC 100, and BPM 24) and the second factor was water content (30%, 60%, and 90%). The study was arranged on a factorial randomized block design and repeated three times. Characteristics observed were total sugar (µM), proline (mg/L), chlorophyll a, b, total (µg/mL), hydrogen peroxidase (µmol/g), ascorbate peroxidase (unit/mg), superoxide dismutase (unit/mg), and peroxide dismutase (unit/mg). Results: The tolerance ability of the IRR 400 series rubber clones to drought stress was determined by observing the characteristics of sugar total and proline. The concentration of total sugar and proline were higher when the plant was treated with a lower water content. The selected clones tolerant to drought stress are RR 425 and IR 434 with high total sugar content and proline. Other characteristics, namely chlorophyll a, b, and total, as well as hydrogen peroxidase, ascorbate peroxidase, super oxide dismutase, peroxide dismutase, cannot be used as selection characteristics for this study. Conclusions: This drought study of IRR 400 clones with varying water content percentages illustrated that the total sugar and proline characteristics could be used to distinguish tolerance levels from other observed characteristics.