Characterization of the Seed Biopriming, Plant Growth-Promoting and Salinity-Ameliorating Potential of Halophilic Fungi Isolated from Hypersaline Habitats.

Salinity stress is one of the major abiotic factors limiting crop yield in arid and semi-arid regions. Plant growth-promoting fungi can help plants thrive in stressful conditions. In this study, we isolated and characterized 26 halophilic fungi (endophytic, rhizospheric, and soil) from the coastal region of Muscat, Oman, for plant growth-promoting activities. About 16 out of 26 fungi were found to produce IAA, and about 11 isolates (MGRF1, MGRF2, GREF1, GREF2, TQRF4, TQRF5, TQRF5, TQRF6, TQRF7, TQRF8, TQRF2) out of 26 strains were found to significantly improve seed germination and seedling growth of wheat. To evaluate the effect of the above-selected strains on salt tolerance in wheat, we grew wheat seedlings in 150 mM, 300 mM NaCl and SW (100% seawater) treatments and inoculated them with the above strains. Our findings showed that fungal strains MGRF1, MGRF2, GREF2, and TQRF9 alleviate 150 mM salt stress and increase shoot length compared to their respective control plants. However, in 300 mM stressed plants, GREF1 and TQRF9 were observed to improve shoot length. Two strains, GREF2 and TQRF8, also promoted plant growth and reduced salt stress in SW-treated plants. Like shoot length, an analogous pattern was observed in root length, and different salt stressors such as 150 mM, 300 mM, and SW reduced root length by up to 4%, 7.5%, and 19.5%, respectively. Three strains, GREF1, TQRF7, and MGRF1, had higher catalase (CAT) levels, and similar results were observed in polyphenol oxidase (PPO), and GREF1 inoculation dramatically raised the PPO level in 150 mM salt stress. The fungal strains had varying effects, with some, such as GREF1, GREF2, and TQRF9, showing a significant increase in protein content as compared to their respective control plants. Under salinity stress, the expression of DREB2 and DREB6 genes was reduced. However, the WDREB2 gene, on the other hand, was shown to be highly elevated during salt stress conditions, whereas the opposite was observed in inoculated plants.

Synergistic Effect of Melatonin and Lysinibacillus fusiformis L. (PLT16) to Mitigate Drought Stress via Regulation of Hormonal, Antioxidants System, and Physio-Molecular Responses in Soybean Plants.

Drought is one of the most detrimental factors that causes significant effects on crop development and yield. However, the negative effects of drought stress may be alleviated with the aid of exogenous melatonin (MET) and the use of plant-growth-promoting bacteria (PGPB). The present investigation aimed to validate the effects of co-inoculation of MET and Lysinibacillus fusiformis on hormonal, antioxidant, and physio-molecular regulation in soybean plants to reduce the effects of drought stress. Therefore, ten randomly selected isolates were subjected to various plant-growth-promoting rhizobacteria (PGPR) traits and a polyethylene-glycol (PEG)-resistance test. Among these, PLT16 tested positive for the production of exopolysaccharide (EPS), siderophore, and indole-3-acetic acid (IAA), along with higher PEG tolerance, in vitro IAA, and organic-acid production. Therefore, PLT16 was further used in combination with MET to visualize the role in drought-stress mitigation in soybean plant. Furthermore, drought stress significantly damages photosynthesis, enhances ROS production, and reduces water stats, hormonal signaling and antioxidant enzymes, and plant growth and development. However, the co-application of MET and PLT16 enhanced plant growth and development and improved photosynthesis pigments (chlorophyll a and b and carotenoids) under both normal conditions and drought stress. This may be because hydrogen-peroxide (H2O2), superoxide-anion (O2-), and malondialdehyde (MDA) levels were reduced and antioxidant activities were enhanced to maintain redox homeostasis and reduce the abscisic-acid (ABA) level and its biosynthesis gene NCED3 while improving the synthesis of jasmonic acid (JA) and salicylic acid (SA) to mitigate drought stress and balance the stomata activity to maintain the relative water states. This may be possible due to a significant increase in endo-melatonin content, regulation of organic acids, and enhancement of nutrient uptake (calcium, potassium, and magnesium) by co-inoculated PLT16 and MET under normal conditions and drought stress. In addition, co-inoculated PLT16 and MET modulated the relative expression of DREB2 and TFs bZIP while enhancing the expression level of ERD1 under drought stress. In conclusion, the current study found that the combined application of melatonin and Lysinibacillus fusiformis inoculation increased plant growth and could be used to regulate plant function during drought stress as an eco-friendly and low-cost approach.

Silicon-Induced Morphological, Biochemical and Molecular Regulation in Phoenix dactylifera L. under Low-Temperature Stress.

Climate changes abruptly affect optimum growth temperatures, leading to a negative influence on plant physiology and productivity. The present study aimed to investigate the extent of low-temperature stress effects on date palm growth and physiological indicators under the exogenous application of silicon (Si). Date palm seedlings were treated with Si (1.0 mM) and exposed to different temperature regimes (5, 15, and 30 °C). It was observed that the application of Si markedly improved fresh and dry biomass, photosynthetic pigments (chlorophyll and carotenoids), plant morphology, and relative water content by ameliorating low-temperature-induced oxidative stress. Low-temperature stress (5 and 15 °C), led to a substantial upregulation of ABA-signaling-related genes (NCED-1 and PyL-4) in non Si treated plants, while Si treated plants revealed an antagonistic trend. However, jasmonic acid and salicylic acid accumulation were markedly elevated in Si treated plants under stress conditions (5 and 15 °C) in comparison with non Si treated plants. Interestingly, the upregulation of low temperature stress related plant plasma membrane ATPase (PPMA3 and PPMA4) and short-chain dehydrogenases/reductases (SDR), responsible for cellular physiology, stomatal conductance and nutrient translocation under silicon applications, was observed in Si plants under stress conditions in comparison with non Si treated plants. Furthermore, a significant expression of LSi-2 was detected in Si plants under stress, leading to the significant accumulation of Si in roots and shoots. In contrast, non Si plants demonstrated a low expression of LSi-2 under stress conditions, and thereby, reduced level of Si accumulation were observed. Less accumulation of oxidative stress was evident from the expression of superoxide dismutase (SOD) and catalase (CAT). Additionally, Si plants revealed a significant exudation of organic acids (succinic acid and citric acid) and nutrient accumulation (K and Mg) in roots and shoots. Furthermore, the application of Si led to substantial upregulation of the low temperature stress related soybean cold regulated gene (SRC-2) and ICE-1 (inducer of CBF expression 1), involved in the expression of CBF/DREB (C-repeat binding factor/dehydration responsive element binding factor) gene family under stress conditions in comparison with non Si plants. The current research findings are crucial for exploring the impact on morpho-physio-biochemical attributes of date palms under low temperature and Si supplementation, which may provide an efficient strategy for growing plants in low-temperature fields.

Genome and Transcriptome-Wide Analysis of OsWRKY and OsNAC Gene Families in Oryza sativa and Their Response to White-Backed Planthopper Infestation.

Plants are threatened by a wide variety of herbivorous insect assaults, and display a variety of inherent and induced defenses that shield them against herbivore attacks. Looking at the massive damage caused by the white-backed planthopper (WBPH), Sogatella furcifera, we undertook a study to identify and functionally annotate OsWRKY and OsNAC transcription factors (TFs) in rice, especially their involvement in WBPH stress. OsWRKY and OsNAC TFs are involved in various developmental processes and responses to biotic and abiotic stresses. However, no comprehensive reports are available on the specific phycological functions of most of the OsWRKY and OsNAC genes in rice during WBPH infestation. The current study aimed to comprehensively explore the OsWRKY and OsNAC genes by analyzing their phylogenetic relationships, subcellular localizations, exon-intron arrangements, conserved motif identities, chromosomal allocations, interaction networks and differential gene expressions during stress conditions. Comparative phylogenetic trees of 101 OsWRKY with 72 AtWRKY genes, and 121 OsNAC with 110 AtNAC genes were constructed to study relationships among these TFs across species. Phylogenetic relationships classified OsWRKY and OsNAC into eight and nine clades, respectively. Most TFs in the same clade had similar genomic features that represented similar functions, and had a high degree of co-expression. Some OsWRKYs (Os09g0417800 (OsWRKY62), Os11g0117600 (OsWRKY50), Os11g0117400 (OsWRKY104) and OsNACs (Os05g0442700, Os12g0630800, Os01g0862800 and Os12g0156100)) showed significantly higher expressions under WBPH infestation, based on transcriptome datasets. This study provides valuable information and clues about predicting the potential roles of OsWRKYs and OsNACs in rice, by combining their genome-wide characterization, expression profiling, protein-protein interactions and gene expressions under WBPH stress. These findings may require additional investigation to understand their metabolic and expression processes, and to develop rice cultivars that are resistant to WBPH.

Biological Potentials and Phytochemical Constituents of Raw and Roasted Nigella arvensis and Nigella sativa.

Nigella species are widely used to cure various ailments. Their health benefits, particularly from the seed oils, could be attributed to the presence of a variety of bioactive components. Roasting is a critical process that has historically been used to facilitate oil extraction and enhance flavor; it may also alter the chemical composition and biological properties of the Nigella seed. The aim of this study was to investigate the effect of the roasting process on the composition of the bioactive components and the biological activities of Nigella arvensis and Nigella sativa seed extracts. Our preliminary study showed that seeds roasted at 50 °C exhibited potent antimicrobial activities; therefore, this temperature was selected for roasting Nigella seeds. For extraction, raw and roasted seed samples were macerated in methanol. The antimicrobial activities against Streptococcus agalactiae, Streptococcus epidermidis, Streptococcus pyogenes, Candida albicans, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, and Klebsiella oxytoca were determined by measuring the diameter of the zone of inhibition. The cell viability of extracts was tested in a colon carcinoma cell line, HCT-116, by using a microculture tetrazolium technique (MTT) assay. Amino acids were extracted and quantified using an automatic amino acid analyzer. Then, gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify the chemical constituents and fatty acids. As a result, the extracts of raw and roasted seeds in both Nigella species showed strong inhibition against Klebsiella oxytoca, and the raw seed extract of N.arvensis demonstrated moderate inhibition against S. pyogenes. The findings of the MTT assay indicated that all the extracts significantly decreased cancer cell viability. Moreover, N. sativa species possessed higher contents of the measured amino acids, except tyrosine, cystine, and methionine. The GC-MS analysis of extracts showed the presence of 22 and 13 compounds in raw and roasted N. arvensis, respectively, and 9 and 11 compounds in raw and roasted N. sativa, respectively. However, heat treatment decreased the detectable components to 13 compounds in roasted N. arvensis and increased them in roasted N. sativa. These findings indicate that N. arvensis and N. sativa could be potential sources of anticancer and antimicrobials, where the bioactive compounds play a pivotal role as functional components.

Aroma Profile and Biological Effects of Ochradenus arabicus Essential Oils: A Comparative Study of Stem, Flowers, and Leaves.

The present analysis explores the chemical constituents and determines the in vitro antimicrobial, antidiabetic, and antioxidant significance of the essential oils (EOs) of the stem, leaves, and flowers of Ochradenus arabicus for the first time. The EOs of the flowers presented seventy-four constituents contributing to 81.46% of the total EOs, with the major compounds being 24-norursa-3,12-diene (13.06%), 24-norursa-3,12-dien-11-one (6.61%), and 24-noroleana-3,12-diene (6.25%). The stem EOs with sixty-one compounds contributed 95.95% of the total oil, whose main bioactive compounds were (+)-camphene (21.50%), eremophilene (5.87%), and δ-selinene (5.03%), while a minimum of fifty-one compounds in the leaves' EOs (98.75%) were found, with the main constituents being n-hexadecanoic acid (12.32%), octacosane (8.62%), tetradecanoic acid (8.54%), and prehydro fersenyl acetone (7.27%). The antimicrobial activity of the EOs of O. arabicus stem, leaves, and flowers was assessed against two bacterial strains (Escherichia coli and Streptococcus aureus) and two fungal strains (Penicillium simplicissimum and Rhizoctonia solani) via the disc diffusion assay. However, the EOs extracted from the stem were found effective against one bacterial strain, E. coli, and one fungal strain, R. Solani, among the examined microbes in comparison to the standard and negative control. The tested EOs samples of the O. arabicus stem displayed a maximum potential to cure diabetes with an IC50 = 0.40 ± 0.10 µg/mL, followed by leaves and flowers with an IC50 = 0.71 ± 0.11 µg/mL and IC50 = 10.57 ± 0.18 µg/mL, respectively, as compared to the standard acarbose (IC50 = 377.26 ± 1.20 µg/mL). In addition, the EOs of O. arabicus flowers had the highest antioxidant activity (IC50 = 106.40 ± 0.19 µg/mL) as compared to the standard ascorbic acid (IC50 = 73.20 ± 0.17 µg/mL) using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. In the ABTS assay, the EOs of the same sample (flower) depicted the utmost potential to scavenge the free radicals with an IC50 = 178.0 ± 0.14 µg/mL as compared with the ascorbic acid, having an IC50 of 87.34 ± 0.10 µg/mL the using 2,2-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic acid (ABTS) assay. The EOs of all parts of O. arabicus have useful bioactive components due to which they present antidiabetic and antioxidant significance. Furthermore, additional investigations are considered necessary to expose the responsible components of the examined biological capabilities, which would be effective in the production of innovative drugs.

Melatonin Ameliorates Thermotolerance in Soybean Seedling through Balancing Redox Homeostasis and Modulating Antioxidant Defense, Phytohormones and Polyamines Biosynthesis.

Global warming is impacting the growth and development of economically important but sensitive crops, such as soybean (Glycine max L.). Using pleiotropic signaling molecules, melatonin can relieve the negative effects of high temperature by enhancing plant growth and development as well as modulating the defense system against abiotic stresses. However, less is known about how melatonin regulates the phytohormones and polyamines during heat stress. Our results showed that high temperature significantly increased ROS and decreased photosynthesis efficiency in soybean plants. Conversely, pretreatment with melatonin increased plant growth and photosynthetic pigments (chl a and chl b) and reduced oxidative stress via scavenging hydrogen peroxide and superoxide and reducing the MDA and electrolyte leakage contents. The inherent stress defense responses were further strengthened by the enhanced activities of antioxidants and upregulation of the expression of ascorbate-glutathione cycle genes. Melatonin mitigates heat stress by increasing several biochemicals (phenolics, flavonoids, and proline), as well as the endogenous melatonin and polyamines (spermine, spermidine, and putrescine). Furthermore, the positive effects of melatonin treatment also correlated with a reduced abscisic acid content, down-regulation of the gmNCED3, and up-regulation of catabolic genes (CYP707A1 and CYP707A2) during heat stress. Contrarily, an increase in salicylic acid and up-regulated expression of the defense-related gene PAL2 were revealed. In addition, melatonin induced the expression of heat shock protein 90 (gmHsp90) and heat shock transcription factor (gmHsfA2), suggesting promotion of ROS detoxification via the hydrogen peroxide-mediated signaling pathway. In conclusion, exogenous melatonin improves the thermotolerance of soybean plants and enhances plant growth and development by activating antioxidant defense mechanisms, interacting with plant hormones, and reprogramming the biochemical metabolism.

Silicon-induced thermotolerance in Solanum lycopersicum L. via activation of antioxidant system, heat shock proteins, and endogenous phytohormones.

BACKGROUND: Abiotic stresses (e.g., heat or limited water and nutrient availability) limit crop production worldwide. With the progression of climate change, the severity and variation of these stresses are expected to increase. Exogenous silicon (Si) has shown beneficial effects on plant growth; however, its role in combating the negative effects of heat stress and their underlying molecular dynamics are not fully understood. RESULTS: Exogenous Si significantly mitigated the adverse impact of heat stress by improving tomato plant biomass, photosynthetic pigments, and relative water content. Si induced stress tolerance by decreasing the concentrations of superoxide anions and malondialdehyde, as well as mitigating oxidative stress by increasing the gene expression for antioxidant enzymes (peroxidases, catalases, ascorbate peroxidases, superoxide dismutases, and glutathione reductases) under stress conditions. This was attributed to increased Si uptake in the shoots via the upregulation of low silicon (SlLsi1 and SlLsi2) gene expression under heat stress. Interestingly, Si stimulated the expression and transcript accumulation of heat shock proteins by upregulating heat transcription factors (Hsfs) such as SlHsfA1a-b, SlHsfA2-A3, and SlHsfA7 in tomato plants under heat stress. On the other hand, defense and stress signaling-related endogenous phytohormones (salicylic acid [SA]/abscisic acid [ABA]) exhibited a decrease in their concentration and biosynthesis following Si application. Additionally, the mRNA and gene expression levels for SA (SlR1b1, SlPR-P2, SlICS, and SlPAL) and ABA (SlNCEDI) were downregulated after exposure to stress conditions. CONCLUSION: Si treatment resulted in greater tolerance to abiotic stress conditions, exhibiting higher plant growth dynamics and molecular physiology by regulating the antioxidant defense system, SA/ABA signaling, and Hsfs during heat stress.

Amelioration of heavy metal stress by endophytic Bacillus amyloliquefaciens RWL-1 in rice by regulating metabolic changes: potential for bacterial bioremediation.

This study aimed to investigate the bioremediation efficiency of phytohormone-producing endophytic Bacillus amyloliquefaciens RWL-1 isolated from rice seeds. In this study, we tested RWL-1 against various heavy metals (Cu, Cr, Pb, and Cd). Among the tested heavy metals, RWL-1 showed the highest tolerance for Cu stress and we observed alterations in growth kinetics with various Cu concentrations (1, 2.5, and 5 mM). We confirmed the biosorption potential of RWL-1 by scanning electron microscopy coupled with energy-dispersive X-ray spectrometry showing that Cu ions were adsorbed on RWL-1 cell surfaces. We further tested RWL-1 for its plant growth promoting and stress reliance efficiency in response to a dose-dependent increase in soil Cu (1, 2.5, and 5 mM). The RWL-1 inoculation significantly increased seedling biomass and growth attributes compared with non-inoculated control seedlings with and without Cu stress. Moreover, RWL-1 inoculation significantly promoted a physiochemical response in seedlings with and without Cu stress by reducing Cu uptake, improving carbohydrate levels (glucose, sucrose, fructose, and raffinose), enhancing amino acids regulation, and augmenting antioxidant levels (POD, PPO, and GHS). Levels of stress-responsive phytohormones such as abscisic acid (ABA) and jasmonic acid were significantly reduced in RWL-1-inoculated seedlings as compared with non-inoculated control seedlings under normal condition and same levels of Cu stress. In conclusion, the inoculation of B. amyloliquefaciens RWL-1 can significantly improve plant growth in Cu-contaminated soil and reduce metal accumulation, thus making plants safer for consumption. This approach could be tremendously helpful for safe and sustainable agriculture in heavy metal-contaminated areas.

Silicon-mediated alleviation of combined salinity and cadmium stress in date palm (Phoenix dactylifera L.) by regulating physio-hormonal alteration.

We investigated the physio-molecular effects of separate and combined cadmium (Cd; 200 µM) and salinity (NaCl; 100 mM) stress on date palm during silicon (Si; 1.0 mM) applications. The results showed that exogenous Si led to significant improvements in plant growth, as well as physiology when compared with non-Si-treated seedling under stressed (Cd/NaCl) conditions. Interestingly, Si application led to lower metal (Cd) uptake and enhanced plant macronutrient uptake under combined stress, in turn, alleviating the combined salinity- and Cd-induced oxidative stress by lowering the lipid peroxidation rate, and peroxidase and catalase activities. Furthermore, ascorbate peroxidase level and the cytosolic Cu/Zn superoxide dismutase expression were significantly enhanced by Si application under combined stress. We further analyzed the effect of Si on modulation of stress-related hormonal crosstalk. Si markedly downregulated endogenous salicylic acid, jasmonic acid, and abscisic acid under NaCl stress and combined NaCl-Cd stress. However, during Cd toxicity alone, Si showed varying accumulation of these phytohormones. The results suggest that hindering the Cd uptake and enhancing silicon accumulation ultimately led to improvement of biomass and efficiency of the antioxidant system for alleviating combined stress. Moreover, higher transcript accumulation of PROLINE TRANSPORTER 2 and GAPDH and downregulation of ABA RECEPTOR by Si treatment under combined stress in date palm seedlings indicate the stress-ameliorative role of Si. The study provides evidence of the positive influence of Si on alleviating the combined toxicity of Cd and NaCl in date palm and can be further extended for field trials in Cd- and salinity-affected areas.

Bacillus amyloliquefaciens RWL-1 as a New Potential Strain for Augmenting Biochemical and Nutritional Composition of Fermented Soybean.

Soybean (Glycine max L.) is a good source of natural antioxidants and commonly consumed as fermented products such as cheonggukjang, miso, tempeh, and sufu in Asian countries. The aim of the current study was to examine the influence of novel endophytic bacterial strain, Bacillus amyloliquefaciens RWL-1 as a starter for soybean fermentation. During fermentation, the cooked soybeans were inoculated with different concentrations (1%, 3%, and 5%) of B. amyloliquefaciens RWL-1. The changes in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, total phenolic contents, isoflavones (Daidzin, Genistin, Glycitin, Daidzein, Glycitein, and Genistein), amino acids (aspartic acid, threonine, serine, glutamic acid, glycine, alanine, cysteine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, and proline) composition, and minerals (calcium, copper, iron, potassium, magnesium, manganese, sodium, nickel, lead, arsenic, and zinc) were investigated. The level of antioxidants, total phenolic contents, isoflavones, and total amino acids were higher in fermented soybean inoculated with 1% B. amyloliquefaciens RWL-1 after 60 h of fermentation as compared to control, 3% and 5% B. amyloliquefaciens RWL-1. Additionally, fermented soybean inoculated with 5% B. amyloliquefaciens RWL-1 showed the highest values for mineral contents. Changes in antioxidant activities and bioactive compounds depended on the concentration of the strain used for fermentation. From these results, we conclude that fermented soybean has strong antioxidant activity, probably due to its increased total phenolic contents and aglycone isoflavone that resulted from fermentation. Such natural antioxidants could be used in drug and food industries and can be considered to alleviate oxidative stress.

Indole-3-acetic-acid and ACC deaminase producing Leclercia adecarboxylata MO1 improves Solanum lycopersicum L. growth and salinity stress tolerance by endogenous secondary metabolites regulation.

BACKGROUND: The utilization of plant growth-promoting microbes is an environment friendly strategy to counteract stressful condition and encourage plants tolerance. In this regards, the current study was designed to isolate ACC deaminase and indole-3-acetic acid (IAA) producing halotolerant bacteria to promote tomato (Solanum lycopersicum L.) growth and tolerance against salinity stress. RESULTS: The selected bacterial isolate MO1 was identified as Leclercia adecarboxylata and IAA quantification results revealed that MO1 produced significant amount of IAA (9.815 ± 0.6293 µg mL- 1). The MO1 showed the presence of ACC (1-Aminocyclopropane-1-Carboxylate) deaminase responsible acdS gene and tolerance against salinity stress. A plant microbe interaction experiment using tomato (Solanum lycopersicum L.) with glycine betaine (GB) as a positive control was carried out to investigate the positive role MO1 in improving plant growth and stress tolerance. The results indicated that MO1 inoculation and GB application significantly increased growth attributes under normal as well as saline condition (120 mM NaCl). The MO1 inoculation and GB treatment approach conferred good protection against salinity stress by significantly improving glucose by 17.57 and 18.76%, sucrose by 34.2 and 12.49%, fructose by 19.9 and 10.9%, citric acid by 47.48 and 34.57%, malic acid by 52.19 and 28.38%, serine by 43.78 and 69.42%, glycine by 14.48 and 22.76%, methionine by 100 and 124.99%, threonine by 70 and 63.08%, and proline by 36.92 and 48.38%, respectively, while under normal conditions MO1 inoculation and GB treatment also enhanced glucose by 19.83 and 13.19%, sucrose by 23.43 and 15.75%, fructose by 15.79 and 8.18%, citric acid by 43.26 and 33.14%, malic acid by 36.18 and 14.48%, serine by 46.5 and 48.55%, glycine by 19.85 and 29.77%, methionine by 22.22 and 38.89%, threonine by 21.95 and 17.07%, and proline by 29.61 and 34.68% compared to levels in non-treated plants, respectively. In addition, the endogenous abscisic acid (ABA) level was noticeably lower in MO1-inoculated (30.28 and 30.04%) and GB-treated plants (45 and 35.35%) compared to their corresponding control plants under normal condition as well as salinity stress, respectively. CONCLUSION: The current findings suggest that the IAA- and ACC-deaminase-producing abilities MO1 can improve plants tolerance to salinity stress.

Metabolic and proteomic alteration in phytohormone-producing endophytic Bacillus amyloliquefaciens RWL-1 during methanol utilization.

INTRODUCTION: Methanol utilization by bacteria is important for various industrial processes. Methylotrophic bacteria are taxonomically diverse and some species promote plant growth and induce stress tolerance. However, methylotrophic potential of bacterial endophytes is poorly understood. OBJECTIVE: The current study aimed to evaluate the metabolomic and proteomic changes in endophytic Bacillus amyloliquefaciens RWL-1 caused by its methanol utilization and the resultant influence on its phytohormone production. METHODS: B. amyloliquefaciens RWL-1 was grown in LB medium with different concentrations [0 (control), 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4%) of methanol to examine its methylotrophic potential. SDS-PAGE analysis was carried out for bacterial protein confirmation. Moreover, the phytohormones (indole 3 acetic acid (IAA), gibberellins (GAs), abscisic acid (ABA)) produced by RWL-1 in methanol supplemented medium were quantified by GC-MS/SIM (6890N Network GC system, and 5973 Network Mass Selective Detector; Agilent Technologies, Santa Clara, CA, USA), while the antioxidants were estimated spectrophotometrically (T60 UV-VIS spectrophotometer, Leicester, UK). The amino acid quantification was carried out by amino acid analyzer (HITACHI L-8900, Japan). Furthermore, Nano-liquid chromatography (LC)-MS/MS analysis was performed with an Agilent system (Wilmington, DE, USA) for proteomic analysis while mascot algorithm (Matrix science, USA) was used to identify peptide sequences present in the protein sequence database. RESULTS: RWL-1 showed significant growth in media supplemented with 2 and 3.5% methanol, when compared with other concentrations. Mass spectroscopy analysis revealed that RWL-1 utilizes methanol efficiently as a carbon source. In the presence of methanol, RWL-1 produced significantly higher levels of IAA but lower levels of ABA, when compared with the control. Further, enzymatic antioxidants and functional amino acids were significantly up-regulated, with predominant expression of glutamic acid and alanine. Nano-liquid chromatography, quadrupole time-of-flight analysis, and quantitative analysis of methanol-treated bacterial cells showed expression of eight different types of proteins, including detoxification proteins, unrecognized and unclassified enzymes with antioxidant properties, proteases, metabolism enzymes, ribosomal proteins, antioxidant proteins, chaperones, and heat shock proteins. CONCLUSION: Results demonstrate that RWL-1 can significantly enhance its growth by utilizing methanol, and could produce phytohormones when growing in methanol-supplemented media, with increased expression of specific proteins and different biochemicals. These results will be useful in devising strategies for utilizing methylotrophic bacterial endophytes as alternative promoters of plant growth. Understanding RWL-1 ability to utilize methanol. The survival and phytohormones production by Bacillus amyloliquefaciens RWL-1 in methanol supplemented media whistle inducing metabolic and proteomic changes.

Endophytic fungus Paecilomyces formosus LHL10 produces sester-terpenoid YW3548 and cyclic peptide that inhibit urease and α-glucosidase enzyme activities.

Endophytic fungi have been used to obtain novel bioactive secondary metabolites with potential applications in medical and agricultural sectors, which can also act as lead targets for pharmaceutical and medicinal potential. In the present study, the endophytic fungus Paecilomyces formosus LHL10 isolated from the root of cucumber plant was tested for its enzyme inhibitory potential. The ethyl acetate (EtOAc) extract of LHL10 was screened for its inhibitory effect on acetylcholinesterase (AChE), α-glucosidase, urease, and anti-lipid peroxidation. The findings suggest that the EtOAc extract from LHL10 possesses significant inhibitory potential against urease and α-glucosidase. The EtOAc extract was thus, subjected to advanced column chromatographic techniques for the isolation of pure compounds. The structure elucidation was carried out through spectroscopic analysis and comparison with literature data, and these compounds were confirmed as known a sester-terpenoid (1) and a known cyclic peptide (2). The enzyme inhibition bioassay indicated that Compounds 1 and 2 exhibited remarkable inhibitory rate against α-glucosidase and urease, with an IC50 value of 61.80 ± 5.7, 75.68 ± 6.2 and 74.25 ± 4.3, 190.5 ± 10.31 µg/g, respectively. Thus, the current study concludes the enzyme inhibitory potential of endophyte LHL10 and provides the basis for further investigations of bioactive compounds, which could be used as potent drugs for enzyme inhibition.

Mechanisms of Cr(VI) resistance by endophytic Sphingomonas sp. LK11 and its Cr(VI) phytotoxic mitigating effects in soybean (Glycine max L.).

Chromium Cr(VI) is highly toxic and leads to impaired phenotypic plasticity of economically important crops. The current study assessed an endophytic-bacteria assisted metal bio-remediation strategy to understand stress-alleviating mechanisms in Glycine max L (soybean) plants inoculated with Sphingomonas sp. LK11 under severe Cr(VI) toxicity. The screening analysis showed that high Cr concentrations (5.0 mM) slightly suppressed LK11 growth and metal uptake by LK11 cells, while significantly enhancing indole-3-acetic acid (IAA) production. Endophytic LK11 significantly upregulated its antioxidant system compared to control by enhancing reduced glutathione (GSH), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities to counteract Cr-induced oxidative stress. Cr toxicity induced cell morphological alteration, as shown by SEM-EDX analysis and triggered significant lipid peroxidation. The interaction between LK11 and soybean in Cr-contaminated soil significantly increased plant growth attributes and down-regulated the synthesis of endogenous defense-related phytohormones, salicylic acid and abscisic acid, by 20% and 37%, respectively, and reduced Cr translocation to the roots, shoot, and leaves. Additionally, Cr-induced oxidative stress was significantly reduced in LK11-inoculated soybean, regulating metal responsive reduced GSH and enzymatic antioxidant CAT. Current findings indicate that LK11 may be a suitable candidate for the bioremediation of Cr-contaminated soil and stimulation of host physiological homeostasis.

Characterization of New Bioactive Enzyme Inhibitors from Endophytic Bacillus amyloliquefaciens RWL-1.

Endophytic bacteria are known to produce a wide array of bioactive secondary metabolites with beneficial effects on human health. In the current study, a novel endophytic bacterial strain, Bacillus amyloliquefaciens RWL-1, was isolated from the seeds of Oryza sativa. Initially, the crude extract of RWL-1 was assessed for potential biological effects of enzyme inhibition and cytotoxicity and was found to exhibit a broad spectrum inhibition for α-glucosidase (37 ± 0.09%) and urease (49.4 ± 0.53%). The screening results were followed by bioassay-guided isolation of secondary metabolite(s) from RWL-1. Extensive chromatographic and spectrophotometry analyses revealed the presence of compound 1 (S)-2-hydroxy-N-((S)-1-((S)-8-hydroxy-1-oxoisochroman-3-yl)-3-methylbutyl)-2-((S)-5-oxo-2,5-dihydrofuran-2-yl)acetamide. Further bioassays of compound 1 showed significant inhibition of α-glucosidase (52.98 ± 0.8%) and urease (51.27 ± 1.0%), compared with positive control values of 79.14 ± 1.9% and 88.24 ± 2.2%, and negative controls (0.08 ± 0.1% and 0.05 ± 0.01%), respectively. The current study suggests that bacterial endophytes are a rich source of novel bioactive compounds with high therapeutic value.

Comparison of antioxidants potential, metabolites, and nutritional profiles of Korean fermented soybean (Cheonggukjang) with Bacillus subtilis KCTC 13241.

This study was carried out to determine the effect of different concentrations of Bacillus subtilis (0, 1, 3, 5, and 7%) on the antioxidant potential and biochemical constituents of traditional Korean fermented soybean, Cheonggukjang (CKJ). The antioxidant capacity was studied using the reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) assays and the total phenolic contents (TPC) were measured using the Folin-Ciocalteu method. CKJ prepared using 1% B. subtilis revealed the highest TPC (5.99 mg/g), total amino acids (7.43 mg/g), DPPH (94.24%), and ABTS (86.03%) radical-scavenging activity and had the highest value of palmitic acid (11.65%), stearic acid (2.87%), and linolenic acid (11.76%). Results showed that the calcium, iron, sodium, and zinc contents increased in the CKJ prepared using 7% B. subtilis from 1481.38 to 1667.32, 41.38 to 317.00, 48.01 to 310.07, and 32.82 to 37.18 mg/kg respectively. In conclusion, the present results indicate that the fermentation of soybean with B. subtilis (KCTC 13241) significantly augments the nutritional and antioxidant potential of CKJ and it can be recommended as a health-promoting food source.

Effects of Bacterial Fermentation on the Biochemical Constituents and Antioxidant Potential of Fermented and Unfermented Soybeans Using Probiotic Bacillus subtilis (KCTC 13241).

Fermented soybeans, cheonggukjang (CKJ), are considered to be more wholesome than soybeans in Korea. To select the best soybean cultivar for making functional CKJ, a comparison was made between the biological activities of four soybean cultivars in their unfermented soybean (UFS) and CKJ states. Changes in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays, superoxide dismutase (SOD)-like activity, total phenolic compounds, total amino acids, and isoflavones were investigated. The levels of DPPH, ABTS, SOD-like activity, and total phenolic compounds increased in CKJ among all cultivars. The isoflavone aglycone and total amino acids showed the highest amount in CKJ prepared from soybean cultivar Aga 3. These results suggest that the improved antioxidant activity of CKJ in all cultivars might occur because of the higher levels of aglycones and total phenolic compounds achieved during fermentation. Moreover, CKJ prepared from soybean cultivar Aga 3 showed higher antioxidant activity than the other cultivars and so can be considered for the commercial production of functional foods in the future.

Biochemical Constituents and in Vitro Antioxidant and Anticholinesterase Potential of Seeds from Native Korean Persimmon Genotypes.

In the current study, the functional and biochemical potential of the seeds of four persimmon cultivars (PC1, PC2, PC3 and PC4) and their role against oxidative stress and acetylcholinesterase (AChE) inhibition were evaluated. In terms of biochemical compositions, free amino acids, fatty acids and organic acids analysis was performed. The free amino acids ranged from 2617.31 (PC2) to 3773.01 µg∙g(-1) dry weight (PC4). Oleic acid and linoleic acid were the principal fatty acids, which were significantly higher in PC4 and PC1, respectively. PC4 presented the highest amount of organic acid content (4212 mg∙kg(-1)), whereas PC2 presented the lowest (2498 mg∙kg(-1)). PC2 contained higher total phenolic content and flavonoid content, whereas PC3 had the lowest amount as compared to other cultivars. The in vitro DPPH, ABTS and superoxide anion radicals scavenging activity increased in a dose-dependent manner, whereas PC2 showed significantly higher scavenging activities as compared to PC1, PC2 and PC4 types. In the case of AChE inhibition, PC4 showed a moderate activity (67.34% ± 1.8%). In conclusion, the current findings reveal that the studied persimmon seeds cultivars are a source of bioactive natural antioxidants and AChE inhibitors. Such natural products could be employed in pharmaceutical and food industries, whilst can also be considered for the treatment of neurodegenerative diseases such as Alzheimer's.

Regulatory Dynamics of Plant Hormones and Transcription Factors under Salt Stress.

The negative impacts of soil salinization on ion homeostasis provide a significant global barrier to agricultural production and development. Plant physiology and biochemistry are severely affected by primary and secondary NaCl stress impacts, which damage cellular integrity, impair water uptake, and trigger physiological drought. Determining how transcriptional factors (TFs) and hormone networks are regulated in plants in response to salt stress is necessary for developing crops that tolerate salt. This study investigates the complex mechanisms of several significant TF families that influence plant responses to salt stress, involving AP2/ERF, bZIP, NAC, MYB, and WRKY. It demonstrates how these transcription factors (TFs) help plants respond to the detrimental effects of salinity by modulating gene expression through mechanisms including hormone signaling, osmotic stress pathway activation, and ion homeostasis. Additionally, it explores the hormonal imbalances triggered by salt stress, which entail complex interactions among phytohormones like jasmonic acid (JA), salicylic acid (SA), and abscisic acid (ABA) within the hormonal regulatory networks. This review highlights the regulatory role of key transcription factors in salt-stress response, and their interaction with plant hormones is crucial for developing genome-edited crops that can enhance agricultural sustainability and address global food security challenges.