Melatonin: The Multifaceted Molecule in Plant Growth and Defense.

Melatonin (MEL), a hormone primarily known for its role in regulating sleep and circadian rhythms in animals, has emerged as a multifaceted molecule in plants. Recent research has shed light on its diverse functions in plant growth and defense mechanisms. This review explores the intricate roles of MEL in plant growth and defense responses. MEL is involved in plant growth owing to its influence on hormone regulation. MEL promotes root elongation and lateral root formation and enhances photosynthesis, thereby promoting overall plant growth and productivity. Additionally, MEL is implicated in regulating the circadian rhythm of plants, affecting key physiological processes that influence plant growth patterns. MEL also exhibits antioxidant properties and scavenges reactive oxygen species, thereby mitigating oxidative stress. Furthermore, it activates defense pathways against various biotic stressors. MEL also enhances the production of secondary metabolites that contribute to plant resistance against environmental changes. MEL's ability to modulate plant response to abiotic stresses has also been extensively studied. It regulates stomatal closure, conserves water, and enhances stress tolerance by activating stress-responsive genes and modulating signaling pathways. Moreover, MEL and nitric oxide cooperate in stress responses, antioxidant defense, and plant growth. Understanding the mechanisms underlying MEL's actions in plants will provide new insights into the development of innovative strategies for enhancing crop productivity, improving stress tolerance, and combating plant diseases. Further research in this area will deepen our knowledge of MEL's intricate functions and its potential applications in sustainable agriculture.

Halotolerant Pseudomonas koreensis S4T10 mitigate salt and drought stress in Arabidopsis thaliana.

Salt and drought are documented among the most detrimental and persistent abiotic stresses for crop production. Here, we investigated the impact of Pseudomonas koreensis strain S4T10 on plant performance under salt and drought stress. Arabidopsis thaliana Col-0 wild type and atnced3 mutant plants were inoculated with P. koreensis or tap water and exposed to NaCl (100 mM) for five days and drought stress by withholding water for seven days. P. koreensis significantly enhanced plant biomass and photosynthetic pigments under salt and drought stress conditions. Moreover, P. koreensis activated the antioxidant defence by modulating glutathione (GSH), superoxide dismutase (SOD), peroxidase (POD), and polyphenol oxidase (PPO) activities to scavenge the reactive oxygen species produced due to the stress. In addition, the application of P. koreensis upregulated the expression of genes associated with antioxidant responses, such as AtCAT1, AtCAT3, and AtSOD. Similarly, genes linked to salt stress, such as AtSOS1, AtSOS2, AtSOS3, AtNHX1, and AtHKT1, were also upregulated, affirming the positive role of P. koreensis S4T10 in streamlining the cellular influx and efflux transport systems during salt stress. Likewise, the PGPB inoculation was observed to regulate the expression of drought-responsive genes AtDREB2A, AtDREB2B, and ABA-responsive genes AtAO3, AtABA3 indicating that S4T10 enhanced drought tolerance via modulation of the ABA pathway. The results of this study affirm that P. koreensis S4T10 could be further developed as a biofertilizer to mitigate salt and drought stress at the same time.

New Onset Seizures in Hospitalized COVID-19 Patients; A Systematic Review and Meta-Analysis.

Objective: Seizures in COVID-19 patients continue to be a common reason for consulting the neurology service in the inpatient setting. This paper assesses the frequency of new onset seizures in adult hospitalized COVID-19 patients. Method: PubMed and EMBASE were searched, with fifteen cohort studies identified to calculate the primary outcome, which was the frequency of new onset seizures in hospitalized COVID-19 patients. An inverse variance meta-analysis of single proportions with a random effects model was applied to these cohort studies to calculate the primary outcome. Risk of bias in individual studies was assessed using the 10-item risk of bias tool for prevalence studies. Results: The meta-analysis revealed a frequency of .71% (95% confidential interval: .32-1.25, I2 = 89%, 147/28242 patients) for acute symptomatic seizures in patients with COVID-19. For secondary outcomes, the risk of seizures in patients who had EEG completed was 8.49% (95% confidential interval: .62-24.07, I2 = 14%, 44/535 patients). Slightly less than half of patients with COVID-19 and seizures were reported to have acute imaging abnormalities (45.7%) with acute vascular insults being commonly reported. Only a small percentage of COVID-19 patients with seizures (2.8%) met the criteria for COVID-19 encephalitis as determined by the international encephalitis consortium. Conclusion: The frequency of seizures in COVID-19 was .71% (95% confidential interval: .32-1.25). Slightly less than half of COVID-19 patients had head imaging abnormalities as a complication of COVID-19 infection. Only a small percentage of patients with seizures and COVID-19 met the criteria for COVID-19 encephalitis.

Brevundimonas vesicularis (S1T13) Mitigates Drought-Stress-Associated Damage in Arabidopsis thaliana.

Drought stress is a significant threat to agricultural productivity and poses challenges to plant survival and growth. Research into microbial plant biostimulants faces difficulties in understanding complicated ecological dynamics, molecular mechanisms, and specificity; to address these knowledge gaps, collaborative efforts and innovative strategies are needed. In the present study, we investigated the potential role of Brevundimonas vesicularis (S1T13) as a microbial plant biostimulant to enhance drought tolerance in Arabidopsis thaliana. We assessed the impact of S1T13 on Col-0 wild-type (WT) and atnced3 mutant plants under drought conditions. Our results revealed that the inoculation of S1T13 significantly contributed to plant vigor, with notable improvements observed in both genotypes. To elucidate the underlying mechanisms, we studied the role of ROS and their regulation by antioxidant genes and enzymes in plants inoculated with S1T13. Interestingly, the inoculation of S1T13 enhanced the activities of GSH, SOD, POD, and PPO by 33, 35, 41, and 44% in WT and 24, 22, 26, and 33% in atnced3, respectively. In addition, S1T13 upregulated the expression of antioxidant genes. This enhanced antioxidant machinery played a crucial role in neutralizing ROS and protecting plant cells from oxidative damage during drought stress. Furthermore, we investigated the impact of S1T13 on ABA and drought-stress-responsive genes. Similarly, S1T13 modulated the production of ABA and expression of AO3, ABA3, DREB1A, and DREB2A by 31, 42, 37, 41, and 42% in WT and 20, 29, 27, 38, and 29% in atnced3. The improvement in plant vigor, coupled with the induction of the antioxidant system and modulation of ABA, indicates the pivotal role of S1T13 in enhancing the drought stress tolerance of the plants. Conclusively, the current study provides valuable insights for the application of multitrait S1T13 as a novel strain to improve drought stress tolerance in plants and could be added to the consortium of biofertilizers.

Nitric Oxide, a Key Modulator in the Alleviation of Environmental Stress-Mediated Damage in Crop Plants: A Meta-Analysis.

Nitric oxide (NO) is a small, diatomic, gaseous, free radicle, lipophilic, diffusible, and highly reactive molecule with unique properties that make it a crucial signaling molecule with important physiological, biochemical, and molecular implications for plants under normal and stressful conditions. NO regulates plant growth and developmental processes, such as seed germination, root growth, shoot development, and flowering. It is also a signaling molecule in various plant growth processes, such as cell elongation, differentiation, and proliferation. NO also regulates the expression of genes encoding hormones and signaling molecules associated with plant development. Abiotic stresses induce NO production in plants, which can regulate various biological processes, such as stomatal closure, antioxidant defense, ion homeostasis, and the induction of stress-responsive genes. Moreover, NO can activate plant defense response mechanisms, such as the production of pathogenesis-related proteins, phytohormones, and metabolites against biotic and oxidative stressors. NO can also directly inhibit pathogen growth by damaging their DNA and proteins. Overall, NO exhibits diverse regulatory roles in plant growth, development, and defense responses through complex molecular mechanisms that still require further studies. Understanding NO's role in plant biology is essential for developing strategies for improved plant growth and stress tolerance in agriculture and environmental management.

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.

Enhanced Resistance of atnigr1 against Pseudomonas syringae pv. tomato Suggests Negative Regulation of Plant Basal Defense and Systemic Acquired Resistance by AtNIGR1 Encoding NAD(P)-Binding Rossmann-Fold in Arabidopsis thaliana.

Nitric oxide (NO) regulates several biological and physiological processes in plants. This study investigated the role of Arabidopsis thaliana Negative Immune and Growth Regulator 1 (AtNIGR1), encoding an NAD(P)-binding Rossmann-fold superfamily, in the growth and immunity of Arabidopsis thaliana. AtNIGR1 was pooled from the CySNO transcriptome as a NO-responsive gene. Seeds of the knockout (atnigr1) and overexpression plants were evaluated for their response to oxidative [(hydrogen peroxide (H2O2) and methyl viologen (MV)] or nitro-oxidative [(S-nitroso-L-cysteine (CySNO) and S-nitroso glutathione (GSNO)] stress. Results showed that the root and shoot growth of atnigr1 (KO) and AtNIGR1 (OE) exhibited differential phenotypic responses under oxidative and nitro-oxidative stress and normal growth conditions. To investigate the role of the target gene in plant immunity, the biotrophic bacterial pathogen Pseudomonas syringae pv. tomato DC3000 virulent (Pst DC3000 vir) was used to assess the basal defense, while the Pst DC3000 avirulent (avrB) strain was used to investigate R-gene-mediated resistance and systemic acquired resistance (SAR). Data revealed that AtNIGR1 negatively regulated basal defense, R-gene-mediated resistance, and SAR. Furthermore, the Arabidopsis eFP browser indicated that the expression of AtNIGR1 is detected in several plant organs, with the highest expression observed in germinating seeds. All results put together suggest that AtNIGR1 could be involved in plant growth, as well as basal defense and SAR, in response to bacterial pathogens in Arabidopsis.

Alleviation of Hg-, Cr-, Cu-, and Zn-Induced Heavy Metals Stress by Exogenous Sodium Nitroprusside in Rice Plants.

The cultivation of rice is widespread worldwide, but its growth and productivity are hampered by heavy metals stress. However, sodium nitroprusside (SNP), a nitric oxide donor, has been found to be effective for imparting heavy metals stress tolerance to plants. Therefore, the current study evaluated the role of exogenously applied SNP in improving plant growth and development under Hg, Cr, Cu, and Zn stress. For this purpose, heavy metals stress was induced via the application of 1 mM mercury (Hg), chromium (Cr), copper (Cu), and zinc (Zn). To reverse the toxic effects of heavy metals stress, 0.1 mM SNP was administrated via the root zone. The results revealed that the said heavy metals significantly reduced the chlorophyll contents (SPAD), chlorophyll a and b, and protein contents. However, SNP treatment significantly reduced the toxic effects of the said heavy metals on chlorophyll (SPAD), chlorophyll a and b, and protein contents. In addition, the results also revealed that heavy metals significantly increased the production of superoxide anion (SOA), hydrogen peroxide (H2O2), malondialdehyde (MDA), and electrolyte leakage (EL). However, SNP administration significantly reduced the production of SOA, H2O2, MDA, and EL in response to the said heavy metals. Furthermore, to cope with the said heavy metals stress, SNP administration significantly enhanced the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and polyphenol peroxidase (PPO). Furthermore, in response to the said heavy metals, SNP application also upregulated the transcript accumulation of OsPCS1, OsPCS2, OsMTP1, OsMTP5, OsMT-I-1a, and OsMT-I-1b. Therefore, SNP can be used as a regulator to improve the heavy metals tolerance of rice in heavy-metals-affected areas.

Nitric Oxide Acts as a Key Signaling Molecule in Plant Development under Stressful Conditions.

Nitric oxide (NO), a colorless gaseous molecule, is a lipophilic free radical that easily diffuses through the plasma membrane. These characteristics make NO an ideal autocrine (i.e., within a single cell) and paracrine (i.e., between adjacent cells) signalling molecule. As a chemical messenger, NO plays a crucial role in plant growth, development, and responses to biotic and abiotic stresses. Furthermore, NO interacts with reactive oxygen species, antioxidants, melatonin, and hydrogen sulfide. It regulates gene expression, modulates phytohormones, and contributes to plant growth and defense mechanisms. In plants, NO is mainly produced via redox pathways. However, nitric oxide synthase, a key enzyme in NO production, has been poorly understood recently in both model and crop plants. In this review, we discuss the pivotal role of NO in signalling and chemical interactions as well as its involvement in the mitigation of biotic and abiotic stress conditions. In the current review, we have discussed various aspects of NO including its biosynthesis, interaction with reactive oxygen species (ROS), melatonin (MEL), hydrogen sulfide, enzymes, phytohormones, and its role in normal and stressful conditions.

The Key Roles of ROS and RNS as a Signaling Molecule in Plant-Microbe Interactions.

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) play a pivotal role in the dynamic cell signaling systems in plants, even under biotic and abiotic stress conditions. Over the past two decades, various studies have endorsed the notion that these molecules can act as intracellular and intercellular signaling molecules at a very low concentration to control plant growth and development, symbiotic association, and defense mechanisms in response to biotic and abiotic stress conditions. However, the upsurge of ROS and RNS under stressful conditions can lead to cell damage, retarded growth, and delayed development of plants. As signaling molecules, ROS and RNS have gained great attention from plant scientists and have been studied under different developmental stages of plants. However, the role of RNS and RNS signaling in plant-microbe interactions is still unknown. Different organelles of plant cells contain the enzymes necessary for the formation of ROS and RNS as well as their scavengers, and the spatial and temporal positions of these enzymes determine the signaling pathways. In the present review, we aimed to report the production of ROS and RNS, their role as signaling molecules during plant-microbe interactions, and the antioxidant system as a balancing system in the synthesis and elimination of these species.

Exogenous Phytohormones and Fertilizers Enhance Jatropha curcas L. Growth through the Regulation of Physiological, Morphological, and Biochemical Parameters.

Jatropha curcas L. is a perennial plant, that emerged as a biodiesel crop attracting the great interest of researchers. However, it is considered a semi-wild plant and needed to apply crop-improving practices to enhance its full yield potential. This study was conducted to improve the growth and development of the J. curcas plant by exogenous application of Gibberellic acid (GA), indole acetic acid (IAA), and fertilizer (nitrogen, phosphorus, potassium (NPK)). The experiment was conducted in pots in triplicate and 100 ppm and 250 ppm of GA and IAA were applied separately while NPK was applied in two levels (30 and 60 g/pot). The results revealed a significant difference in growth parameters with the application of hormones and fertilizer. The highest shoot length (47%), root length (63%), root fresh weight (72%), and root dry weight (172%) were shown by plants treated with GA 250 ppm. While plants treated with NPK 60 g showed the highest increases in shoot fresh weight and shoot dry weight compared to control plants. The highest increase in leaves number (274%) and branches number (266%) were shown by the plants treated with GA 100 ppm and GA 250 ppm, respectively, while GA 250 ppm and IAA 250 ppm highly increased stem diameter (123%) and stem diameter was also shown by GA 250 ppm-treated plants. NPK 60 g highly increased proximate composition (protein content, carbohydrate, fat, moisture content, and ash content) compare with hormones and control plants. Our results concluded the optimized concentration of IAA, GA, and NPK significantly increases J. curcas growth vigor.

Parthenium hysterophorus's Endophytes: The Second Layer of Defense against Biotic and Abiotic Stresses.

Parthenium hysterophorus L. is considered an obnoxious weed due to its rapid dispersal, fast multiplications, and agricultural and health hazards. In addition to its physio-molecular and phytotoxic allelochemical usage, this weed most probably uses endophytic flora as an additional line of defense to deal with stressful conditions and tolerate both biotic and abiotic stresses. The aim of this article is to report the diversity of endophytic flora (fungi and bacteria) in P. hysterophorus and their role in the stress mitigation (biotic and abiotic) of other important crops. Various endophytes were reported from P. hysterophorus and their roles in crops evaluated under biotic and abiotic stressed conditions. These endophytes have the potential to alleviate different stresses by improving crops/plants growth, development, biomass, and photosynthetic and other physiological traits. The beneficial role of the endophytes may be attributed to stress-modulating enzymes such as the antioxidants SOD, POD and APX and ACC deaminases. Additionally, the higher production of different classes of bioactive secondary metabolites, i.e., flavonoids, proline, and glutathione may also overcome tissue damage to plants under stressed conditions. Interestingly, a number of medicinally important phytochemicals such as anhydropseudo-phlegmcin-9, 10-quinone-3-amino-8-O methyl ether 'anhydropseudophlegmacin-9, 10-quinone-3-amino-8-Omethyl ether were reported from the endophytic flora of P. hysterophorus. Moreover, various reports revealed that fungal and bacterial endophytes of P. hysterophorus enhance plant growth-promoting attributes and could be added to the consortium of biofertilizers.

Melatonin Function and Crosstalk with Other Phytohormones under Normal and Stressful Conditions.

Melatonin was discovered in plants in the late nineties, but its role, signaling, and crosstalk with other phytohormones remain unknown. Research on melatonin in plants has risen dramatically in recent years and the role of this putative plant hormone under biotic and abiotic stress conditions has been reported. In the present review, we discuss the main functions of melatonin in the growth and development of plants, its role under abiotic stresses, such as water stress (waterlogging and drought), extreme temperature (low and high), salinity, heavy metal, and light-induced stress. Similarly, we also discuss the role of melatonin under biotic stresses (antiviral, antibacterial, and antifungal effects). Moreover, the present review meticulously discusses the crosstalk of melatonin with other phytohormones such as auxins, gibberellic acids, cytokinins, ethylene, and salicylic acid under normal and stressful conditions and reports melatonin receptors and signaling in plants. All these aspects of melatonin suggest that phytomelatonin is a key player in crop improvement and biotic and abiotic stress regulation.

Bioactivity and Therapeutic Potential of Kaempferol and Quercetin: New Insights for Plant and Human Health.

Plant secondary metabolites, especially flavonoids, are major metabolites widely found in plants that play several key roles in plant defence and signalling in response to stress conditions. The most studied among these flavonoids are kaempferol and quercetin due to their anti-oxidative potential and their key roles in the defence system, making them more critical for plant adaptation in stress environments. Kaempferol and quercetin in plants have great therapeutic potential for human health. Despite being well-studied, some of their functional aspects regarding plants and human health need further evaluation. This review summarizes the emerging potential of kaempferol and quercetin in terms of antimicrobial activity, bioavailability and bioactivity in the human body as well as in the regulation of plant defence in response to stresses and as a signalling molecule in terms of hormonal modulation under stress conditions. We also evaluated the safe use of both metabolites in the pharmaceutical industry.

Exogenously Applied Sodium Nitroprusside Mitigates Lead Toxicity in Rice by Regulating Antioxidants and Metal Stress-Related Transcripts.

Sustainable agriculture is increasingly being put in danger by environmental contamination with dangerous heavy metals (HMs), especially lead (Pb). Plants have developed a sophisticated mechanism for nitric oxide (NO) production and signaling to regulate hazardous effects of abiotic factors, including HMs. In the current study, we investigated the role of exogenously applied sodium nitroprusside (SNP, a nitric oxide (NO) donor) in ameliorating the toxic effects of lead (Pb) on rice. For this purpose, plants were subjected to 1.2 mM Pb alone and in combination with 100 µM SNP. We found that under 1.2 mM Pb stress conditions, the accumulation of oxidative stress markers, including hydrogen peroxide (H2O2) (37%), superoxide anion (O2-) (28%), malondialdehyde (MDA) (33%), and electrolyte leakage (EL) (34%), was significantly reduced via the application of 100 µM SNP. On the other hand, under the said stress of Pb, the activity of the reactive oxygen species (ROS) scavengers such as polyphenol oxidase (PPO) (60%), peroxidase (POD) (28%), catalase (CAT) (26%), superoxide dismutase (SOD) (42%), and ascorbate peroxidase (APX) (58%) was significantly increased via the application of 100 µM SNP. In addition, the application of 100 µM SNP rescued agronomic traits such as plant height (24%), number of tillers per plant (40%), and visible green pigments (44%) when the plants were exposed to 1.2 mM Pb stress. Furthermore, after exposure to 1.2 mM Pb stress, the expression of the heavy-metal stress-related genes OsPCS1 (44%), OsPCS2 (74%), OsMTP1 (83%), OsMTP5 (53%), OsMT-I-1a (31%), and OsMT-I-1b (24%) was significantly enhanced via the application of 100 µM SNP. Overall, our research evaluates that exogenously applied 100 mM SNP protects rice plants from the oxidative damage brought on by 1.2 mM Pb stress by lowering oxidative stress markers, enhancing the antioxidant system and the transcript accumulation of HMs stress-related genes.

Correction: Pande et al. Nitric Oxide Signaling and Its Association with Ubiquitin-Mediated Proteasomal Degradation in Plants. Int. J. Mol. Sci. 2022, 23, 1657.

The authors wish to make the following corrections to the original publication [...].

Phytohormonal Regulation Through Protein S-Nitrosylation Under Stress.

The liaison between Nitric oxide (NO) and phytohormones regulates a myriad of physiological processes at the cellular level. The interaction between NO and phytohormones is mainly influenced by NO-mediated post-translational modifications (PTMs) under basal as well as induced conditions. Protein S-nitrosylation is the most prominent and widely studied PTM among others. It is the selective but reversible redox-based covalent addition of a NO moiety to the sulfhydryl group of cysteine (Cys) molecule(s) on a target protein to form S-nitrosothiols. This process may involve either direct S-nitrosylation or indirect S-nitrosylation followed by transfer of NO group from one thiol to another (transnitrosylation). During S-nitrosylation, NO can directly target Cys residue (s) of key genes involved in hormone signaling thereby regulating their function. The phytohormones regulated by NO in this manner includes abscisic acid, auxin, gibberellic acid, cytokinin, ethylene, salicylic acid, jasmonic acid, brassinosteroid, and strigolactone during various metabolic and physiological conditions and environmental stress responses. S-nitrosylation of key proteins involved in the phytohormonal network occurs during their synthesis, degradation, or signaling roles depending upon the response required to maintain cellular homeostasis. This review presents the interaction between NO and phytohormones and the role of the canonical NO-mediated post-translational modification particularly, S-nitrosylation of key proteins involved in the phytohormonal networks under biotic and abiotic stresses.

The Combined Inoculation of Curvularia lunata AR11 and Biochar Stimulates Synthetic Silicon and Potassium Phosphate Use Efficiency, and Mitigates Salt and Drought Stresses in Rice.

Synthetic chemical fertilizers are a fundamental source of nutrition for agricultural crops; however, their limited availability, low plant uptake, and excessive application have caused severe ecological imbalances. In addition, the gravity of environmental stresses, such as salinity and water stress, has already exceeded the threshold limit. Therefore, the optimization of nutrient efficiency in terms of plant uptake is crucial for sustainable agricultural production. To address these challenges, we isolated the rhizospheric fungus Curvularia lunata ARJ2020 (AR11) and screened the optimum doses of biochar, silicon, and potassium phosphate (K2HPO4), and used them-individually or jointly-to treat rice plants subjected to salt (150 mM) and drought stress (20-40% soil moisture). Bioassay analysis revealed that AR11 is a highly halotolerant and drought-resistant strain with an innate ability to produce gibberellin (GA1, GA3, GA4, and GA7) and organic acids (i.e., acetic, succinic, tartaric, and malic acids). In the plant experiment, the co-application of AR11 + Biochar + Si + K2HPO4 significantly improved rice growth under both salt and drought stresses. The plant growth regulator known as abscisic acid, was significantly reduced in co-application-treated rice plants exposed to both drought and salt stress conditions. These plants showed higher Si (80%), P (69%), and K (85%) contents and a markedly low Na+ ion (208%) concentration. The results were further validated by the higher expression of the Si-carrying gene OsLSi1, the salt-tolerant gene OsHKT2, and the OsGRAS23's drought-tolerant transcriptome. Interestingly, the beneficial effect of AR11 was significantly higher than that of the co-application of Biochar + Si + K2HPO4 under drought. Moreover, the proline content of AR11-treated plants decreased significantly, and an enhancement of plant growth-promoting characteristics was observed. These results suggest that the integrated co-application of biochar, chemical fertilizers, and microbiome could mitigate abiotic stresses, stimulate the bioavailability of essential nutrients, relieve phytotoxicity, and ultimately enhance plant growth.