Gibberellic Acid Research Articles

The Influence of Gibberellins and Smoke Water as a Stimulant for Germination and Vegetative Growth of Syzygium aromaticum (L.) Merr. & L. M. Perry

Clove or cengkeh (Syzygium aromaticum) is one of Indonesia’s commodities with high domestic and international potential, considering that this plant is used as raw material for the cigarette industry. Therefore, it is necessary to optimize the production of Indonesian cloves, one of which is by using growth stimulators such as plant growth regulators (PGR). This study uses gibberellic acid (GA3) and smoke water as exogenous growth triggers. The treatment given was soaking S. aromaticum seeds in gibberellic acid (GA3) and liquid smoke for 24 h. The GA3 concentrations used were 100 ppm, 75 ppm, 50 ppm, and 25 ppm. Smoke water was obtained from the pyrolysis of coconut shells, and the concentrations used were 0.5%, 1%, 2%, and 3%. Observations were conducted for 11 weeks and divided into two phases, namely the germination phase and the vegetative growth phase. Parameters measured included germination percentage, radicle, and plumula length in the first phase, root length, plant height, and number and area of leaves in the second phase. The best results were achieved with the soaking treatment using 0.5% smoke water, which showed a significant increase in all observed growth parameters. This is due to the content of karrikin in smoke water, which acts like a growth hormone and triggers the performance of other growth hormones. In addition, karrikin plays an active role in the germination process by changing the morphology of the seeds.

Evaluating the anti-cancer potential and pharmacological in-sights of Physalis angulata Root Extract as a strong candidate for future research

The research targeting the prevention of complications through natural constituents, instigated by the cancer has recently drawn much more attention over the globe. The research in this direction also revealed that the use of natural constituents would considered a promising strategy for diminishing the aforementioned disease and its consequences. Because of the easy availability and safe nature, the recent years, natural resources as strong anticancer agents. In this regard, here we introduced the possibility of using the methanolic extract of Physalis angulata root as a strong candidate and implemented the applicability of LC-MS to unveil the presence of various phytocompounds. The anticancer potential exhibited by Physalis angulata root followed by its ability to induce toxicity against the microbial population enhanced the interest in unveiling the phytochemical compounds including Absintholide, Curcumin dimer 1, Mytilin A, Ginsenoside F1, Encecalin , Ganoderic acid TQ, Alnustone, Rhamnetin 3-sophoroside, Gibberellin A14 aldehyde, Thiolutin, Euglobal III and Epomusenin B. The presence of various macro and micronutrients suggested that Physalis angulata is a prominent resource for future research targeting pharmacological research, especially anticancer research.

Effect of intra-row spacing, gibberellic acid concentration and N:P<sub>2</sub>O<sub>5</sub>:K<sub>2</sub>O ratio on growth and yield of potato variety Royal

The potato variety Royal is suitable to make French fries due to its frying qualities. However, the tubers lack the long-oval shape which is preferred in processing of French fries. Despite the lower nitrogen (N) requirement of variety Royal, farmers apply same recommendation ignoring the varietyspecific needs. Thus, two experiments were conducted to (a) evaluate the possibility of changing tuber shape by manipulating intra-row spacing and gibberellic acid (GA3) application and to (b) identify the best N:P2O5:K2O ratio to optimize growth and yield. The first experiment was conducted with 45 cm inter-row spacing, as a two-factor factorial RCBD. Factors one and two were intra-row spacing (15, 20, 25, 30, and 35 cm) and foliar-applied GA3 concentration (0, 150, 200, and 250 ppm), respectively. In the second experiment, recommended N:P2O5:K2O ratio, 8.0:3.5:8.5, (Department of Agriculture, Sri Lanka) with organic manure (control) and the same without organic manure were compared with three other N:P2O5:K2O ratios. Each treatment had 4 replicates, with 12 plants per replicate in both experiments. Data were analysed with Two-Way ANOVA in the first experiment and One-Way ANOVA in the second, using Minitab 17. Tukey’s mean comparison test was used to compare the mean values of both experiments. Intra-row spacing and GA3 interaction did not significantly (P>0.05) affect the tuber yield and shape. By increasing IRS, yield per plant increased, but yield per unit land area (YPL) decreased. The effect of GA3 on tuber yield was not significant (P>0.05). GA3 at 200 ppm recorded the highest number of long-oval tubers (62% increment). N:P2O5:K2O ratio had no significant (P>0.05) effect on growth, yield, and quality. Therefore, a fertilizer ratio with low nutrient input will be more sustainable and cost-effective for potato variety Royal with lower nutrient needs. Closer intrarow spacing (15 cm) with 200 ppm GA3 can be recommended for higher YPL with higher number of long-oval tubers.

Impact of gibberellic acid GA3, quantum dot biochar, and rhizosphere bacteria on fenugreek plant growth and stress responses under lead stress

Lead (Pb) is a stress that can cause problems with several aspects of a plant’s metabolism, potentially impeding the plant’s ability to grow and develop. The use of gibberellic acid (GA3), quantum dot biochar (QDBC), and rhizobacteria (RB) can be effective methods to overcome this problem. Gibberellic acid is a crucial plant hormone that regulates plant growth, cell division, tissue differentiation, flowering, photosynthesis, and transpiration rate. It also significantly impacts crop resilience to stress, affecting plant morphology, enzymatic activity, and physiology. Biochar, a soil supplement, enhances plant development soil health, and reduces stress effects. Due to its large surface area and porosity, it increases soil water-holding capacity, nutrient retention, and microbial activity. Quantum dots, semiconductor nanoparticles, have been proposed as a potential method to alleviate plant stress by acting as antioxidants, reducing oxidative stress, and controlling nutrient and growth regulators. Rhizobacteria, soil bacteria in plant roots, stimulate plant growth, nutrient absorption, and harvesting capacity. They produce phytohormones, increase mineral and nitrogen accessibility, and can induce systemic resistance (ISR), affecting plant defense. This study investigates the effects of combining GA3, QDBC, and RB as amendments to fenugreek, both with 500 Pb stress and without Pb stress. Treatments (control, 0.25 GA3mg/L-QDBC, 0.5 GA3mg/L-QDBC, 0.25 GA3mg/L-QDBC + RB, and 0.5 GA3mg/L-QDBC + RB) were applied in six replications using a completely randomized design. Results demonstrate that the combination of 0.5 GA3mg/L-QDBC + RB with 500 Pb stress led to significant enhancements in fenugreek shoot fresh weight (15.62%), root fresh weight (73.53%), shoot dry weight (24.00%), and root dry weight (36.53%) compared to the control. Additionally, there were notable improvements in chlorophyll a (57.23%), chlorophyll b (19.21%), and total chlorophyll (36.23%) compared to the control under Pb stress, also showing the potential of 0.5 GA3mg/L-QDBC + RB with 500 Pb stress. The study suggests that combining 0.5 GA3mg/L-QDBC + RB with 500 Pb stress can effectively mitigate Pb stress in fenugreek.

Enhancement of Secondary Metabolite Production in Tinospora cordifolia Suspension Cultures Using Gibberellic Acid Elicitation: A Comprehensive Analysis of Alkaloids and Phenols

Tinospora cordifolia, a medicinal plant known for its rich bioactive compounds, holds significant pharmacological importance due to its alkaloid and phenolic content. In this study, the effect of gibberellic acid (GA), a plant growth regulator, on the enhancement of total phenols and alkaloids in in vitro cell cultures of T. cordifolia was investigated. Cells were treated with different concentrations of GA (1–5 mg/L), and the maximum metabolite production was observed at 3 mg/L after 30 days of culture. GA treatment led to a significant increase in total alkaloid content, peaking at 9.454 mg/g DW in the cell extracts, demonstrating GA’s role in stimulating alkaloid biosynthesis. Similarly, total phenol content was highest at 3 mg/L GA, with 20.5 mg/g DW in the cell extracts, confirming GA’s influence on phenolic pathways. These results highlight GA’s potential as an elicitor for enhancing the production of bioactive compounds, offering promising applications for large- scale secondary metabolite production in Tinospora cordifolia under controlled conditions.

Genomic profiling and assessment of the plant growth-enhancing traits in the novel actinomycete, Plantactinospora soli sp. nov.

Strain KLBMP 9567T, an isolate from weathered soil, was identified as a new actinobacterial species through a comprehensive polyphasic approach. Phylogenetic evaluations relying on 16S rRNA gene sequence placed KLBMP 9567T within the genus Plantactinospora, alongside its close relatives Plantactinospora veratri NEAU-FHS4T and Plantactinospora sonchi NEAU-QY2T, both sharing 98.6% sequence similarity. However, KLBMP 9567T demonstrated low digital DNA-DNA hybridization values with P. veratri NEAU-FHS4T and P. sonchi NEAU-QY2T, recorded at 48.5 and 29.1%, respectively. Meanwhile, the average nucleotide identity values were correspondingly recorded at 91.1 and 83.1%. The cell wall of KLBMP 9567T contained meso-diaminopimelic acid, with xylose, mannose, glucose and galactose as diagnostic sugars. The diagnostic dominant phospholipids included diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. Given phenotypic and genotypic data, KLBMP 9567T is recognized as a new species within the Plantactinospora genus, named Plantactinospora soli sp. nov., with the type strain KLBMP 9567T (= CGMCC 4.7773T = NBRC 115787T). Genome mining revealed genes associated with plant growth promotion, specifically those encoding enzymes for synthesizing plant hormones like indole acetic acid and gibberellic acid. Experimental validation demonstrated that KLBMP 9567T can produce significant quantities of indole acetic acid (20.6 mg l-1) and gibberellic acid (42.6 mg l-1). Moreover, co-culture with Arabidopsis showed marked growth enhancements: a 56.3% increase in lateral root proliferation, a 16.7% elongation in primary root length and a 44.8% boost in biomass accumulation. These findings underscore the strain's potent plant growth-promoting attributes, providing profound insights into the mechanisms by which KLBMP 9567T enhances plant growth.

Phytohormone augmented biomass and lipid production in Dunaliella salina under two-stage cultivation strategy: A comprehensive characterization of biomass and lipid using DLS, FTIR, CHNS and NMR for bioenergy prospects

Increasing population, climatic shifts, and decreasing fossil-fuels worldwide led scientists to explore microalgae as a renewable energy resource. The present study unravels the impact of gibberellic acid (GA3) on biomass production, enzymatic activities, macromolecular synthesis, and metabolome analysis of Dunaliella salina using two-stage cultivation strategy. The results indicated a marked increase in biomass (1.44-fold), photosynthetic yield (Fv/Fm 0.68), along with RuBisCO activity (1.66-fold), with an increased in absolute value of zeta potential(ζ) in cultures treated with 10 µM GA3 compared to controls (Stage I). Interestingly, 15 µM GA3-treated cells significantly enhanced lipid content (42.36 %), and carbohydrates (16.56 %) with elevated antioxidative enzymes (SOD, CAT, and APX) activities (Stage II). Enhanced lipid content was further confirmed through FTIR spectra (2928 cm-1, and 1740 cm-1) and 1H NMR signals (1.0– 2, 3.5–4.5 ppm), indicating an increase in both saturated (SFA) and polyunsaturated fatty acids (PUFAs). Elemental analysis demonstrated higher carbon and hydrogen percentages, reflected in higher heating value (HHV) and H/C ratio at 15 µM GA3. The increased lipid content was found to be significantly correlated with ACCase and GPAT activities, suggesting the allocation of carbon flux toward lipid biosynthesis pathways. To substantiate the carbon flux, HR-MS-based metabolomic analysis was performed, indicating a reduction in TCA and Calvin cycle intermediates with a significant rise in carotenoid biosynthesis, as well as metabolic shift towards fatty acid biosynthesis reflecting in the enhanced SFA and PUFAs. Thus, these findings highlighted GA3 significant role in the carbon flux allocation towards the neutral lipid biosynthesis for bioenergy prospects.

Induction and genetic verification of homologous double haploid plants obtained through the anther culture of Citrus cultivars

In this study, an anther culture system was developed for two Citrus varieties known for their genetic value: blood orange (Moro) and mandarin (Lee). Anthers were inoculated on N6 solid medium containing thidiazuron (TDZ, 0.44 mg/L), 6-benzylaminopurine (0.8 mg/L), zeatin (0.43 mg/L), kinetin (0.44 mg/L), 1-naphthaleneacetic acid (0.2 mg/L), 2,4-Dichlorophenoxyacetic acid (0.2 mg/L), and malt extract (500 mg/L). The inoculated anthers were treated with N6 liquid medium containing spermidine (200 µM) and gibberellic acid (GA3, 1 mg/L), and cultured for 6 weeks. Thereafter, the swollen anthers were transferred to a Murashige and Skoog (MS) basal medium enriched with malt extract (500 mg/L), sucrose (50 g/L), TDZ (0.5 mg/L), GA3 (1 mg/L), and gelrite (0.2%), which induced callus and somatic embryos. These somatic embryos, from both varieties, were then transferred to a germination medium (MS basal medium containing sorbitol [0.05 M], galactose [0.05 M], malt extract [500 mg/L], GA3 [0.5 mg/L], and gelrite [2 g/L]) to develop into normal plants. However, Lee exhibited significantly slower shoot and root growth compared to Moro. Genetic analysis using barley microsatellite-derived cleaved amplified polymorphic sequence markers indicated that Lee likely originated from haploid plants, whereas Moro retained heterozygosity similar to the parent. Ploidy analysis confirmed Lee as a diploid, identical to the control. Internal transcribed spacer region analysis confirmed that Lee was an anther-cultured haploid-derived plant, estimated to be a homozygous diploid carrying recessive genes. These findings highlight potential applications in marker development for haploid-derived plants focused on recessive trait-associated phenotypes and genotypes.

Impact of Different Plant Growth Regulators on Growth, Yield and Quality of Fennel (Foeniculum vulgare Mill.) in Alluvial Regions of West Bengal

An experiment was conducted during the rabi seasons (November, 2018 –April, 2020) at the Horticultural Research Station, Mondouri, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal (741 252), India to assess the impact of different plant growth regulators on the growth, yield, and quality of fennel (Foeniculum vulgare Mill.). The experiment was designed in Randomized Block Design with a total of 9 treatment combinations that were replicated three times. Fennel seeds were sown during the first week of November in 2.5×1.5 m2 plots with a spacing of 50×30 cm2. Growth regulators were applied at 30, 45, and 60 days after sowing. The results revealed that the application of naphthalene acetic acid @ 100 ppm significantly optimized fennel yield and quality in the alluvial regions of West Bengal. This was evident through various yield and its attributing parameters, including number of umbel plant-1, number of umbellate umbel-1, number of seeds umbellate-1, test weight (g), and seed yield (22.95 q ha-1) as well as quality parameters including total soluble sugar content (2.91 mg 100 mg-1) and volatile oil content (1.448%). Additionally, Kinetin @ 10 parts per million significantly enhanced the total chlorophyll content (0.344 mg g-1), while gibberellic acid positively influenced growth parameters like plant height, number of primary and secondary branches, days to 50% flowering, flower stalk length, and umbel diameter.

Preharvest Gibberellic Acid Treatment Increases Both Modulus of Elasticity and Resistance in Sweet Cherry Fruit (cv. ‘Bing’ and ‘Lapins’) at Harvest and Postharvest During Storage at 0 °C

Fruit firmness in sweet cherries (Prunus avium L.) is a critical quality parameter highly valued by consumers as it is associated with fruit freshness. In general, firm fruit also cope better with storage and handling. Gibberellic acid (GA) is commonly used by sweet cherry producers to increase firmness, soluble solids content and fruit size. This study evaluated the effects of GA on the rheological properties of sweet cherry fruit at harvest and postharvest storage. Specifically, GA’s influence on susceptibility to mechanical damage during handling was evaluated. The following GA treatments were applied to two sweet cherry cultivars ‘Bing’ and ‘Lapins’: T0, control, T30—GA at 15 ppm applied at pit-hardening and straw-colour stages; T45—GA at 25 ppm at pit-hardening and GA at 20 ppm at straw-colour; and T60—GA at 30 ppm applied at pit-hardening and straw-colour. The results indicate that GA delayed harvest by two to four days in both cultivars, with ‘Lapins’ also showing a significant increase in fruit size. Regardless of spray concentration, GA increased the modulus of elasticity and fruit resistance evaluated as stress at the maximum point at harvest. These effects persisted after 35 days of storage at 0 °C and an additional three days of shelf-life at 15 °C. While the strain or deformation capacity of the fruit at bioyield at harvest was constant across treatments, it was, however, lower in the GA-treated fruit than in the controls during storage at 0 °C under the high-humidity conditions of modified atmosphere packaging. The less mature fruit harvested at colour 3.0 (red/mahogany) were stiffer (reduced deformation) and more sensitive to induced mechanical injury than the fruit harvested later at colour 3.5 (mahogany). The GA treatments increased fruit resistance to damage without increasing tissue deformability. Other questions associated with stiffer tissues and lower deformability during storage at 0 °C under high humidity should be further studied, specifically cultivars that are naturally high in box-cracking sensitivity during storage.

Influence of Boron and Gibberellic Acid on Growth and Yield of Summer Tomato

Tomato (Solanum lycopersicum L.) is a globally significant vegetable crop, valued for its nutritional and economic contributions. However, maximizing its yield and quality, particularly under challenging summer conditions, remains a critical agricultural concern. To assess the influence of boron (B) and Gibberellic Acid (GA3) on the growth, yield and quality of summer tomato (BARI Hybrid Tomato 8), a field experiment was conducted at the Department of Agriculture, Noakhali Science and Technology University, Noakhali, from May 2023 to August 2023. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications of each treatment. The unit plot size was 1.0 m × 1.0 m. There were 4 treatments T0: control (without Gibberellic acid and Boron), T1: 50 ppm GA3, T2: 100 ppm Boron and T3: combinations of T1 and T2 in the experiment comprising Boron (100 ppm) and GA3 (50 ppm). The effect of boron, gibberellic acid and their combined effect showed significant variations in growth, yield and quality of tomato. In this study between the individual application of Boron @ 100 ppm and GA3 @ 50 ppm, GA3 gave the higher plant height, leaf number, fruit weight and yield per plant than Boron. Combined effect of GA3 and Boron at treatment T3 (50 ppm GA3 + 100 ppm Boron) gives the highest plant height (104.23), branch number (18.76), no. of leaves per plant (82.5), flower clusters per plant (14.05), flower per plant (52.1), fruit per plant (17.72), fruiting percentage (34.05), fruit weight per plant (964.21g), total yield (33.06 t ha-1). From this experiment, it can be concluded that the interactive effect of 50 ppm GA3 with 100 ppm Boron treatment is suitable dose for higher yield of tomato by improving all the parameters numerically.

High-throughput root phenotyping and association analysis identified potential genomic regions for phosphorus use efficiency in wheat (Triticum aestivum L.).

Association analysis identified 77 marker-trait associations (MTAs) for PUE traits, of which 10 were high-confidence MTAs. Candidate-gene mining and in-silico expression analysis identified 13 putative candidate genes for PUE traits. Bread wheat (Triticum aestivum L.) is a major cereal crop affected by phosphorus (P) deficiency, which affects root characteristics, plant biomass, and other attributes related to P-use efficiency (PUE). Understanding the genetic mechanisms of PUE traits helps in developing bread wheat cultivars that perform well in low-P environments. With this objective, we evaluated a bread wheat panel comprising 304 accessions for 14 PUE traits with high-throughput phenotyping under low-P and optimum-P treatments and observed a significant genetic variation among germplasm lines for studied traits. Genome-wide association study (GWAS) using 14,025 high-quality single-nucleotide polymorphisms identified 77 marker-trait associations (MTAs), of which 10 were chosen as high-confidence MTAs as they had > 10% phenotypic variation with logarithm of odds (LOD) scores of more than five. Candidate-gene (CG) mining from high-confidence MTAs identified 180 unique gene models, of which 78 were differentially expressed (DEGs) with at least twofold change in expression under low-P over optimum-P. Of the 78-DEGs, 13 were thought to be putative CGs as they exhibited functional relevance to PUE traits. These CGs mainly encode for important proteins and their products involved in regulating root system architecture, P uptake, transport, and utilization. Promoter analysis from 1500bp upstream of gene start site for 13 putative CGs revealed the presence of light responsive, salicylic-acid responsive, gibberellic-acid (GA)-responsive, auxin-responsive, and cold responsive cis-regulatory elements. High-confidence MTAs and putative CGs identified in this study can be employed in breeding programs to improve PUE traits in bread wheat.

Gibberellic and salicylic acids improve seedling emergence, early growth and some physiological characteristics of Phaseolus vulgaris L. under soil compaction

Heavy soil compaction and crusting adversely affect the percentage and speed of seedling emergence, particularly in dicotyledonous epigeal plants. This study aimed to evaluate ways to cope with this phenomenon in kidney bean through hormonal priming. A factorial experiment was conducted based on a completely randomised design with three replications. The factors were seed priming (control, hydropriming, gibberellic acid 50 mg kg−1 (GA 50), GA 100, salicylic acid 50 mg kg−1 (SA 50), SA 100 and GA 50 + SA 50) and soil compaction (bulk density 1 340, 1 410, 1 470, 1 540 and 1 610 kg m–3). Results showed that soil compaction decreased root length and increased root branches. The longest root was observed following priming with GA 50 + SA 50 and no soil compaction (intact soil). Seed priming significantly affected seedling emergence and early growth indices. Priming improved root length and the number of root branches, while soil compaction suppressed root length and increased the number of root branches. Seed priming also significantly affected chlorophyll a, carotenoid, catalase and superoxide dismutase levels. Superoxide dismutase and catalase activities were increased by soil compaction, especially at 15% and 20% soil bulk density (ρ) (ρ = 1 540 and 1 610 kg m−3). In general, mild soil compaction (5% or ρ = 1 410 kg m−3) accelerated seedling emergence and improved growth. However, increased soil compaction by 15% or more, decreased root and shoot growth. Hydropriming decreased seedling emergence under soil compaction, and was unsuitable for such conditions. Combined hormonal priming (GA 50 + SA 50) was the best treatment for seed resilience to soil compaction.

Effect of Seed Treatments on Seed Germination Studies in Ramphal (Annona reticulata L.)

Annona reticulata L., commonly known as bullock's heart, is a tropical fruit-bearing tree belonging to the Annonaceae family. It is prized for its flavourful and nutritious fruit. The plants are used for anti-inflammatory, stress reliever, antimutagenic, curing wounds, anti-anxiety, and spasmolytic properties and have all been used. In this fruit, the seeds are poor due to seed dormancy, and viability is easily lost. To overcome this problem in bullock’s heart, an experiment was laid out in the Floriculture unit, Department of Horticulture, Faculty of Agriculture, Annamalai University, Tamil Nadu on seed germination studies in Ramphal (Annona reticulata L.). Amongst the different pre-sowing seed treatments, treatment with Gibberellic Acid @ 1000 ppm significantly improved the germination percentage (90.63%) and reduced the number of days taken for initiation of seed germination (17.02 days), days taken for 50 percent of seed germination (22.44 days), span of seed germination (25.09 days) as compared to control. This experiment concluded that Gibberellic Acid @ 1000 ppm treated seeds have better seed germination characteristics.

Improving Performance and Yield of Solanum Melongena L. through Growth Regulator Applications

This study was conducted in an agricultural area located in Dharmabad, Nanded district, Maharashtra. The experiment followed a randomized design with three replications and involved the application of ten different growth regulator treatments. The findings indicated that foliar treatment significantly influenced the vigor of Brinjal plants and their yield-contributing features when compared to the control group. Specifically, the foliar application of Tricontanol and Gibberellic acid during the flowering and bud stages resulted in notable improvements in plant height, plant spread, number of branches, and number of fruits per plant. These treatments also demonstrated positive effects on various yield-contributing characteristics such as days to 25% flowering, fruit set, fruit length, and fruit diameter, as compared to the control group.

Scrutinizing harsh habitats endophytic fungi and their prospective effect on water-stressed maize seedlings.

Drought constitutes a significant abiotic stressor that hinders plant growth and productivity in many countries. Habitat-adapted endophytic fungi offer an environmentally sustainable approach to address this issue by promoting plant development and enhancing resilience against abiotic stresses. In this study, 30 endophytic fungal isolates were recovered from some wild plants in the extreme habitats of Port Said Governorate, Egypt, and evaluated for their drought tolerance using polyethylene glycol (PEG-6000). Only eight isolates demonstrated drought tolerance properties and were further evaluated for their plant growth-promoting biochemical activities and ability to improve maize germination under simulated drought conditions. All eight isolates exhibited enzyme activity for endo-1,4-β-glucanase, amylase, and pectinase, and most displayed significant nutrient mobilization, with siderophores production ranging from 4 to 89%, ammonia production from 1 to 7μmol/ml, and phosphate solubilization from 129to 256µg/ml. Additionally, all isolates showed strong antioxidant activity and high total phenolic content, with some also producing notable levels of indole acetic acid (IAA) and gibberellic acid (GA3) as plant growth hormones. Coating maize grains with spore suspensions of the eight fungal isolates, in general, significantly increased their germination parameters and seedling vigor in vitro under 8% PEG-6000. This enhancement was particularly pronounced with Neurospora sitophila (P8L4M1) and Penicillium tardochrysogenum (P15L4M1), which increased the vigor of maize seedlings by approximately 308% compared to untreated control. Molecular identification of P8L4M1 and P15L4M1 was performed by amplifying the 28S rRNA gene. This study disclosed unique endophytic fungal isolates with promising potential for enhancing drought resistance in maize.

Light Drought Stress Positively Influenced Root Morphological and Endogenous Hormones in Pinus massoniana Seedlings Inoculated with Suillus luteus

Aims An ectomycorrhizal fungus (ECMF) may enhance plant drought resistance. However, there is limited information regarding the effects of ECMFs on drought resistance in Pinus massoniana Lamb., a native species representing an afforestation pioneer tree in subtropical regions of China. Methods In this study, a pot experiment was conducted to determine the effects of ECMF Suillus luteus inoculation on the root morphology and endogenous hormones of P. massoniana, including roots, leaves, and stems, under various water treatment conditions. Four water levels (regular, light, moderate, and severe drought) and three inoculations (inoculated Suillus luteus, numbered S12 and S13, and non-ECMF-inoculated) were compared using a factorial design. Results Under drought stress, P. massoniana seedlings inoculated with S12 and S13 had significantly increased root morphology development (p < 0.05). Light drought positively influenced root development, resulting in a more than twofold increase in root length and root surface area compared to non-inoculated seedlings. Concentrations of gibberellic acid (GA), zeatin riboside (ZR), and indole-3-acetic acid (IAA) in roots, stems, and leaves of inoculated S12 and S13 plants were elevated, whereas abscisic acid (ABA) concentrations were significantly lower, compared to non-inoculated seedlings. The ABA concentrations in the roots of S12 and S13 inoculated seedlings under light drought stress were 1.5 times lower than those in non-inoculated controls. Moreover, root development was positively correlated with plant total GA, IAA, and ZR but negatively correlated with ABA. ConclusionsS. luteus can promote the root growth and development of P. massoniana seedlings, notably by regulating the balance in the concentration of endogenous hormones, thus improving the drought resistance of P. massoniana seedlings.

Gibberellin action‐based strategies show promise in the control of Striga—A major threat to global agriculture

Societal Impact StatementThe root‐parasitic plant Striga hermonthica can cause severe crop failure, leading to significant agricultural and economic losses in Africa. Despite the promising target offered by the Striga seed germination mechanism for developing control methods, effective control methods have yet to be established. For seed germination, Striga must undergo an incubation under warm and humid conditions, a process termed conditioning, which allows it to germinate. Here, we report that the plant hormone gibberellin stimulates the conditioning process in Striga seeds. Our findings suggest that the quantitative control of gibberellin in plants is a promising approach for controlling Striga infestations and may help alleviate substantial threats to food security.Summary The root‐parasitic plant S. hermonthica is a serious agricultural threat in Africa. Although a number of control methods have been employed to combat Striga, there is still a need to develop more effective control methods. Striga seeds germinate only in the presence of host plants, owing to the need for host‐released stimulants, primarily strigolactone. To detect signals from the host, Striga seeds must be exposed to a specific warm, dark, and moist environment, which is known as conditioning. Gibberellin directly promotes germination in many nonparasitic plants, but Striga seeds are insensitive to exogenous gibberellin. Consequently, the role of gibberellin in the germination of Striga seeds is unclear. We demonstrated that the effect of the gibberellin biosynthesis inhibitor paclobutrazol was higher in seeds during the conditioning, compared with those already conditioned, suggesting that gibberellin primarily regulates conditioning rather than germination. The content of an active form gibberellin, gibberellin A4 (GA4) exhibited an increase throughout the conditioning period, and we quantified the elevated expression levels of some gibberellin biosynthesis genes. The GA4 treatment shortened the conditioning period required for strigolactone‐induced seed germination. We also discovered that gibberellin upregulated ShACO1, the gene responsible for ethylene synthesis, during conditioning, and that the inhibition of GR24‐induced germination by the ethylene biosynthesis inhibitor α‐aminoisobutyric acid was gradually alleviated by GA4. Our findings demonstrate that gibberellin is critical for conditioning and germination processes but acts as a minor stimulant in Striga seeds. This study demonstrates the potential of quantitative endogenous gibberellin control for Striga management, providing valuable insights for alleviating food security issues.

Exploring Metalloprotease from Dunaliella sp.: Production, Regulation, and Structural Insight

A green microalgal strain, identified as Dunaliella sp., was isolated from the Tunisian southern region. The enhancement of its protein and protease production was performed through culture condition optimization using the response surface methodology. The optimal conditions for protein and protease production were found to be, respectively, (i) NaCl concentrations of 135 and 45.55 g/L, (ii) NaHCO3 concentrations of 0.5 and 1.5 g/L, (iii) temperature of 28 °C for both, and (iv) light intensities of 400 and 100 µmol photons/m2/s. The optimization led to an increase in microalgae protein content from 11.98% ± 0.26 to 18.39% ± 0.10 and microalgae proteolytic activity from 7.36 ± 0.74 U/mg to 12.54 ± 0.86 U/mg. Specific focus was attributed to ATP-dependent metalloprotease, namely, FtsH2, which is involved in numerous cellular processes including cell division, cell differentiation, signal transduction, and stress response. Differential expression of the FtsH2 gene under various stress conditions showed that this expression was upregulated in response to salt stress, gibberellic acid, and Indole-3-butyric acid. A 3D modeling demonstrated two possible arrangements where the ATPase ring shows either a perfect six-fold symmetry with an open circular entrance covering the crucial pore residues, or a translocated model triggered by substrate binding inward movement of the aromatic pore residues.

Classification of Seed Dormancy in Pedicularis hallaisanensis Hurusawa: An Endemic and Endangered Species Native to Korea

Pedicularis hallaisanensis Hurusawa, native to Mt. Halla and Gaya, is an endangered endemic species. To support conservation efforts, this study investigated its germination characteristics and kind of seed dormancy. The seeds of P. hallaisanensis had fully developed linear embryos at dispersal, with no additional embryo growth observed. Water imbibition was observed prior to germination. The seeds were water-permeable. The seeds did not germinate at four temperature treatments (4 °C/1 °C, 15 °C/6 °C, 20 °C/10 °C, and 25 °C/15 °C). However, cold stratification and gibberellic acid treatments broke seed dormancy. Total germination was 15%, 15%, and 45% at 12, 16, and 20 weeks of cold stratification, respectively. Total germination at 25 °C /15 °C for GA treatments were 0%, 25%, 25%, and 80% at 500, 1000, 1500, and 2000 mg/L, respectively. This study showed that the seeds of P. hallaisanensis have intermediate physiological dormancy, requiring 20 weeks of cold stratification or more than 2000 mg/L GA concentration to maximize total germination. These results are useful for understanding ecophysiological mechanisms related to the species’ habitat and for mass propagation to conserve this endangered species.