Hormone Indoleacetic Acid Research Articles

Innovative auxin-micronutrient based nanocomposites (IAA-Fe2O3NPs and IAA-Mn2O3NPs) shield strawberry plants from lead toxicity.

Smart nanohybrid technology with potential advantages to plants has recently been developed formanaging the widespread pollution of heavy metals. Herein, we disclose a novel strategy to combat Pb stress in strawberry (Fragaria spp. cv. Fertona) through a newly designed nano-based system that conjugates indole acetic acid (IAA) with nanoparticles (NPs) of iron (Fe) and manganese (Mn) micronutrients, forming IAA-Mn2O3NPs (IAA-MnNPs) and IAA-Fe2O3NPs (IAA-FeNPs) nanocomposites and illuminates the underlying mechanisms involved. NPs were synthesized, yielding cubic Mn2O3 NPs (50nm) and spheric Fe2O3 NPs (30-40nm), and evidenced by various characterization techniques. The incorporation of IAA hormone to the surface of NPs was examined using FT-IR spectroscopy. Results showed that Pb harshly hindered strawberry growth and promoted stress oxidative markers, i.e., MDA and ROS byproducts. Notably, the application of IAA-MnNPs and IAA-FeNPs at 50 and 100ppm moderated the deleterious effects of Pb toxicity in strawberry plants, as revealed by enhanced growth indices, photosynthetic traits, membrane stability, and nutrient profiles of Mn and Fe, as well as higher IAA accumulation. This is pertinent to lessen Pb accumulation and impaired Pb-induced oxidative stress. The decrease in Pb content holds to be filled in with escalating Pb-detoxification mechanisms by enhancing enzymatic antioxidants' activities such as catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), glutathione S-transferases (GST), phenylalanine ammonia-lyase (PAL), nitrate reductase (NR), and attenuating polyphenol oxidase (PPO). On top of that, IAA-MnNPs and IAA-FeNPs elevated the content of non-enzymatic antioxidants, e.g., ascorbic acid and flavonoids, and enhanced the accumulation of chelating agents, i.e., proline, glutathione, and phytochelatins. We posit that the novel-engineered IAA-MnNPs and IAA-FeNPs nanohybrids present an effective approach that could fend off Pb stress in strawberry plants in contaminated croplands.

Standardization of Panchagavya for Enhanced Nutrient Content and Seed Germination in Sustainable Organic Farming

The detrimental effects of chemical-intensive agriculture have spurred interest in eco-friendly farming practices, particularly organic farming. Central to organic farming are organic manures, including various liquid organic formulations such as Panchagavya, which are rooted in Indigenous Technical Knowledge (ITK). Due to the variability in local production methodologies, there is a pressing need to standardize the production techniques of liquid organic manures, specifically Panchagavya, and to characterize their properties. The study standardizes Panchagavya production to reduce local variability. Eight ingredients were used, with 81 different combinations. Physical and chemical properties of prepared Panchagavya were analyzed, and principal component analysis was performed to determine optimal combinations for improved soil health and crop productivity. The nitrogen content of different combinations of Panchagavya ranged from 1.12% to 2.66%, phosphorus between 0.12% to 0.385%, potassium between 0.345% to 0.65%. The Ca content ranged between 186.3 mg L⁻¹ and 256.66 mg L⁻¹. Mg content the range was between 52.1 mg L-1 to 92.4 mg mg L-1, S varies between 0.08% and 0.3%, the Fe content in Panchagavya ranged from 49.7 mg L⁻¹ to 53.1 mg L⁻¹, Mn content ranged from 2.60 mg L⁻¹ to 5.05 mg L⁻¹, Zn content ranged from 4.1 mg L⁻¹ to 6.35 mg L⁻¹, and Cu content ranged from 12.50 mg L⁻¹ to 14.95 mg L⁻¹. with higher levels associated with increased quantities of cow urine, milk, curd, and ghee. Germination study indicated that Panchagavya positively affected seed germination and root growth increased from 3.45% to 114.66%. The growth hormone indole acetic acid values was between 56.6 µg mL⁻¹ and 104.19 µg mL⁻¹. Similarly, the gibberellic acid values ranged from 138.34 µg mL⁻¹ to 185.23 µg mL⁻¹. From the 81 treatment 10 best treatment was selected by principle component analysis of nutrient content of Panchagavya. Microbial analysis of selected Panchagavya demonstrated significant populations: bacteria (7.57 to 8.03 log cfu mL⁻¹), fungi (4.3 to 4.73 log cfu mL⁻¹), and actinomycetes (3.15 to 3.9 log cfu mL⁻¹). The presence of IAA and GA further substantiates its efficacy as an organic fertilizer. This research confirms that Panchagavya enhances nutrient content, microbial activity, and hormone levels, resulting in improved seed germination and root development. These findings highlight its potential as a sustainable alternative to chemical fertilizers, promoting organic farming practices and contributing to healthier soils.

Metabolomic Analyses Reveal That IAA from Serratia marcescens Lkbn100 Promotes Plant Defense during Infection of Fusarium graminearum in Sorghum.

Global sorghum production has been significantly reduced due to the occurrence of sorghum root rot caused by the fungus Fusarium graminearum. The utilization of biocontrol microorganisms has emerged as an effective strategy. However, the underlying mechanisms remain unclear. Therefore, the aim of this study was to investigate the effectiveness of biocontrol bacteria in inducing sorghum resistance against sorghum root rot and explore the potential induced resistance mechanisms through metabolomics analysis. The results revealed that the biocontrol bacteria Lnkb100, identified as Serratia marcescens (GenBank: PP152264), significantly enhanced the resistance of sorghum against sorghum root rot and promoted its growth, leading to increased seed weight. Targeted metabolomics analysis demonstrated that the highest concentration of the hormone IAA (indole-3-acetic acid) was detected in the metabolites of Lnkb100. Treatment with IAA enhanced the activity of disease-related enzymes such as SOD, CAT, POD and PPO in sorghum, thereby improving its resistance against sorghum root rot. Further untargeted metabolomic analysis revealed that IAA treatment resulted in higher concentrations of metabolites involved in the resistance against F. graminearum, such as geniposidic acid, 5-L-Glutamyl-taurine, formononetin 7-O-glucoside-6″-O-malonate, as well as higher concentrations of the defense-related molecules volicitin and JA. Additionally, "secondary bile acid biosynthesis" and "glycerophospholipid metabolism" pathways were found to play significant roles in the defense response of sorghum against fungal infection. These findings provide a reliable theoretical basis for utilizing biocontrol microorganisms to control sorghum root rot.

Studies on the Impact of Microbial Consortia towards Enhancing the Growth of Red Sanders

The use of plant growth-promoting microorganisms, either alone or combined, as bioinoculants presents an economical and eco-friendly alternative to chemical fertilizers. This method provides a comprehensive solution for enhancing plant growth and yield. This study aimed to develop robust microbial consortia possessing plant growth-promoting capabilities and evaluate their effectiveness in enhancing tree seedling growth. Six bacterial strains were collected and screened for specific traits linked to promoting plant growth. Selected strains were then assessed for compatibility with each other, resulting in the formation of bacterial consortia. These consortia demonstrated diverse plant growth-promoting properties, including the production of the plant growth hormone indole acetic acid and the synthesis of exopolysaccharides. Consequently, these bacterial consortia exhibit significant potential as bioinoculants, offering a promising approach to enhancing plant growth and productivity in an environmentally friendly manner. This contributes to the progress of efforts aimed at promoting seedling growth.

Rhizosphere Bacteria Plumeria acuminata Increases Growth of Zea mays After Root Inoculation

The bacteria found in the rhizosphere are called plant growth promoting rhizobacteria (PGPR), namely bacteria that can stimulate plant growth by producing growth hormones, one of which is the hormone indole acetic acid (IAA) which plays a role in regulating plant growth and development. Five isolates of rhizosphere bacteria were isolated on frangipani roots (P26, P31, P36, P37 and P38). Previous research showed that five bacterial isolates were capable of producing the hormone IAA. However, evidence of its potential as a PGPR has not been obtained. Therefore, the aim of this study was to test the effect of inoculation of rhizosphere bacteria on maize plants. The research method uses a quantitative experimental method, namely 15 repetitions for each treatment. Data collection was carried out 1 day after planting (HTS) until the 14th day. Data were analyzed using a 95% confidence student t-test or with a significance level of 5% (a=0.05). This inoculation begins with germinating maize seeds and observing the roots. The germinated maize seeds are then soaked in the bacterial suspension for one hour at room temperature. The results showed that inoculation with isolates P36, P37 and P38 significantly increased the height of maize plants, while isolate P37 significantly increased the number of leaves and root length of corn plants, isolate P38 could significantly increase the number of roots of corn plants.Thus, these results support the evidence that rhizosphere bacteria from frangipani have an effect on increasing the growth of maize plants

Pantoea: A Versatile bacterial Candidate of Agricultural Importance

Genus Pantoea is a diverse group of the family Enterobacteriaceae which inhabit various ecological niches. Various species of Pantoea are found associated with a diverse host range that include plants, animals, insects and humans. Besides this Pantoea spp. has been widely distributed in nature including water, soil, dairy products, meat and fish. It is commonly associated with plants as epiphyte or pathogen. Pantoea was first recognized as a genus about 25 years ago, but since then, approximately 20 species with a wide range of characteristics have been discovered. Identification of plant-pathogenic Pantoea species is difficult, due to the high degree of phenotypic similarity between species of this genus and related Enterobacteriaceae. Pantoea species are typically characterized based on colony morphology, physiological and biochemical tests, and in some cases, fatty acid analysis or quinone composition. These have a wide range of plant hosts where they live as nonpathogenic endophytes as well as epiphytes that colonize the leaves, stems and roots. In this perspective, some Pantoea strains can be beneficial to the plant host by providing growth promoting substances such as the plant-growth hormone indole-acetic acid (IAA), phosphate solubilization or nitrogen fixation. Number of Pantoea species are also involved in bioremediation of various pesticides and organic chemical compounds. This indicates the potential to degrade some recalcitrant and xenobiotic compounds. Some Pantoea strains also provide effective protection to plants against various bacterial and fungal diseases and post-harvest fruit rots. On the other hand, some of the species are recognized as a human pathogen and has led to controversy as limited documented cases of P. agglomerans bacteremia and infections have been reported. Most of the cases reported among immunocompromised patients or the pediatric population. Thus, Pantoea is a multifaceted bacterium that plays a significant role in agriculture as a plant growth promoter by producing hormone like IAA, inorganic pollutant degradation by producing potent enzymes and also protects some plants against pathogens by producing antibacterial and antifungal compounds. In some cases, these also cause diseases in human beings. Therefore, this genus is very important for studies. In this review, the industrial, agricultural as well as ecological significance of the genus Pantoea is emphasized.

Physiological and Biochemical Effects of Exogenous Calcium on Camellia oleifera Abel under Drought Stress

High temperature and drought are the main factors restricting the increase in Camellia oleifera Abel production that can seriously harm its physiological and biochemical functions. This study aimed to explore the effect by which Ca2+ enhances the drought resistance of C. oleifera. Four-year-old potted plants of the ‘Xianglin 210’ variety were treated with four levels of CaCl2 solution (0, 10, 20, and 40 mmol/L) and subjected to natural drought stress. The drought levels were categorized as CS (non-drought), LD (light drought), MD (moderate drought), and SD (severe drought). The effects of drought stress on the growth and physiological-biochemical characteristics of C. oleifera were measured. Under drought stress, spraying CaCl2 solution on leaves could significantly increase the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), endogenous hormone indoleacetic acid (IAA) content, abscisic acid (ABA) content, and gibberellic acid (GA) content in organs and tissues; enhance the superoxide dismutase (SOD) activity; and decrease the concentration of intercellular carbon dioxide (Ci) and number of dehiscence fruits. Spraying 10 mmol/L CaCl2 effectively alleviates the damage of drought stress to tung oil trees. The study provides references for alleviating drought stress and increasing economic benefits in C. oleifera production.

Effects of exogenous glycine betaine and cycloleucine on photosynthetic capacity, amino acid composition, and hormone metabolism in Solanum melongena L.

Although exogenous glycine betaine (GB) and cycloleucine (Cyc) have been reported to affect animal cell metabolism, their effects on plant growth and development have not been studied extensively. Different concentrations of exogenous glycine betaine (20, 40, and 60 mmol L−1) and cycloleucine (10, 20, and 40 mmol L−1), with 0 mmol L−1 as control, were used to investigate the effects of foliar spraying of betaine and cycloleucine on growth, photosynthesis, chlorophyll fluorescence, Calvin cycle pathway, abaxial leaf burr morphology, endogenous hormones, and amino acid content in eggplant. We found that 40 mmol L−1 glycine betaine had the best effect on plant growth and development; it increased the fresh and dry weight of plants, increased the density of abaxial leaf hairs, increased the net photosynthetic rate and Calvin cycle key enzyme activity of leaves, had an elevating effect on chlorophyll fluorescence parameters, increased endogenous indoleacetic acid (IAA) content and decreased abscisic acid (ABA) content, and increased glutamate, serine, aspartate, and phenylalanine contents. However, cycloleucine significantly inhibited plant growth; plant apical dominance disappeared, plant height and dry and fresh weights decreased significantly, the development of abaxial leaf hairs was hindered, the net photosynthetic rate and Calvin cycle key enzyme activities were inhibited, the endogenous hormones IAA and ABA content decreased, and the conversion and utilization of glutamate, arginine, threonine, and glycine were affected. Combined with the experimental results and plant growth phenotypes, 20 mmol L−1 cycloleucine significantly inhibited plant growth. In conclusion, 40 mmol L−1 glycine betaine and 20 mmol L−1 cycloleucine had different regulatory effects on plant growth and development.

Isolation, Identification, and Characterization of Phosphate-Solubilizing Bacteria from Tunisian Soils

Soil microorganisms play an important role in maintaining natural ecological balance through active participation in carbon, nitrogen, sulfur, and phosphorous cycles. Phosphate-solubilizing bacteria (PSB) are of high importance in the rhizosphere, enhancing the solubilization of inorganic phosphorus complexes into soluble forms available for plant nutrition. The investigation of this species of bacteria is of major interest in agriculture, as they can be used as biofertilizers for crops. In the present study, 28 isolates of PSB were obtained after the phosphate enrichment of soil samples from five Tunisian regions. Five PSB species were identified by 16S rRNA gene sequencing including Pseudomonas fluorescens, P. putida, and P. taiwanensis, Stenotrophomonas maltophilia, and Pantoea agglomerans. Solid and liquid Pikovskaya's (PVK) and National Botanical Research Institute's (NBRIP) media containing insoluble tricalcium phosphate were used for the evaluation of the phosphate solubilization ability of the bacterial isolates by two methods: visual evaluation of the solubilization zone around colonies (halo) and determination of solubilized phosphates in liquid medium by the colorimetric method of the vanado-molybdate yellow. Based on the results of the halo method, the isolate of each species that showed the higher phosphate solubilization index was selected for evaluation of phosphate solubilization by the colorimetric method. In the liquid media, the bacterial isolates showed phosphate solubilization ranging from 535.70 to 618.57 µg mL-1 in the NBRIP medium, and 374.20 to 544.28 µg mL-1 in the PVK medium, with the highest values produced by P. fluorescens. The best phosphate solubilization ability and higher reduction in broth pH, which indicates higher organic acid production, were achieved in NBRIP broth for most of the PSB. Strong correlations were observed between the average capability of PSB to solubilize phosphates and both the pH and total phosphorous content in the soil. The production of the hormone indole acetic acid (IAA), which can promote plant growth, was observed for all five PSB species. Among them, P. fluorescens obtained from the forest soil of northern Tunisia showed the highest production of IAA (50.4 ± 0.9 µg mL-1).

Potential of Bacillus sp. from Kebun Raya Liwa as a Producer of Indole Acetic Acid (IAA) Hormone

Kebun Raya Liwa’s soil has the potential to allow for a population of microorganisms such as the Bacillus sp. Bacillus sp. Kebun Raya Liwa are known to produce phytohormones that have the potential to help plant growth and development, one of which is the hormone Indole Acetic Acid (IAA). This study aims to determine the potential of Bacillus sp. from the soil of Kebun Rawa Liwa in producing IAA hormones. The research method included taking soil samples, preparing Nutrient Agar (NA) medium, measuring soil pH samples, isolating soil bacteria, purifying and characterizing Bacillus sp., preparing IAA standard curves, and testing the potency of Bacillus sp. IAA production was carried out in two ways, namely measuring the content of IAA with the addition of tryptophan and without the addition of tryptophan. IAA concentration was measured using a spectrophotometer with a wavelength of 520 nm. The data obtained is presented in tabular form. The isolation results obtained 10 isolates that were able to produce IAA hormone with and without tryptophan. The highest IAA production without tryptophan was isolate BP 5 with a concentration of 1.18 ppm, and the isolate that was able to produce the highest IAA with tryptophan was isolate BP 13 with a concentration of 3.90 ppm. This indicates that the isolate Bacillus sp. from the soil rhizosphere Kebun Raya Liwa can produce IAA hormones.

Comprehensive physio-biochemical and transcriptomic characterization to decipher the network of key genes under waterlogging stress and its recuperation in Prunus persica.

Waterlogging is a major abiotic stress that plants encounter as a result of climate change impacts. Peach is very sensitive to hypoxia during waterlogging, which causes poor tree vigor and huge economic losses. The molecular mechanism underlying the peach response to waterlogging and reoxygenation remains unclear. Here, the physiological and molecular responses of 3-week-old peach seedlings under waterlogged and recovery conditions were comprehensively analyzed. As a result, waterlogging significantly reduced plant height and biomass with inhibition of root growth when compared with control and reoxygenation. Similar results were observed for photosynthetic activities and gaseous exchange parameters. Waterlogging increased lipid peroxidation, hydrogen peroxide, proline, glutamic acid and glutathione contents, while superoxide dismutase, peroxidases and catalase activities were decreased. The glucose and fructose contents were accumulated, contrary to sucrose which was reduced remarkably throughout the stress periods. The level of endogenous indole acetic acid (IAA) was increased in waterlogging but decreased after reoxygenation. However, the change trends of jasmonic acid (JA), cytokinins and abscisic acid (ABA) levels were opposite to IAA. In transcriptomic analysis, there were 13,343 differentially expressed genes (DEGs) with higher and 16,112 genes with lower expression. These DEGs were greatly enriched in carbohydrate metabolism, anaerobic fermentation, glutathione metabolism and IAA hormone biosynthesis under waterlogging, while they were significantly enriched in photosynthesis, reactive oxygen species scavenging, ABA and JA hormones biosynthesis in reoxygenation. Moreover, several genes related to stress response, carbohydrate metabolism and hormones biosynthesis were significantly changed in waterlogging and reoxygenation, which indicated unbalanced amino acid, carbon and fatty acid pools in peach roots. Taken together, these results suggest that glutathione, primary sugars and hormone biosynthesis and signaling might play key roles in plant response to waterlogging. Our work provides a comprehensive understanding of gene regulatory networks and metabolites in waterlogging stress and its recuperation, which will facilitate peach waterlogging control.

Estimation of indole acetic acid in some local algae and study the optimal conditions for its production of cyanobacteria Gloeocapsa sp. PCC7428

A In this study, isolates and diagnoses of some local microbial isolates were diagnosed by phenotypic and hereditary diagnosis. Indole Acetic Acid (IAA) was also evaluated in these isolates and in the presence and absence of amino acid tryptophan. The IAA is externally isolated into the middle and internal hormone And identified the best isolates for the production of the hormone and concluded that the IAA secreted from the outside can be adopted as a source of production better than the internal hormone for ease of separation and the possibility of utilization of the organism and other times of production and low production cost to dispense with the destruction of cells to remove the internal content of the Hormone as well as the superior efficacy of the hormone externally excreted on the internal hormone. The cyanobacteria showed Gloeocapsa sp. PCC7428 The best efficacy for the production of the hormone 12.682 ml / μg in a medium equipped with 0.5 L / gm tryptophan was for the sex of Chlorella sp. IFRPD 1018 8.313 ml/μg This result was confirmed when comparing the effectiveness of the hormone of these two species when they were developed in simple light reactors where there was a large and clear variation in the production of externally isolated IAA. Cyanobacteria recorded an efficiency of 109.694 ml / μg on day 12 of development, The highest level of activity in the day 14 was 38.005 ml / μg, which confirms that cyanobacteria are better and faster to produce the hormone. It is also observed that the production of the hormone by the cyanobacteria is clearly affected by changes in surrounding conditions, especially pH and concentration of tryptophan Added to the food medium and lighting agent and add The highest effect of the hormone was observed in the medium with pH = 7 followed by 8 and the highest efficacy at 14 days for both fixed farms 24.719 ml / μg and shaking 23.917 ml / μg with affinity Effectiveness of both species, although the advantage of faltering farms at pH 7 on day 7 was evident on fixed farms. The concentration of tryptophan was found to be proportional to the effectiveness of the hormone and to all the treatments during all periods of measurement and the superiority of the shaking farms 46.119 ml / μg on the constant 25.433 ml / μg within 7 days at the concentration of 4 L / gm and 14 days of development. For the light factor, continuous light treatment showed the highest hormone production on the vibratory farms in the first week only 19.637 ml / μg. The hormone activity decreased with the recording of the fixed plant more effective in light during the second and third weeks (35.241 and 25.165 ml / μg) respectively, In contrast to the continuous dark treatment in which the fixed farms exceeded the first week only 19.28 ml / μg and the hormone decreased during the other weeks with the superiority of the faltering farms in the second and third weeks, The measurement was recorded at 37.113 ml / μg at 14 days. When using different sources of nitrogen in the middle proved the susceptibility of cyanobacteria to exploit the substance Treptone partially containing tryptophan, which is the raw material for the production of the hormone IAA, making it better compared to the rest of the additives to the center so can be considered a successful tryptophan alternative to tryptophan .

Protective Effect (Safener) of Melatonin on Vigna Radiata L. Seedlings in the Presence of the Fungicide Copper Oxychloride

Melatonin (N-acetyl-5-methoxytriptamine) is a novel plant regulatory molecule currently under study. Its role as a biostimulator and protector against abiotic and biotic stressors, through the regulation of the redox network and change in the expression of many elements of primary and secondary metabolism, is of great interest. The possible protective effect of melatonin in mungbean seedlings, previously primed seed treated with the fungicide copper oxychloride, was studied. The effect of melatonin and fungicide in growth of seedlings and photosynthetic pigments, leakage membranes, lipid peroxidation, antioxidant activity, and phytomelatonin content was studied. Also, the effect of exogenous melatonin on endogenous plant hormones indoleacetic acid, gibberellins, cytokinins, abscisic acid, salicylic acid, and jasmonic acid levels, in the absence and presence of fungicide, was analyzed. Melatonin improved growth of roots and aerial parts in the presence of fungicide; chlorophyll and carotenoid contents were protected by melatonin in the presence of melatonin and in melatonin-fungicide co-treatments. Membrane damage due to fungicide was lessened by melatonin. The hormonal profile (auxin, gibberellins, cytokinins, abscisic acid, ethylene precursor, salicylic acid, and jasmonic acid) in roots and leaves was greatly affected by copper fungicide and melatonin treatments. In general, an increasing in plant tolerance response has been detected, proposing melatonin as a natural safener molecule of plants in the presence of copper fungicide.

Characterization of three Stenotrophomonas strains isolated from different ecosystems and proposal of Stenotrophomonas mori sp. nov. and Stenotrophomonas lacuserhaii sp. nov.

Members of the genus Stenotrophomonas, and particularly Stenotrophomonas maltophilia, are opportunistic human pathogens, but not enough research has evaluated the identification of environmental Stenotrophomonas spp. However, most Stenotrophomonas spp. serves as plant-probiotic bacteria.In this study, we obtained and characterized three Stenotrophomonas strains from different ecosystems. Based on phenotypic differences, chemotaxonomic properties, ANI and dDDH identity values, and phylogenetic analyses, two novel Stenotrophomonas species are proposed for the strains identified here. The encoding genes related to plant-growth promotion in the genomes of the newly recovered Stenotrophomonas spp. were retrieved. Follow-on experiments confirmed that these strains produced the important plant hormone IAA. Thus, these Stenotrophomonas spp. could considerably contribute to shaping and maintaining ecological stability in plant-associated environments, particularly while acting as plant-probiotic microorganisms.

Physiological characters of Sisyrinchium palmifolium with fertilization treatment and IAA hormone

Abstract. Alifah EN, Mudyantini W, Solichatun. 2022. Physiological characteristics of Sisyrinchium palmifolium with fertilization treatment and IAA hormone. Cell Biol Dev 6: 51-60. Dayak onion (Sisyrinchium palmifolium L., Syn.: Eleutherine palmifolia L. Merr.) is a typical Central Kalimantan, Indonesia medicinal plant. Optimizing the function of the S. palmifolium is done to increase cultivation and community interest; more fertilization and growth regulator treatments are needed to accelerate plant growth. In this study, the physiological properties of S. palmifolium will be examined regarding fertilization and the IAA (Indole Acetic Acid) hormone. CRD factorial pattern with four levels of fertilization variation (soil; soil + chicken manure (1:1); soil + vermicompost fertilizer (1:1); soil + chicken manure + vermicompost (1:1:1)) and three levels of hormone concentration (0 ppm; 100 ppm; 200 ppm) resulting in 12 treatment combinations which are used in this experiment. It was repeated three times for each therapy. It was shown that the number and length of leaves, the number of flowers and their flowering time, bulb weights, chlorophyll content, and flavonoid levels were all correlated with the number of leaves. The data were examined for significant changes between the treatments using the Analysis of Variant (ANOVA) and Duncan's Multiple Test (DMRT) at a 5% significance level. The physiological and biochemical features were altered by fertilization and the IAA hormone. The IAA hormone and fertilization on S. palmifolium enhanced the number of leaves, their width, the ratio of shoot roots to roots, and flavonoids. The maximum yields of wet weight, dry weight, and leaf carotenoids were obtained with vermicompost (1: 1) and a hormone at 200 ppm (P2H2) adding. Combining vermicompost treatment with the IAA hormone produced the highest level of flavonoids (P2H0).

Use of Bacillus as a Plant Growth-Promoting Rhizobacteria to Improve Phosphate and Potassium Availability in Acidic and Saline Soils

Bacillus is a rhizobacterium that can help with the nutrient cycle in the soil. Plant growth-promoting rhizobacteria (PGPR) can be found in the rhizosphere of many plants. This research was divided into two parts: (1) a test of the ability of Bacillus genus isolates to withstand various NaCl concentrations in saline and acidic soils; and (2) quantification of the secondary metabolites produced by the rhizobacteria in the form of hormones and organic acids. Bacillus valezensis (BPF2), which can dissolve phosphate, Bacillus sp (BPK1), and Bacillus subtilis (BPK2), which can dissolve potassium, were the isolates tested. Bacillus increased the availability of phosphate and potassium in the saline and acidic soils and the secondary metabolites produced, such as organic acids and the hormone indole acetic acid. The results showed that the three isolates could still dissolve phosphorous and potassium with a 3% NaCl addition, but the concentration decreased as the incubation time increased to H+15. On the 30th day, Bacillus valezensis inoculation improved soil phosphate availability by up to 88% in the acidic soil and 73% in the saline soil compared to the control. On the other hand, Bacillus sp. and Bacillus subtilis raised the potassium concentration in the acidic soil until day 10, reaching a maximum of 0.37 me.100g−1. The three PGPRs (Bacillus valezensis, Bacillus sp., and Bacillus subtilis) produced 13.25, 11.97, and 14.97 g.mL−1 of indole acetic acid metabolites, respectively. Acetic, lactic, citric, malic, and oxalic acids were among the organic acids produced. Bacillus valezensis produced the most lactic acid at 4.94 mg.L−1, while Bacillus sp. and Bacillus subtilis produced the most acetic acid, at 2.91 and 2.55 mg,L−1, respectively. Keywords: Bacillus, Organic acid, Indole acetic acid

Indole Acetic Acid-Producing and Phosphate-Solubilizing Bacteria From the Rhizosphere of Clove (Syzygium Aromaticum L.) in Bali, Indonesia

Clove plants are routinely fertilized with synthetic fertilizer to increase yield. The use of synthetic fertilizer reduces soil productivity. Biofertilizer can be used as an alternative for increasing soil fertility. The goal of this study was to determine the potency of bacteria isolates capable of producing indole acetic acid (IAA) hormone and solubilizing phosphate, and to identify bacteria species from the rhizosphere of clove plants. Soil samples were collected from the clove plants’ rhizosphere, environmental parameters were measured, the potency of IAA-producing and phosphate-solubilizing bacteria was analyzed, and bacteria were molecularly identified. After 48 hours of incubation, isolate TCKI 5 from Karangasem produced the highest IAA hormone levels (19.64 ppm), and isolate TCBP 6 from Buleleng had the highest index of solubilizing phosphate (1.91). A compatibility test between the three best isolates of IAA hormone-producing and phosphate-solubilizing bacteria revealed that TCKI 5 was able to associate with TCBP 6. Isolate TCKI 5 was identified as Leclercia adecarboxylata C107 with a 99.92% similarity, and isolate TCBP 6 as Burkholderia cepacia GJ8 with a 99.61% similarity. Keywords: Bacteria, clove, Indole Acetic Acid, phosphate, rhizosphere

Effect of Indole Acetic Acid (IAA) by Serratia marcescens strain MBC1 on Soybean (Glycine max L.) Germination

Indole Acetic Acid (IAA) is one type of hormone that can stimulate plant growth. IAA hormone is able to accelerate plant growth, especially in the early stages of growth. IAA hormones are not always found in plants, one of which can be found in microorganisms. Rhizobacteria group have the ability to produce IAA hormones. This study aims to determine whether the IAA produced by Serratia marcescens strain MBC1 is able to accelerate the germination process of soybean seeds (Glycine max L.). The results of the Analysis of Variance (ANOVA) giving the production of IAA Serratia marcescens strain MBC1 of 8.31 ppm and 9.35 ppm to soybean seed germination significantly increased root length and stem length. The increase in germination from the administration of IAA Serratia marcescens MBC1 was still smaller than the positive control using synthetic IAA with a concentration of 8 ppm which was able to significantly increase soybean germination.

Induction of Systemic Resistance against Sheath Blight in Rice by Different Pseudomonas Isolates.

Sheath blight disease is a fungal pathogen that causes leaf blight in rice plants, resulting in significant yield losses throughout the growing season. Pseudomonas spp. have long been used as biocontrol agents for a variety of plant diseases. Four Pseudomonas isolates were tested for their ability to promote rice growth and generate systemic resistance to Rhizoctonia solani, the causal pathogen of sheath blight disease. In vitro, Pseudomonas isolates produced the growth hormone indole acetic acid (0.82–1.82 mg L−1). Additionally, seed treatment with Pseudomonas putida suspension outperformed P. brassicacearum, P. aeruginosa and P. resinovorans in terms of germination and vigor evaluation. The maximum seed germination of 89% was recorded after seed treatments with a fresh suspension of P. putida, followed by 87% germination in P. aeruginosa treatment, compared with only 74% germination in the untreated controls. When compared with the infected control plants, all Pseudomonas isolates were non-pathogenic to rice and their co-inoculation considerably enhanced plant growth and health by reducing the disease index to 37% and improving plant height (26%), fresh weight (140%) and dry weight (100%). All Pseudomonas isolates effectively reduced sheath blight disease incidence, as well as the fungicide carbendazim, which is recommended for field management of R. solani. In comparison to untreated control seedlings, treatment with Pseudomonas isolates enhanced the production of peroxidase and polyphenol oxidase enzymes and the expression of the phenylalanine ammonia lyase (PAL) and NPR1 genes, which could be involved in disease incidence reduction. In conclusion, the use of Pseudomonas spp. has been demonstrated to improve rice growth and resistance to R. solani while also providing an environmentally acceptable option to the agroecosystems.

Bacillus-Mediated Silver Nanoparticle Synthesis and Its Antagonistic Activity against Bacterial and Fungal Pathogens.

In this article, the supernatant of the soil-borne pathogen Bacillus mn14 was used as the catalyst for the synthesis of AgNPs. The antibacterial and antifungal activity of Bs-AgNPs was evaluated, in which S. viridans and R. solani showed susceptibility at 70 µL and 100 µL concentrations. Enzyme properties of the isolates, according to minimal inhibitory action and a growth-enhancing hormone–indole acetic acid (IAA) study of the isolates, were expressed in TLC as a purple color with an Rf value of 0.7. UV/Vis spectroscopy revealed the presence of small-sized AgNPs, with a surface plasmon resonance (SPR) peak at 450 nm. The particle size analyzer identified the average diameter of the particles as 40.2 nm. The X-ray diffraction study confirmed the crystalline nature and face-centered cubic type of the silver nanoparticle. Scanning electron microscopy characterized the globular, small, round shape of the silver nanoparticle. AFM revealed the two-dimensional topology of the silver nanoparticle with a characteristic size ranging around 50 nm. Confocal microscopy showed the cell-wall disruption of S. viridans treated with Bs-AgNPs. High-content screening and compound microscopy revealed the destruction of mycelia of R. solani after exposure to Bs-AgNPs. Furthermore, the Bs-AgNPs cured sheath blight disease by reducing lesion length and enhancing root and shoot length in Oryza sativa seeds. This soil-borne pathogen Bacillus-mediated synthesis approach of AgNPs appears to be cost-efficient, ecofriendly, and farmer-friendly, representing an easy way of providing valuable nutritious edibles in the future.