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AbstractA large number of beneficial microorganisms have been used as inoculants in agriculture to increase grain yield. The objective of the study was to evaluate the response of common bean (Phaseolus vulgaris) to inoculation and co-inoculation with rhizobia, azospirilla and cyanobacteria combined with doses of N-fertilizer. A field experiment was carried out in two growing seasons to assess twelve treatments using single and combined inoculation of rhizobia (Rhizobium tropici + R. freirei), Azospirillum brasilense, Anabaena cylindrica, and Calothrix brevissima, and application of 30 and 60 kg N kg ha−1 as topdressing in a factorial design. A control without N-mineral and inoculation was included. Co-inoculation of common bean (cv. IPR Curió) using A. cylindrica, C. brevissima with rhizobia, and A. brasilense, with the application of 30 kg N ha−1 in topdressing increases grain yields. Regardless of the growing season and the N dose, the dual inoculation of rhizobia and C. brevissima stood out in the increase of grain yield concerning the control without inoculation, showing that it is an efficient agronomic practice for common bean under tropical conditions. [ABSTRACT FROM AUTHOR]

Phasins are proteins located on the surface of poly-3-hydroxybutyrate (P3HB) granules that affect the metabolism of the polymer, the size and number of the granules, and some also have stress-protecting and growth-promoting effects. This study evaluated the effect of inactivating two new phasins (PhbP2 or PhbP3) on the cellular growth, production, and molecular mass of P3HB in cultures under low or high oxygen transfer rates (OTR). The results revealed that under high OTRₘₐₓ conditions (between 8.1 and 8.9 mmol L−1 h−1), the absence of phasins PhbP2 and PhbP3 resulted in a strong negative effect on the growth rate; in contrast, the rates of specific oxygen consumption increased in both cases. This behavior was not observed under a low oxygen transfer rate (3.9 ± 0.71 mol L−1 h−1), where cellular growth and oxygen consumption were the same for the different strains evaluated. It was observed that at high OTR, the absence of PhbP3 affected the production of P3HB, decreasing it by 30% at the end of cultivation. In contrast, the molecular weight remained constant over time. In summary, the absence of phasin PhbP3 significantly impacted the growth rate and polymer synthesis, particularly at high maximum oxygen transfer rates (OTRₘₐₓ). [ABSTRACT FROM AUTHOR]

One of the alternatives for reducing nitrogen fertilization is the use of plant growth-promoting bacteria (PGPB), such as Pseudomonas fluorescens and Azospirillum brasilense, which can provide a sustainable form of production, with increased profitability for rural producers, because bacteria are a low-cost technology compared to fertilizer. In view of the above, the objective of this study was to evaluate the effect of inoculation with plant growth-promoting bacteria (P. fluorescens and A. brasilense) combined with the supply or not of Si and doses of nitrogen (N) in zoysia grass sod production area. The experimental design was in randomized blocks with 12 treatments arranged in a 3 × 2 × 2 factorial scheme, with four replications, in plots of 9 m2. The treatments were: two inoculations with PGPB (A. brasilense and P. fluorescens) and non-inoculated, combined with two doses of N, with or without supply of Si through fertilization (through the commercial fertilizer known as Potasil). There was an increase in the shoot dry matter with the supply of Si, the standard dose of N and the inoculation with PGPB. The standard dose of N promoted an increase in the content of nitrogen (N), phosphorus (P) and potassium (K) in the shoot of Zoysia japonica. There was an effect of inoculation with plant growth-promoting bacteria combined with the supply of silicon and N rates in the zoysia grass production area, where the use of Pseudomonas combined with the application of Si with 75% of the N dose is recommended. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microbial agents + fertilizers boost bacterial richness in the rhizosphere soil. • Microbial agents + fertilizers resulted in a reduction of fungal diversity. • Microbial agents + fertilizer modify rhizosphere soil's microbial community structure. • Microbial agents + fertilizer reduce the pathogenic fungi. • Microbial agents + fertilizer significantly boost plant growth and yield of peanut. The soil harbors a diverse array of microorganisms, and these are essential components of terrestrial ecosystems. The presence of microorganisms in the soil, particularly in the rhizosphere, is closely linked to plant growth and soil fertility. The primary objective of this study is to assess the potential advantages of integrating microbial inoculants with compound fertilizer in enhancing peanut yield. We utilized Illumina MiSeq high-throughput sequencing technology to conduct our investigation. The experimental design consists of four treatment groups: compound fertilizers (CF), compound fertilizers supplemented with microbial agents (CF + MA), compound fertilizers supplemented with microbial fertilizers (CF + MF), and compound fertilizers supplemented with both microbial agents and microbial fertilizers (CF + MM). The experimental results demonstrated a significant increase in peanut yield upon application of CF + MA, CF + MF, and CF + MM treatments. During the blossom stage and pod-setting stage, the soil's catalase, urease, and acid phosphatase activities were significantly increased in the CF + MA, and CF + MM treatments compared to the CF treatment. The application of CF + MA resulted in an increase in bacterial richness in the rhizosphere soil of peanuts, as indicated by the sequencing results. The application of CF + MA, CF + MF, and CF + MM resulted in a reduction of fungal diversity. Proteobacteria , Actinobacteria , and Acidobacteria were the dominant bacterial phyla, while Ascomycota and Basidiomycota were the dominant phyla in the fungal component of the rhizosphere soil microbiome across all experimental treatments. Microbial agents and fertilizers modify the peanut rhizosphere soil's microbial community structure, as per our findings. The abundance of potentially beneficial bacteria (Bradyrhizobium , Rhizobium, and Burkholderia) and fungi (Trichoderma and Cladophialophora) could increase, while pathogenic fungi (Penicillium and Fusarium) decreased, thereby significantly promoting plant growth and yield of peanut. [ABSTRACT FROM AUTHOR]

Bacteria of the genus Azotobacter sp. produce two classes of biologically important biocompatible and biodegradable polymers, polyoxyalkanoates, which are the bacterial reserve, and alginates (ALG), which perform the function of protecting nitrogenase from oxygen. Both polymers are becoming increasingly important for use in bioengineering, pharmaceuticals, and medicine, so studies of their biosynthesis and properties are currently highly relevant. The present work shows the possibility of regulating alginate and poly(3-hydroxybutyrate) (PHB) synthesis by a culture of A. vinelandii 12 depending on the increase in the sucrose concentration in the medium under different aeration conditions. At high aeration and high sucrose concentrations in the medium (50 g/L), the maximum yield of free (1.08 g/L) and capsular ALG (2.26 g/L) in the medium was obtained. Under low aeration conditions, the synthesis of free ALG was completely inhibited. The maximum value of РНB synthesis was observed at medium aeration and a high concentration of sucrose (50 g/L) in the medium. The maximum molecular weight (MW) of ALG was 477 kDa, while the maximum MW of PHB was much higher, reaching 1479 kDa. At low sucrose concentrations in the medium (5 to 20 g/L), capsular ALG is predominantly synthesized (up to 100% of the sum of all polymers) at all aeration levels. With increasing sucrose concentration, PHB is predominantly synthesized (68%) under low aeration conditions, an equal ratio of PHB and capsular ALG synthesis is observed under medium aeration conditions, and free ALG is actively synthesized under high aeration conditions. This work demonstrates the possibility of obtaining a selective synthesis of ALG or PHB by A. vinelandii 12 by modifying its cultivation conditions. The results obtained can be used for the development of directed biosynthesis of target products (PHB and ALG) in biotechnology. [ABSTRACT FROM AUTHOR]

Having in mind food security and the fact that basil (Ocimum basilicum L.) is used as fresh seasoning, the development of innovative technologies for its cultivation is required. This study aimed to isolate and characterize plant growth-promoting rhizobacteria (PGPR) isolates from basil rhizospheric soil and monitor the effects of their application on basil growth under different water stress conditions. Isolation, determination of isolates biochemical and PGP properties, evaluation of isolates influences on seed germination and parameters of growth of basil plant, growing under well-watered conditions (70% water holding capacity, WHC), under water deficit stress (35% WHC), and flooded conditions (95% WHC), were done. A total of five representative bacterial isolates were selected: Two Azotobacter isolates (A13, A14), one Pseudomonas isolate (P57), and two Bacillus isolates (B79, B82). The results of this experiment revealed that rhizospheric bacteria of O. basilicum L. var. minimum have multiple biochemical and PGP properties. The most intensive reactions on tested abiotic stressors - drought (higher total phenolics, reduced glutathione, and malondialdehyde content) and flooding (higher superoxide dismutase activity) - were from basil plants inoculated with Pseudomonas sp. P57 isolate, yet along with Azotobacter sp. isolate A13. The highest number of germinated seeds was obtained with the A13 isolate (96.0%), while the highest response for vigour index was observed with Azotobacter isolates (7200.0% and 5628.0%). In well-watered conditions, basil mass inoculated with P57 was 34.2% higher than control. In drought-stressed conditions, plant mass inoculated with A13 isolate was 90% higher than control. In flooded-stressed conditions, the plant mass inoculated with Azotobacter and Pseudomonas isolates increased by more than 100%. [ABSTRACT FROM AUTHOR]

To investigate the influence of biostimulants and organic mulch on the soil microbial population of strawberry cv. Katrain Sweet, an experiment was carried out in the Department of Fruit Science and in the Biocontrol lab, Department of Plant Pathology, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, during two subsequent years i.e., 2022-2023 and 2023-2024. The results showed substantial enhancements in microbial growth of both fungi and bacteria with the use of Azotobacter, Trichoderma harzianum and PSB, applied in combination with organic mulch, particularly in treatment (T12) Azotobacter (8g/plant) + PSB (8g/plant) + Trichoderma harzianum (6g/plant) + dried leaves. This treatment resulted in the highest bacterial population count of 8.97×10v cfu g-1 of soil and a fungal population of 5.93×10t cfu g-1 of soil, significantly outperforming over the control. The findings underscore the potential for using biostimulants and organic mulches to enhance soil microbial growth in strawberry production, offering a sustainable approach for improving yield and plant health. [ABSTRACT FROM AUTHOR]

A study was done during two consecutive seasons of 2022/2023 and 2023/2024 to study the effects of humic acid (HU 4, 8, and 12 kg/hectare) as the main plot and BM (Azotobacter chrococum, Azospirulm Brasiliense, and Bacillus polymaxa) and algae extracts (ALG) as the subplot as well as their interactions on plant growth. The design of the experiment was a split plot, including 16 treatments and three replicates. The results showed that the growth parameters, fruit yield measurement, and oil production were noticeably enhanced using humic acid and biostimulants (BM and ALG). In this concern, the high-rise values were obtained by utilizing the high level of HU (12 kg/hectare) with bio-fertilizer (BM + ALG) application compared with control during both seasons. Also, GCMS analysis of the volatile oil revealed that HU and a mixture of bacteria and algae extract had improved the primary volatile oil components of coriander (Linalool - α-Pinene - γ-Terpinene - P-Cymene - Geranial Acetate). [ABSTRACT FROM AUTHOR]

A study was done during two consecutive seasons of 2022/2023 and 2023/2024 to study the effects of humic acid (HU 4, 8, and 12 kg/hectare) as the main plot and BM (Azotobacter chrococum, Azospirulm Brasiliense, and Bacillus polymaxa) and algae extracts (ALG) as the subplot as well as their interactions on plant growth. The design of the experiment was a split plot, including 16 treatments and three replicates. The results showed that the growth parameters, fruit yield measurement, and oil production were noticeably enhanced using humic acid and biostimulants (BM and ALG). In this concern, the high-rise values were obtained by utilizing the high level of HU (12 kg/hectare) with bio-fertilizer (BM + ALG) application compared with control during both seasons. Also, GCMS analysis of the volatile oil revealed that HU and a mixture of bacteria and algae extract had improved the primary volatile oil components of coriander (Linalool - α-Pinene - γ-Terpinene - P-Cymene - Geranial Acetate).

ABSTRACTProlonged and excessive use of chemical fertilizers has resulted in serious harm to soil health and ecosystems. This study aimed to reduce the cultivation costs for apricot trees, nearly 1/3rd of which are spent on fertilizers. The research was conducted on fully grown apricot trees of the cultivar “New Castle,” in the Solan district of Himachal Pradesh, India. The experiment consisted of fourteen treatment combinations evaluated in triplicate and statistically analyzed using a randomized block design (RBD). Results revealed that treatment T12 [50% Nitrogen (Calcium Nitrate) + 50% Nitrogen (Urea) + Azotobacter + Phosphate Solubilizing Bacteria + Vermicompost] resulted in the highest percent increase in tree trunk girth (6.82%), highest leaf chlorophyll content (3.00 mg g−1 fresh weight), leaf area (58.29 cm), fruit set (61.00%) and total yield (61.9 kg tree−1). In terms of nutrient status, T12 had the highest leaf N (2.95%), leaf K (2.60%), soil N (386.33 kg ha−1), soil P (51.00 kg ha−1) and soil organic carbon (1.81%). The highest net return and profit over recommended dose of fertilizers (RDF) was also recorded in treatment T12. The results of this study show that judicious fertilizer use along with integrated organic manure and bio-fertilizers can reduce cultivation costs, improve soil health, and increase fruit production with minimum ecosystem damage.

A study was conducted in sandy clay loam soils in a subtropical zone of Bihar to evaluate the effect of frequent application of organic amendments on sulphur fractions. Different organic amendments, including farmyard manure (FYM), vermicompost, azotobacter, phosphate solubilizing bacteria (PSB), panchagawya, and neem cake, were applied through nine treatments that resulted in a significant increase of water-soluble S, available S, heat-soluble S, adsorbed S, and organic S in organic treatment compared to the recommended dose of fertilizer (RDF) and control treatment. The maximum increment was observed in the treatment where the recommended dose of nitrogen was replaced by 75% recommended dose of nitrogen substituted farmyard manure + 25% recommended dose of nitrogen (vermicompost) along with azotobacter + PSB + one foliar spray of panchagawya. The total S content varied widely from 382 to 736 mg kg-1. Increment in all the forms of sulphur is observed as a result of the application of different organic nutrient sources. All the forms of sulphur share a mutual positive and significant correlation with each other. Regression analysis suggested that the availability of sulphur was dominated by organic sulphur, which alone can explain 97.8% of the variation in availability of available sulphur in soil.

Duckweed is a future food and a source of affordable protein that has the potential to replace animal protein. This study aims to formulate a bio-fertilizer consisting of mangrove-associated bacteria to boost the growth and protein of duckweeds as a sustainable approach to increase plant-based protein yields. The culture-depending technique was performed by using Aleksandrow agar, Pikovskaya's agar, and Jensen agar to screen potassiumsolubilizing bacteria, phosphate-solubilizing bacteria and nitrogen-fixing bacteria, respectively, from mangrove soil sediments. Mangrove-associated bacteria that are close to Acinetobacter radioresistens, Brachybacterium paraconglomeratum, and Enterobacter cloacae, which are known as nitrogen-fixing bacteria, Klebsiella quasipneumoniae, Bacillus tropicus, and Paenibacillus pasadenensis known as potassium-solubilizing bacteria, and Bacillus cereus and Bacillus thuringiensis known as phosphate-solubilizing bacteria were identified through 16S rRNA gene sequencing. After that, three sets of biofertilizers were randomly formulated. Each set consisted of nitrogen-fixing bacteria, potassium- and phosphate-solubilizing bacteria, as well as commercial compost as a carrier. These formulated bio-fertilizers were evaluated for plant growth promotion and protein production on duckweed plants under temperatures between 26 and 30°C. The results showed that each set of our formulated bio-fertilizer can increase the nitrogen (N), phosphorus (P), and potassium (K), duckweed growth, and protein content when compared to the control group. It indicates that bio-fertilizers formulated with mangrove-associated bacteria and high NPK contents could enhance the growth of duckweed as well as its protein content, which could supply our future plant-based protein sustainably. [ABSTRACT FROM AUTHOR]

This work aimed to assess Rhizobium tropici, Azospirillum brasilense, and Trichoderma asperellum co-inoculation effects, besides N-fertilizer supplementation as determined by the nitrogen sufficiency index (NSI) on the development of common bean. Field trials were carried out in a randomized block design with four replicates at three different locations. Treatments consisted of sole or combined inoculation of R. tropici, A. brasilense, and T. asperellum, besides N-fertilization. Seeds were inoculated with R. tropici and/or T. asperellum using 10 g of each inoculant kg−1 of seed. At the phenological stage V2/V3 A. brasilense was inoculated using 300 ml ha−1. Nitrogen sufficiency index (NSI), number of nodules (NN), nodule dry mass (NDM), root dry mass (RDM), shoot dry mass (SDM), number of pods (NP), number of grains (NG), and grain yield (GY) were assessed. NN and NDM were higher under R. tropici, A. brasilense, and T. asperellum co-inoculation. This same co-inoculation provided RDM and SDM similar to the use of 120 kg ha−1 of N. R. tropici, A. brasilense, and T. asperellum co-inoculation supplemented with N-fertilizer at the phenological stage R5, provide NP and NG similar to 120 kg ha−1 N, and to 80 kg ha−1 N supplemented with N at the phenological stage V4. NSI was effective to determine the N needs of common bean. The co-inoculation of two doses ha−1 of R. tropici, three doses ha−1 of A. brasilense and two doses ha−1 of T. asperellum, supplemented with N-fertilizer at phenological stage V4 based on NSI, stimulated growth and yield components of common bean, providing GY equivalent to the N-fertilized treatments. [ABSTRACT FROM AUTHOR]

Beneficial microbes colonizing plant tissues are recognized as a value-added soil amendment for enhancing soil fertility. The present study aimed to evaluate the effects of co-inoculation with plant growth-promoting endophytic actinobacteria and nitrogen-fixing rhizobacteria for improved growth attributes, soil properties, microbial activity, yield, and nutrient uptake of wheat under field conditions for two consecutive years. Three endophytic actinobacterial isolates, Streptomyces sp. strain WR27, Streptomyces sp. strain WR15, and Streptomyces sp. strain WS6 were evaluated alone and in combination with nitrogen-fixing bacteria, Azotobacter in field experiment with recommended fertilization rate in north-western Indian plains. Results of the study indicated that all the growth attributes were higher in treatments receiving microbial inoculants than un-inoculated control. It was also observed that inoculation with actinobacterial isolates significantly increased total number of tillers m−2, spike length, number of grains spike−1, and 1000 grain weight as compared to control. Streptomyces sp. strain WR27 + Azotobacter and Streptomyces sp. strain WR15 + Azotobacter exhibited maximum grain yield (5.7 t ha−1, respectively) as compared to control (5.0 t ha−1). The treatment involving inoculation with Streptomyces sp. strain WR27 + Azotobacter recorded higher nutrient contents. Soil properties were significantly increased by application of actinobacterial inoculants in both years over the un-inoculated control. Furthermore, among different inocula, Streptomyces sp. strain WR27 + Azotobacter dual inoculation exhibited highest response efficiency for all the traits studied. Therefore, the results revealed multiple benefits of plant growth-promoting actinobacteria and Azotobacter inoculation for wheat crop in terms of improved soil properties and macronutrient content without hampering the soil fertility and productivity. Thus, it could be recommended as a plant growth-promoting bacteria for wheat at the recommended level of fertilizer application rates for field use in north-western India. [ABSTRACT FROM AUTHOR]

A study was conducted in sandy clay loam soils in a subtropical zone of Bihar to evaluate the effect of frequent application of organic amendments on sulphur fractions. Different organic amendments, including farmyard manure (FYM), vermicompost, azotobacter, phosphate solubilizing bacteria (PSB), panchagawya, and neem cake, were applied through nine treatments that resulted in a significant increase of water-soluble S, available S, heat-soluble S, adsorbed S, and organic S in organic treatment compared to the recommended dose of fertilizer (RDF) and control treatment. The maximum increment was observed in the treatment where the recommended dose of nitrogen was replaced by 75% recommended dose of nitrogen substituted farmyard manure + 25% recommended dose of nitrogen (vermicompost) along with azotobacter + PSB + one foliar spray of panchagawya. The total S content varied widely from 382 to 736 mg kg-1. Increment in all the forms of sulphur is observed as a result of the application of different organic nutrient sources. All the forms of sulphur share a mutual positive and significant correlation with each other. Regression analysis suggested that the availability of sulphur was dominated by organic sulphur, which alone can explain 97.8% of the variation in availability of available sulphur in soil. [ABSTRACT FROM AUTHOR]

Organic fertilizers produced from agricultural waste materials using earthworms have many advantages. The impact of vermicompost bio-organic fertilizer (VcF) prepared from waste mushroom bran on the quality of Chinese herbal medicine and soil health deserves attention. We conducted a field experiment to explore the quality of Rhizoma atractylodis and soil, using chemical fertilizer and VcF at dosages of 30 t·ha−1 and 40 t·ha−1. The results demonstrated that VcF significantly increased the contents of atractylenolide II, β-eudesmol, atractylenol, and atractylenolone by 34%, 175%, 72%, and 24%, respectively, along with a 70% increase in yield compared to the control. VcF significantly increased the available phosphorus content and the activity of the soil enzymes (α-Galactosidase, β-Galactosidase, and peroxidase), while reducing the nitrate nitrogen content. The addition of vermicompost did not change the soil bacterial diversity, while it significantly increased the soil fungal diversity. VcF improved the soil fungal diversity and significantly enhanced the relative abundance of the bacterial phylum Actinobacteriota and WPS-2, as well as the fungal phylum Ascomycota. Vermicompost significantly increased the relative abundance of bacteria phylum Actinobacteriota and WPS-2, as well as the fungi phylum Ascomycota. Actinobacteria mainly participate in the decomposition of detritus and the heterotrophic nutrient cycle. A Principal Coordinates Analysis of the soil bacterial and fungi communities suggested a significant impact of vermicompost application on the community structure of the soil bacteria. Conversely, no significant variance was detected in the bacterial community composition across the two levels of vermicompost. This study contributes to the enhancement of fertilization strategies for Atractylodes macrocephala, broadens the application scope of vermicompost, and advances the growth of organic agriculture. [ABSTRACT FROM AUTHOR]

A two-seasonal experiment was conducted in a plastic house at the protected cultivation department in Zakho Technical Institute, Dohuk Polytechnic University, Kurdistan region/ Iraq for autumn seasons (2021- 2022) and (2022-2023) to examine the effect of azotobacter, compost and humic acid on growth, and mineral composition of lettuce cv. (Alfajr). The study encompassed azotobacter (with and without), soil addition of compost with three levels (0, 1, and 2) ton.donum-1 and foliar spraying of humic acid at four concentrations (0, 2, 4.and 8) ml.L-1 and their combinations compared to control. The experiment was designed according to randomized complete block design (RCBD) with three replicates. The results displayed that the individual dose and dual interactions of all studied factors significantly improved foliage attributes [head length (cm), leaf area (cm2), chlorophyll content (SPAD)] and leaf mineral content of N, P, and K in both seasons with the superiority for the second season over the first season. The highest ever values of all investigated attributes were measured for plants given azotobacter and compost at (2) ton.donum-1 plus humic acid at concentration (8) ml.L-1 in comparison with control. The azotobacter with compost and humic acid is recommended for organic production of Alfajr cultivar of lettuce. [ABSTRACT FROM AUTHOR]

The article provides information on an experiment which evaluated the effect of media and plant growth promoting rhizo-microorganisms (PGPR) on sprouting of cuttings and growth in bush pepper during the year 2022-2023. Topics include geographical location of the experimental site, preparation of rooting media and PGPRs, and effect of media and PGPR on sprouting and growth in bush pepper.

Mango is the most important and commercially grown fruit crop in India. The area under mango is increasing rapidly but the limited availability of genuine planting material is the most important bottleneck in the expansion of the area. The application of liquid plant growth promoting rhizomicrobial consortia (PGPR) at the nursery stage will enhance the seedling vigour and graft success. Hence, an experiment was conducted at the College of Horticulture, Hiriyur during the academic year 2022-23. The experiment was laid out in Completely Randomized Design with eight treatments and three replications. In this study, liquid PGPRs were applied to the media (soil, sand and FYM @ 3:1:1), the different PGPRs viz., Control- (T1), Azotobacter chroococcum (T2), Bacillus megaterium (T3), Frateuria aurantia (T4), Azotobacter chroococcum + Bacillus megaterium (T5), Azotobacter chroococcum + Frateuria aurantia (T6), Bacillus megaterium + Frateuria aurantia (T7), Azotobacter chroococcum + Bacillus megaterium + Frateuria aurantia (T8). Among different treatments, T8 has showed significantly maximum sprout success (82.22 % and 84.44 % at 30 and 60 days after grafting), survival per cent (84.55 %), sprout length (9.30 cm), sprout girth (4.76 mm), number of leaves (15.37), leaf length (14.08 cm) and leaf breadth (3.29 cm) at 120 days after grafting. Hence, it is concluded that the mango rootstocks treated with Azotobacter chroococcum, Bacillus megaterium and Frateuria aurantia resulted in better physiological growth and graft success. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of solely and integrated application of inorganic (NPK), commercial organic (NC), and biological (MIX, mixed strains Ensifer meliloti and Azotobacter chroococcum) fertilizers on the chemical characteristics of arugula biomass and its yield, as well as changes in soil microbiological parameters after the experiment in relation to the control treatment (Ø). The experiment was performed in semi-controlled greenhouse conditions, in pots, from the 4th decade of March to the 2nd decade of September, in 2023, at three cutting times/swaths, during one agricultural season, with Vertisol soil. For soil characterization, the following parameters were analysed: granulometric composition using sieving and sedimentation procedure; soil acidity—potentiometrically; SOM—soil organic matter by Kotzmann method; total N using CNS analyser; available P—spectrophotometrically; available K—flame photometrically; total number of microorganisms on an agarized soil extract medium; fungi on a solid Czapek agar; actinomycetes on a solid Krasiljnikov agar with saccharose; Azotobacter spp. on a liquid Fyodorov medium with mannitol; ammonifiers on a liquid medium with asparagine; and dehydrogenase activity—spectrophotometrically. For plant characterization, the following parameters were determined: N and C, both on CNS analyser; P on spectrophotometer; K on flame photometer; air-dried yield biomass. A stimulative effect on all microbiological parameters was found in the treatment with integrated use of organic and biological fertilizer, except for fungi, which grew better in the treatments with separate inorganic and organic fertilizers. Generally, the stimulative impact on plant chemical parameters manifested in combined inorganic and biological, organic and biological, and inorganic and organic fertilization treatments, and was inhibited in treatment without fertilization, in all three swaths, which could also be stated for the plant yield. Positive influence of all fertilization treatments on chemical parameters was observed for the second swath in relation to the first and the third. The total yield in the NPK+MIX treatment was 121%, and in the NC+MIX treatment, it was 87% higher compared to the control (Ø). In general, integrated use of inorganic and biological, organic and biological, and inorganic and organic fertilizers, respectively, could be proposed as an optimal fertilization treatment in arugula cultivation. [ABSTRACT FROM AUTHOR]

Introduction: The castor bean (Ricinus communis L.), is an oilseed of relevant economic and social importance. From its seeds is extracted an oil of excellent properties, having wide use as industrial input and several applications. It is cultivated since the times of the ancient civilizations, the castor bean is a rustic plant, resistant to drought, belonging to the family of Euphorbiaceae, Drought stress, in addition to the negative effect on yield, causes or exacerbates other stresses, especially the stress of nutrient deficiencies for the plant. The purpose of this investigation was to study the effect of irrigation levels and Superabsorbents and biofertilizers on the agronomic properties of castor oil. Materials and methods: This experiment was conducted in West Azarbaijan Agricultural Research and Education Center, Orumieh-Iran in 2018-2021 crop season. A field experiment was carried out by a split-plot design based on a completely randomized block design with three replications. The first factor included Four levels (70, 100, 130, and 160 mm of evaporation pan), in the main plot and Sub-factor includes application of biofertilizer combination in four levels (Azospirillium, Citrobacter, combination of application of Azospirillium in Citrobacter and control without fertilizer) and superabsorbent in two levels (superabsorbent consumption and non-superabsorbent consumption) as factorial were placed in subplots. In this study, Chlorophyll a, Chlorophyll b, Cartonoid, Soluble sugar, prolin content, Catalase, Malondialdehyde, and protein content were measured. Also Traits were analyzed by using SAS 9.2 software and means comparison was tested by least significant difference (LSD). Results and discussion: Based on the results of the combined analysis of the variance of the data, there was a significant difference in was observed between the two years in terms of malondialdehyde content. There was a significant difference between the irrigation levels in terms of the effect on all traits of the probability level of 1%. The interaction effect of year and irrigation was significant only on leaf proline content at the level of 1% probability. There was a significant difference between the biofertilizer treatments and the interaction effect of biofertilizer on irrigation and superabsorbent levels in terms of the effect on all traits at the level of one percent probability. The interaction effect of irrigation with superabsorbent on chlorophyll a and b content and soluble sugar content at 1% probability level and on proline content and protein percentage at 5% probability level was significant. Between treatments of biofertilizer with superadd interaction in terms of the effect on chlorophyll b content, soluble sugar, proline content, malondialdehyde content, and protein percentage at the level of 1% percent and in terms of the effect on chlorophyll content, carotenoids and catalase activity in 5% probability level There was a significant difference. The results showed the highest chlorophyll a (23.00 mg g-1) and b content (14.93 mg g-1) as well as carotenoids (30.39 mg g-1) and the lowest amount of soluble sugar (113.33 micromol g-1 fresh weight), catalase (32.97ΔA240 mg-1 protein), malondialdehyde (132.44 nmol g-1 FW) and protein percentage (4.69%) were assigned to with Citrobacter treatment and irrigation after 70 mm of evaporation. Also, the highest soluble sugar content (131.42 micromol g-1 FW), proline (65.91 micromol g-1 FW), protein (11.48 %) was assigned to the treatment with Azosprilium + Citrobacter and irrigation after 160 mm of evaporation. In this study, the use of superabsorbent in the irrigation treatment of 70 mm evaporation had the highest chlorophyll a (21.29 mg g-1) and b content (12.78 mg g-1) and the lowest amount of soluble sugar (112.50 micromol g-1 FW), proline (26.50 micromol g-1 FW), catalase (35.99 ΔA mg-1 protein) and protein percentage (5.00%), While the highest soluble sugars content (129.12 micromols g-1 FW), proline (58.70 micromols g-1 FW), malondialdehyde (159.71 nmol g-1 FW), and protein (10.37 %), was observed in the treatment of superabsorbent application along with irrigation after 160 mm. In this study, the simultaneous application of superabsorbent and inoculation with azospirlium showed the highest chlorophyll a (22.25 mg g-1), b content (13.79 mg g-1), carotenoid (29.02 mg g-1), protein (7.99%) and the lowest content of catalase enzyme (39.58 ΔA240 mg-1 protein), The highest soluble sugar content (122.88 micromol g-1 FW) and the lowest amount of malondialdehyde (141.82 nmol g-1 FW) were detected in the treatment of superabsorbent application with Citrobacter. Conclusion: In this study, water deficit had an adverse effect on the physiological properties of castor oil. However, the use of biofertilizers and superplasticizers by improving biochemical and antioxidant properties was able to moderate the effect of drought stress on physiological properties and stabilize photosynthetic pigments, and the stability of photosynthetic pigments can improve photosynthetic properties and plant growth under water deficit conditions. [ABSTRACT FROM AUTHOR]

The addition of phosphate-solubilizing microorganisms (PSM) as biofertilizers can improve the quality of soil properties. A meta-analysis study was conducted to analyze the effect of PSM on soil properties. This metaanalysis has analyzed 20 research articles published between 1990 and 2023, which have reported the influence of PSM on soil properties. The value of effect size (ES) Hedges'd of available-P is 3.047 (p<0.001), ES of available K is 2.102 (p<0.001), ES of soil nitrogen (N) is 1.706 (p<0.001), ES of pH is - 2.738 (p<0.001), ES of soil organic carbon (SOC) is 1.087 (p=0.004), ES of N-NH4 is 0.636 (p=0.013), ES of N-NO3 is 2.643 (p<0.001), ES of phosphatase is 5.001 (p<0.001), ES of alkaline phosphatase is 22.956 (p<0.001), and ES of acid phosphatase is 23.104 (p<0.001). The results showed that in terms of phosphate solubility, PSM is more effective on alkaline soils with high SOC content, very high P availability, and a sandy loam texture. PSM is more effective for K solubility on acidic soils, with very high SOC content, high P availability, and a loamy texture. PSM is effective in increasing soil N with acid soil characteristics, low SOC content, moderate available P content, and clay texture. According to this study, the Penicillium fungus ranks second in the fungal group in terms of phosphate solubilization capacity after the genus Azotobacter. The genus Peronospora showed the greatest potential in increasing soil N. In contrast, Burkholderia showed the greatest effectiveness in solubilizing K. [ABSTRACT FROM AUTHOR]

Non-symbiotic N2-fixation would greatly increase the versatility of N-biofertilizers for sustainable agriculture. Genetic modification of diazotrophic bacteria has successfully enhanced NH4+ release. In this study, we compared the competitive fitness of A. vinelandii mutant strains, which allowed us to analyze the burden of NH4+ release under a broad dynamic range. Long-term competition assays under regular culture conditions confirmed a large burden for NH4+ release, exclusion by the wt strain, phenotypic instability, and loss of the ability to release NH4+. In contrast, co-inoculation in mild autoclaved soil showed a much longer co-existence with the wt strain and a stable NH4+ release phenotype. All genetically modified strains increased the N content and changed its chemical speciation in the soil. This study contributes one step forward towards bridging a knowledge gap between molecular biology laboratory research and the incorporation of N from the air into the soil in a molecular species suitable for plant nutrition, a crucial requirement for developing improved bacterial inoculants for economic and environmentally sustainable agriculture. Key points: • Genetic engineering for NH4+ excretion imposes a fitness burden on the culture medium • Large phenotypic instability for NH4+-excreting bacteria in culture medium • Lower fitness burden and phenotypic instability for NH4+-excreting bacteria in soil [ABSTRACT FROM AUTHOR]

Simple Summary: The sustainability of the tomato industry is increasingly debatable, necessitating innovative approaches to maximize productivity while minimizing environmental impact. The exploration of Synthetic Communities (SynComs) comprising nitrogen-fixing bacteria and mycorrhizal fungi represents a promising avenue toward achieving this balance. This work demonstrates that SynComs not only support tomato production under reduced fertilizer inputs, but also contribute to enhancing soil microbial biodiversity. This dual benefit underscores the potential of SynComs as a soil management strategy, offering a pathway toward sustainable agriculture and environmental stewardship. The agricultural sector is currently encountering significant challenges due to the effects of climate change, leading to negative consequences for crop productivity and global food security. In this context, traditional agricultural practices have been inadequate in addressing the fast-evolving challenges while maintaining environmental sustainability. A possible alternative to traditional agricultural management is represented by using beneficial micro-organisms that, once applied as bioinoculants, may enhance crop resilience and adaptability, thereby mitigating the adverse effects of environmental stressors and boosting productivity. Tomato is one of the most important crops worldwide, playing a central role in the human diet. The aim of this study was to evaluate the impact of a nitrogen-fixing bacterial-based biostimulant (Azospirillum sp., Azotobacter sp., and Rhizobium sp.) in combination or not with a commercial inoculum Micomix (Rhizoglomus irregulare, Funnelliformis mosseae, Funnelliformis caledonium, Bacillus licheniformis, and Bacillus mucilaginosus) (MYC) on the native rhizosphere communities and tomato production. Bacterial populations in the different samples were characterized using an environmental metabarcoding approach. The bioinocula effect on the native rhizosphere microbiota resulted in significant variation both in alpha and beta diversity and in a specific signature associated with the presence of biostimulants. [ABSTRACT FROM AUTHOR]

The utilization of saline water for irrigating plants in arid and semi-arid regions has become imperative because of the scarcity of water resources. Nevertheless, under salt stress conditions, plants undergo a multitude of variation, which result in delayed growth and adversely affect the plant metabolism. Adopting appropriate and sustainable strategies such as using bio-organic fertilizers from animal and plant waste or integrating microorganisms (symbiotic fungi), can improve plant resilience against salt stress. The purpose of this study was to elucidate the impact of arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis alone and/or combined with compost on growth, nutrient uptake, antioxidant activities, and photosynthesis-related performance of Stevia rebaudiana Bertoni under salt stress conditions. Salt stress negatively affected all studied parameters. However, the application of R. irregulare strain in a substrate amended with 5% compost is more effective in enhancing salt stress tolerance in stevia plants compared to the compost and AMF strain applied separately. The synergistic effect of the co-application of these two biofertilizers under salt stress resulted in increased stomatal conductance (276%), chlorophyll fluorescence (38%), antioxidant enzyme activities, and the uptake of K+ (78%), Ca2+ (117%), and P (149%). In conclusion, the application of compost combined with AMF may be a promising sustainable strategy for improving salt stress resistance in stevia. [ABSTRACT FROM AUTHOR]

Among the epimerases specific to alginate, some of them in Azotobacter genera convert β‐d‐mannuronic acid to α‐l‐guluronic acid but also have lyase activity to degrade alginate. The remarkable characteristics of these epimerases make it a promising enzyme for tailoring alginates to meet specific demands. Here, we determined the structure of the bifunctional mannuronan C‐5 epimerase AlgE3 from Azotobacter chroococcum (AcAlgE3) in complex with several mannuronic acid oligomers as well as in apo form, which allowed us to elucidate the binding manner of each mannuronic acid oligomer, and the structural plasticity, which is dependent on calcium ions. Moreover, a comprehensive analysis of the lyase activity profiles of AcAlgE3 combined with structural characteristics explained the preference for different chain length oligomers. [ABSTRACT FROM AUTHOR]

This article shows the result of the research carried out on the El Jardín farm belonging to the Provincial Flora and Fauna Company, located at km 15 of the Palmar - La Tagua highway, in the Manuel Tames municipality of the province. from Guantánamo, where the bioproducts azotobacter, phosphorin, an efficient microorganism are used as alternatives for the production of bean crops, with the objective of evaluating the response of bean plants to the application of alternative products under conditions of La Tagua. A randomized block design was used, with four treatments and four replications. The variables of plant height, stem thickness, number of leaves, number of legumes per plant and number of seeds per legume were evaluated. On the different days of evaluations, the best plant responses were recorded in treatment four, where an efficient microorganism was used, achieving an increase in general, highlighting that the other variants evaluated were superior to the production control. Therefore, the application of bioproducts would be an alternative to increase the yields of bean crops. [ABSTRACT FROM AUTHOR]

The current paper deals with new metabolites of different groups produced by Azotobacter chroococcum XU1. The strain's metabolic diversity is strongly altered by different factors, and some secondary metabolites are being reported for the first time for this species. As an abiotic/biotic stress response, the strain produced a broad spectrum of indole ring-containing compounds, n-alkanes (eicosane, heneicosane, docosane, tetracosane, and hexacosane), alkanes (7-hexyl eicosane and 2-methyloctacosane), saturated fatty acids (hexanoic and octanoic acids), esters (hexadecanoic acid methyl and pentadecanoic acid-14-methyl-methyl esters), and amides (9-Octadecenamide, (Z)- and 13-Docosenamide, (Z)-). Furthermore, to mitigate the abiotic stress the strain actively produced exopolysaccharide (EPS) to biosorb the Na+ ions. Apart from these metabolites, A. chroococcum XU1 synthesized lactones, namely 1,5-d-gluconolactone and d, l-mevalonic acid lactone in response to carbon source modification. [ABSTRACT FROM AUTHOR]

The study of the main patterns of distribution of microorganisms that synthesise melanins, which are precursors and components of humus molecules in agrocenosis soils is an urgent scientific task. The purpose of this study was to determine the influence of agrochemical factors on the number of melanin-synthesising microbial species and bacteria in grey forest soil. Microbiological, laboratory and analytical, and statistical methods were employed in the study. It was found for the first time that the number of melanin-synthesising micromycetes is minimal in the soil of the variant without fertilisers, liming with one dose according to hydrolytic acidity contributes to an increase in their number by 86.8%, application of mineral fertilisers in a dose of N30Р30К45 – 2.0 times, compatible use of lime and mineral fertilisers – 2.94 times. A 1.5-fold increase in the dose of mineral fertilisers leads to a 2.54-fold increase in the number of colony-forming units (CFU) of melanin-synthesising microbial species compared to a single dose of fertilisers, and a 2.0-2.62-fold increase in the dose of fertilisers, which coincides with the results of the analysis of the humus content in the soil of these variants – it exceeds the humus content in the variant with a single dose of fertilisers by 26.5% and 16.3%, respectively (correlation coefficient is 0.811). The number of melanin-synthesising bacteria in grey forest soil is 2-3 orders of magnitude higher than the number of melanin-synthesising micromycetes. However, the patterns of influence of anthropogenic factors on their number coincide with those established for micromycetes: liming with one dose of hydrolytic acidity leads to an increase in the number of melanin-synthesizing bacteria by 26.1%, application of mineral fertilizers in a dose of N30Р30К45 – 2.03 times, combined use of lime and mineral fertilisers – 2.48 times. A 1.5-fold increase in the dose of mineral fertilisers leads to a 5.8-fold increase in the number of melanin-synthesising bacteria compared to a single dose of fertiliser, while a 2.0-fold increase in the dose of fertiliser leads to a 13.3-fold increase, respectively. The correlation coefficient between the number of melanin-synthesising bacteria and the humus content in the soil is 0.417. The findings of the presented research can be used to develop recommendations for measures to increase the humus content of agricultural soils

Food loss and wastage occur in large quantities globally every year and it occurs in the entire supply chain right from the production to the processing stage. The loss of food is due to various factors like adopting traditional cultivation practices, low investment in the food sector, and more loss from poor pests and disease management of agricultural crops. The most important and major cause is due to microbial spoilage; fungi are most harmful to the consumers and also to the agriculture sector. Synthetic chemical strategies can prevent fungal growth and may reduce wastage but still causes accumulation of chemical substances in the environment and food chain in a long run. For these reasons, the use of bio-control technologies can be a great solution to agriculture and food sector as well. In view of this, the present study has been conducted using an efficient Azotobacter species, which belongs to the PGPR group. In this study, antifungal compounds produced by Azotobacter have been extracted by following solvent extraction protocols and identified using GCMS methods. The antifungal compounds were tested against the major fungal pathogens viz., Aspergillus, Fusarium, and Penicillium species. The metabolites produced by Azotobacter species were efficient in controlling the growth of the fungal species. These compounds can be used as a potential bio-preservative in the food sector instead of synthetic chemicals. Thus, these compounds can further be analyzed and tested on the food sample, having a great scope in the future to replace the chemical preservatives.

Plant epiphytic microorganisms have established a unique symbiotic relationship with plants, which has a significant impact on their growth, immune defense, and environmental adaptation. However, the impact of fertilization methods on the epiphytic microbial community and their correlation with the yield and quality of medicinal plant was still unclear. In current study, we conducted a field fertilization experiment and analyzed the composition of epiphytic bacterial and fungal communities employing high throughput sequencing data in different organs (roots, stems, and leaves) of Salvia miltiorrhiza, as well as their correlation with plant growth. The results showed that fertilization significantly affected the active ingredients and hormone content, soil physicochemical properties, and the composition of epiphytic microbial communities. After fertilization, the plant surface was enriched with a core microbial community mainly composed of bacteria from Firmicutes, Proteobacteria, and Actinobacteria, as well as fungi from Zygomycota and Ascomycota. Additionally, plant growth hormones were the principal factors leading to alterations in the epiphytic microbial community of S. miltiorrhiza. Thus, the most effective method of fertilization involved the application of base fertilizer in combination with foliar fertilizer. This study provides a new perspective for studying the correlation between microbial community function and the quality of S. miltiorrhiza, and also provides a theoretical basis for the cultivation and sustainable development of high-quality medicinal plants. [ABSTRACT FROM AUTHOR]

Nitrogenase reduces N2 to NH3 at its active‐site cofactor. Previous studies of an N2‐bound Mo‐nitrogenase from Azotobacter vinelandii suggest binding of three N2 species via asymmetric belt‐sulfur displacements in the two cofactors of its catalytic component (designated Av1*), leading to the proposal of stepwise N2 reduction involving all cofactor belt‐sulfur sites; yet, the evidence for the existence of multiple N2 species on Av1* remains elusive. Here we report a study of ATP‐independent, EuII/SO32−‐driven turnover of Av1* using GC‐MS and frequency‐selective pulse NMR techniques. Our data demonstrate incorporation of D2‐derived D by Av1* into the products of C2H2‐ and H+‐reduction, and decreased formation of NH3 by Av1* concomitant with the release of N2 under H2; moreover, they reveal a strict dependence of these activities on SO32−. These observations point to the presence of distinct N2 species on Av1*, thereby providing strong support for our proposed mechanism of stepwise reduction of N2 via belt‐sulfur mobilization. [ABSTRACT FROM AUTHOR]

Due to climate change and exacerbated population growth, the search for new sustainable strategies that allow for greater food productivity and that provide greater nutritional quality has become imperative. One strategy for addressing this problem is the combined use of fertilization with a reduced dose of nitrogen and biostimulants. Celery processing produces a large amount of waste with its concomitant pollution. Therefore, it is necessary to address the valorization of its byproducts. Our results revealed reductions in the biomass, Na, P, Mn, B, sugars, and proteins in the byproducts and increased lipid peroxidation, Fe (all celery parts), and K (byproducts) when the N supplied was reduced. Plants inoculated with Azotobacter salinestris obtained a greater biomass, a higher accumulation of K (byproducts), a build-up of sugars and proteins, reduced concentrations of P, Cu, Mn, B, Fe (petioles), and Zn (byproducts), and reduced lipid peroxidation. The application of Se at 8 μM reinforced the beneficial effect obtained after inoculation with Azotobacter salinestris. In accordance with our results, edible celery parts are recommended as an essential ingredient in the daily diet. Furthermore, the valorization of celery byproducts with health-promoting purposes should be considered. [ABSTRACT FROM AUTHOR]

The ecotoxicity of Ag particles of different size has been assessed by microbiological, biochemical, and phytotoxic indicators for the upper layer (0–20 cm) of ordinary chernozem (Haplic Chernozem) in a laboratory model experiment. The effect has been studied of nano- (10 and 100 nm) and microparticles (1000 nm) of Ag at concentrations of 1, 10, and 100 mg/kg on the biological parameters of ordinary chernozem 30 days after contamination: the activity of catalase, dehydrogenases, ferrireductase, urease, peroxidase, polyphenol oxidase, invertase, phosphatase, the total number of bacteria, the abundance of bacteria of Azotobacter genus, the number of germinated seeds and the length of radish roots. It was found that the ecotoxicity of Ag particles depended on their size: in most cases, Ag particles 10 nm in size had a stronger ecotoxic effect on the biological parameters than particles 100 and 1000 nm in size. There were no significant differences in the ecotoxicity of 100 and 1000 nm Ag particles. The difference in the effects of Ag particles of different sizes increased with increasing Ag concentration in the soil: the higher the Ag concentration was in the soil (from 1 to 100 mg/kg), the more pronounced the difference was in ecotoxicity between 10 nm Ag particles and 100 and 1000 nm Ag particles. Phytotoxic indicators were more sensitive to contamination by Ag nanoparticles at all concentrations studied (1, 10 and 100 mg/kg); the total number of bacteria, invertase and phosphatase activity at 10 and 100 mg/kg; the abundance of bacteria of Azotobacter genus and the activity of dehydrogenases at 100 mg/kg. It is advisable to use these indicators in biodiagnostics of the ecotoxicity of Ag nanoparticles. [ABSTRACT FROM AUTHOR]

To optimize the application of plant growth-promoting rhizobacteria (PGPR) in field trials, tracking methods are needed to assess their shelf life and to determine the elements affecting their effectiveness and their interactions with plants and native soil microbiota. This work developed a real-time PCR (qtPCR) method which traces and quantifies bacteria when added as microbial consortia, including five PGPR species: Burkholderia ambifaria, Bacillus amyloliquefaciens, Azotobacter chroococcum, Pseudomonas fluorescens, and Rahnella aquatilis. Through a literature search and in silico sequence analyses, a set of primer pairs which selectively tag three bacterial species (B. ambifaria, B. amyloliquefaciens and R. aquatilis) was retrieved. The primers were used to trace these microbial species in a field trial in which the consortium was tested as a biostimulant on two wheat varieties, in combination with biochar and the mycorrhizal fungus Rhizophagus intraradices. The qtPCR assay demonstrated that the targeted bacteria had colonized and grown into the soil, reaching a maximum of growth between 15 and 20 days after inoculum. The results also showed biochar had a positive effect on PGPR growth. In conclusion, qtPCR was once more an effective method to trace the fate of supplied bacterial species in the consortium when used as a cargo system for their delivery. [ABSTRACT FROM AUTHOR]

In this study, two important commercial species, Buxus microphilla and B. herlandii, were evaluated. People do not want polluting and toxic fertilizers used to cultivate the plants they use for nutrition, and they do not want the plants they use as ornamental plants. The study investigated the effects of mycorrhizal and bacterial applications on plant growth and chlorophyll content. As a result of the study, it was concluded that bacterial applications on the development of boxwoods are more effective than mycorrhizal applications. Shading further increased the effect of the applications. In B. microphilla, in a 70% shade, plant height increased by 18.5% with mycorrhizal application, and plant width increased by 29.7% with bacterial application. In B. herlandii, bacterial application increased plant height by 13.3% and plant width by 20.4%. In shadowless application, the amount of chlorophyll in B. herlandii leaves was found to increase by 47.20% with bacteria and in B. microphilla, it increased by 65.86. In shadow application in B. herlandii, leaves were found to increase by 76.70% with bacteria; in B. microphilla, it increased by 94.93%. It was concluded that the bacteria application is more effective than others because Azotobacters fix the free nitrogen in the air to the boxwood soil, which needs continuous nitrogen for growth and development. For this reason, N-fixing bacteria applications to the soil can be used as an alternative to chemical fertilizer applications in boxwood cultivation or hedge formation. [ABSTRACT FROM AUTHOR]

Leaves of Camellia sinensis plants are used to produce tea, one of the most consumed beverages worldwide, containing a wide variety of bioactive compounds that help to promote human health. Tea cultivation is economically important, and its sustainable production can have significant consequences in providing agricultural opportunities and lowering extreme poverty. Soil parameters are well known to affect the quality of the resultant leaves and consequently, the understanding of the diversity and functions of soil microorganisms in tea gardens will provide insight to harnessing soil microbial communities to improve tea yield and quality. Current analyses indicate that tea garden soils possess a rich composition of diverse microorganisms (bacteria and fungi) of which the bacterial Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Chloroflexi and fungal Ascomycota, Basidiomycota, Glomeromycota are the prominent groups. When optimized, these microbes' function in keeping garden soil ecosystems balanced by acting on nutrient cycling processes, biofertilizers, biocontrol of pests and pathogens, and bioremediation of persistent organic chemicals. Here, we summarize research on the activities of (tea garden) soil microorganisms as biofertilizers, biological control agents and as bioremediators to improve soil health and consequently, tea yield and quality, focusing mainly on bacterial and fungal members. Recent advances in molecular techniques that characterize the diverse microorganisms in tea gardens are examined. In terms of viruses there is a paucity of information regarding any beneficial functions of soil viruses in tea gardens, although in some instances insect pathogenic viruses have been used to control tea pests. The potential of soil microorganisms is reported here, as well as recent techniques used to study microbial diversity and their genetic manipulation, aimed at improving the yield and quality of tea plants for sustainable production. [ABSTRACT FROM AUTHOR]

The nitrogen (N) requirement for barley cultivation can vary from 90 to 130 kg ha−1 cycle−1, representing 30% of production costs. Furthermore, obtaining mineral N is difficult due to constant conflicts involving producing countries. Excess N will increase the cost of production and contaminate the soil and groundwater, unbalancing the fauna, flora, and microbiology of the environment. The objective of this research was to evaluate the management of inoculation and N fertilization with A. brasilense on the development and productivity of barley. Field experiment was carried out for two years. A randomized block design was used in a 5 (Factor A) × 2 (Factor D) factorial arrangement with four replications. In which the "factor A" included five doses of A. brasilense, whereas the "factor D" was evaluated N management (with or without N management). The inoculant used had approximately of 2.0 × 108 viable cells mL−1 (Ab-V5 and Ab-V6 strains). Innoculation was carried out on the seeds 1 hour before sowing, in order to homogenize the inoculant in the seeds, to guarantee homogeneity of the distribution of microorganisms on the seeds. The best dose of A. brasilense was 12.5 mL kg−1 of seed, which provided an increase in plant height, number of ears, mass and grain productivity. The use of A. brasilense showed significant improvements in management with or without the use of mineral N. However, better results are obtained when the association between N management and the use of inoculant is made. Thus, when using up to 22.5 kg of N, the best results were observed. [ABSTRACT FROM AUTHOR]

The stringent response exerted by (p)ppGpp and RNA-polymerase binding protein DksA regulates gene expression in diverse bacterial species. To control gene expression (p)ppGpp, synthesized by enzymes RelA and SpoT, interacts with two sites within the RNA polymerase; site 1, located in the interphase between subunits β' and ω (rpoZ), and site 2 located in the secondary channel that is dependent on DksA protein. In Escherichia coli, inactivation of dksA results in a reduced sigma factor RpoS expression. In Azotobacter vinelandii the synthesis of polyhydroxybutyrate (PHB) is under RpoS regulation. In this study, we found that the inactivation of relA or dksA, but not rpoZ, resulted in a negative effect on PHB synthesis. We also found that the dksA, but not the relA mutation reduced both rpoS transcription and RpoS protein levels, implying that (p)ppGpp and DksA control PHB synthesis through different mechanisms. Interestingly, despite expressing rpoS from a constitutive promoter in the dksA mutant, PHB synthesis was not restored to wild type levels. A transcriptomic analysis in the dksA mutant, revealed downregulation of genes encoding enzymes needed for the synthesis of acetyl-CoA, the precursor substrate for PHB synthesis. Together, these data indicate that DksA is required for optimal expression of RpoS which in turn activates transcription of genes for PHB synthesis. Additionally, DksA is required for optimal transcription of genes responsible for the synthesis of precursors for PHB synthesis. [ABSTRACT FROM AUTHOR]

Background and Objectives: Barley (Hordeum vulgare L.) is one of the crops that has a high nutritional value and can be used as animal feed and cover crops to increase soil fertility, as well as has various uses in the food industry. In order to increase the efficiency of nutritional elements, the use of efficient crop cultivars is a cheap and accessible method for farmers. Based on the principles of sustainable agriculture, one of the methods to improve the nutrition status of crops is to use biological fertilizers. Considering the importance of barley cultivation in Lorestan province, this study was conducted to investigate the effect of biological fertilizer in combination with common cultivars in this region. Materials and Methods: The experiment was conducted in the form of split plots in the form of a randomized complete block design with three replications in 2014-2016. The main plot includes three varieties of barley, including Mahor (M), Izeh (I) and Khorram (K). The subplot of four types of biofertilizer treatments included control (without biofertilizer), Azotobacter (A), mycorrhizal (M) and Azotobacter + mycorrhizal (AM). Barley seeds were inoculated with biofertilizers according to their instructions before planting. The seeds were poured on nylon in the shade, and one package of biological fertilizer per hectare was dissolved in an appropriate volume of chlorine-free water. After filtering the fertilizer solution with a thin cloth, it was sprayed on the seeds with a sprayer and mixed well. All of them should be evenly coated with fertilizer. At the time of plant harvesting, some growth characteristics, including seed yield, straw yield, number of seeds per spike, number of spikes per square meter and weight of 1000 seeds per plot, were measured. Results: The result of the analysis of variance showed that cultivar has a significant effect on grain yield, straw yield, number of seeds per spike, number of spikes per square meter, and thousand-grain weight. The result of the mean comparison showed that the highest grain yield, straw yield, number of seeds per cluster, number of clusters per square meter and weight of 1000 seeds are related to M-AM treatment. As a result, the Mahor variety had the highest grain yield compared to the other two varieties. Among the fertilizers used, Azotobacter + Mycorrhiza was the most effective. Therefore, the interaction effect of these two treatments has the greatest effect on grain yield (4931 kg/ha), straw yield (8797 kg/ha), number of seeds per spike (16), number of spikes per square meter (546) and weight of 1000 seeds (17.8 g). Conclusion: The finding indicates that in order to achieve the highest seed yield, it is suggested to cultivate Mahor cultivar along with Azotobacter and Mycorrhiza treatment in the region. Further assessments should be conducted to explore alternative cultivars and other biofertilizers for the region. [ABSTRACT FROM AUTHOR]

This document presents a comparative study on the effects of planting time, growth regulator, and biofertilizer on the growth, yield, and quality of strawberry plants. The study found that the combination of planting on October 15th, 75 ppm GA3 concentration, and Azotobacter application was the most effective in promoting growth, yield, and quality traits of the strawberry plants. The results provide valuable information for researchers and individuals interested in understanding the factors that influence the growth and yield of strawberry plants. [Extracted from the article]

The factorial experiment based on a randomized complete block design was conducted with three replications at the research greenhouse of Tabriz University in 2017. The experimental factors include three levels of salinity stress (non-saline, salinity 3 and 6 dS/m) from the source of sodium chloride, foliar spraying in three levels without hormonal and nutritional foliar spraying, foliar spraying of 2 mM silicon and foliar spraying of 1mM salicylic acid, and the third factor, bacterial inoculation in four levels included: no inoculation, inoculation with Azosprilium, inoculation with Azotobacter and combined inoculation of two bacteria. The results of this research showed that the salt stress reduced the growth and yield of garlic. Spraying of salicylic acid and silicon and inoculation with bacteria improved potassium absorption, plant height, and leaf surface area, number of leaves per plant, yield components, biomass, and yield of garlic. The treatments significantly reduced the sodium concentration in both roots and leaves. The positive effects of the proposed treatments not only improved plant growth and performance under salinity stress conditions but also under non-saline conditions. Among the studied treatments, salicylic acid and silicon foliar applications along with the combined use of Azospirillium and Azotobacter showed more favorable effects on the growth and productivity of garlic than the other treatments. Finally, it was suggested to use growth-promoting bacteria in combination with salicylic acid and silicon solution spraying to mitigate the effects of salinity stress in garlic plants. [ABSTRACT FROM AUTHOR]

In order to clarify the effect of biochar fertilizer on tobacco root knot nematode disease and rhizosphere soil, a field experiment was conducted to study the effect of different amounts of biochar fertilizer on rhizosphere soil of tobacco plant with root knot nematode disease. The results showed that the disease index of tobacco root knot nematode disease could significantly reduced by applying enzyme biocarbon fertilizer in the mixed pond when the amount of conventional fertilization was reduced by 10%. When 350 g⋅plant-1 enzyme biocarbon fertilizer was applied in the mixed pond, the control effect of tobacco root knot nematode disease was better, reaching 23.98%, the agronomic characters of tobacco plants were better, the activities of catalase, urease and phosphatase in rhizosphere soil were higher, the contents of phenolic acid in rhizosphere soil decreased, and allelopathy and autotoxicity weakened. The number of soil fungi in each treatment increased first and then decreased with the advance of growth period. When 350 g⋅plant-1 enzyme biocarbon fertilizer was applied, the bacterial number in the rhizosphere soil decreased gradually with the growth period. The number of fungi in the soil at each growth stage was high, the number of bacteria was low, and the value of fungi/bacteria was high. Above results indicated that, in tobacco planting, 10% reduction in fertilization and 350 g⋅plant-1 application of enzyme biocarbon fertilizer in the pond could increase the number of fungi in the soil, reduce the number of bacteria in the soil, significantly improve soil fertility and enzyme activity, which provided scientific basis for biocarbon fertilizer to regulate the rhizosphere microecology of susceptible root knot nematodes. [ABSTRACT FROM AUTHOR]

The increasing global demand for food, coupled with concerns about the environmental impact of synthetic fertilizers, underscores the urgency of developing sustainable agricultural practices. Nitrogen-fixing bacteria, known as diazotrophs, offer a potential solution by converting atmospheric nitrogen into bioavailable forms, reducing the reliance on synthetic fertilizers. However, a deeper understanding of their interactions with plants and other microbes is needed. In this study, we introduce a recently developed label-free 3D quantitative phase imaging technology called dynamic quantitative oblique back-illumination microscopy (DqOBM) to assess the functional dynamic activity of diazotrophs in vitro and in situ. Our experiments involved three different diazotrophs (Sinorhizobium meliloti, Azotobacter vinelandii, and Rahnella aquatilis) cultured on media with amendments of carbon and nitrogen sources. Over 5 days, we observed increased dynamics in nutrient-amended media. These results suggest that the observed bacterial dynamics correlate with their metabolic activity. Furthermore, we applied qOBM to visualize microbial dynamics within the root cap and elongation zone of Arabidopsis thaliana primary roots. This allowed us to identify distinct areas of microbial infiltration in plant roots without the need for fluorescent markers. Our findings demonstrate that DqOBM can effectively characterize microbial dynamics and provide insights into plant-microbe interactions in situ, offering a valuable tool for advancing our understanding of sustainable agriculture. [ABSTRACT FROM AUTHOR]

Vermicompost tea (VCT), an eco-friendly biofertilizer, is becoming increasingly popular due to its notable benefits on plant and soil health. However, the reasons behind its efficacy, whether due to growth regulators, minerals, microorganisms, or their combination, remain ambiguous. Seedlings of tomato (Solanum lycopersicum cv. Rutgers) were treated with VCT, autoclaved VCT (AVCT), or water (control) for three times over 7 weeks to determine if the effects of this biological fertilizer on plant growth are due to the presence of microorganisms or chemical nutrients. A significant increase was observed in plant growth with either the VCT or AVCT treatments compared to the control, while for most measures, plant growth was higher in the AVCT versus the VCT treatment. Autoclaving VCT increased pH and plant-available minerals, including NH4+, NO3−, K, Mg, Zn, Fe, and Mn. Metagenomic analysis of bacterial specimens in VCT revealed the most abundant genera as Novosphingobium, Sphingobium, Luteimonas, Pseudomonas, Planctomyces, Rhodoplanes, Mycoplana, Bacillus, Achromobacter, and Devosia. Although many of these genera contain known plant-growth-promoting bacteria, the major benefits of VCT do not necessarily require living organisms as both VCT and AVCT increased plant biomass. Thus, the growth-promoting potential of VCT may not be associated with microbial biomass by itself but rather with the release of extracellular microbial signals/nutrients and/or the nutrient availability of the applied VCT. The advantages of autoclaving VCT are the increased shelf life and the potential use of biofertilizers within organic hydroponic systems without technical challenges due to clogging from microbial activity. [ABSTRACT FROM AUTHOR]

Food loss and wastage occur in large quantities globally every year and it occurs in the entire supply chain right from the production to the processing stage. The loss of food is due to various factors like adopting traditional cultivation practices, low investment in the food sector, and more loss from poor pests and disease management of agricultural crops. The most important and major cause is due to microbial spoilage; fungi are most harmful to the consumers and also to the agriculture sector. Synthetic chemical strategies can prevent fungal growth and may reduce wastage but still causes accumulation of chemical substances in the environment and food chain in a long run. For these reasons, the use of bio-control technologies can be a great solution to agriculture and food sector as well. In view of this, the present study has been conducted using an efficient Azotobacter species, which belongs to the PGPR group. In this study, antifungal compounds produced by Azotobacter have been extracted by following solvent extraction protocols and identified using GCMS methods. The antifungal compounds were tested against the major fungal pathogens viz., Aspergillus, Fusarium, and Penicillium species. The metabolites produced by Azotobacter species were efficient in controlling the growth of the fungal species. These compounds can be used as a potential bio-preservative in the food sector instead of synthetic chemicals. Thus, these compounds can further be analyzed and tested on the food sample, having a great scope in the future to replace the chemical preservatives. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi, plant-growth-promoting bacteria (PGPB) and vermicompost constitute important environmental and economic resources for improving the production and quality of tomato fruits. The present research aims to determine the single and combined effect of Glomus fasciculatum (Gf) fungus, Azotobacter chroococcum (Azot), PGPB and vermicompost leachate (VL) organic fertilizer on the yield and quality of tomato fruit. Thus, an open-field experiment was established with seven treatments, a control and three replicates. Total soluble solids, vitamin C, acidity, fruit mass and fruit diameter were evaluated as fruit quality variables; the yield was recorded and estimated in tons per hectare−1. The results showed that Gf, Azot and VL were effective in promoting tomato yield and fruit quality. As a trend, the triple combination (Gf + Azot + VL) evidently obtained the highest values of total soluble solids, vitamin C and fruit acidity. The range of improvement concerning the fruit size was 66.6% (single treatment) compared to 78.5% (triple combination). The maximum yield of 54.5 t/ha−1 was recorded for the Gf + Azot + VL combination. Therefore, G. fasciculatum, A. chroococcum and VL are considered useful as organic alternatives for open-field tomato biofertilization programs in tropical countries. [ABSTRACT FROM AUTHOR]