Biofertilizer Agent Research Articles

Comparative genomics of Metarhizium brunneum strains V275 and ARSEF 4556: unraveling intraspecies diversity.

Entomopathogenic fungi belonging to the Order Hypocreales are renowned for their ability to infect and kill insect hosts, while their endophytic mode of life and the beneficial rhizosphere effects on plant hosts have only been recently recognized. Understanding the molecular mechanisms underlying their different lifestyles could optimize their potential as both biocontrol and biofertilizer agents, as well as the wider appreciation of niche plasticity in fungal ecology. This study describes the comprehensive whole genome sequencing and analysis of one of the most effective entomopathogenic and endophytic EPF strains, Metarhizium brunneum V275 (commercially known as Lalguard Met52), achieved through Nanopore and Illumina reads. Comparative genomics for exploring intraspecies variability and analyses of key gene sets were conducted with a second effective EPF strain, M. brunneum ARSEF 4556. The search for strain- or species-specific genes was extended to M. brunneum strain ARSEF 3297 and other species of genus Metarhizium, to identify molecular mechanisms and putative key genome adaptations associated with mode of life differences. Genome size differed significantly, with M. brunneum V275 having the largest genome amongst M. brunneum strains sequenced to date. Genome analyses revealed an abundance of plant-degrading enzymes, plant colonization-associated genes, and intriguing intraspecies variations regarding their predicted secondary metabolic compounds and the number and localization of Transposable Elements. The potential significance of the differences found between closely related endophytic and entomopathogenic fungi, regarding plant growth-promoting and entomopathogenic abilities, are discussed, enhancing our understanding of their diverse functionalities and putative applications in agriculture and ecology.

Application of Plant Growth Promoting Rhizobacteria on Vegetative Growth in Chili Plants (Capsicum frutescens L.)

Cayenne pepper is a significant plant in tropical regions, utilized not only as a culinary spice but also in the pharmaceutical industry. An effective strategy for enhancing the physical, chemical, and biological quality of soil is the employment of plant growth-promoting rhizobacteria (PGPR). PGPR, a soil microorganism that colonizes plant roots, can accelerate growth and protect against certain pathogens. The use of PGPR, particularly in biocontrol of plant pathogens and biofertilization, is prevalent across various global regions. This study evaluates the effectiveness of PGPR in boosting the growth of cayenne pepper and was conducted in Peresak Village, Narmada District, West Lombok Regency, NTB Province. The methodology implemented was a Completely Randomized Design (CRD) experiment with five treatments and five replications, totaling 25 plant units. The treatments included a control (P0 ml/L) and four PGPR concentrations: P1 (10 ml/L), P2 (20 ml/L), P3 (30 ml/L), and P4 (40 ml/L). Each PGPR dose was dissolved in 1 liter of water and administered at 200 ml per polybag. The findings indicated that PGPR application significantly impacted the growth of cayenne pepper plants, notably increasing plant height, leaf count, branch count, and flower count. The 30 ml/L PGPR concentration (P3) proved most effective in enhancing these growth parameters. The results underscore the substantial benefits of incorporating PGPR as a biofertilizer agent in agricultural practices to optimize crop yields.

Characterization of rhizosphere fungi of the ebony plant (Diospyros celebica Bakh.) which has the potential to produce Indole-3-Acetic Acid and Gibberelic Acid Phytohormones

Ebony (Diospyros celebica Bakh.) is a slow-growing species that is an impacting factor in the extinction of this species. Efforts to reduce the ebony population can be performed by employing microbes to stimulate ebony growth. This study aimed to obtain bacterial isolates with the potential of producing IAA and GA3 that can be further utilized as biofertilizer agents. Research stages encompassed soil sample isolation, isolation of bacteria, and analysis of IAA and GA3. The research was in complete randomized design (CRD). Thirteen isolates were successfully purified and analyzed with their IAA and GA3 hormones. The highest IAA concentrations were observed in EP1b at 48 incubation hours (44.39 ppm), EP3d at 72 incubation hours (34.93 ppm), and EP3c at 72 incubation hours (34.48 ppm). EP2c, EP2e, and EP2a produced the highest GA3 concentration at 24 incubation hours which were 3.88 ppm, 3.88 ppm, and 3.81 ppm, respectively.

Potential of Aspergillus flavus Isolated from Marginal Saline Soil as a Biofertilizer Agent: A Comparative Study with Trichoderma esperellum

This study aimed to assess the potential of Aspergillus flavus, isolated from marginal saline soil, as a biofertilizer agent by comparing its in vitro diversity with the biological agent Trichoderma esperellum (collected from the UMSIDA Microbiology and Biotechnology Laboratory). The research was conducted at the Microbiology and Biotechnology Laboratory, University of Muhammadiyah Sidoarjo. Macroscopic and microscopic morphological tests were performed on Aspergillus flavus isolated from rice root soil. The sensitivity test of the biological agents on saline soil showed no influence on their growth. Notably, the findings indicated that Aspergillus flavus exhibited faster growth on saline soil compared to its growth on PDA-c media. Moreover, the combination of PDA-c and saline soil in ratios of 1:1 and 2:1 significantly enhanced the growth response of A. flavus by 50% and 70%, respectively, two days after inoculation. These results suggest the promising potential of Aspergillus flavus as a biofertilizer agent to enhance soil fertility in saline environments. 
 Highlights:
 
 Potential of Aspergillus flavus: The study aimed to determine the potential of the fungus Aspergillus flavus, isolated from marginal saline soil, as a biofertilizer agent. The research activity included comparing its diversity in vitro with the biological agent Trichoderma esperellum.
 Morphological Tests: The fungus Aspergillus flavus was subjected to macroscopic and microscopic morphological tests. Morphological observations of the growth of biological agents were carried out macroscopically and microscopically.
 Sensitivity of Biological Agents: The test of the sensitivity of biological agents on saline soils showed no influence on the growth of biological agents on saline soil media.

ISOLASI, ENUMERASI, DAN KARAKTERISASI BAKTERI PELARUT FOSFAT (BPF) INDIGENUS TANAH DESA KEBUNAN SUMENEP SEBAGAI AGEN PUPUK HAYATI ORGANIK

Phosphate Solubilizing Bacteria (PSB) are known that have important role to improve plant phosphate uptake as biofertilizer. These Microorganism hold potential to promote organic agriculture as eco friendly and efficiency. This study aims to isolate, enumerate and characterize indigenous PSB from Kebunan Village soil as the organic biofertilizer agent. Isolation and enumeration were carried out using the spread plate method on PCA media for enumeration of the total bacteria and Pikovskaya media (PKV) and NBRIP for BPF selection and enumeration. characterization includes observing the morphological colonies and cells. These experimental studies found that the soil pH was 6.5, the temperature range was 28-35 °C, the total P content was from 0.59 to 1.09 and the dissolved phosphate content sequentially from the smallest is 0.53 (KB2), 29.41 (KB1), 60.45 (KB3). The total abundance of bacteria at 3 different locations showed variations between 1.97 x 106 to 287 x 106. The highest abundance of BPF reached 5.45 x 106 cfu/g was in the watershed which had the lowest available P content. Total 7 isolates of BPF were successfully isolated and characterized with different colony characters and cell shapes. The selected BPF isolates were dominated by Gram-positive bacilli.

Insights into the Biocontrol Function of a Burkholderia gladioli Strain against Botrytis cinerea.

Pathogenic fungi are the main cause of yield loss and postharvest loss of crops. In recent years, some antifungal microorganisms have been exploited and applied to prevent and control pathogenic fungi. In this study, an antagonistic bacteria KRS027 isolated from the soil rhizosphere of a healthy cotton plant from an infected field was identified as Burkholderia gladioli by morphological identification, multilocus sequence analysis, and typing (MLSA-MLST) and physiobiochemical examinations. KRS027 showed broad spectrum antifungal activity against various phytopathogenic fungi by secreting soluble and volatile compounds. KRS027 also has the characteristics of plant growth promotion (PGP) including nitrogen fixation, phosphate, and potassium solubilization, production of siderophores, and various enzymes. KRS027 is not only proven safe by inoculation of tobacco leaves and hemolysis test but also could effectively protect tobacco and table grapes against gray mold disease caused by Botrytis cinerea. Furthermore, KRS027 can trigger plant immunity by inducing systemic resistance (ISR) activated by salicylic acid- (SA), jasmonic acid- (JA), and ethylene (ET)-dependent signaling pathways. The extracellular metabolites and volatile organic compounds (VOCs) of KRS027 affected the colony extension and hyphal development by downregulation of melanin biosynthesis and upregulation of vesicle transport, G protein subunit 1, mitochondrial oxidative phosphorylation, disturbance of autophagy process, and degrading the cell wall of B. cinerea. These results demonstrated that B. gladioli KRS027 would likely become a promising biocontrol and biofertilizer agent against fungal diseases, including B. cinerea, and would promote plant growth. IMPORTANCE Searching the economical, eco-friendly and efficient biological control measures is the key to protecting crops from pathogenic fungi. The species of Burkholderia genus are widespread in the natural environment, of which nonpathogenic members have been reported to have great potential for biological control agents and biofertilizers for agricultural application. Burkholderia gladioli strains, however, need more study and application in the control of pathogenic fungi, plant growth promotion, and induced systemic resistance (ISR). In this study, we found that a B. gladioli strain KRS027 has broad spectrum antifungal activity, especially in suppressing the incidence of gray mold disease caused by Botrytis cinerea, and can stimulate plant immunity response via ISR activated by salicylic acid- (SA), jasmonic acid- (JA), and ethylene (ET)-dependent signaling pathways. These results indicate that B. gladioli KRS027 may be a promising biocontrol and biofertilizer microorganism resource in agricultural applications.

Construction, Characterization, and Application of an Ammonium Transporter (AmtB) Deletion Mutant of the Nitrogen-Fixing Bacterium Kosakonia radicincitans GXGL-4A in Cucumis sativus L. Seedlings.

Nitrogen is an important factor affecting crop yield, but excessive use of chemical nitrogen fertilizer has caused decline in nitrogen utilization and soil and water pollution. Reducing the utilization of chemical nitrogen fertilizers by biological nitrogen fixation (BNF) is feasible for green production of crops. However, there are few reports on how to have more ammonium produced by nitrogen-fixing bacteria (NFB) flow outside the cell. In the present study, the amtB gene encoding an ammonium transporter (AmtB) in the genome of NFB strain Kosakonia radicincitans GXGL-4A was deleted and the △amtB mutant was characterized. The results showed that deletion of the amtB gene had no influence on the growth of bacterial cells. The extracellular ammonium nitrogen (NH4+) content of the △amtB mutant under nitrogen-free culture conditions was significantly higher than that of the wild-type strain GXGL-4A (WT-GXGL-4A), suggesting disruption of NH4+ transport. Meanwhile, the plant growth-promoting effect in cucumber seedlings was visualized after fertilization using cells of the △amtB mutant. NFB fertilization continuously increased the cucumber rhizosphere soil pH. The nitrate nitrogen (NO3-) content in soil in the △amtB treatment group was significantly higher than that in the WT-GXGL-4A treatment group in the short term but there was no difference in soil NH4+ contents between groups. Soil enzymatic activities varied during a 45-day assessment period, indicating that △amtB fertilization influenced soil nitrogen cycling in the cucumber rhizosphere. The results will provide a solid foundation for developing the NFB GXGL-4A into an efficient biofertilizer agent.

Investigation of some endophytic fungi from five medicinal plants with growth promoting ability on maize (Zea mays L.).

This study aimed to identify endophytic fungi from Anthemis altissima, Matricaria parthenium, Cichorium intybus, Achillea millefolium, and A. filipendulina with plant-promoting ability on the ZP684 maize hybrid-cultivar. Plants were collected from northeast-Iran and endophytic fungi were isolated and identified using partial large subunit nrDNA, internal transcribed spacer, translation elongation factor, and β-tubulin genetic markers. Endophytic fungi that improved seed germination were studied under greenhouse conditions. Ninety-seven endophytic fungi were identified. Preussia africana, Bjerkandera adusta, Schizophyllum commune, Alternaria embellisia, Trichaptum biforme, Septoria malagutii, A. consortiale, Verticillium dahliae, Fusarium avenacearum, and Trametes versicolor significantly improved seed-germination. Alternaria consortiale produced the highest level of indole-3-acetic acid-like compounds and maize growth-promoting. Plant fungal colonization frequency increased with orthometric height. Sampling location Chahar Bagh at 2230 m contained the most endophytic fungi. Fusarium and Alternaria were the most frequently isolated endophytic genera. Therefore, medicinal plants are potential hosts for endophytic fungi that may be suitable biofertilizer agents in agriculture. This study helps to better understand the ecosystem functions by investigating of endophytic fungi distribution under different ecological conditions. Finding effective isolates among these microorganisms with a suitable plant-promoting ability on crops may help to reduce the use of chemical fertilizers in an agroecosystem.

Effect of trichoderma formulated with cultivated oyster mushroom waste toward the growth and yield of shallot (Allium ascalonicum L.)

The utilization of oyster mushroom waste as an organic fertilizer for onion cultivation in former rice fields frequently encounters soil acidity problems. This experiment aims to determine the effect of administering Trichoderma biofertilizer, formulated with Oyster Mushroom Waste (OMW) on the growth and yield of shallots. The experiment was carried out in a greenhouse setting and a completely randomized design with four replications was employed, each experimental unit having six plants. Seeds were planted in a 5 kg capacity polybag containing sterile planting media soil of pH 4.85. The experimental treatments consisted of three types of Trichoderma biofertilizers, each containing a different isolate of the fungi (Tc-Jjr-02, Tc-Pjn-01, and Tc-Clk-02), oyster mushrooms waste fertilizer and the only soil. Each isolates formulated in oyster mushrooms waste through the biofertilizer treatment contained a uniform spore population of 0.375x106 CFU.g-1. Data were collected on plant height, number of leaves per plant, fresh and dry mass of stover, number of tillers per plant, tuber weight, tuber diameter, soil pH, and the population of each Trichoderma isolate at harvest time. The data were analyzed using a one-way analysis of variance (ANOVA). The significant differences between treatments were determined using the Honest Significant Difference test at the 5% level. Based on the growth and yield, the amount of increase for each treatment was calculated compared to the treatment of oyster mushrooms waste fertilizer. Subsequently, the types of isolate and their phylogenetic classes were determined. The results showed that the Trichoderma biofertilizer formulated in OMW affected plant height and number of leaves at 7-28 DAP (p<0.05), fresh weight and dry weight of stover, number of tuber shoot, and tuber weight (p<0.01), tuber diameter (p<0.05), soil pH at six weeks after planting and one week before harvest (p<0.05), and also Trichoderma population (p<0.05). These three types of this biofertilizer can increase stover fresh weight of shallot between 13.97-52.05%, dry stover weight 67.76-151.42%, number of tillers 44.75-47.00%, heavy fresh tuber 20.31-28.13%, and tuber diameter 3.13-10.97%. The three isolates of the biofertilizer agent were identical to Trichoderma asperellum, where the Tc-Jjr-02 isolate showed the best performance in assisting the growth and production of shallot plants in acidic soils. Key words: acid soil, growth, oyster mushroom waste, shallots, Trichoderma isolates, yield

Screening, and Optimization of Fermentation Medium to Produce Secondary Metabolites from Bacillus amyloliquefaciens, for the Biocontrol of Early Leaf Spot Disease, and Growth Promoting Effects on Peanut (Arachis hypogaea L.).

A novel Bacillus amyloliquefaciens BAM strain, with novel fermentation nutrient mediums and compositions, could produce potent antifungal secondary metabolites, as the existing strains face resistance from fungus pathogens. In the current study, we introduced two novel nutrient mediums for the fermentation process, semolina and peanut root extract, as carbon and nitrogen sources in order to maximize the antifungal effects of B. amyloliquefaciens against Cercaspora arachidichola to control early leaf spot disease in peanuts. Based on a single-factor test and the central composite design of response surface methodology, the optimum fermentation medium for Bacillus amyloliquefaciens antagonistic substance was determined, containing 15 gm/L of semolina flour, 12.5 gm/L of beef extract, and 0.5 gm/L of magnesium sulfate, which inhibited the fungal growth by 91%. In vitro, antagonistic activity showed that the fermentation broth of B. amyloliquefaciens BAM with the optimized medium formulation had an inhibition rate of (92.62 ± 2.07)% on the growth of C. arachidichola. Disease control effects in pot experiments show that the pre-infection spray of B. amyloliquefaciens BAM broth had significant efficiency of (92.00 ± 3.79)% in comparison to post-infection spray. B. amyloliquefaciens BAM broth significantly promoted peanut plant growth and physiological parameters and reduced the biotic stress of C. archidechola. Studies revealed that B. amyloliquefaciens BAM with a novel fermentation formulation could be an ideal biocontrol and biofertilizer agent and help in early disease management of early leaf spots in peanuts.

Identification of Several Aspergillus Isolates Candidates for Bio Fertilizer Agents Using Molecular Markers

This research is an activity to characterize and determine several types of soil-borne fungi based on the use of DNA sequences. This study aims to determine the species name and genealogy of four selected fungal isolates from the genus Aspergillus isolated from horticultural fields in Bumiaji, Batu, East Java. The identification of biocontrol agents begins with macroscopic and microscopic morphological observations, followed by DNA isolation, polymerase chain reaction application using ITS 1 and ITS 4 primers. Sequencing is done using Sanger sequencing. The nucleotides generated from the sequencer machine (ABI 3730XL sequencer) were compared with the gene bank using the BLAST-NCBI program, and their relationships were analyzed using MEGA X software. The results showed that based on BLAST analysis of the nucleotide sequences of Aspergilus spp. isolates 6, 7, 17, and 21 were compatible with Aspergillus tamarii with 100% Query Cover and 100% identical rate. These four Aspergillus isolates have the potential as bofertilizer agents and can be used for various industrial purposes.

Isolation and Identification of Nitrogen-Fixing Rhizobacteria associated with Cocoa plantation (Theobroma cacao L) as Biofertilizer Agent

Ringinkembar Village, Sumbermanjing Wetan District, Malang Regency, is one of the centers for cocoa plantations using an organic farming system. However, over time this organic farming system experienced a decrease in fruit production, possibly from soil fertility and biofertilizers that were less available in the soil. This study aims to analyze the nitrogen-fixing ability and identify rhizosphere isolates that excel in nitrogen-fixing obtained from the rhizosphere of cacao (Theobroma cacao L) plant. Bacteria were isolated from the soil surrounding cocoa plant roots and grown on Nfb (Nitrogen free Bromothymol Blue) agar media. The nitrogen-fixing bacteria were analyzed with quantitative and qualitative methods. Six potential nitrogen-fixing isolates were identified based on the 16S rDNA sequence. The total number of isolates obtained from nitrogen-fixing isolation was six isolates. The R3.FN1 isolate showed the highest ammonia index at 0.52 µg.L-1 and was identified as Stenotrophomonas maltophilia KB13 with 99.87% similarity to the 16S rDNA sequence.

Induction of resilience strategies against biochemical deteriorations prompted by severe cadmium stress in sunflower plant when Trichoderma and bacterial inoculation were used as biofertilizers.

Cadmium (Cd) is a highly toxic heavy metal. Its emission is suspected to be further increased due to the dramatic application of ash to agricultural soils and newly reclaimed ones. Thereby, Cd stress encountered by plants will exacerbate. Acute and chronic exposure to Cd can upset plant growth and development and ultimately causes plant death. Microorganisms as agriculturally important biofertilizers have constantly been arising as eco-friendly practices owing to their ability to built-in durability and adaptability mechanisms of plants. However, applying microbes as a biofertilizer agent necessitates the elucidation of the different mechanisms of microbe protection and stabilization of plants against toxic elements in the soil. A greenhouse experiment was performed using Trichoderma harzianum and plant growth-promoting (PGP) bacteria (Azotobacter chroococcum and Bacillus subtilis) individually and integrally to differentiate their potentiality in underpinning various resilience mechanisms versus various Cd levels (0, 50, 100, and 150 mg/kg of soil). Microorganisms were analyzed for Cd tolerance and biosorption capacity, indoleacetic acid production, and phosphate and potassium solubilization in vitro. Plant growth parameters, water relations, physiological and biochemical analysis, stress markers and membrane damage traits, and nutritional composition were estimated. Unequivocal inversion from a state of downregulation to upregulation was distinct under microbial inoculations. Inoculating soil with T. harzianum and PGPB markedly enhanced the plant parameters under Cd stress (150 mg/kg) compared with control plants by 4.9% and 13.9%, 5.6% and 11.1%, 55.6% and 5.7%, and 9.1% and 4.6% for plant fresh weight, dry weight, net assimilation rate, and transpiration rate, respectively; by 2.3% and 34.9%, 26.3% and 69.0%, 26.3% and 232.4%, 135.3% and 446.2%, 500% and 95.6%, and 60% and 300% for some metabolites such as starch, amino acids, phenolics, flavonoids, anthocyanin, and proline, respectively; by 134.0% and 604.6% for antioxidants including reduced glutathione; and by 64.8% and 91.2%, 21.9% and 72.7%, and 76.7% and 166.7% for enzymes activity including ascorbate peroxidase, glutathione peroxidase, and phenylalanine ammonia-lyase, respectively. Whereas a hampering effect mediated by PGP bacterial inoculation was registered on levels of superoxide anion, hydroxyl radical, electrolyte leakage, and polyphenol oxidase activity, with a decrease of 0.53%, 14.12%, 2.70%, and 5.70%, respectively, under a highest Cd level (150 mg/kg) compared with control plants. The available soil and plant Cd concentrations were decreased by 11.5% and 47.5%, and 3.8% and 45.0% with T. harzianum and PGP bacterial inoculation, respectively, compared with non-inoculated Cd-stressed plants. Whereas, non-significant alternation in antioxidant capacity of sunflower mediated by T. harzianum action even with elevated soil Cd concentrations indicates stable oxidative status. The uptake of nutrients, viz., K, Ca, Mg, Fe, nitrate, and phosphorus, was interestingly increased (34.0, 4.4, 3.3, 9.2, 30.0, and 1.0 mg/g dry weight, respectively) owing to the synergic inoculation in the presence of 150 mg of Cd/kg. However, strategies of microbe-induced resilience are largely exclusive and divergent. Biofertilizing potential of T. harzianum showed that, owing to its Cd biosorption capability, a resilience strategy was induced via reducing Cd bioavailability to be in the range that turned its effect from toxicity to essentiality posing well-known low-dose stimulation phenomena (hormetic effect), whereas using Azotobacter chroococcum and Bacillus subtilis, owing to their PGP traits, manifested a resilience strategy by neutralizing the potential side effects of Cd toxicity. The synergistic use of fungi and bacteria proved the highest efficiency in imparting sunflower adaptability under Cd stress.

Residual Effect of Finely-Ground Biochar Inoculated with Bio-Fertilization Impact on Productivity in a Lentil–Maize Cropping System

Biochar fertilization improves soil fertility and carbon sequestration, implying agricultural and environmental advantages. The effect of different sized previously applied biochar and biofertilizer agents on succeeding crops remains poorly known for legume–cereal cropping cycles. This study compared different particle-sized biochar and biofertilizer strains applied to lentils for their residual impact on subsequent maize growth, nutrition, and soil fertility without further polluting the environment. Three particle sizes (<2, 2–5, 5–10 mm) of Babul tree (Acacia arabica) wood biochar was obtained through grinding and sieving and applied prior to the lentil (first) crop at a rate of 500 g m−2. The commercial Rhizobium leguminosarum products Biozote-N and Rhizogold were inoculated to lentil seeds before sowing. The effect of biochar and biofertilizer agents on the succeeding maize (second) crops was evaluated for soil and crop performance. Findings revealed that particle sizes of <2 mm biochar and Biozote-N inoculation enhanced plant height, leaf area and leaf area index, biological yield, and thousand grain weight of the subsequent maize crop. Maize grain yield was enhanced by 2.5%, tissue N uptake by 15%, nitrogen uptake efficiency by 17%, grain protein content by 15%, extractable P by 17%, and soil bulk density by 3% with a residual biochar particle size of <2 mm and Biozote-N inoculation. It was concluded that the finely grounded (<2 mm) biochar particle combined with inoculation of Biozote-N was superior to larger particle sizes for enhancing crop growth and improving soil fertility status at the residual level, benefiting the subsequent crop in a legume–cereal rotation system.

Bambara Groundnut Rhizobacteria Antimicrobial and Biofertilization Potential.

Bambara groundnut, an underutilized crop has been proved to be an indigenous crop in Africa with the potential for food security. The rhizosphere of Bambara groundnut contains Rhizobacteria, with the ability to grow, adapt, and colonize their surroundings even in unfavorable conditions and have not been explored for their plant growth-promoting properties. The aim of this research was to determine the potential of rhizobacteria from Bambara groundnut soil samples as either biofertilizers or biocontrol agents or both to help provide sustainable agriculture in Africa and globally. Bambara groundnut rhizospheric soil samples were collected and analyzed for their chemical composition. Rhizobacteria isolates were cultured from the soil samples. Plant growth-promoting, antifungal activities and phylogenetic analysis using 16S rRNA were carried out on the isolates to identify the rhizobacteria. A 2-year field study planting was carried out to determine the effect of these rhizobacteria as biofertilizers for Bambara groundnut (Vigna subterranean). The study was carried out in a complete randomized block experimental design with three replications. All the isolates were able to produce ammonia and 1-aminocyclopropane-1-carboxylate, while 4.65, 12.28, and 27.91% produced hydrogen cyanide, indole acetic acid, and solubilized phosphate, respectively, making them important targets as biocontrol and biofertilizer agents. The field results revealed that treatment with rhizobacteria had significant results compared with the control. Characterization of selected isolates reveals their identity as B. amyloliquefaciens, B. thuringiensis, and Bacillus sp. These Bacillus isolates have proved to be plant growth-promoting agents that can be used as biofertilizers to enhance the growth of crops and consequent improved yield. This is the first time the rhizobacteria from the Bambara groundnut rhizosphere are applied as biofertilizer.

Antagonistic activities of endophytic bacteria isolated from rice roots against the fungus Magnaporthe oryzae, a causal of rice blast disease

BackgroundThe blast disease of rice caused by the fungus Magnaphorthe oryzae is one of the most destructive diseases in Nam Dinh province, Vietnam. This study aimed to isolate and screen antagonistic bacteria isolated from the rice (Oryza sativa) against M. oryzae.ResultsIn the present study, 14 endophytic bacteria were isolated from rice roots of a Ngoc Xuan variety in Nam Dinh province. The result showed that 6 isolates showed in vitro antagonistic activity against M. oryzae. Of 6, 2 strains, ND06 and ND10, molecularly identified as Bacillus velezensis and Pseudomonas putida, produced a significant inhibition on the pathogenic growth with growth inhibition of 62.87% and 64.25%, respectively, while the other 4 (ND03, ND07, ND09, and ND11) showed a weak inhibition. In addition, the ND06 and ND10 strains also presented antagonistic activity against M. oryzae under greenhouse conditions. Moreover, screening plant growth-promoting (PGP) traits of 2 isolates exhibited all 5 PGP traits including IAA production, phosphate solubilization, and production of ammonia, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, and siderophore. In addition, the greenhouse experimental results indicated that the cultivar rice seedlings inoculated with ND06 or ND10 strain produced a significant enhancement of the agronomic parameters (root length, shoot length, dry matter, and chlorophyll content).ConclusionsThe results indicated that the rice root endophytic bacteria (ND06 and ND10) possessed contemporarily multiple PGP traits and antifungal activity. These 2 strains should be further characterized in order to confirm the beneficial traits to develop as a potential biofertilizer and/or biocontrol agent for rice sustainable production.

Fungistatic Effect of Ipomea Carnea Extract and Trichoderma Esperellum Against Various Fungal Biological Agents

The study aimed to measure the fungistatic effect of Ipomea carnea and Trichoderma esperellum Tc-Jjr-02 biomass extracts against several fungal isolates of biological agents in vitro. Nine selected biological agent fungi were grown in PDA-chloramphenicol media containing 1% fresh extract of I. carnea biomass, four of them were grown in dual culture with isolate Tc-Jjr-02 with an incubation period of 96 hours. The results showed that the I. carnea biomass extract had a fungistatic effect by inhibiting the growth of the entomopathogenic agents Metarrhizium anipsoliae Me-Sdj-16 (27.8±3.2%) and Beuveria bassiana Be-Sj-13 (38.1±2.6%) and Be-Sdj-15 (18.6±1.0%), and the biofertilizer agents Aspergillus sp. As-Sdj-11 (46.7±1.9%), Pénicillium sp. Pc-Sdj-14 42.7±3.5%, and Trichoderma sp. Tc-Sdj-18 38.5±1.0% at 96 hours incubation period (HAI). The biocontrol agent T. esperellum gave a weak fungistatic effect against the biofertilizer agents As-Sdj-11 and Pc-Sdj-07 were 14.4±1.3% and 7.0±1.9% at 96 HAI and did not have a fungistatic effect on the biofertilizer agents Trichoderma Tc-Ba-05 and Tc-Sdj-09. Application of I. carnea biomass as green manure and some biofertilizer agents can be carried out simultaneously; while the application of T. esperellum can be carried out using biofertilizer agents As-Sdj-11 and Pc-Sdj-07 and Tc-Ba-05 and Tc-Sdj-09.

Comparative analysis of defence responses Triticum aestivum L in response to the endophytic Pseudomonas aeruginosa PM389 and the non-host microbial pathogens Erwinia carotovora and Fusarium monaliforme

In the present study, Pseudomonas aeruginosa PM389 has been studied for comparing the defense responses in wheat plant against non-host pathogens Fusarium monaliforme and Erwinia caratovora. The comparative studies of defense enzymes produced on pretreatment of plants in the presence and absence of PM389 were also studied. Apart from it, disease incidence as well as plant growth promotion under in vitro and pot condition was recorded in the presence or absence of PM389 on challenging wheat plant with the non-host pathogen. Induction in all defense enzymes was observed on pretreatment of the plant with PM389 before pathogenic challenge with non-host. It was suggested that PM389 can generate induced systemic resistance in plants against pathogens. A less pathogenic population was recorded in the presence of PM389 than in its absence. In addition, it also showed plant growth promotion in the wheat under in vitro and pot studies. It was observed that PM389 was more effective against fungal pathogen than bacterial pathogen in both plant growth promotions as well as in decreasing disease incidence. Thus, PM389 can serve as a potential candidate as biofertilizer and biocontrol agent for non-host pathogens as well as having chances of cross-infection among various crops.

Evaluation of Trichoderma asperellum Effect toward Anthracnose Pathogen Activity on Red Chili (Capsicum annum L.) As Ecofriendly Pesticide

The use of synthetic pesticides has been widely practiced by farmers to control plant diseases. However, it can promote negative impacts such as environmental pollution, threatening human health, and making pathogens more resistant. This study aims to determine the inhibition of Trichoderma Tc-Jjr-02 in vitro against Colletotrichum sp. and test its ability as a biopesticide and biofertilizer agent in suppressing the growth of anthracnose disease and chili production. The results show that, there was no interaction effect between the application of Trichoderma Tc-Jjr-02 as a biopesticide and biofertilizer agent. The in vitro test reveals that Trichoderma Tc-Jjr-02 could inhibit the growth of pathogenic colonies up to 61.4% at 11 days after inoculation. In vivo test show, that application of Trichoderma 6 hours before inoculation of pathogens (T1) and Trichoderma inoculation concurrent pathogens (T3) can reduce the symptoms intensity of anthracnose attacks 70% and 43%, respectively, then increasing the number of fresh fruit 62.66% and 76.58%, respectively, also increasing fresh fruit weights 84.83% and 91.90% respectively, compared with the pathogen inoculation treatment six hours before the application of Trichoderma. Thus, Trichoderma is more effective when applied before inoculation of pathogens and more suitable as a prevention agent. Using Trichoderma asperellum as biopesticed can protect the environment.

Plant growth‐promoting activity of endophytic bacteria from sweet sorghum (Sorghum bicolor (L.) Moench)

Application of high levels of chemical fertilizers for optimal growth of sweet sorghum causes environmental degradation. Plant growth‐promoting bacteria have biotechnological importance because they can improve the growth and health of important agronomic plants. This study aimed to isolate, characterize, and identify endophytic bacteria associated with sweet sorghum (cv. KCS105), and also to study the inoculation effects of selected isolates on sorghum growth. In this study, 35 isolates were evaluated for their ability to support plant growth. The results showed that seven isolates were diazotrophic, six were capable of dissolving phosphate, six produced IAA and could detect ACC‐deaminase activity, and three inhibited the growth of pathogenic fungi. Nine isolates exhibiting mechanisms for promoting plant growth from the Alphaproteobacteria (Devosia), Firmicutes (Bacillus, Paenibacillus, Staphylococcus), and Actinobacteria (Microbacterium, Brachybacterium) phyla were identified. In addition, the Paenibacillus sp. BB7, Bacillus sp. PIB1B, and Bacillus sp. PLB1B isolates showed increasing effects on plant growth in greenhouse tests. Endophytic bacterial isolates which display plant growth‐promoting features can potentially be employed as biofertilizer agents. They may also address environmental damage problems resulting from the use of chemical fertilizers and pesticides.