Fixation Of Atmospheric Nitrogen Research Articles

Effects of Plant Growth Promoting Halotolerant Pseudomonas Aeruginosa JCM 5962 with Hydrocarbon Degradation Ability, Isolated from Sundarbans Mangrove Area in West Bengal, on Abelmoschus esculentus (Okra) Plant Growth

Plant growth promoting rhizobacteria (PGPR) play a key role in sustainable agricultural practices leading to increased crop productivity. Moreover, PGPR with ability to diminish abiotic stresses like salinity and hydrocarbon contamination in soil, can be developed into potent biofertilizers with maximum ecological benefits. Sundarbans mangrove region in West Bengal, a natural reservoir of diverse microbiota is an important source of PGPR adapted to high salinity and other abiotic stresses like hydrocarbon contamination due to oil spillage and water transport systems, rendering the soil unsuitable for farming. In the present study, a potent PGPR has been isolated from rhizospheric soil of Matla riverbed in mangrove areas of Sundarbans, with simultaneous nitrogen fixing, phosphate solubilizing and plant hormone like indole acetic acid (IAA) producing properties as well as high salt tolerance and hydrocarbon bioremediation abilities. The strain has been identified as Pseudomonas aeruginosa JCM 5962 (NCBI Accession number MK544832.1) on the basis of 16S rRNA analysis. The isolated Pseudomonas aeruginosa strain showed atmospheric nitrogen fixation (3612 ± 2 mg N/ Kg of soil), highest phosphate solubilization index of 3.0 ± 0.06 and 37.14 µg/mL of IAA production. This potent strain also showed salt tolerance upto 7% in culture broth and an uptake of 18.72% of salt. Highest hydrocarbon degradation was shown by this strain in presence of diesel as the sole carbon source. The isolated Pseudomonas aeruginosa strain showed overall improvement in growth of Abelmoschus esculentus (Okra) plants in pot experiments in different conditions like absence of any abiotic stress, presence of 5% salt stress and presence of 1% diesel contaminant. These results indicate that Pseudomonas aeruginosa JCM 5962 can be developed as a potent biofertilizer to be used in agricultural lands of Sundarbans mangrove regions and other areas which are plagued by high salinity and increasing hydrocarbons, particularly petroleum contamination.

Nitrogen uptake, grain yield, and oil concentration of dwarf castor beans under nitrogen rates and inoculation of rhizobacteria in grasses-legumes rotation.

Plant growth-promoting bacteria (PGPB) have been primarily studied for atmospheric nitrogen (N) fixation but they also have the capacity to improve nutrition and yield of crop plants. Therefore, the objective of this research was to investigate the effects of inoculation with PGPB in association with different N rates on N uptake, grain yield, and oil concentration of dwarf castor beans in succession to legumes and grasses in Ilha Solteira, Brazil. The treatments consisted of N rates (0 to 180 kg ha-1 of N) and inoculation with three plant growth-promoting bacteria (Azospirillum brasiliense, Bacillus subtilis, and Pseudomonas fluorescens, applied by leaf) and a control with no-inoculation. The grain and oil yields of castor beans were increased by 20 and 40% at a rate of 103 kg ha-1 of N in succession to grasses as compared to without N application. In addition, the grain yield of castor bean after legumes was increased by 28, 64, and 40% with estimated rates of 97, 113, and 92 kg ha-1 of N in combination with inoculations of A. brasilense, B. subtilis, and P. fluorescens as compared to without N application, respectively. Shoot, grain, and total N uptake were improved with foliar inoculation of A. brasilense, B. subtilis, and P. fluorescens at the N rates of 45, 90, and 135 kg ha-1, respectively. Topdressing of N at the rate of 103 kg ha-1 and foliar inoculation in succession to grasses and 180 kg ha-1 of N without the effect of foliar inoculation in succession to legumes are recommended for higher grain and oil yield of castor beans. Foliar inoculations with A. brasilense, B. subtilis, and P. fluorescens increased grain yield under reduced use of N fertilizer by 44, 37, and 49% in dwarf castor cultivation in succession to legumes, potentially contributing to sustainable agriculture.

The role of FraI in cell-cell communication and differentiation in the hormogonia-forming cyanobacterium Nostoc punctiforme.

The filament-forming cyanobacterium Nostoc punctiforme serves as a valuable model for studying cell differentiation, including the formation of nitrogen-fixing heterocysts and hormogonia. Hormogonia filaments play a crucial role in dispersal and plant colonization, providing a nitrogen source through atmospheric nitrogen fixation, thus holding promise for fertilizer-free agriculture. The coordination among the hormogonia cells enabling uniform movement toward the positive signal remains poorly understood. This study investigates the role of septal junction-mediated communication in hormogonia differentiation and motility, by studying a ΔfraI mutant with significantly impaired communication. Surprisingly, impaired communication does not abolish synchronized filament movement, suggesting an alternative coordination mechanism. These findings deepen our understanding of cyanobacterial biology and have broader implications for multicellular behavior in prokaryotes.

A Review of Plant Growth Promoting Rhizobacteria and Their Characteristics as Potential Biofertilizer

The growing demand for agricultural products for food requirements caused the use of excessive inorganic chemical fertilisers, insecticides, fungicides, and pesticides for a quick and simple way to maximise and boost crop yield. This practice harmed food safety and caused the degradation of environmental, physical, and biological conditions. It has become alarming, and now is the time for a greener approach to increase agricultural output while minimising the use of inorganic chemical fertilisers. It was proven through many previous studies that using environmentally friendly biofertilisers has managed to increase crop yield while reducing the usage of chemical fertilisers. Plant growth-promoting rhizobacteria (PGPR) are mostly used in biofertiliser production because these types of microbes will enhance plant growth and yield by mobilising the available nutrients through several biological mechanisms, including fixation of atmospheric nitrogen, solubilisation, and mobilisation of phosphate and potassium, phytohormones production, disease suppression, and stress protection. Understanding their characteristics, biological mechanisms of action, and the nutritional and physical requirements for growth is important for successfully formulating and applying PGPR as a biofertiliser. The selection of the right PGPR with the desired characteristics, the ability to adapt to the environment, and the ideal formulation of the biofertiliser are the main criteria that should be emphasised when determining the success of biofertiliser. Knowledge and awareness regarding the use, benefits, and production of PGPR as a potential biofertiliser are important and should be explored to fulfil the crop’s nutritional requirements more economically and sustainably.

Assessment of soil-groundwater nitrogen cycling processes in the agricultural region through flux model, stable isotope

The nitrogen cycle in the soil-groundwater system of agricultural land is a crucial process within the global nitrogen cycle. Human activities have significantly intensified this cycling process in agricultural fields, consequently leading to substantial accumulation of nitrogen in the soil-groundwater system and giving rise to numerous ecological health issues. Quantitative assessment of soil-groundwater nitrogen cycling processes can facilitate the optimization of nitrogen management strategies in agricultural fields and the prevention and management of groundwater nitrogen pollution. However, accurately quantifying the intricate soil-groundwater nitrogen cycling dynamics in agro-irrigation areas characterized by diverse nitrogen sources and complex hydrogeological conditions poses a significant challenge. The Songhua River Basin in the Sanjiang Plain was selected as the study area for this investigation. We utilized the INCA-N model to simulate annual nitrogen fluxes in the soil-groundwater system of an agricultural watershed, and employed stable isotope and water chemistry methods to identify sources of groundwater nitrogen contamination and transformation processes. Ultimately, we conducted a comprehensive assessment of nitrogen cycling within the soil-groundwater system of the agricultural watershed. The findings revealed that atmospheric deposition, nitrogen fixation, and fertilization constituted the primary mechanisms of soil nitrogen input. Plant uptake, riverine nitrogen transport, and denitrification were identified as the three principal processes responsible for soil-groundwater nitrogen export. The results obtained from the MIXSIAR model demonstrate a substantial contribution of nitrogen fertiliser and soil nitrogen to groundwater nitrate, followed by faeces and sewage. Additionally, the annual input fluxes of nitrogen simulated by INCA-N reveal that fertiliser application is the primary contributor, which aligns to some extent with the findings of the MIXSIAR model. Soil nitrogen can serve as a relatively stable source of groundwater nitrate, while anthropogenic activities such as fertilizer application, manure deposition, and sewage discharge are likely to be the primary drivers of groundwater nitrate pollution. By quantifying the N input and output fluxes, it was determined that approximately 58% of the total annual nitrogen input has the potential to accumulate within the soil-groundwater system. The effective utilization of legacy nitrogen can contribute to the reduction of soil-groundwater nitrogen fluxes, while maintaining crop yields and mitigating greenhouse gas emissions. This study aims to optimize nitrogen management practices in agricultural areas and provide valuable insights for water conservation strategies.

Novel Bacillus and Prestia isolates from Dwarf century plant enhance crop yield and salinity tolerance

Soil salinity is a major environmental stressor impacting global food production. Staple crops like wheat experience significant yield losses in saline environments. Bioprospecting for beneficial microbes associated with stress-resistant plants offers a promising strategy for sustainable agriculture. We isolated two novel endophytic bacteria, Bacillus cereus (ADJ1) and Priestia aryabhattai (ADJ6), from Agave desmettiana Jacobi. Both strains displayed potent plant growth-promoting (PGP) traits, such as producing high amounts of indole-3-acetic acid (9.46, 10.00 µgml−1), ammonia (64.67, 108.97 µmol ml−1), zinc solubilization (Index of 3.33, 4.22, respectively), ACC deaminase production and biofilm formation. ADJ6 additionally showed inorganic phosphate solubilization (PSI of 2.77), atmospheric nitrogen fixation, and hydrogen cyanide production. Wheat seeds primed with these endophytes exhibited enhanced germination, improved growth profiles, and significantly increased yields in field trials. Notably, both ADJ1 and ADJ6 tolerated high salinity (up to 1.03 M) and significantly improved wheat germination and seedling growth under saline stress, acting both independently and synergistically. This study reveals promising stress-tolerance traits within endophytic bacteria from A. desmettiana. Exploiting such under-explored plant microbiomes offers a sustainable approach to developing salt-tolerant crops, mitigating the impact of climate change-induced salinization on global food security.

Phosphate-solubilizing rhizobacteria and their effects on the growth and phosphorus uptake by wheat plants

Wheat represents a fundamental component of the diet that contributes to ensuring global food security. However, its cultivation faces various abiotic and biotic constraints that result in fluctuating yields. The use of plant growth promoting rhizobacteria (PGPR) with the ability to solubilize phosphate presents itself as an environmentally friendly solution aimed to at enhancing sustainable agriculture practices. The objective of the present study is to assess the potential of PGPR in augmenting both yield and phosphorus (P) levels in wheat plants (Triticum durum L). under semi-controlled environmental conditions. Initially, the strains under investigation were screened for their capacity to dissolve different forms of mineral complex P, along with other plant growth promoting attributes such as iron chelation, Indole acetic acid (IAA) production, nitrogen fixation, and production of exopolysaccharides. Plant response to inoculation with PGPR was studied through an experiment conducted in a greenhouse involving four distinct treatments: (1) Control plants without any inoculation, (2) Inoculation with the PGP27 strain (Rahnella aquatilis), (3) Inoculation with the PGP25 strain (Erwinia persicina), and (4) Inoculation with the PGP374 strain (Raoultella terrigena). Results demonstrated that the studied strains exhibited significant promoting activities, including the solubilization of complex phosphate, the production of exopolysaccharides, IAA, siderophores, and atmospheric nitrogen fixation. Furthermore, the inoculation of plants with PGPR led to an increase in both biomass and plant phosphate concentrations, surpassing those observed in the control group. In conclusion, the findings propose that species like Raoultella and Erwinia have the potential to offer agronomic advantages as rhizobacteria that promote plant growth.

Bioprospecting of endophytic diazotrophic microbes in sustainable agriculture: Review and prospects

Endophytic diazotrophic bacteria play an important role in developing sustainable modern agriculture. Endophytic bacteria can increase plant growth and yield by exhibiting antibiosis against phytopathogens. Biological mechanisms of atmospheric nitrogen fixation, phosphate solubilization, production of phytohormones and inhibition of plant pathogens and pests promote plant growth avoiding the need for chemical fertilizers and control agents. This review evaluates the groups of different endophytic bacteria, their prospects and challenges for sustainable agriculture. Several new bacterial strains were protected as bioinoculants or biopesticides. Formulations containing endophytic bacteria mainly were intended for seed coating or spraying and acted directly in the control of pests and diseases, as well as in increasing resistance to environmental stress. In many cases, they performed well in promoting the growth of plants by producing hormones that regulate or increase nutrient uptake. Bioprospecting in the case of this review is a systematic overview of the rational approach in harnessing beneficial plant-associated microbes to ensure food security in the future.

Green Manure for Sustainable Crop Production: A Review

Green manuring is an economical and eco-friendly scientific approach to achieve more resilient and sustainable food production for agricultural systems. Incorporation of green manure improves soil condition by increasing soil physical, chemical and biological properties such as organic matter, availability of nitrogen, phosphorus and potassium and also improves soil structure by preventing soil erosion, increasing water holding capacity etc. Green manure acts as a natural fertilizer, releasing nutrients into the soil as it decomposes and increases the nutrient content in the soil and shows positive effect on plant growth and development. Addition of green manure crops contribute to greater fixation of atmospheric nitrogen, and when decomposed, makes the nitrogen availability in the soil, reducing the need for synthetic nitrogen fertilizers in crops. Furthermore, it has a significant impact on several plant growth and yield parameters, resulting in increased agricultural productivity and ecosystem health.

Agronomic, Nutritional Traits, and Alkaloids of Lupinus albus, Lupinus angustifolius and Lupinus luteus Genotypes: Effect of Sowing Dates and Locations.

Lupins (Lupinus spp.) are legumes with high relevance for the sustainability of agricultural systems as they improve the soil quality, namely, through the fixation of atmospheric nitrogen, and have good adaptability to different climates and soil conditions. Besides, they possess high nutritive value, especially due to the high protein content of the seeds. Nevertheless, the plants' productivity and metabolism can be influenced by the genotype, the edaphoclimatic conditions, and the sowing practices. In this work, the effect of edaphoclimatic conditions and sowing dates on the productivity, nutritional factors, and alkaloids of the seeds of L. albus cv. Estoril, L. angustifolius cv. Tango, and L. luteus cv. Cardiga was evaluated. High variability in the seeds and protein productions, nutritional traits, and alkaloid content related to the species was observed, along with a significant effect of the location. Lupinus albus cv. Estoril showed a good compromise between productivity and low alkaloid content, being an interesting genotype for food and feed use in the conditions of this trial.

Restoration of soil fertility and improvement of phytosanitary condition of soil in short rotation of crops in Polissia of Ukraine

With the intensification of agricultural land use and changes in natural conditions, soil quality in Ukraine is deteriorating, with a decrease in humus content, the average annual loss of which is about 0.6 t/ha. Therefore, its reproduction is now becoming increasingly important through the use of organic raw materials and the introduction of legumes into the crop rotation, which leads to a partial replacement of nitrogen from mineral fertilisers with biological nitrogen. The purpose of this study was to find ways to provide the topsoil with organic residues, develop soil microflora, and improve the activity of nitrogen-fixing bacteria in a short grain legume crop rotation. The study was conducted in 2019-2023 using the following methods: visual – to determine the stages of organogenesis; field – to determine the interaction of abiotic factors; physiological – to determine the symbiotic fixation of atmospheric nitrogen. It was found that due to mineralisation of organic residues of legume crop rotation, the amount of macro- and microelements in the soil layers 0-10 cm, 10-20 cm, and 20-30 cm increased by 45.1-46.9-43.1 mg/kg, respectively. It was found that saturation of short crop rotation by 50% with legumes, straw residues, and green manure contributed to the reduction of pathogenic microorganisms and the growth of suppressive ones. It was found that in a short rotation of crops, 10.3 t/ha of organic matter in the form of stubble and root residues, straw and green manure enters the soil, which contributed to the cultivation of environmentally friendly agricultural products with the restoration of soil fertility. The biological activity of the soil during the growing season in the layer of 10-20 cm reached 47.4%, and the content of alkaline hydrolysed nitrogen in the rhizosphere of the root system increased by 43.9 mg/kg. The value of the study lies in the fact that the introduction of short organic crop rotations in farms of various forms of ownership is an innovative approach to providing light grey soils with organic raw materials, restoring and maintaining their fertility, improving their phytosanitary condition, promoting biodiversity, achieving environmental sustainability and high yields

Unravelling HetC as a peptidase-based ABC exporter driving functional cell differentiation in the cyanobacterium Nostoc PCC 7120.

The export of peptides or proteins is essential for a variety of important functions in bacteria. Among the diverse protein-translocation systems, peptidase-containing ABC transporters (PCAT) are involved in the maturation and export of quorum-sensing or antimicrobial peptides in Gram-positive bacteria and of toxins in Gram-negative organisms. In the multicellular and diazotrophic cyanobacterium Nostoc PCC 7120, the protein HetC is essential for the differentiation of functional heterocysts, which are micro-oxic and non-dividing cells specialized in atmospheric nitrogen fixation. HetC shows similarities to PCAT systems, but whether it actually acts as a peptidase-based exporter remains to be established. In this study, we show that the N-terminal part of HetC, encompassing the peptidase domain, displays a cysteine-type protease activity. The conserved catalytic residues conserved in this family of proteases are essential for the proteolytic activity of HetC and the differentiation of heterocysts. Furthermore, we show that the catalytic residue of the ATPase domain of HetC is also essential for cell differentiation. Interestingly, HetC has a cyclic nucleotide-binding domain at its N-terminus which can bind ppGpp in vitro and which is required for its function in vivo. Our results indicate that HetC is a peculiar PCAT that might be regulated by ppGpp to potentially facilitate the export of a signaling peptide essential for cell differentiation, thereby broadening the scope of PCAT role in Gram-negative bacteria.IMPORTANCEBacteria have a great capacity to adapt to various environmental and physiological conditions; it is widely accepted that their ability to produce extracellular molecules contributes greatly to their fitness. Exported molecules are used for a variety of purposes ranging from communication to adjust cellular physiology, to the production of toxins that bacteria secrete to fight for their ecological niche. They use export machineries for this purpose, the most common of which energize transport by hydrolysis of adenosine triphosphate. Here, we demonstrate that such a mechanism is involved in cell differentiation in the filamentous cyanobacterium Nostoc PCC 7120. The HetC protein belongs to the ATP-binding cassette transporter superfamily and presumably ensures the maturation of a yet unknown substrate during export. These results open interesting perspectives on cellular signaling pathways involving the export of regulatory peptides, which will broaden our knowledge of how these bacteria use two cell types to conciliate photosynthesis and nitrogen fixation.

Dissolved nitrogen uptake versus nitrogen fixation: Mode of nitrogen acquisition affects stable isotope signatures of a diazotrophic cyanobacterium and its grazer.

Field studies suggest that changes in the stable isotope ratios of phytoplankton communities can be used to track changes in the utilization of different nitrogen sources, i.e., to detect shifts from dissolved inorganic nitrogen (DIN) uptake to atmospheric nitrogen (N2) fixation by diazotrophic cyanobacteria as an indication of nitrogen limitation. We explored changes in the stable isotope signature of the diazotrophic cyanobacterium Trichormus variabilis in response to increasing nitrate (NO3-) concentrations (0 to 170 mg L-1) under controlled laboratory conditions. In addition, we explored the influence of nitrogen utilization at the primary producer level on trophic fractionation by studying potential changes in isotope ratios in the freshwater model Daphnia magna feeding on the differently grown cyanobacteria. We show that δ 15N values of the cyanobacterium increase asymptotically with DIN availability, from -0.7 ‰ in the absence of DIN (suggesting N2 fixation) to 2.9 ‰ at the highest DIN concentration (exclusive DIN uptake). In contrast, δ 13C values of the cyanobacterium did not show a clear relationship with DIN availability. The stable isotope ratios of the consumer reflected those of the differently grown cyanobacteria but also revealed significant trophic fractionation in response to nitrogen utilization at the primary producer level. Nitrogen isotope turnover rates of Daphnia were highest in the absence of DIN as a consequence of N2 fixation and resulting depletion in 15N at the primary producer level. Our results highlight the potential of stable isotopes to assess nitrogen limitation and to explore diazotrophy in aquatic food webs.

A COLLECTION OF INDUSTRIALLY VALUABLE CULTURES OF MICROORGANISMS FOR AGRICULTURAL BIOLOGY

The Engineering and Technological Institute "Biotechnic" of the National Academy of Sciences of Ukraine has collected and preserve the viable collection of microorganisms, which was formed on the basis of expediency and efficiency in the biologization of agriculture. The microbial gene pool of the Collection bacterial and fungal strains of microorganisms that are used in biotechnologies for the production of plant protection products and their quality control. Microbiopreparations with fungicidal, entomocidal, phosphate-mobilizing, nematicidal, cellulolytic, and growth-stimulating properties have been created on the basis of collection microorganisms. The Collection also preserve strains that influenced on the atmospheric nitrogen fixation processes. The great interest present the microorganisms isolated from natural sources of different regions of Ukraine (author's strains), most of which are in studying and accumulating information about them. To determine the biological activity of fungicides, the Collection supports fungal test objects that are the causative agents of diseases of vegetable, grain, fruit and berry crops. The Collection of non-pathogenic microorganisms was created for working in the field of plant protection, as well as for teaching students of biology, biotechnologies, and agronomists. The collection is specialized, therefore the preservation of such unique objects is a priority task, since the losts of collection microorganisms can have negative consequences for the further improvement and development of biotechnology, in particular, the production of microbiological preparations for plant protection using the potential of the Collection. Taking into account all of the above, on November 4, 2022, the collection was entered into the State Register of Scientific Objects, which constitute national property (Resolution of the Cabinet of Ukraine of November 4, 2022, No. 1243).

Spatio-temporal coherence of circadian clocks and temporal control of differentiation in Anabaena filaments.

Circadian clock arrays in multicellular filaments of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 display remarkable spatio-temporal coherence under nitrogen-replete conditions. To shed light on the interplay between circadian clocks and the formation of developmental patterns, we followed the expression of a clock-controlled gene under nitrogen deprivation, at the level of individual cells. Our experiments showed that differentiation into heterocysts took place preferentially within a limited interval of the circadian clock cycle, that gene expression in different vegetative intervals along a developed filament was discoordinated, and that the circadian clock was active in individual heterocysts. Furthermore, Anabaena mutants lacking the kaiABC genes encoding the circadian clock core components produced heterocysts but failed in diazotrophy. Therefore, genes related to some aspect of nitrogen fixation, rather than early or mid-heterocyst differentiation genes, are likely affected by the absence of the clock. A bioinformatics analysis supports the notion that RpaA may play a role as master regulator of clock outputs in Anabaena, the temporal control of differentiation by the circadian clock and the involvement of the clock in proper diazotrophic growth. Together, these results suggest that under nitrogen-deficient conditions, the clock coherent unit in Anabaena is reduced from a full filament under nitrogen-rich conditions to the vegetative cell interval between heterocysts.IMPORTANCECircadian clocks, from unicellular organisms to animals, temporally align biological processes to day and night cycles. We study the dynamics of a circadian clock-controlled gene at the individual cell level in the multicellular filamentous cyanobacterium Anabaena, under nitrogen-stress conditions. Under these conditions, some cells along filaments differentiate to carry out atmospheric nitrogen fixation and lose their capability for oxygenic photosynthesis. We found that clock synchronization is limited to organismic units of contiguous photosynthetic cells, contrary to nitrogen-replete conditions in which clocks are synchronized over a whole filament. We provided evidence that the circadian clock regulates the process of differentiation, allowing it to occur preferentially within a limited time window during the circadian clock period. Lastly, we present evidence that the signal from the core clock to clock-regulated genes is conveyed in Anabaena as in unicellular cyanobacteria.

The elemental composition of Nostoc commune (Cyanoprokaryota) from the Baikal region

We have established concentrations of 32 elements (Ag, Al, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Sr, Ti, V, W, Y, Zn) in the thalloms of the terrestrial algae Nostoc commune from the Baikal region, functioning in the meadow steppe on sod-carbonate soil. Nostoc commune is a widespread species in terrestrial ecosystems, capable of oxygenic photosynthesis and fixation of atmospheric nitrogen. The concentrations of elements in the Nostoc commune from the Baikal region according to the degree of reduction are presented in the following series: Al > Ca > Mg > K > Fe > P > S > Ti > Na > Ba > Sr > Mn > Cr > Zn > V > Li > Ni > Ce > Cu > La > Bi > Sb > W >Y > Pb > Sc > Co > As > Mo > Ag > Be > Cd. High correlations between the content of Ca, Mg, K in the soil and thalloms of the species were revealed.

In Vitro Studies of Endophytic Bacteria Isolated from Ginger (Zingiber officinale) as Potential Plant-Growth-Promoting and Biocontrol Agents against Botrytis cinerea and Colletotrichum acutatum

Agriculture currently confronts a multitude of challenges arising from the excessive utilization of chemical pesticides and the proliferation of phytopathogenic fungi strains that exhibit resistance to commonly employed active compounds in the field. Botrytis cinerea and Colletotrichum acutatum are phytopathogenic fungi that inflict substantial economic losses within agriculture and food due to their high impacts on crops both pre- and post-harvest. Furthermore, the emergence of fungal strains that are resistant to commercial fungicides has exacerbated this problem. To explore more environmentally sustainable alternatives for the control of these pathogens, an investigation into the endophytic bacteria associated with ginger (Zingiber officinale Rosc.) was conducted. The primary focus of this study involved evaluating their inhibitory efficacy against the fungi and assessing their potential for promoting plant growth. The endophytic bacteria genera Lelliottia, Lysinibacillus, Kocuria, Agrococcus, Acinetobacter, Agrobacterium, Zymobacter, and Mycolicibacterium were identified. All isolates showed remarkable in vitro antagonistic ability against B. cinerea (>94%) and C. acutatum (>74%). Notably, the Lelliottia amnigena J29 strain exhibited a notable proficiency in producing extracellular enzymes and indole compounds (IAA), solubilizing phosphate and potassium, and forming biofilm. Furthermore, the Lysinibacillus capsici J26, Agrococcus citreus J28, and Mycolicibacterium sp. J5 strains displayed the capacity for atmospheric nitrogen fixation and siderophore production. These findings underscore the agricultural and biotechnological potential of endophytic bacteria derived from ginger plants and suggest the feasibility of developing alternative approaches to manage these two phytopathogenic fungi.

Legume-cereal intercropping as a strategy of regenerative agriculture supporting reverse of biodiversity loss - relevance of microbiome-based research

Adverse environmental impacts connceted with high chemicals and fertilizers use is one of the causes of biodiversity loss. Therefore, there is a need to looking for more natural and non-hazardous alternative approaches to make agriculture more sustain. The legume-cereal intercropping is currently one of the „hot topics” in the area of sustainable and regenerative agriculture. These intercropping practices are increasingly gaining attention as a way for enhancing soil ecosystem services and reversal biodiversity loss, as well as as a strategy of harnesing plant yield quality and soil health. Legume-cereal systems are the most common intercropping combinations used in sustainable agriculture models because of their noncompeting niche requirements and atmospheric nitrogen fixation which improve a balance of this nutrient in soil and plant and decrease the amount of mineral fertilizers use. However, conventional crop rotations in the EU are largely dominated by cereals while legume cultivation has declined in recent years. The idea of the LEGUMINOSE project includes that multi-species assemblages of plants deliver rhizosphere functions that are greater than the sum of the functions delivered by the rhizospheres of individual plants growing alone as a monoculture. We hypotheses that the higher plant diversity in intercropping will increase plant health, improve soil biodiversity and reduce the use of pesticides in agroecosystems. However ther is a knowledge gap concerning plant-soil-microbe interactions under root exudation from single and diverse plant assemblage and role of soil microbiomes in soil ecosystem functionality and plant production. Therefore we will focus on understanding these interactions by the microbiome research of soil and plant niches, including bulk soil, rhisozphere, roots and shoots of cereal and legume plants in order to assess the percentage of microbiota transfered between them within monocropping and intercropping fields and understand relationships of that microbiomes in plant health improvement. This project will design and implement sustainable environmental practices based on legume-cereal intercropping systems that account for the nature, impacting to global biogeosphere changes. Research funded in the frame of Horizon Europe Programme, agreement no. Project 101082289 — LEGUMINOSE.

Influence of biologisation of the nutrition system on the transformation of biological nitrogen and formation of soybean productivity

Rising prices for mineral fertilisers stimulate the search for alternative ways to optimise the existing and develop new technological methods of growing crops, including soybeans. One of these approaches is the intensive use of biological ways to enhance the ability of legumes to symbiosis and natural fixation of biological nitrogen from the soil air, which will help reduce the cost of plant cultivation technology. That is why the purpose of this study was to determine the effect of biological preparations on atmospheric nitrogen fixation by soybean plants using symbiotic nodule bacteria. In these studies, the method of calculation based on active symbiotic potential and symbiotic specific activity was used to determine the amount of biologically fixed nitrogen. The study analysed the effect of some inoculants and biofertilisers intended for foliar application on the development and formation of symbiotic processes in soybean plants, namely, the specific features of the formation of both general and active symbiotic potential in the vegetation stages. The influence of symbiotic productivity on soybean grain yield was also determined. Treatment of seeds with the selected preparations for the entire period of symbiosis duration provided an increase in the total symbiotic potential and active symbiotic potential. It was found that the treatment of seeds with the inoculant Bioinoculant BTU (2 l/ha) before sowing was more productive. Therewith, the maximum soybean grain yield of 3.31 t/ha was recorded in areas where the preparation Bioinoculant BTU (2 l/t) was treated before sowing and two fertilising applications were made in the 3rd ternate leaf stage and in the budding stage with Helprost soybean fertiliser (2.5 l/ha). The findings of this study indicate a substantial impact of symbiotic productivity and its value on soybean grain yield. Correlation and regression analyses showed that the accumulation of biological nitrogen has a considerable impact on grain yield. Thus, the use of biological preparations is an alternative to mineral fertilisers in soybean cultivation technology and they can be implemented in the production conditions of agricultural enterprises

Fluctuation in redox conditions and the evolution of early Cambrian life constrained by nitrogen isotopes in the middle Yangtze Block, South China

AbstractThe Ediacaran–Cambrian (E-C) transition (∼542–517 Ma) witnessed the rapid evolution of Cambrian animals, which was accompanied by carbon cycling anomalies and a significant increase in the concentration of oxygen in Earth’s atmosphere. The mechanisms stimulating the evolution of complex eukaryotes, however, remain problematic, especially concerning the link between biological evolution and contemporaneous changes in the oceanic environment. In this study, integrated δ13Ccarb–δ13Corg–δ15N compositions were analysed from the YD-4 core samples to understand redox fluctuations and nitrogen cycling of the middle Yangtze Block across the E-C transition. Two negative δ13Ccarb excursions (N1 and N2) and a positive δ13Ccarb excursion (P1) are identified from the studied samples and are supposedly of primary origin. Constrained by of the U-Pb age, biolithology and pattern of isotopic variation, N1, P1 and N2 are comparable to the Basal Cambrian Carbon Isotope Excursion (BACE), Zhujiaqing Carbon Isotope Excursion (ZHUCE) and Shiyantou Carbon Isotope Excursion (SHICE). We interpreted the decreased δ15N values in this study as resulting from intensified atmospheric nitrogen fixation driven by enhanced denitrification associated with expanded marine anoxia, as well as partial ammonium assimilation, while increased δ15N values suggest weakened denitrification associated with an amplified oxic water mass. The temporal coincidence of N1 and N2, with two episodes of negative δ15N excursions, and of P1, with a positive δ15N excursion, suggests that variable oceanic redox conditions and nitrogen bioavailability may have influenced the evolution of the Cambrian eukaryote-dominated community.