Plant Microorganisms Research Articles

Characterization of Pseudomonas bacteria of Piper tuberculatum regarding the production of potentially bio-stimulating compounds for plant growth

ABSTRACT Despite advances in the identification and characterization of endophytic bacteria in various plant species worldwide, little is known about such microorganisms in plants from the Amazon region. Previous studies reported that Piper tuberculatum endophytic Pseudomonas (isolates Pt12 and Pt13, identified as Pseudomonas putida and Pseudomonas sp., respectively) were able to inhibit the in vitro growth of Fusarium solani f. sp. piperis, which causes root rot in black pepper (Piper nigrum), and that Pt13 promoted the growth of P. nigrum. Therefore, the aim here was to characterize these bacteria regarding their ability to produce plant growth-promoting substances [siderophores, indol acetic acid (IAA) and soluble phosphate]. Chrome azurol S assays were performed for the detection of siderophores. For qualitative and quantitative assays of IAA production and phosphate solubilization, Salkowski´s reagent and NBRIP medium with molybdenum blue reagent, respectively, were used. Results revealed that Pt12 and Pt13 were able to synthesize IAA, mainly under a high concentration of L-tryptophan, indicating that they are IAA-producing bacteria, probably through a tryptophan-dependent biosynthesis pathway. The presence of P. nigrum extract positively influenced the IAA production by Pt12 and Pt13, with highest values of 125 and 90 µg mL-1, respectively. In addition, Pt12 was positive for the production of siderophores and produced 56.56 µg mL-1 of soluble phosphate. In contrast, Pt13 showed no ability to produce siderophores or to solubilize phosphate. Besides their potential in controlling plant diseases, Pt12 and Pt13 have potential as biofertilizers, favoring sustainable agriculture.

Creation of novel barley germplasm usingan <italic>Epichloë</italic> endophyte

Plant-endophyte associations play important roles in grassland agricultural ecology. Many studies indicate that endophytic fungi can promote host growth and reduce the biotic and abiotic stresses of host plants. Epichloe endophytes of the family Clavicitaceae are fungal symbionts of Pooideae grasses. These endophytes usually do not express any obvious host symptoms. Many Epichloe endophytes can endow hosts with increased abiotic stress tolerance as a result of enhanced growth, tillering, reproduction and nutrient acquisition, particularly under conditions of drought, cold, salt and nutrient deficiencies and thus, have important roles in pastoral agricultural systems. Animal-safe grass-endophyte associations that confer bio-protective properties for increased pasture persistence and productivity have been developed and commercialized. Artificial inoculation with symbiotic Epichloe microbes is an important technique for the creation of novel germplasm. Selected Epichloe strains can add value to some grass-based forage systems by providing both biotic and abiotic stress resistance. In addition, they can improve and strengthen grass physiological functions and plant vigor. The Epichloe bromicola WBE1 endophyte of Hordeum brevisubulatum played an important role in maintaining the growth of host grass by promoting nutrient absorption and maintaining the ionic balance under salt stress. E. bromicola WBE1 can produce peramine, an alkaloid produced by Epichloe species, that protects host grasses from herbivorous insects. However, this strain was unable to synthesize the alkaloids that are toxic to livestock, such as ergine, ergonovine, ergovaline or lolitrem B. Barley ( Hordeum vulgare ) is one of the most important cereal crops. The importance of barley to human and animal nutrition, and indeed to the foundation and maintenance of human civilization, is well documented. Traditional barley breeding for improved environmental stress tolerance has resulted in good varieties. However, conventional breeding techniques neglect the microorganisms in plants. In this study, animal-safe endophytic E. bromicola WBE1 isolated from wild barley ( H. brevisubulatum ) was artificially inoculated into cultivated hulled barley ( H. vulgare cv. Yangsimai No. 1) and hull-less barley ( H. vulgare var. nudum cv. Chaiqing No. 1), creating novel barley germplasm. Plants that were inoculated with endophytes and those that were free of endophytes were evaluated for growth in the field. The plant height, tiller numbers, biomass and the grain weight per plant of endophyte-inoculated hulled barley plants (Yangsimai No. 1) were 5%, 20%, 46% and 22% higher than those of the control hulled barley plants, respectively, and they matured about 5 days earlier. The tiller numbers, biomass and grain weight per plant of endophyte-inoculated hull-less barley plants (Chaiqing No. 1) were 29%, 37% and 28% higher, respectively, than those of the control hull-less barley plants in the field. However, there was no significant difference between inoculated hull-less barley plants and control hull-less barley plants in the plant height and growth period. A novel germplasm of barley containing the endophyte was successfully created. E. bromicola improves plant characteristics and the growth of host. The results presented here provide evidence that the inoculation of barley with E. bromicola may be used to improve its germplasm. E. bromicola can be successfully inoculated into other phylogenetically close host species, and this technique has the potential to improve the growth of Hordeae cereal crops and serve as a broad application to produce agriculturally useful synthetic novel symbioses in germplasm.

Trichoderma in the promotion of growth and nutrition of dwarf cashew rootstock

Inoculation of microorganisms in plants performs important functions related to plant growth and nutrition. The responses are based on hormonal stimulation and improved absorption and efficiency in the use of nutrients. Thus, the objective of this study was to evaluate the ability of Trichoderma strains (T. longibrachiatum and T. asperellum) to promote growth and improve the nutrition in dwarf cashew rootstock. The experiment was conducted in a shade net house with 50% of shading located in the Experimental Field of Pacajus, belonging to Embrapa Agroindustria Tropical, in Pacajus/CE, Brazil. The experimental design used was completely randomized, with three treatments and ten replicates. Each experimental unit consisted of a tube with a 288 cm3 capacity containing one seedling of dwarf cashew. At sixty days (60) after germination, the plants were evaluated for biometric parameters, Dickson’s quality index, and nutritional diagnosis of leaves. To verify the growth-promoting mechanisms, the strains were reisolated by indirect plating of roots. Nutrient accumulation in the leaves was not influenced by the application of the isolates; however, the seedlings were adequately supplied. The strains showed similarities in relation to growth-promotion mechanisms. The Trichoderma longibrachiatum strain promoted an increase in the growth, so its use as a supplement for the planting substrate is recommended.

Актиномицеты как основа пробиотиков для растений

The present review describes the concept of probiotics for plants and analyzes the prospects for using actinomycetes as producers of these drugs. The minimum requirements for plant probiotic microorganisms are proposed, similar to those for human probiotic microorganisms. These are utility, efficiency and safety for plants, as well as mandatory isolation from plant samples. It is noted that these requirements are usually met by endophytic and rhizosphere microorganisms that stimulate plant growth and provide them with protection from phytopathogens. Evidence is given for the possibility of attributing actinomycetes to probiotic plant bacteria, due to the close relationship of these microorganisms with plants, their wide distribution in populations of endophytic and rhizosphere microorganisms, and the presence of phytoregulatory activity. The review provides examples of genera and species of actinomycetes that are promising producers of probiotics for agronomically important crops. The most studied and commercialized of them are representatives of the Streptomyces genus. The current state, prospects and problems in commercialization of probiotics based on actinomycetes are discussed. probiotic microorganisms of plants, associative actinomycetes, endophytes, rhizosphere, biological preparations

The applications of medical thermography in alfitherapy

Recently, medical thermography has attracted more and more attention from physicians and physiologists, especially in the study of complex diseases. Thermograms show the distribution of thermal fields, corresponding or not corresponding to normal thermography of specific areas. The presence of a pathological thermal picture indicates a certain pathology. Medical thermography makes it possible to conduct an examination in a short time (5-10 minutes) with the construction of accurate heat maps and is a safe method of primary diagnosis. Infrared thermal mapping provides a study of the development of a thermoactive process in time, which increases the diagnostic capabilities of the method, especially in the early stages of disease development. The aim of this work is to study the possibilities of medical thermography in the treatment of malignant meningioma by the method of alfitherapy. Alphitherapy (algo – algae, phyto– plants) is a direction in medicine, veterinary medicine, cosmetology, which is distinguished by the fact that it allows you to completely restore the entire body and get rid of hormonal, chronic, acute and concomitant diseases due to a proper balanced diet, which consists of algae, plants, macro- and microelements, vitamins with the presence of plant microorganisms. The data obtained as a result of many years of research indicate that alpha drugs contain a rich set of biologically active substances with versatile pharmacological activity, which are successfully used to treat a wide range of cardiovascular and oncological diseases, injuries and other health disorders. The results of application of the method of medical thermography in alfitherapy based on the portable thermograph IRTIS-2000 ME are presented. A patient was considered whose results of thermographic examination revealed malignant meningioma (brain cancer). As a result of the use of the alfitherapy method, the malignant meningioma was completely cured without surgery. A description of the biological mechanisms of alfitherapy and alfitherapeutic action for the treatment of cardiovascular and oncological diseases is given. The areas of application of medical thermography in medical diagnostics are presented. It has been shown that the use of medical thermography allows non-invasive primary diagnostics and monitoring of the state of human health, and alfitherapy allows effective non-surgical restoration of the whole organism, regardless of nosology.

Impact of management of cover crop–soybean agroecosystems on rhizosphere microbial communities

AbstractKnowledge of the rhizosphere and use of quality microbial bioinputs are tools to achieve agricultural sustainability. The impact of management of cover crop–soybean agroecosystems on rhizosphere microbial communities was evaluated. A field experiment in a randomized complete block design with factorial arrangement in sub‐divided plots was performed. Effects of fertilization (0 and 45 kg·ha−1), oats, rye and control without cover crops, plant growth promoting rhizobacteria (PGPR) co‐inoculation of Azospirillum brasilense and Pseudomonas fluorescens, and three sampling times on microbial counts, community‐level physiological profiles (CLPP) and terminal restriction fragment length polymorphism (T‐RLFP) were studied. CLPP were drastically changed at three sampling times: before glyphosate, after glyphosate and at soybean harvest. Before glyphosate application, the interaction between PGPR inoculation and coverage treatments modified the functional and structural profiles of the rhizosphere microbial communities. Furthermore, the highest microbial counts and the greatest functional diversity indices were observed before glyphosate application but significantly decayed after glyphosate application and at soybean harvest, showing a permanent impact of glyphosate application on the rhizosphere microbial community functionality, which was confirmed with several statistical analyses. For the cover crop–soybean agroecosystems, we can conclude that the rhizosphere microbial communities showed high sensitivity to glyphosate. PGPR inoculation only increased the aerial biomass of rye at the jointing and grain‐filling stages. Inoculated plants without fertilization and non‐inoculated plants with fertilization showed similar aerial biomass production of this crop. This work demonstrates that different management decisions can change plant–microorganism relationships in the rhizospheres of cover crops and impact aboveground biomass production. A better understanding of microbial ecology will allow the sustainable use of available resources.Highlights A field experiment was conducted using oats and rye as cover crops in succession with soybean. Management decisions changed plant–microorganism relationships and impact on microbial ecology. Management of cover crops with glyphosate had negative impacts on rhizosphere microbial communities. Co‐inoculation with Azospirillum brasilense and Pseudomonas fluorescens increased the aerial biomass production of rye.

Effect of extracts of amazonian bee propolis on Xanthomonas axonopodis pv. passiflorae in the State of Pará-Brazil

The yellow passionfruit (Passiflora edulis Sims f. flavicarcarpa Deg.) is important culture in Brazilian Amazon agriculture, especially in the state of Pará. But its cultivation has been suffering the reduction of its areas and productivity due the diseases caused by bacteria, where chemical control, sometimes does not present the expected results. The propolis of Africanized bees (Apis mellifera L.) is an important natural antibiotic for the control of undesirable microorganisms of plants and animals. The present work aimed at the in vitro study of the antibiotic activity of different propolis extracts of Africanized bees from two different locations in the state of Pará in the agent that causes the passionfruit bacterial blight (Xanthomonas axonopodis pv. passiflorae). A factorial analysis of three factors was performed: origin X solvent X concentration. It was verified that the concentrations of 0.5% were statistically superior to the others, with average growth inhibition power of 86%, and the propolis extract from an apiary in Santa Izabel do Pará, Pará, Brazil, obtained in ethanol at 80%, was statistically different and superior for the inhibitory effect of the growth of colony forming units (CFU) of X. axonopodis pv. passiflorae.

Effects of Heavy Metal Contents on Phyllosphere and Rhizosphere Fungal Communities for Bothriochloa ischaemum in Copper Tailings Area

There are complex interrelationships between plant microorganisms (phyllosphere and rhizosphere) and host plants, which can promote plant growth and enhance the tolerance of host plants to stress. In this study, we selected the dominant species Bothriochloa ischaemum as the research subject in a copper tailings dam. Using high-throughput sequencing, we investigated the structures of the fungal communities and diversities in the phyllosphere and rhizosphere of B. ischaemum. This study also explored the effects of heavy metal content on fungal community characteristics. The results showed that Ascomycota and Basidiomycota were the dominant phyla in the phyllosphere and rhizosphere of B. ischaemum. The diversities and richness of the rhizosphere fungal community were higher than that of the phyllosphere fungal community. The diversities of rhizosphere and phyllosphere fungal communities was affected by different heavy metals. Phyllosphere fungal diversity was mainly affected by the content of Zn and Cu in leaves, and the content of Pb in roots was the key factor affecting the diversity of the rhizophere fungal community. Furthermore, Pleosporaceae had a very significant positive correlation with Cd in the phyllosphere, and Nectriaceae had a significant positive correlation with Zn in the rhizosphere. These fungal communities could be used as indicators of ecological recovery in areas with heavy metal pollution. The results could provide an ecological basis for the exploration and utilization of phyllosphere or rhizosphere fungi resources during ecological restoration processes. This study also provides guidance for selecting the plant-microbial symbionts during ecological restoration in areas with heavy metal pollution.

Simultaneous occurrence and analysis of both anammox and n-damo bacteria in five full-scale wastewater treatment plants

Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) processes are two newly discovered biochemical pathways for removal of reactive nitrogen species and methane. An investigation was initiated to investigate the simultaneous removal of ammonium and methane and the corresponding microorganisms in a full-scale sewage treatment plant and four landfill leachate treatment plants. In this study, hzsB and pmoA genes were used to amplify the genomic DNA of these samples to reveal the diversity of anammox bacteria and n-damo bacteria in these WWTPs. Both anammox bacteria and n-damo bacteria were detected successfully in all samples. The hzsB gene-based PCR amplified sequences featured three genera of Candidatus (Ca.) Brocadia, Ca. Kuenenia and Ca. Jettenia in these WWTPs, while the pmoA gene amplification showed two species of Ca. Methylomirabilis oxyfera and Ca. Methylomirabilis sinica. It was observed that after inoculation of anammox sludge, Brocadia becomes more dominant from the initial co-existing consortium of Kuenenia and Brocadia, and the community diversity decreased accordingly. Based on quantitative 16S rRNA gene PCR, the abundance of anammox bacteria ranged from 2.64 × 106 to 1.73 × 1013 copies per gram dry sludge in the five plants, particularly high on the carriers of landfill leachate wastewaters and the abundance of n-damo bacteria ranged from 2.52 × 107 to 2.19 × 108 copies per gram dry sludge in the five plants. Results shows that abundances of anammox bacteria and AOB (ammonium oxidizing bacteria) were limited by the lower ammonium in the sewage treatment plant, but were higher corresponding to ammonium concentration. Successful inoculation of anammox bacteria was achieved in practical engineering systems and the co-occurrence of anammox bacteria and n-damo bacteria plays an important role in N and C removal in WWTPs.

Pinewood Nematode Alters the Endophytic and Rhizospheric Microbial Communities of Pinus massoniana.

Pinewood nematode, Bursaphelenchus xylophilus, is one of the greatest threats to pine trees and is spreading all over the world. During the nematode's pathogenesis, plant microorganisms play important roles. However, many microbial communities, such as that in Pinus massoniana, a major host of B. xylophilus that is widely distributed in China, are not well studied, especially the fungal communities. Here, the endophytic and rhizospheric bacterial and fungal communities associated with healthy and B. xylophilus-infected P. massoniana were analyzed. The results showed that 7639 bacterial and 3108 fungal OTUs were annotated from samples of P. massoniana, the rhizosphere, and B. xylophilus. There were significant diversity differences of endophytic microbes between healthy and infected P. massoniana. The abundances of endophytic bacteria Paenibacillus, unidentified_Burkholderiaceae, Serratia, Erwinia, and Pseudoxanthomonas and fungi Penicillifer, Zygoascus, Kirschsteiniothelia, Cyberlindnera, and Sporothrix in infected pines were greater than those in healthy pines, suggesting an association of particular microbial abundances with the pathogenesis of B. xylophilus in pines. Meanwhile, the abundances of microbes of unidentified_Burkholderiaceae, Saitozyma, and Pestalotiopsis were greater and Acidothermus and Trichoderma were lower in the rhizosphere under infected pines than those under healthy pines and the differences might be caused by B. xylophilus-induced weakening of the health of pines. Our study explored the endophytic and rhizospheric microbial community changes potentially caused by B. xylophilus infection of pines.

Comparing in vivo data and in silico predictions for acute effects assessment of biocidal active substances and metabolites for aquatic organisms

The purpose of this study was to determine the acute toxicity in aquatic organisms of one biocidal active substance and six metabolites derived from biocidal active substances and to assess the suitability of available QSAR models to predict the obtained values. We have reported the acute toxicity in sewage treatment plant (STP) microorganisms, in the freshwater microalgae Pseudokirchneriella subcapitata and in Daphnia magna following OECD test methods. We have also identified in silico models for acute toxicity of these trophic levels currently available in widely recognized platforms such as VEGA and the OECD QSAR ToolBox. A total of six, four and two models have been selected for Daphnia, algae and microorganisms, respectively. Finally, we have compared the in silico and in vivo data for the seven compounds plus two previously assayed biocidal substances. None of the compounds tested were toxic for Daphnia and STP microorganisms. For microalgae, CGA71019 (1,2,4 triazole) presented an ErC50 value of 38.3 mg/L. The selected in silico models have provided lower EC50 values and are therefore more conservative. Models from the OECD QSAR ToolBox predicted values for 7 out of 9 and for 4 out of 9 chemicals for Daphnia and P. subcapitata, respectively. No predictive models were identified in such platform for STP microorganism's acute effects. In terms of models's specificity, biocide-specific models, developed from curated datasets integrated by biocidal active substances and implemented in VEGA, perform better in the case of microalgae but for Daphnia an alternative, non biocide-specific has revealed a better performance. For STP microorganisms only biocide-specific models have been identified.

WWTP Effluent Quality Improvement for Agricultural Reuse Using an Autonomous Prototype

Wastewater reuse presents a promising way to mitigate the risk to global water resources and achieve sustainability in water, especially in agricultural areas in the southeast of Spain, such as the Murcia region. However, the risks related to the presence of contaminants of emerging concern (CECs) or pathogenic microorganisms in wastewater treatment plant (WWTP) effluent suggest the need to implement effective and relatively low-cost tertiary treatments. With this aim, a self-sustainable pilot prototype based on three combined modules (disc-filtration, granular activated carbon (GAC) bed adsorption and UV disinfection) assisted by solar panels was installed as an alternative tertiary treatment in a conventional WWTP in the Murcia region. The obtained results clearly confirmed the efficiency of the proposed prototype for CECs removal, and showed optimal results at a workflow of 500 L/h. In all cases, high removal efficiency was obtained for the different indicator microorganisms described in the recently published Regulation (EU) 2020/741 (E. coli, F-specific coliphages, somatic coliphages, total coliphages, and Clostridium perfringens). The protection of the activated carbon by disc-filters and the energy autonomy and self-operation of the prototype resulted in an efficient and economically viable methodology for its implementation in both conventional WWTPs and in isolated areas attached to crops.

Remediation of vanadium contaminated soil by alfalfa (Medicago sativa L.) combined with vanadium-resistant bacterial strain

Abstract Vanadium (V) in soils exerts toxic effects on human health. To develop a plant–microorganism combined remediation strategy for V-contaminated soil, pot experiments were conducted with alfalfa (Medicago sativa L.) and V-resistant bacterial strain Arthrobacter sp. 5k4-8-1 in different levels of V-contaminated soil. At 500 mg kg − 1 spiked V(V), alfalfa survived only in the soils inoculated with high-level bacterial strain (1010 CFU mL − 1 , 15 mL), indicating that strain 5k4-8-1 worked effectively on alleviating the stress of V on plant growth. Compared with non-inoculated controls, the V accumulation in alfalfa plants was increased conspicuously by inoculation of strain 5k4-8-1. After the remediation process by the combination of strain 5k4-8-1 and alfalfa, the proportion of V(V) in total V decreased in all soils, indicating that the strain may possess a mechanism of reducing V(V) to V(IV). Moreover, the strain 5k4-8-1 led to an obvious reduction of soil V bioavailability and mobility in inoculation treatments. These results provide insights into the plant–microorganism combined bioremediation of V-contaminated soil.

Chemotactic Host-Finding Strategies of Plant Endoparasites and Endophytes.

Plants interact with microorganisms in the environment during all stages of their development and in most of their organs. These interactions can be either beneficial or detrimental for the plant and may be transient or long-term. In extreme cases, microorganisms become endoparastic or endophytic and permanently reside within a plant, while the host plant undergoes developmental reprogramming and produces new tissues or organs as a response to the invasion. Events at the cellular and molecular level following infection have been extensively described, however the mechanisms of how these microorganisms locate their plant hosts via chemotaxis remain largely unknown. In this review, we summarize recent findings concerning the signalling molecules that regulate chemotaxis of endoparasitic/endophytic bacteria, fungi, and nematodes. In particular, we will focus on the molecules secreted by plants that are most likely to act as guidance cues for microorganisms. These compounds are found in a wide range of plant species and show a variety of secondary effects. Interestingly, these compounds show different attraction potencies depending on the species of the invading organism, suggesting that cues perceived in the soil may be more complex than anticipated. However, what the cognate receptors are for these attractants, as well as the mechanism of how these attractants influence these organisms, remain important outstanding questions. Host-targeting marks the first step of plant—microorganism interactions, therefore understanding the signalling molecules involved in this step plays a key role in understanding these interactions as a whole.

Towards Better Understanding of the Interactions and Efficient Application of Plant Beneficial Prebiotics, Probiotics, Postbiotics and Synbiotics.

It is well known that a gram of soil contains thousands of individual microbial taxa including bacteria, fungi, protists, oomycetes and viruses. Many of them play the main role in ecosystem functioning determining soil fertility and provide plant growth promotion and disease suppression, (van der Heijden et al., 2008; Glick, 2012; Serna-Chavez et al., 2013; Maron et al., 2018). However, after many years of chemical fertilization, soils lost their natural fertility, plant diversity and microbial richness (Huang et al., 2019). In addition, an increasing number of stress factors are observed such as salinity, alkalinity/acidity, contamination, nutrient deficiency or overload of chemical fertilizers, drought, soil erosion due to climate change, and various biotic factors (Fitzpatrick et al., 2019). The use of plant beneficial microorganisms (PBM) to mitigate these 0problems in cultivated crop production is now a common practice particularly in the modern, sustainable agriculture and in the context of increasing world population and environmental and climate concerns (Shilev et al., 2019). During the last 20–30 years, a large number of microorganisms have been isolated, characterized and tested as biofertilizers and biocontrol agents in controlled and natural conditions. The results confirmed the beneficial effect of the selected microorganisms on plant growth and health, enhancing nutrient content and improving soil properties. Now, the emphasis of the scientific activity in the field of microbial inoculants is on developing environmentally friendly and efficient microbial formulations and analyse how the introduced microorganisms affect microbial community, diversity, and the specific plant–microorganisms interactions, which determine the plant holobiome functioning (Berg et al., 2017). Therefore, at this moment, at least two major lines of research can be distinguished: the first one deals with holobiome/hologenome studies including molecular mechanisms and genetic regulation (and epigenetic mechanisms) of beneficial microbiota (Corbin et al., 2020) and, another important line of research on the process of establishing a plant beneficial microbiome includes development of efficient single or multiple microbial inoculants. A combination of pro- and postbiotics could be applied to manage and stimulate the existing beneficial microbiome.

A new combined electrocoagulation-electroflotation process for pretreatment of synthetic and real Moquette-manufacturing industry wastewater: Optimization of operating conditions

Abstract Moquette-manufacturing industry produces wastewaters containing high-concentrations of polyvinyl acetate (PVAc), which is highly toxic and can inhibit the activity of microorganisms in biological wastewater treatment plants. In the present study, a new combined electrocoagulation-electroflotation process was used to treat the high organic load wastewater of the moquette manufacturing industry. For this purpose, the efficiency was evaluated on the basis of the removal of chemical oxygen demand (COD), total suspended solid (TSS), PVAc, total dissolved solid (TDS) and electrical conductivity (EC) from the synthetic and real wastewater. The results showed that process efficiency increased with increasing current density (CD) and retention time and with decreasing electrode distant. Under the optimum conditions (electrode distance =1 cm, reaction time = 20 min, pHo = 7, CD = 22 mA/cm2), the removal efficiencies of COD, TSS, PVAc, TDS and EC for the synthetic and actual wastewater were 84.8, 81.9, 91.6, 68.7 and 76.4 and 93.9, 92.9, 95.9, 90.5 and 85 %, respectively. In addition, the iron electrode is preferred to the aluminum electrode because of its higher efficiency, lower cost and lower electrical energy consumption. It was found that this process facilitated the floatation and compaction of the flocs at the surface of the electrochemical reactor and finally eliminated the need for the sedimentation/flotation unit.

Bifunctional Inhibitors from Capsicum chinense Seeds with Antimicrobial Activity and Specific Mechanism of Action Against Phytopathogenic Fungi.

Antimicrobial peptides (AMPs) are found in the defense system in virtually all life forms, being present in many, if not all, plant species. The present work evaluated the antimicrobial, enzymatic activity and mechanism of action of the PEF2 fraction from Capsicum chinense Jack. seeds against phytopathogenic fungi. Peptides were extracted from C. chinense seeds and subjected to reverse-phase chromatography on an HPLC system using a C18 column coupled to a C8 guard column, then the obtained PEF2 fraction was rechromatographed using a C2/C18 column. Two fractions, named PEF2A and PEF2B, were obtained. The fractions were tested for antimicrobial activity on Colletotrichum gloeosporioides, Colletotrichum lindemuthianum, Fusarium oxysporum and Fusarium solani. Trypsin inhibition assays, reverse zymographic detection of protease inhibition and α-amylase activity assays were also performed. The mechanism of action by which PEF2 acts on filamentous fungi was studied through analysis of membrane permeability and production of reactive oxygen species (ROS). Additionally, we investigated mitochondrial functionality and caspase activation in fungal cells. It is possible to observe that PEF2 significantly inhibited trypsin activity and T. molitor larval α-amylase activity. The PEF2 fraction was able to inhibit the growth of C. gloeosporioides, C. lindemuthianum and F. oxysporum. PEF2A inhibited the growth of C. lindemuthianum (75%) and F. solani (43%). PEF2B inhibited C. lindemuthianum growth (66%) and F. solani (94%). PEF2 permeabilized F. solani cell membranes and induced ROS in F. oxysporum and F. solani. PEF2 could dissipate mitochondrial membrane potential but did not cause the activation of caspases in all studied fungi. The results may contribute to the biotechnological application of these AMPs in the control of pathogenic microorganisms in plants of agronomic importance.

Microbiome structure and function in rhizosphere of Jerusalem artichoke grown in saline land

The improvement and development of saline-alkali soils is currently a hot economic and scientific issue, and exploring the correlation between rhizosphere microorganisms of plants growing on saline-alkali soils and their salt tolerance has become the key point of related research. In our study, the community structure of microorganism and various properties of saline soils were characterized in which Jerusalem artichoke grown along a soil salinity gradient. A variety of basic soil properties were measured and the amplicon was performed as well as metagenomic sequencing on coastal saline soils using various techniques (such as RDA analysis and the assembly of genomes) to evaluate microbial functions. In addition, WGCNA (Weighted gene coexpression network analysis) method was used to identify the species related to salt stress and the sequence binning to assemble two enriched putative bacterial genomes. The research showed the cultivation of Jerusalem artichoke on saline soil changed soil physico-chemical and enzymatic properties; most of the rapidly changing as well as the long-term stable properties differed significantly between the rhizosphere and bulk soils. The amplicon and metagenomic sequencing revealed the function and structure of microorganisms varied between the rhizosphere and bulk soils, with greater microbial diversity in the rhizosphere. Catalase activity and the moisture content were the factors with the greatest impact on microorganisms. The putative genomes of two species of microorganisms (belong to Nitrospira and Gemmatimonas) were assembled, identified microbial species that were highly responsive to salt stress and that may play a key role in saline soil, stressed the important role of archaea in microbial communities in response to salt stress. The study provides a comprehensive understanding of the microbial community structure in the rhizosphere of Jerusalem artichoke to enable the improvement and economic development of saline land.

Potential local microorganisms of local plants as a source of probiotics for livestock

The use of antibiotics as a growth promotor in livestock in Indonesia has been banned since January 2018 due to the negative effects of antibiotic resistance. Therefore, this study was conducted aiming to obtain the potential of natural probiotics derived from local plants as an alternative of antibiotics. This study used materials in the form of roots and leaves that exist on the coast, in plantation areas, and in mountainous areas. The coastal area is the crown flower (Calotropis gigantean Dryand), in the plantation area is the fern plant (Nephrolepis biserrata), and in the mountainous area is the citronella plant (Cymbopogon nardus). Plant parts taken are roots and leaves. Each part of the roots and leaves was chopped by 1-2 cm, then as much as 1 kg of material soaked in 4 l of water containing 100 grams of sugar and then stored at room temperature for 21 days in a closed container. This research was conducted in vitro. The parameters measured were physical, namely odor, chemical in the form of pH and total acid, and microbiology, namely total lactic acid microbes. The data obtained were analyzed descriptively and displayed in the form of figures and tables. The results showed that all materials were seen from the physical odor that smelled rather acidic, chemically pH of 3.09-3.58 and had a total acid of 1.07-2.09% microbiologically there was total lactic acid bacteria (LAB) of 1.5-223 cfu/ml. Potential the best amount of LAB is in crown flower and ferns is in the roots, while the citronella is in the leaves. In conclusion, the three plants studied have the potential of local microorganisms to be used as natural probiotics for livestock, so that alternative antibiotics are cheap, safe and easy to obtain.

The effect of combined ecological remediation (plant microorganism modifier) on rare earth mine wasteland.

Due to the vegetation destruction and soil desertification caused by excessive exploitation at Ganzhou ion-type rare earth mine in the mid-1980s, it is essential to carry out ecological remediation. The symbiotic mycorrhiza formed by the developed perennial ryegrass (Lolium perenne L.) roots infected with arbuscular mycorrhizal fungi (AMF) can significantly improve the growth and resistance of plants. In this study, the combination of symbiotic mycorrhiza and soil modifier was used to construct the ryegrass-AMF-soil modifier combined remediation technology, which achieved effective ecological remediation of soil tailings. The orthogonal experiment of soil modifier showed that the most efficient formula for ryegrass biomass, soil organic matter, soil alkaline hydrolysis, soil available phosphorus, and soil pH was 5g/kg sepiolite, 3g/kg chicken manure, 2g/kg humic acid, and 2g/kg biochar (A4B3C3D3), and chicken manure (B), humic acid (C), and biochar (D) had significant effects on the improvement of ryegrass biomass, soil organic matter, soil alkaline nitrogen, and soil available phosphorus. Sepiolite (A) had a significant improvement in soil pH. Furthermore, the AMF infection results indicated that Glomus moss (G.m.) had higher affinity with ryegrass. The T4 treatment-combined remediation using G.m. inoculation had the most significant effect on ryegrass growth; plant height increased by 39.19% compared with T1 treatment-inoculation using G.m. Under combined remediation, soil pH, organic matter, alkali nitrogen, and effective phosphorus content also significantly improved after combined treatment. Under G.m. inoculation treatment (T4 treatment), the soil nutrient content reached the three criteria of the soil nutrient grading standard.