Induced protein profile changes in arsenate tolerant and sensitive pseudomonas fluorescens strains

Pseudomonas fluorescens are gram‐negative, motile, rod‐shaped bacteria known for their metabolic versatility. Many strains of this species possess excellent capability to colonize plant roots, promoting plant growth in soils contaminated with toxic metals. P. fluorescens biotype F is a strain tolerant to arsenic which had been isolated previously from soil contaminated with arsenic and other toxic metals and characterized as a promoter of plant growth and accumulation of arsenic. In the present work we studied the protein profile of this strain together with the profile of a sensitive P. fluorescens CECT 378 in the presence and absence of sodium arsenate using two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE). The gels were analyzed by PDQuest, while the statistical significance was proved by ANOVA. We found 9 differentially expressed proteins in the tolerant strain ‐ 4 new proteins, 4 upregulated proteins and 1 downregulated proteins in the presence of 1000 ppm As. In the non‐tolerant strain there were 7 differentially expressed proteins ‐ 1 new protein, 3 upregulated proteins and 3 downregulated proteins. The identification of the proteins with MALDI‐TOF is in progress. Proteino profilio pakeitimai, sukelti arseną toleruojančioje ir jautriose pseudomonas fluorescens atmainose Santrauka Pseudomonas fluorescens yra gramneigiama, judanti lazdelės formos bakterija, žinomas jos metabolinis universalumas. Daugelis šios rūšies atmainų gerai sugeba kolonizuotis augalų šaknyse ir padeda augti augalams toksiniais metalais užterštame dirvožemyje. P. fluorescens biotipas F yra tolerantiškas arsenui, jis buvo atskirtas nuo dirvožemio, užteršto arsenu ir kitais toksiniais metalais ir charakterizuotas kaip augalų augimo aktyviklis bei arseno akumuliatorius. Tirtas šios atmainos proteino profilis kartu su jautriojo P. fluorescens CECT 378 profiliu, kai natrio arsenatas yra ir kai jo nėra, naudojant dviejų dimensijų poliakrilamido gelių elektroforezę (2D-PAGE). Geliai buvo analizuoti PDQuest, statistinė reikšmė patikrinta su ANOVA. Atrasti 9 skirtingai išreikšti proteinai toleruojančioje atmainoje. Netoleruojančioje atmainoje buvo skirtingai išreikšti 7 baltymai. Daug nuveikta identifikuojant proteinus su MALDI-TOF. Reikšminiai žodžiai: arsenas, Pseudomonus fluorescens, toleravimas, proteinai, 2D-elektroforezė, rizobakterijos. Изменения профиля протеина, вызванные толерантными к мышьяку и чувствительными разновидностями pseudomonas fluorescens Резюме Pseudomonas fluorescens – это грамм-отрицательная, движущаяся бактерия в виде палочки. Известна ее метаболическая универсальность. Большинство разновидностей этого вида способны создавать колонии в корнях растений, способствуя росту растений в загрязненной тяжелыми металлами почве. Биотип P. fluorescens толерантен к мышьяку, ранее выделенному из почвы, зараженной мышьяком и другими токсичными металлами, и характеризуется как активатор роста растений и аккумуляции мышьяка. Нами исследовался профиль протеина этой разновидности совместно с профилем чувствительного CECT 378 P. fluorescens в случае с мышьяком и с применением для электрофореза (2D-PAGE) двухдименсионного полиакриламидного геля. Гель был проанализирован в PDQuest, статистическое значение было подтверждено с помощью ANOVA. Были обнаружены 9 дифференцированно выраженных протеинов в толерантной разновидности при 1000 ppm As. В нетолерантной разновидности были дифференцированно выделены 7 протеинов. Идентификация протеинов с помощью MALDI-TOF продолжается. Ключевые слова: мышьяк, Pseudomonas fluorescens, толеранция, протеин, 2-дименсионный электрофорез, ризобактерия, обработка протеинов. First Published Online: 14 Oct 201

Fermentation Strategies to Improve Soil Bio-Inoculant Production and Quality

This work was supported by the project EXCALIBUR funded from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 817946 and project P18-HO-4279 Junta de Andalucia-PAIDI 2020, Spain.The application of plant beneficial microorganisms has been widely accepted as an efficient alternative to chemical fertilizers and pesticides. Isolation and selection of efficient microorganisms, their characterization and testing in soil-plant systems are well studied. However, the production stage and formulation of the final products are not in the focus of the research, which affects the achievement of stable and consistent results in the field. Recent analysis of the field of plant beneficial microorganisms suggests a more integrated view on soil inoculants with a special emphasis on the inoculant production process, including fermentation, formulation, processes, and additives. This mini-review describes the different groups of fermentation processes and their characteristics, bearing in mind different factors, both nutritional and operational, which affect the biomass/spores yield and microbial metabolite activity. The characteristics of the final products of fermentation process optimization strategies determine further steps of development of the microbial inoculants. Submerged liquid and solid-state fermentation processes, fed-batch operations, immobilized cell systems, and production of arbuscular mycorrhiza are presented and their advantages and disadvantages are discussed. Recommendations for further development of the fermentation strategies for biofertilizer production are also considered.project EXCALIBUR - European Union's Horizon 2020 research and innovation programme 817946Junta de Andalucia-PAIDI 2020, Spain P18-HO-427

Effect of easily biodegradable amendments on heavy metal solubilization and accumulation in technical crops ‐ a field trial

Heavy‐metal soil pollution is a common environmental problem all over the world. In the induced phytoextraction process plants can transport and translocate to their above‐ground tissues significant concentration of contaminants. Since some heavy metals are mostly presented in non‐soluble state, the application of chelating agents is needed. In this study we introduced into the rhizosphere of maize (var. Kneja 530) and sunflower (var. Favorit) plants 1 and 5 mmol l−1 of EDDS and NTA, and 5 g kg−1 of nutrients to enhance the accumulated concentrations of cadmium, lead and zinc. The fraction of CaCl2‐extractable metals increased incrementing the concentration of chelates. This was clearly pronounced for all the metals in the treatments with NTA and for Pb in those with EDDS. Generally, under all the experimental conditions the accumulated heavy‐metal concentrations were found to be significantly higher than in the control. Thus, in the case of higher concentration of NTA and EDDS, the accumulated Cd in the leaves of sunflower was found to be threefold higher. The highest accumulation of Pb in the leaves of maize was observed when nutrients were added (62 mg kg−1). On the other hand, negative effects of the used chelating agents on soil bacteria and fungi at plant harvest were not observed. Moreover, when nutrients were added, the number of studied microorganisms significantly increased. Lengvai biodegradavimą pagerinančių pataisymų priemonių poveikis sunkiųjų metalų tirpumui ir akumuliacijai techniniuose pasėliuose – lauko bandymai Santrauka Dirvožemio užterštumas sunkiaisiais metalais yra dažna aplinkos problema visame pasaulyje. Inicijuotas fitoekstrakcijos procesas augaluose gali perkelti į jų antžeminius audinius dideles teršalų koncentracijas. Kadangi kai kurie sunkieji metalai dažniausiai esti netirpios būsenos, reikia pritaikyti chelatų agentus. Į kukurūzus buvo įterpta rizosfera (var. Kneja 530) ir saulėgrąžos (var. Favorit) EDDS bei NTA 1 ir 5 mmol–1 ir 5 g kg–1 mineralinių medžiagų, padidinant kadmio, švino ir cinko akumuliuotas koncentracijas. Ekstrahuotos CaCl2 metalo frakcijos padidino chelatų koncentracijos didėjimą. Tai pasireiškė visiems metalams, apdorotiems su NTA, ir švinui, paveiktam su EDDS. Visuose eksperimentuose akumuliuoto sunkiojo metalo koncentracijos buvo daug didesnės nei kontroliniame bandinyje. Vadinasi, didesnės NTA ir EDDS koncentracijos atveju akumuliuotas Cd saulėgrąžos lapuose buvo 3 kartus didesnis. Didžiausia Pb akumuliacija miežių lapuose išmatuota, pridėjus mineralinių medžiagų (62 mg kg–1). Kita vertus, neigiamas chelatų agentų naudojimo poveikis dirvožemio bakterijoms ir grybeliams augalų derliuje nebuvo nustatytas. Be to, kai buvo pridėta mineralinių medžiagų, padaugėjo nagrinėjamų mikroorganizmų. Reikšminiai žodžiai: sunkieji metalai, fitoekstrakcija, kviečiai, saulėgrąžos, EDDS, NTA, lauko bandymai, rizosferos mikroorganizmai. Полевые испытания влияния мер, способствующих деградации тяжелых металлов, их разложению и накапливанию в технических посевах Резюме Загрязнение почв тяжелыми металлами – наиболее часто отмечаемая проблема во всем мире. Инициированный процесс фитоэкстракции в растениях может способствовать переносу значительных концентраций загрязнителей в их поверхностные ткани. В связи с тем, что некоторые тяжелые металлы находятся в нерастворенном состоянии, необходимо применение агентов хелатов. В настоящем исследовании в кукурузу была введена ризосфера (вар. Kneja 530) и подсолнечник (вар. favorit) EDDS и NTA 1 и 5 ммоль–1 ir 5 г кг–1 минеральных веществ для увеличения аккумулированных концентраций кадмия, свинца и цинка. Экстрагированные фракции металла CaCl2 способствовали увеличению концентрации хелатов. Это подтверждено исследованием всех металлов, подвергшихся воздействию NTA, и свинца, обработанного с помощью EDDS. Во всех экспериментах концентрации аккумулированного тяжелого металла были значительно больше, чем в контрольном образце. Следовательно, в случае большей концентрации NTA и EDDS содержание аккумулированного в листьях подсолнечника Cd было в три раза больше. Наибольшая аккумуляция Cd в листьях ячменя зафиксирована в случае добавления минеральных веществ (62 мг кг–1). Не было обнаружено и отрицательного воздействия от применения агентов хелатов на бактерии почвы и грибки в урожае растений. Кроме того, в результате добавления минеральных веществ количество исследуемых микроорганизмов увеличилось. Ключевые слова: тяжелые металлы, фитоэкстракция, ячмень, подсолнечник, NTA, EDDS полевые испытания, микроорганизмы ризосферы. First Published Online: 14 Oct 201

Long-term field metal extraction by pelargonium:phytoextraction efficiency in relation to plant maturity

The long length of periods required for effective soil remediation via phytoextraction constitutes a weak point that reduces its industrial use. However, these calculated periods are mainly based on short-term and/or hydroponic controlled experiments. Moreover, only a few studies concern more than one metal, although soils are scarcely polluted by only one element.In this scientific context, the phytoextraction of metals and metalloids (Pb, Cd, Zn, Cu,and As) by Pelargonium was measured after a long-term field experiment. Both bulk and rhizosphere soils were analyzed in order to determine the mechanisms involved in soil-root transfer. First, a strong increase in lead phytoextraction was observed with plant maturity, significantly reducing the length of the period required for remediation. Rhizosphere Pb, Zn, Cu, Cd, and As accumulation was observed (compared to bulk soil), indicating metal mobilization by the plant, perhaps in relation to root activity. Moreover, metal phytoextraction and translocation were found to be a function of the metals’ nature. These results, taken altogether, suggest that Pelargonium could be used as a multi-metal hyperaccumulator under multi-metal soil contamination conditions, and they also provide an interesting insight for improving field phytoextraction remediation in terms of the length of time required, promoting this biological technique

Plant-Growth-Promoting Bacteria Mitigating Soil Salinity Stress in Plants

Soil deterioration has led to problems with the nutrition of the world’s population. As one of the most serious stressors, soil salinization has a negative effect on the quantity and quality of agricultural production, drawing attention to the need for environmentally friendly technologies to overcome the adverse effects. The use of plant-growth-promoting bacteria (PGPB) can be a key factor in reducing salinity stress in plants as they are already introduced in practice. Plants having halotolerant PGPB in their root surroundings improve in diverse morphological, physiological, and biochemical aspects due to their multiple plant-growth-promoting traits. These beneficial effects are related to the excretion of bacterial phytohormones and modulation of their expression, improvement of the availability of soil nutrients, and the release of organic compounds that modify plant rhizosphere and function as signaling molecules, thus contributing to the plant’s salinity tolerance. This review aims to elucidate mechanisms by which PGPB are able to increase plant tolerance under soil salinity

Revealing Fungal Diversity in Mesophilic and Thermophilic Habitats of Sewage Sludge Composting by Next-Generation Sequencing

The accumulation of sewage sludge is a severe problem in many countries. Its utilization through composting has the potential to become a widely applied technology. From this perspective, our study investigated the diversity of fungi in mesophilic and thermophilic habitats when composting biosolids, cow manure and wheat straw. It was conducted using a metagenomic approach and next-generation Illumina HiSeq2000 sequencing to reveal the fungal diversity. We found significantly enhanced microbial activity in the thermophilic phase. In contrast, the activity of enzyme β-glucosidase was 29% higher in the mesophilic zone. The range of α-diversity values was more pronounced in the mesophilic habitats than in the thermophilic habitats based on diversity indices. At the class level, the mesophilic fungi were represented by Sordariomycetes—58.7%, Pezizomycetes—15.1% and Agaricomycetes—12.3%, while the most abundant thermophilic fungi found were Sordariomycetes—39.5% and Pezizomycetes—9.8%. In the further clarification of genera diversity, it is striking that at 37.2 °C, Psathyrella was the most abundant with 35.91%, followed by Chaetomidium with 20.11%. Among the thermophiles, Thielavia and Mortierella were the most common. Further research on microbial diversity changes over time is needed to manage the metabolic processes in obtaining quality soil amendment

Treatment and valorization of bio-waste in the EU

Moving away from fossil feedstock requires industrial sectors to switch to renewable raw materials. One option is the processing of biomass. However, agricultural, forestry and marine production of biomass cannot be expanded indefinitely. The linear value chains established in the fossil-based economy, leading from primary raw material to products and then to waste, are therefore no sustainable option. Instead circular value chains that recycle waste and make it available again as a raw material are needed. This also applies to bio-waste, as it arises in the primary production of biomass, as well as residual and waste materials from their processing, use and disposal. This paper reports on the volumes and current processing of bio- and biogenic wastes in the EU, presents recycling options that can lead to higher value added and employment as well as a lower environmental footprint, and also discusses the research, infrastructure and framework conditions needed

Safety of food crops on land contaminated with trace elements

Contamination of agricultural soils with trace elements (TEs) through municipal and industrial wastes, atmospheric deposition and fertilisers is a matter of great global concern. Since TE accumulation in edible plant parts depends on soil characteristics, plant genotype and agricultural practices, those soil- and plant-specific options that restrict the entry of harmful TEs into the food chain to protect human and animal health are reviewed. Soil options such as in situ stabilisation of TEs in soils, changes in physicochemical parameters, fertiliser management, element interactions and agronomic practices reduce TE uptake by food crops. Furthermore, phytoremediation and solubilisation as alternative techniques to reduce TE concentrations in soils are also discussed. Among plant options, selection of species and cultivars, metabolic processes and microbial transformations in the rhizosphere can potentially affect TE uptake and distribution in plants. For this purpose, genetic variations are exploited to select cultivars with low uptake potential, especially low-cadmium accumulator wheat and rice cultivars. The microbial reduction of elements and transformations in the rhizosphere are other key players in the cycling of TEs that may offer the basis for a wide range of innovative biotechnological processes. It is thus concluded that appropriate combination of soil- and plant-specific options can minimise TE transfer to the food chain