Bakterijska inokulacija - postupak za stimulaciju rasta crvene deteline gajene u zagađenom zemljištu

Red clover (Trifolium pratense L.) seeds were inoculated with several plant growth-promoting bacteria (PGPB) and sown in the substrate contaminated with polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organometallic derivatives of tin (OT). The aim was to determine if selected PGPB strains can promote the growth of red clover in the substrate contaminated with several organic pollutants. The influence of bacteria on red clover growth (height, root length and biomass) was monitored during the three-month experimental period. The most significant improvements of seedling height were noted in the treatment with Bacillus amyloliquefaciens D5 ARV and Pseudomonas putida P1 ARV. Root growth was positively affected by Serratia liquefaciens Z-I ARV. The same isolates significantly affected biomass production. Those isolates caused total biomass increases of 70%, 48% and 33% compared to control. Bacterial strains used in this study were already confirmed as PGPB by biochemical testing, as well as by an in vivo test of mixed inoculums on several woody plants grown in the coal-mine overburden site. This work is the first-time record on their individual effects on one plant species. Obtained results confirmed that inoculation with several PGPB strains can enhance red clover growth in polluted soil.Seme crvene deteline (Trifolium pratense L.), inokulisno sa nekoliko bakterija stimulatora biljnog rasta (PGPB), posejano je u supstrat kontaminiran policikličnim aromatičnim ugljovodonicima (PAHs), polihlorovanim bifenilima (PCBs) i organometalnim derivatima kalaja (OT). Cilj je bio da se utvrdi da li selektovane PGPB mogu promovisati rast crvene deteline u supstratu kontaminiranom sa nekoliko organskih zagađujućih materija. Uticaj bakterija na rast crvene deteline (visina, dužina korena i biomasa) praćen je tri meseca. Najveća visina je zabeležena kod biljaka inokulisanih sa Bacillus amyloliquefaciens D5 ARV i Pseudomonas putida P1 ARV. Rast korena je stimulisan od strane Serratia liquefaciens Z-I ARV. Ovi izolati su značajno uticali i na produkciju biomase. Ukupna biomasa dobijena tokom celog ogleda je za 70%, 48% i 33% veća u odnosu na kontrolu. Bakterijski sojevi korišćeni u ovoj studiji su prethodno potvrđeni kao PGPB kroz biohemijske i in vivo testove mešanog inokuluma na nekoliko drvenastih vrsta gajenih u jalovini. Ovaj rad prvi put beleži njihove pojedinačne efekte na jednu biljnu vrstu. Dobijeni rezultati potvrđuju da inokulacija sa nekoliko PGPB sojeva može ubrzati rast crvene deteline u zagađenom zemljištu

Filamentous fungi isolated from grape marc as antagonists of botrytis cinerea

In this paper we report on the isolation and identification of three filamentous fungi from grape marc, and antifungal effect of their cell-free culture filtrates on the growth of Botrytis cinerea, causal agent of gray mold. Grape marc is a waste material that has been used as soil amendment in sustainable agriculture. Isolates originating from grape marc were identified on the basis of morphological features and internal transcribed spacer rDNA or beta-tubulin gene sequencing. The presence of three different species, Penicillium paneum, Penicillium chrysogenum and Aspergillus fumigatus has been detected expressing different effect on the growth of B. cinerea. The effect of crude culture filtrates of selected fungi on B. cinerea growth was tested. Heat sensitivity of the established inhibition effect was examined by autoclaving the crude culture filtrate prior to testing. Additional aim was to determine whether antifungal effect was influenced by previous exposure to B. cinerea in dual liquid cultures. Crude culture filtrate of A. fumigatus K16/2 showed the lowest suppression of B. cinerea growth. A maximal percentage inhibition achieved within the study was 38.2%, 39.8% and 23.8 for crude filtrates of P. paneum K7/1, P. chrysogenum K11/1 and A. fumigatus K16/2, respectively. Presence of B. cinerea in dual liquid culture induced significant increase in antifungal capacity of the culture filtrates in comparison to pure culture filtrates of the chosen isolates. The antifungal activity of all of the isolates' culture filtrates retained after heat treatment suggesting the presence of some thermostable antifungal metabolites. The results indicate the complexity and specificity of the interaction between filamentous fungi and B. cinerea. Grape marc is a good source for isolation od B. cinerea fungal antagonists and their antifungal metabolites. Specificity of fungal-fungal interactions suggests that further research on the antagonistic mechanisms and factors affecting them should be studied separately for each pair of antagonists

Uticaj proizvoda komposta na klijanje semena povrća

The aim of this work is determination of influence of different compost leachates and teas types on vegetables seed germination. Composts used for leachate and tea production were produced of municipal waste (MSW) and waste from tobacco industry (TW). Results achieved with MSW products were comparable to control. Compost products derived from TW showed significant phytotoxicity, which can be correlated with their chemical composition. Leachates from MSW compost lead to the lower germination index in comparison to MSW compost teas, which indicates the possibilites their application.Cilj ovog rada je određivanje uticaja različitih kompostnih čajeva i ekstrakata na klijanje semena povrća. Kompost korišćen za dobijanje ekstrakata i čajeva potiče od komunalnog otpada (MSW) i otpada iz duvanske industrije (TW). Rezultati postignuti sa komposnim produktima MSW su uporedivi sa kontrolom. Kompostni produkti dobijeni od TW pokazuju značajnu fitotoksičnost koja se može dovesti u vezu sa njihovim hemijskim sastavom. Ekstrakti od MSW komposta doveli su do nižeg germinacionog indeksa u poređenju sa čajevima, što ukazuje na mogućnosti njihove primene

Izolacija i karakterizacija bakterija i kvasaca iz kontaminiranog zemljišta

Plant growth promoting (PGP) bacteria and yeasts play an important role in bioremediation processes. Thirty bacterial and ten yeast isolates were obtained from PAH and PCB contaminated soil with an aim of determining the presence of PGP mechanisms (production of ammonia, indoleacetic acid, siderophores and solubilization of inorganic phosphate). As a result, three bacterial (Serratia liquefaciens, Micrococcus sp. and Serratia sp.) and two yeast isolates (Candida utilis and Candida tropicalis) were recognized as PGP strains. Among them, Serratia sp. showed the highest indole production (25.5 μg/ml). Analyses of metal tolerance (Cu+2, Cr+6 and Ni+2) revealed that Serratia liquefaciens, Micrococcus sp., Serratia sp. and Candida tropicalis were capable to tolerate significant concentration of metals. As a result of this study several bacterial and yeast strains were attributed as potential plant growth promoters which can be applied in future remediation activities and environmental quality improvements.Zemljište predstavlja dinamičan ekosistem naseljen brojnim mikroorganizmima među kojima su bakterije najbrojnije. Najveći broj je skoncentrisan u uskoj zoni zemljišta koja okružuje koren i koja se naziva rizosfera. Procenjuje se da 1-2% bakterija koje naseljavaju ovu zonu imaju sposobnost da promovišu rast biljaka (engl. plant growth promoting bacteria - PGPB). Pored bakterija, sve više je podataka da i zemljišni kvasci poseduju ove sposobnosti. Mikroorganizmi koji stimulišu rast biljaka koriste različite mehanizme kojima povećavaju dostupnost nutrijenata biljkama, regulišu njihov hormonski status kao i odnos prema biljnim patogenima. Bakterije i kvasci koji stimulišu rast biljaka igraju važnu ulogu i u procesima bioremedijacije. Trideset bakterijskih i deset izolata kvasaca je izolovano iz kontaminiranog zemljišta (PAH i PCB) i testirano na prisustvo mehanizama kojima se pospešuje rast biljaka. Cilj je bio doći do sojeva koji su prilagođeni na život u zagađenom zemljištu, a istovremeno imaju i potencijalno stimulativno dejstvo. Nakon izvršenih biohemijskih analiza (produkcija amonijaka, indol-sirćetne kiseline, siderofora, rastvaranje neorganskog fosfora) u stimulatore biljnog rasta svrstana su tri bakterijska (Serratia liquefaciens, Micrococcus sp. i Serratia sp.) i dva izolata kvasaca (Candida utilis i Candida tropicalis). Među njima najveću sposobnost produkcije indol-sirćetne kiseline je pokazao izolat Serratia sp. (25,5 μg/ml). Analize tolerancije na prisustvo teških metala (Cu+2, Cr+6 i Ni+2) pokazale su da su izolati Serratia liquefaciens, Micrococcus sp., Serratia sp. i Candida tropicalis sposobni da podnesu više koncentracije. Rezultati ovih istraživanja mogu imati praktičnu primenu u budućim remedijacionim aktivnostima i unapređenju kvaliteta životne sredine

Copper tolerance of trichoderma species

Some Trichoderma strains can persist in ecosystems with high concentrations of heavy metals. The aim of this research was to examine the variability of Trichoderma strains isolated from different ecosystems, based on their morphological properties and restriction analysis of ITS fragments. The fungal growth was tested on potato dextrose agar, amended with Cu(II) concentrations ranging from 0.25 to 10 mmol/l, in order to identify copper-resistant strains. The results indicate that some isolated strains of Trichoderma sp. show tolerance to higher copper concentrations. Further research to examine the ability of copper bioaccumulation by tolerant Trichoderma strains is needed

Endorhizosphere of indigenous succulent halophytes: a valuable resource of plant growth promoting bacteria

The adaptability of halophytes to increased soil salinity is related to complex rhizosphere interactions. In this study, an integrative approach, combining culture-independent and culture-dependent techniques was used to analyze the bacterial communities in the endorizosphere of indigenous succulent halophytes Salicornia europaea, Suaeda maritima, and Camphorosma annua from the natural salt marshes of Slano Kopovo (Serbia). The 16 S rDNA analyses gave, for the first time, an insight into the composition of the endophytic bacterial communities of S. maritima and C. annua. We have found that the composition of endophyte microbiomes in the same habitat is to some extent influenced by plant species. A cultivable portion of the halophyte microbiota was tested at different NaCl concentrations for the set of plant growth promoting (PGP) traits. Through the mining of indigenous halotolerant endophytes, we obtained a collection representing a core endophyte microbiome conferring desirable PGP traits. The majority (65%) of the selected strains belonged to the common halotolerant/halophilic genera Halomonas, Kushneria, and Halobacillus, with representatives exhibiting multiple PGP traits, and retaining beneficial traits in conditions of the increased salinity. The results suggest that the root endosphere of halophytes is a valuable source of PGP bacteria supporting plant growth and fitness in salt-affected soils. © 2023, The Author(s)

Biopriming: multiple effects on soybean germination metrics

Biopriming is a pre-sowing seed inoculation technique based on beneficial microorganisms. The aim of the study was to estimate biopriming potential of microbial consortium on soybean seeds. Obtained results showed a stimulative effect of biopriming resulting in 8% higher germination percentage. Inoculated seeds were characterised as more vigorous according to vigor I, vigor II and electrical conductivity results. Accelerated aging test decreased germination percentage of both treatments to approximately 66±2%. Inoculated seeds were marked as more vigorous according to vigor I index. Biopriming of soybean seeds resulted in an increase of germination parameters that suggest stimulative effects on seed quality

BIOPRIMING: A SUSTAINABLE SUPPORT FOR CROP ESTABLISHMENT

Crop yields are highly depended on germination and early stages of plant growth. Numerous priming techniques are being developed aimed to improve germination. Biopriming represents a sustainable approach based on seed treatment in bacterial suspension of selected plant growth promoting strains. One of the most promising plant growth promoting bacteria is Azotobacter chroococcum. The aim of the research was to evaluate the effects of A. chroococcum F8/2 as a biopriming agent on germination of various cultivable plants: basil, white mustard, cucumber, tomato, wheat, canola, and soybean. After surface sterilization, seeds were bioprimed in the bacterial suspension (107CFU/ml). Uninoculated seeds represented control treatment. Germination test was conducted with 100 seeds per treatment and the germination was monitored for 7 days. Following germination parameters were determined: germination percentage, germination index, mean germination time, vigor I, vigor II, length and dry biomass of the seedlings. The bacterial inoculation caused higher germination percentages of cucumber, tomato, wheat and soybean. The highest increase in germination index was observed in wheat (an increase of 19.8%). Tomato and basil were the only plants where vigor I was not increased by inoculation. Generally, the most favorable effects of A. chroococcum biopriming were observed in wheat where vigor I was increased more than twice, and vigor II was higher by 75.4% in inoculated seeds. The results indicate a significant potential for A. chroococcum use in biopriming. The observed effects of seed priming on germination parameters were crop-specific, with the most prominent potential in wheat biopriming

Use of overburden waste for London plane (Platanus x acerifolia) growth: the role of plant growth promoting microbial consortia

Overburden waste dumps represent a huge threat to environmental quality. The reduction of their negative impact can be achieved by vegetation cover establishment. Usually, this action is complicated due to site-specific characteristics, such as nutrient deficiency, elevated metal concentration, low pH value, lack of moisture and lack of organic matter. Establishment of vegetation can be facilitated by inoculation with plant growth promoting bacteria (PGPB) which improve the physicochemical and biological properties of degraded substrates and make them more hospitable for plants. In this study we selected several strains based on the ability to produce ammonia, indole-3-acetic acid, siderophores and lytic enzymes, and to solubilize inorganic phosphates. This selection resulted in microbial consortia consisting of Serratia liquefaciens Z-I ARV, Ensifer adhaerens 10_ARV, Bacillus amyloliquefaciens D5 ARV and Pseudomonas putida P1 ARV. The effects of PGPB consortia on one-year-old London plane (Platanus x acerifolia [Aiton] Willd.) seedlings replanted into overburden waste from Kolubara Mine Basin were examined. After seven months, inoculated seedlings were 32% higher with 45% wider root collar diameter and over 80% higher total dry biomass compared to uninoculated seedlings grown in Kolubara's overburden. Inoculation resulted in higher amounts of total soluble proteins, higher chlorophyll and epidermal flavonoids content and higher total antioxidative capacity in the leaves. This study represents a successful search for effective PGPB strains and shows that microbial consortia have an important role in enhancing the growth of seedlings in nutrient deficient and degraded substrates such as overburden waste from open-pit coal mines. Positive response of London plane seedlings suggest that inoculation may help widening the opus of species for reforestation of post mining areas and speed up natural succession processes and recovery of degraded landscapes

Microbial diversity in soils suppressive to Fusarium diseases

Fusarium species are cosmopolitan soil phytopathogens from the division Ascomycota, which produce mycotoxins and cause significant economic losses of crop plants. However, soils suppressive to Fusarium diseases are known to occur, and recent knowledge on microbial diversity in these soils has shed new lights on phytoprotection effects. In this review, we synthesize current knowledge on soils suppressive to Fusarium diseases and the role of their rhizosphere microbiota in phytoprotection. This is an important issue, as disease does not develop significantly in suppressive soils even though pathogenic Fusarium and susceptible host plant are present, and weather conditions are suitable for disease. Soils suppressive to Fusarium diseases are documented in different regions of the world. They contain biocontrol microorganisms, which act by inducing plants’ resistance to the pathogen, competing with or inhibiting the pathogen, or parasitizing the pathogen. In particular, some of the Bacillus, Pseudomonas, Paenibacillus and Streptomyces species are involved in plant protection from Fusarium diseases. Besides specific bacterial populations involved in disease suppression, next-generation sequencing and ecological networks have largely contributed to the understanding of microbial communities in soils suppressive or not to Fusarium diseases, revealing different microbial community patterns and differences for a notable number of taxa, according to the Fusarium pathosystem, the host plant and the origin of the soil. Agricultural practices can significantly influence soil suppressiveness to Fusarium diseases by influencing soil microbiota ecology. Research on microbial modes of action and diversity in suppressive soils should help guide the development of effective farming practices for Fusarium disease management in sustainable agriculture