Characterization of microorganisms with PGP characteristics and their survival in the rhizosphere

PGP mikroorganizmi (Plant Growth Promoting) su predmet mnogobrojnih istraživanja, čiji je glavni cilj pronalaženje adekvatnog načina njihove primene u poljoprivredi, hortikulturi, šumarstvu i zaštititi životne sredine. Cilj ovih istraživanja bio je izolacija i karakterizacija mikroorganizama sa PGP svojstvima iz rizosfere engleskog ljulja, ispitivanje sposobnosti njihovog preživljavanja nakon unošenja u zemljište, kao i praćenje uticaja njihove primene na parametre prinosa i mikrobiološku aktivnost u rizosferi biljke. Karakterizacija izolata roda Pseudomonas, Bacillus i Streptomyces obuhvatila je određivanje fizioloških, biohemijskih i PGP osobina. Uticaj introdukcije odabranih izolata i gljive Trichoderma asperellum na brojnost i mikrobiološku aktivnost u rizosferi engleskog ljulja, određivan je standardnim metodama na selektivnim hranljivim podlogama, a dehidrogenazna aktivnost spektrofotometrijskom metodom. U laboratorijskim uslovima ispitivan je efekat primene izolata na klijavost, dužinu korenka i stabaoca klice semena engleskog ljulja. U toku godine, uzimana su tri otkosa i pri tome su određivani dužina nadzemnog dela i korena biljke (cm) i prinos zelene i suve materije nadzemnog dela biljke po otkosu (t/ha). Na osnovu morfoloških, fiziološko-biohemijskih, kao i PGP osobina koje su izolati pokazali, te na osnovu rezultata mnogobrojnih dosadašnjih istraživanja, može se zaključiti da izolati P1 i P9 pripadaju vrsti Pseudomonas putida, izolat P12 Pseudomonas fluorescens, izolati B1, B3 i B6 vrsti Bacillus subtilis, a izolati A1, A2, A3 rodu Streptomyces. Brojnost pojedinih sistematskih i fizioloških grupa mikroorganizama kao i enzimatska aktivnost u rizosferi engleskog ljulja, zavisila je od primenjenih inokulanata. Primena izolata Pseudomonas sp. P12 pozitivno je uticala na povećanje ukupnog broja mikroorganizama, brojnost gljiva, aminoheterotrofa i aktinomiceta. Izolat Bacillus sp. B1 uticao je na povećanje ukupnog broja mikroorganizama, brojnosti gljiva i azotobaktera. Primena izolata Streptomyces sp. A3 dovela je do povećanja broja aktinomiceta i oligonitrofila, dok je primena Trichoderma asperellum uticala pozitivno na povećanje broja aminoheterotrofa i azotobaktera. Primena izolata Pseudomonas sp. P12 i Streptomyces sp. A3 imala je najveći efekat na dehidrogenaznu aktivnost. Inokulacija je imala pozitivan uticaj na klijavost, svežu i suvu masu biljke, visinu i dužinu korena biljaka. Primena gljive Trichoderma asperellum i izolata Streptomyces sp. A3 delovala je pozitivno na klijavost, dužinu korenka i stabaoca klice. U proseku, najbolji efekat na prinos sveže i suve materije, kao i na visinu nadzemnog dela i dužinu korena biljke, imala je primena izolata Pseudomonas sp.P12 i Bacillus sp. B1.U proizvodnji krmnih trava mikroorganizmi još nisu našli značajniju praktičnu primenu iako je veći i kvalitetniji prinos jedan od ciljeva stočarske proizvodnje. Rezultati ovih istraživanja su pokazali da se primenom mikroorganizama mogu postići pozitivni efekti i u proizvodnji engleskog ljulja. Zbog toga je veoma značajno da se vrše dalja ispitivanja uzajamnog odnosa primenjenih mikroorganizama i engleskog ljulja u poljskim uslovima, kako bi se optimizirao način i vreme primene inokulanataPGP microorganisms (Plant Growth Promoting) have been the subject of many research projects, whose main goal is to find appropriate methods of their use in agriculture, horticulture, forestry and environmental protection. The aim of this study is the isolation and characterization of microorganisms with PGP characteristics from the rhizosphere of perennial ryegrass, testing their ability to survive after entering the soil, and monitoring the impact of their application on yield parameters and microbial activity in the rhizosphere of plants. Characterization of Pseudomonas, Bacillus and Streptomyces included determination of the physiological, biochemical and PGP characteristics. Impact of the introduction of selected isolates and fungi Trichoderma asperellum on quantity and microbial activity in the rhizosphere of ryegrass was determined by using the standard method of selective media; dehydrogenase activity by the spectrophotometric method. The effects of the implementation of isolates on germination, seedling length sprouts seeds of perennial ryegrass were studied under laboratory conditions. During the year, three cuttings were taken. At each of the three cuttings, length of stem and roots of plants (cm) and yields of fresh and dry matter of the plant (t / ha) were measured. Based on morphological, physiological and biochemical characteristics and PGP characteristics observed in the isolates, and based on the results of many previous studies, it can be concluded that (1) P1 and P9 isolates belong to the species Pseudomonas putida, (2)Pseudomonas fluorescens P12 isolate, isolates of B1, B3, B6, belong to the species Bacillus subtilis, and (3) A1, A2 and A3 isolates belong to the ordo Streptomyces. The quantity of systematic and physiological groups of microorganisms and enzymatic activity in the rhizosphere of ryegrass depended on the applied inoculants. Application of Pseudomonas sp. P12 had positive effects on increasing the total number of microorganisms, fungi, aminoheterotrophs and actinomycetes. Isolate Bacillus sp. B1 affected the increase of the total number of micro-organisms in the fungi and Azotobacter. Application of Streptomyces sp. isolates A3 led to an increase in the number of actinomycetes and oligonitrophyls, while the application of Trichoderma asperellum had positive impact on increasing the number aminoheterotrophs and Azotobacter. Application of Pseudomonas sp. P12 and Streptomyces sp. A3 had the greatest effect on dehydrogenase activity. Inoculation had a positive effect on germination, fresh and dry weight of plant, height and rootlength of plants. Introduction of fungus Trichoderma asperellum and Streptomyces sp. A3 isolate acted positively on germination, length of seedling of germs. On average, the best effects on the yield of fresh and dry matter, the height of the stem of the plant and the length of the root were attained by the application of Pseudomonas sp.P12 and Bacillus sp. B1 isolates. Microorganisms have not yet found significant practical use in the production of forage grasses, even though more qualitative yield has been sought in livestock production. The results of this study demonstrate that positive results in the production of perennial ryegrass can be achieved by the use of microorganisms. Therefore, it is very important to carry out further studies of the relationship between applied microorganisms and ryegrass under field conditions in order to optimize the method and time of application of inoculants

Effects of plant growth promoting rhizobacteria on maize in greenhouse and field trial

The aim of the study was to investigate ability of Pseudomonas sp. Q4b, Bacillus sp. Q5a and Azotobacter chroococcum strain 8 to enrich a population of plant growth promoting rhizobacteria (PGPR) in rhizosphere and thus enhance maize growth (Zea mays L.). Experiments were carried out under greenhouse and field conditions, on a chernozem soil. In vitro screening for PGP properties showed significant difference between indole-3-acetic acid (IAA) and siderophores production and phosphosolubilization between Pseudomonas sp. Q4b and Bacillus sp. Q5a. Pseudomonas was estimated as a better producer of hydrogen cyanide (HCN) and siderophores than Bacillus. Bacterial treatments had a significant effect on the number of investigated microbial groups in rhizosphere, and maize growth and yield. Co-inoculation had an advantage compared to single inoculation, while in case of single strains, better effects were achieved in Pseudomonas and Azotobacter treatments. Inoculation increased the number of azotobacters (103.25%), pseudomonads (82.29%) and aerobic spore-forming bacteria (52.65%) as well as height (17.15%) and dry weight (35.48%) of maize plants. The highest plant height was recorded in treatment with Pseudomonas and Bacillus. The highest dry weight and yield were recorded in the treatment with mixture of these three strains

Mikrobiološke transformacije jedinjenja fosfora i sumpora u kiselim zemljištima

The dynamics of phosphorus and sulphur in soil is closely related to the dynamics of the biological cycle in which microorganisms play a central role. There is not much microbiological activity in acid soils because aerobes are scarce, rhizosphere is restricted to the shallow surface layer, and the biomass of microorganisms decreases with higher acidity. The aim of the research was to investigate the number of microorganisms, which decompose organic and inorganic phosphorus compounds and organic sulphur compounds in calcocambisol, luvisol, and pseudogley. The following parameters were determined in the soil samples: pH in H2O and in 1MKCl; the content of CaCO3 (%); humus content (%), nitrogen content (%); the content of physiologically active phosphorus and potassium (mg P2O5/100g of soil; mg K2O/100g of soil). The number of microorganisms was determined by the method of agar plates on appropriate nutrient media: the number of microorganisms solubilizing phosphates on a medium by Muramcov; the number of microorganisms that decompose organic phosphorus compounds on a medium with lecithin; and the number of microorganisms that transform organic sulphur compounds on a medium by Baar. All three types of soil are acid non-carbonate soils with a low level of available phosphorus and a more favorable amount of potassium, nitrogen, and humus. The largest number of bacteria, which transform organic phosphorus compounds, was found in calcocambisol. The largest number of phosphate solubilizing bacteria was recorded in pseudogley, whereas the largest number of phosphate solubilizing fungi was recorded in calcocambisol. The largest number of bacteria, which transform organic sulphur compounds, was recorded in pseudogley.Dinamika fosfora i sumpora u zemljištu tesno je povezana sa dinamikom biološkog ciklusa u kojem mikroorganizmi imaju centralnu ulogu. Mikrobiološka aktivnost u kiselim zemljištima nije velika, jer su potisnuti aerobi, rizosfera je ograničena na plitku površinsku zonu, a sa povećanjem kiselosti smanjuje se i biomasa mikroorganizama. Cilj ovih istraživanja je bio da se ispita zastupljenost mikroorganizama koji razlažu organska i neorganska jedinjenja fosfora i organska jedinjenja sumpora u kalkokambisolu, luvisolu i pseudogleju. U uzorcima zemljišta određeni su sledeći parametri: reakcija zemljišta (pH) u H2O i u 1MKCl; sadržaj CaCO3 (%); sadržaj humusa (%); sadržaj azota (%); sadržaj fiziološki aktivnog fosfora i kalijuma (mg P2O5/100g zemljišta; mg K2O/100g zemljišta). Broj mikroorganizama određivan je metodom agarnih ploča na odgovarajućim selektivnim hranjivim podlogama: broj mikroorganizama koji razlažu fosfate na podlozi po: Muramcov, broj mikroorganizama koji razlažu organska fosforna jedinjenja na podlozi sa lecitinom, a broj mikroorganizama koji transformišu organska jedinjenja sumpora na podlozi po Baar-u. Sva tri tipa zemljišta spadaju u grupu kiselih beskarbonatnih zemljišta, sa niskim sadržajem pristupačnog fosfora i povoljnijim sadržajem kalijuma, azota i humusa. Najveći broj bakterija koje transformišu organska jedinjenja fosfora utvrđen je u kalkokambisolu. Najveći broj bakterija koje razlažu fosfate utvrđen je u pseudogleju, a najveći broj gljiva koje razlažu fosfate u kalkokambisolu. Najveći broj bakterija koje transformišu organska jedinjenja sumpora utvrđen je u pseudogleju

Stimulating effect of microalgae on germination and initial growth of red radish (Raphanus sativus L. var. Radicula Pers.)

Microalgal application in plant producton are becoming promising alternative practice aiming to enhance seed germination performance. Red radish is one of the most commonly eaten vegetables in early spring in Serbia. The effect of two microalgae on red radish germination and growth promotion was tested. Two concentrations (1 and 2%) of Chlorella sp. (strains 71 and 72) suspension were prepared. The root and shoot length, weight of fresh biomass and germination percentage were assessed. The highest germination, root and shoot length were determined after Chlorella sp. strain 71 treatment with 2% concentrated suspension. Lower concentration of the same microalga led to the highest fresh shoot biomass. Red radish root (+106 %) and shoot length (+27%) were increased by 1 % and 2% Chlorella sp. (72) water suspension, respectively

Effect of inoculation with PGPR on basil antioxidant activity

Basil (Ocimum basilicum L.) is a widely utilized culinary herb. It is used to flavour foods such as vegetables, meats, fish, etc. In traditional medicine is used for treatment of various disorders such as colds, respiratory diseases, cardiovascular diseases, metabolic and gastrointestinal disorders, etc. The effects of climate changes on agriculture can result in lower yield and nutritional quality of plants. The inoculation of plants with plant growth-promoting rhizobacteria (PGPR) such as Azotobacter, Streptomyces, and Bacillus are well known to lead to improvement in germination, growth, and yield. Also, it was found that PGPR enhance defence capacity of the plant. In this study, the basil seed were inoculated with selected PGPR isolates: Bac3, Azb, and Act. Control seeds were immersed into distilled water. After 6 weeks plant material was collected, and methanol extracts were prepared for antioxidant determinations. The changes in total phenol and flavonoid content, as well as antioxidant activity, were monitored. PGPR applied in the experiment have not cause significant changes in total phenol content. However, treatments with Azb and Act isolates have increased flavonoid content in basil plants. The antioxidant activity of basil plant has been measured as the ability of plant extracts to reduce DPPH radicals. Obtained results show that only treatment with Azb isolates significantly increases the antioxidant activity of basil plants. Results obtained in this study suggested that investigated isolates have different effects on the antioxidant characteristics of the basil plant. Further investigation is still needed to explore the possibility of using these PGPRs as potent bio-fertilizer in basil production

Selective isolation and characterization of agriculturally beneficial bacteria from rhizospheric soil of Cannabis sativa L., Vojvodina, Serbia

Biljke, uključujući i konoplju (Cannabis sativa L), su domaćini različitih korisnih mikrobnih zajednica. Ovi mikroorganizmi se mogu naći u rizosfernom zemljištu, na biljci ili unutar biljnih tkiva, i svi zajedno čine biljnu mikrobnu zajednicu. Mikroorganizmi označeni kao biljna mikrobna zajednica se sistematski proučavaju dugi niz godina, i velika većina naučne literature se slaže oko njihove centralne uloge u podržavanju rasta, razvoja i opšteg zdravlja biljke. Cilj ovog istraživanja bio je da se iz rizosfernog zemljišta konoplje (Cannabis sativa L) izoluju bakterije roda Pseudomonas, Bacillus i Azotobacter i ispita njihov biostimulatorni (PGP od plant growth-promoting) i biokontrolni potencijal. Ova studija je potvrdila da autohtone rizosferne bakterije konoplje imaju različite sposobnosti tolerancije na abiotičke faktore i više različitih svojstava kojima mogu podstaći rast biljaka. Izolati roda Pseudomonas su pokazali sposobnost da žive na niskim (10ºC) i visokim (37 ºC) temperaturama. Svi izolati su imali minimalan rast na pH 9. Dva izolata označena kao P37 i P39 su tolerisala visoke koncentracije NaCl. Izolati su imali sposobnost da koriste različite izvore ugljenika. Svi Pseudomonas izolati produkovali su lipazu, ureazu, siderofor, cijanovodonik i razlagali jedinjenja organskog i neorganskog fosfora.Plants, including hemp (Cannabis sativa L), host different beneficial microbial communities. These microorganisms can be found in rhizospheric soil, on and inside plants tissues, designated as the plant microbiota or plant-associated microorganisms. The plant-associated microorganisms have been studied systematically for many years, and the vast majority of the scientific literature agrees upon their central role in supporting plant growth, development and overall health. The aim of this study was to isolate bacteria of Pseudomonas, Bacillus, and Azotobacter from the rhizospheric soil of hemp (Cannabis sativa L.) and investigate their biostimulatory (plant growth-promoting – PGP) and biocontrol potential. This study confirmed that indigenous rhizospheric bacteria of hemp have different abiotic stress tolerance abilities and multiple plant growth-promoting (PGP) properties. Pseudomonas isolates showed the ability to live at low (10ºC) and high (37 ºC) temperatures. All isolates had minimal growth on pH 9. Two isolates denoted as P37 and P39 tolerated high concentrations of NaCl. Isolates had the ability to use different sources of carbon. All Pseudomonas isolates produced lipase, urease, siderophore, hydrogen cyanide, and utilized organic and inorganic phosphorus

Azotobacter, Pseudomonas and Bacillus isolates stimulate the germination and seedling growth of Mellisa officinalis

The objective of this study was the isolation and characterization of Azotobacter, Pseudomonas and Bacillus species from the rhizospheric soil of Mellisa officinalis and to examine the effect of isolates application on the seed germination and seedling growth. Isolation, physiological, biochemical, and plant-growth-promoting activity characterization of isolates were done. Monitoring the effects of isolates application on seed germination and seedling growth were evaluated in controlled conditions. The number of germinated seeds, the shoot and root length of seedlings, vigour index and biochemical stress markers (lipid peroxidation intensity and total phenols) were measured. From the rhizosphere of plant 2 Azotobacter (denoted as A5 and A6), 5 Pseudomonas (denoted as P27, P28, P29, P55 and P56) and 6 Bacillus (denoted as B64, B65, B66, B67, B68 and B69) bacteria were isolated. Azotobacter isolates showed the ability to live in the condition of low (5) and high (9) pH. The isolates varied in terms of the utilization of carbon sources. Both isolates produced pectinase, hydrogen cyanide (HCN) and utilized organic and inorganic phosphorus. Pseudomonas isolates had optimal growth at 10 ºC and 37 ºC, and on medium with pH 5 and 9. All Pseudomonas isolates could produce pectinase, lipase, amylose, IAA, siderophores and HCN. All Bacillus isolates could grow on a medium containing 7% NaCl

Influence of green algae Chlorella vulgaris on initial growth of different agricultural crops

The aim of this research was to evaluate the effect of green algae Chlorella vulgaris on the initial growth of wheat, maize, bean and lettuce and the microbiological activity of rhizospheric soil. The experiment was conducted in controlled conditions. The inocula were applied as foliar fertilizer by spraying. Plant material was taken 30 days after plant emergance. Chlorella vulgaris affected positively the length (28.5% increase) and fresh mass (17.9% increase) of maize root, stem length of wheat (24.2% increase) and stem mass of lettuce (56.34% increase). Application of Chlorella vulgaris led to the increase of the total number of bacteria and the number of aminoheterotrophs in the maize rhizosphere, total bacterial number in the wheat rhizosphere, and the number of fungi in the rhizosphere of bean. The number of other investigated groups of microorganisms did not change significantly. The activity of dehydrogenase enzyme was not affected by inoculation with green algae