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

Efekat PGPR sojeva na brojnost mikroorganizama u rizosferi kukuruza u poljskim uslovima

Plant growth promoting rhizobacteria (PGPR) represent a wide variety of bacteria inhabiting the root surface and root vicinity. They are directly or indirectly involved in promoting plant growth and development via production and secretion of various regulatory compounds in the rhizosphere. PGPR are generally beneficial to a wide range of crops including maize. The main objective of this study was to determine the effect of PGPR strains on the microbial abundance in maize rhizosphere. The trial was conducted at Rimski Šančevi experimental field of Institute of Field and Vegetable Crops in Novi Sad, Serbia. The trial included five maize hybrids (NS 3014, NS 4015, NS 5043, NS 6010 and NS 6030) developed at the Institute and three treatments with microorganisms. Non-inoculated treatment was control. Inoculation was performed with Bacillus Q7, Pseudomonas PS2 and their mixture with Azotobacter chroococcum (Q7 + PS2 + AC). Application method was incorporation immediately before planting with liquid culture of strains (density 109 CFU/ml). It was observed that the certain treatment with rhizobacteria increased the number of all three studied microbial groups in the rhizosphere of the same hybrid. The best effect on the number of microorganisms in the rhizosphere of NS 6010 was achieved with Q7 + PS2 + AC, in NS 5043 with Q7 and with PS2 in NS 4015. The results obtained in this study indicate the importance of PGPR in crop production, which requires a constant expansion of knowledge about the mutual interactions of plants and microorganisms.Rizobakterije koje poboljšavaju rast biljaka (PGPR) predstavljaju širok spektar bakterija koje naseljavaju prostor oko/na površini korena. Direktno ili indirektno su uključene u ubrzanje rasta i razvoja biljaka putem proizvodnje i lučenja različitih regulatornih materija u rizosferu. PGPR su generalno korisne kod širokog spektra useva uključujući kukuruz. Osnovni cilj ovog istraživanja bio je ispitivanje efekta PGPR sojeva na zastupljenost mikroorganizama u rizosferi. Ogled je postavljen na eksperimentalnoj parceli Rimski šančevi Instituta za ratarstvo i povrtarstvo u Novom Sadu i uključivao je pet hibrida kukuruza poreklom iz Instituta (NS 3014, NS 4015, NS 5043, NS 6010 i NS 6030); kontrolu (bez inokulacije) i tri tretmana bakterijama koje poboljšavaju rast biljaka. Inokulacija je izvršena sa Pseudomonas PS2, Bacillus Q7 i njihovom mešavinom sa Azotobacter chroococcum (Q7 + PS2 + AC). Sojevi su primenjeni inkorporacijom tečne kulture (gustine 109 CFU/ml) neposredno pre setve. Rezultati su pokazali da kod određenog hibrida određeni tretman rizobakterijama povoljno utiče na brojnost kod sve tri analizirane grupe mikroorganizama. Najpovoljniji efekat na broj mikroorganizama u rizosferi hibrida NS 6010 postignut je primenom tretmana Q7 + PS2 + AC, kod NS 5043 primenom Q7, a kod NS 4015 primenom PS2

The "potato road" and biogeographic history of potato cyst nematode populations from different continents

The general opinion about the introduction of potato in Europe is the one regarding the direction from South America to Spain and subsequent distribution to other continents. Some historical data point out an alternative road. The potato spread from its place of origin to other continents in the light of parasite-host relationship, relying on nematode molecular data, is discussed in the present work. Biogeographic history of potato cyst nematode populations from different continents is in congruence with historical records

Tolerantnost prema osmotskom stresu, PGP osobine i RAPD analiza sojeva Bradyrhizobium japonicum

The osmotic stress tolerance of B. japonicum strains assessed according to their persistence in PEG solution. The lowest tolerance to osmotic stress was observed in strain 511 (43.3%), and the highest tolerance was observed for strain D216 (3.3% growth reduction in presence of PEG). PGP traits of B. japonicum strains were tested. None of five B. japonicum strains produced siderophore, strains 511 and 518 had the urease ability, and only B. japonicum 518 strain showed the ability to solubilize insoluble tricalcium phosphate. RAPD analysis, using AP10, BC318, AF14 and SPH1 primers, indicated genetic differences between Bradyrhizobium strains. The first group (strains 3, 6 and 518) showed more than 80% similarity. Strains 511 and D216 formed separate clusters. Difference between strains D216 and the other strains were more than 60%, with maximum value of 72% in comparison with strain 511. Plant-growth promoting (PGP) traits, osmotic stress tolerance and RAPD analysis highlighted strain D216 as useful for further investigation of B. japonicum impact on drought reduction in symbiosis with soybean.Tolerantnost sojeva B. japonicum prema osmotskom stresu ispitana je na osnovu preživljavanja sojeva u rastvoru PEG-a. Najmanju tolerantnost prema osmotskom stresu pokazao je soj 511 (43.3%), dok je najtolerantniji bio soj D216 (sa 3.3% smanjenja rasta u prisustvu PEG-a). Ispitane su PGP osobine sojeva B. japonicum. Nijedan od pet sojeva B. japonicum nije produkovao siderofore, ureaznu aktivnost pokazali su sojevi 511 i 518, a sposobnost solubilizacije neorganskog tri-kalcijum fosfata imao je samo soj B. japonicum 518. RAPD analiza, prajmerima AP10, BC318, AF14 i SPH1, ukazala je na genetske razlike između sojeva Bradyrhizobium. Prva grupa (sojevi 3, 6 i 518) pokazala je više od 80% sličnosti. Sojevi 511 i D216 formiraju zasebne klastere. Razlika između soja D216 i ostalih sojeva bila je veća od 60%, a maksimalna divergentnost od 72% zabeležena je u poređenju sa sojem 511. PGP osobine, tolerantnost prema osmotskom stresu i RAPD analiza izdvojili su soj D216 kao veoma značajan za dalja istraživanja B. japonicum u smanjenju negativnih posledica suše na simbioznu zajednicu sa sojom

Yield response of five maize hybrids to inoculation with rhizobacteria

The biofertilizers are found positive contribution to soil fertility, resulting in an increase in crop yield without causing any environmental, water or soil pollution hazards. Nitrogen fixing and phosphorus solubilizing bacteria play an important role in nitrogen mobilization and phosphorus solubilization for the benefit of plant growth. A field experiment to study yield response of maize to inoculation with rhizobacteria, was conducted during 2013 at experimental field of Institute of Field and Vegetable Crops in Novi Sad. The maize hybrids (NS 3014, NS 4015, NS 5043, NS 6010 and NS 6030) were used in the study. The field experiment was laid out in randomized complete block design with four treatments (control and 3 inoculations) and four replications. Inoculation was done with Pseudomonas PS2, Bacillus Q7 and their mixture with Azotobacter chroococcum (Q7 + PS2 + AC). Application method was incorporation immidiately before planting with liquid culture of strains (1 l + 300 l H2O ha-1). The results showed significant increase in maize yield with inoculation treatments. The best effect on maize yield was achieved with mixture of strains (19.7%). Significantly higher yield was obtained for hybrids NS6010 and NS 6030. The highest increase in yield of maize was achieved with hybrid NS 6030 (32.2%). Statistically significant differences in comparison to the control were obtained on treatments with Q7 and PS2 + Q7 + AC

The use of metallurgical slag as a by-product of the steel industry in chemical melioration of acid soils

The effect of metallurgical slag application on chemical properties of the soils with limited productive ability (Stagnosol), as well as on chemical composition of cultivated vegetables (spinach and cabbage) as experimental crops, through the vegetative experiments performed in semi-controlled conditions, was studied. The longterm investigations were aimed to define the main parameters for possible wider usage of this secondary raw material (by-product of the steel industry, respectively) for chemical melioration and fertilization of acid soils in Serbia, as well as to indicate the justification of its application in agricultural practice. Generally, it was concluded that the studied metallurgical slag of the standardized chemical composition can be added to the acid soils toward amelioration the fertility without adverse effects.  http://dx.doi.org/10.5937/metmateng1403191

Detekcija XIIA grupe fitoplazmi sorte župljanka u župskom vinogorju RFLP analizom 16s rDNA sekvenci

'Bois noir' (BN) is an important grapevine disease associated with phytoplasmas belonging to ribosomal subgroup 16SrXII-A. Phytoplasmas cause diseases in several hundred plant species. The number of infected cultivars is growing each year and it is important to follow the spreading of the phytoplasma in the different regions and identify which strains are present in specific regions on specific cultivars. Phytoplasmas are identified and classified based on direct sequencing of phytoplasma 16S rDNA or the 16S to 23S intergenic spacer region, but this approach is not always practical when a large number of unknown phytoplasmas is to be analyzed. Classification by RFLP analysis has provided a simple and rapid method that can be used to differentiate and identify a large number of unclarified phytoplasmas. Our objective was to investigate presence of phytoplasmas of 16SrXII-A group (Stolbur) in Zupa vineyard region. Detection was based on RFLP analysis of 16s rDNA sequences using four restriction enzymes: Tru1I, AluI, KpnI and TaqI. We identified phytoplasmas of XIIA group on two of three investigated cultivars (Zupljanka and Frankovka, but not on Plovdina) in the Zupa vineyard regions (Gornje Rataje and Tules locality). This is the first report of Stolbur phytoplasma on cv. Zupljanka in Zupa region.'Bois noir' (BN) je značjna bolest vinove loze izazavana fitoplazmama 16SrXII-A grupe. Fitoplazme izazaivaju bolesti kod nekoliko stotina biljnih vrsta. Ovaj broj se povećeva svake godine, pa je veoma značajno pratiti širenje fitoplazmi u različitim regionima i utvrditi koji izazivač je prisutan u nekom regionu i na određenoj sorti. Identifikacija i klasifikacija fitoplazmi bazirana je na sekvenciranju 16S rDNA ili intergenskog regiona 16S - 23S, ali ovaj metod se retko primenjuje na analizu velikog broja uzoraka. Primena RFLP analize omogućava brzo i jednostavno detektovanje, diferenciranje i klasifikaciju velikog broja fitoplazmi. Cilj ovog rada je detektovanje fitoplazmi 16SrXII-A grupe (Stolbur) u Župskom vinogorju. Detekcija je izvršena RFLP analizom 16s rDNA sekvenci korišćenjem restrikcionih enzima: Tru1I, AluI, KpnI and TaqI. Identifikovane su fitoplazme XIIA grupe na dve od tri ispitivane sorte (na Župljanki i Frankovki, ali ne na Plovdini) u Župskom vinogorju (lokaliteti Gornje Rataje i Tuleš ). U ovim istraživanjima je prvi put dokazano prisustvo Stolbur fitoplazme na sorti Župljanka u Župskom regionu

Proučavanje raznovrsnosti bakterije Pseudomonas syringae poreklom sa različitih voćaka u Srbiji

Pseudomonas syringae is a widespread and economically important plant pathogen, one found on a number of hosts, including fruit trees, field crops, vegetables, and ornamental plants. This bacterium has been experimentally identified as a parasite of pear, apple, apricot, peach, cherry, sour cherry, plum, and raspberry. The present study was designed to establish differences between strains isolated from fruit trees in Serbia. The pathogenic and biochemical characteristics of isolates were studied. The BOX-PCR method was used to generate genomic fingerprints of Pseudomonas syringae isolates and to identify strains that were previously not distinguishable by other classification methods. Different Bacillus sp. strains were tested for in vitro inhibitory activity against Pseudononas syringae isolates. Bacillus sp. strains show inhibitory activity only against P. syringae isolates that originated from peach. The obtained results demonstrate that the population of the bacterium Pseudomonas syringae from the fruit trees in Serbia is very diverse.Pseudomonas syringae je široko rasprostranjena i ekonomski značajna fitopatogena bakterija, sa širokim krugom domaćina koji uključuje voćke, ratarske, povrtarske i ukrasne biljke. Pseudomonas syringae u Srbiji je eksperimentalno potvrđen kao parazit kruške, jabuke, kajsije, breskve, trešnje, višnje, šljive i maline. Cilj ove studije bio je da utvrdi postojanje eventualnih razlika između sojeva izolovanih sa različitih vrsta voćaka u Srbiji. Proučavane su patogene i biohemijske osobine sojeva. BOX-PCR je korišćen za dobijanje profila izolata Pseudomonas syringae u cilju identifikacije sojeva koji se ne mogu utvrditi drugim metodama. Različiti sojevi roda Bacillus su testirani u cilju utvrđivanja njihove in vitro inhibitorne aktivnosti. Sojevi roda Bacillus su pokazali inhibitornu aktivnost samo na P. syringae izolovanih sa breskve. Dobijeni rezultati pokazali suda je populacija bakterije Pseudomonas syringae poreklom sa voća u Srbiji vrlo raznovrsna

Fitoplazmoze lekovitih biljaka

A diversity and incresing economic importance of medicinal plants demand a need to study their diseases. Among them phytopathogenic fungi are of a considerable importance, and in the last decade, phytoplasma diseases. Phytoplasma are important obligate intracellular, insect - transmitted pathogenic agents, found inside the phloem, in particular in the sieve tube cells of many plant species. These plant pathogens are wall-less, non-cultivable prokaryotes belonging to the Mollicutes class. They are the smallest prokaryotic organisms of a varied shape and size (50-1000 nm in diameter) and visible under the electron microscope. Their genome is the shortest known of all prokaryotic organisms (680-1600 kb). The most cited and widely accepted system of identification is based on the similarity in the 16S ribosomal gene sequence as well as their biological characteristics. Phytoplasmas are associated with plant diseases in several hundred plant species, inclu­ding many important vegetable, fruit crops, ornamental and medicinal plants. Disease plants exhibit pathological changes (in plants) which are demonstrated through four ty­pical types of symptoms: (1) phyllody, (2) yellowing and reddening, (3) virescence and (4) proliferation of axillary buds or 'witch's broom'. Typical phytoplasma symptoms are confirmed on the following species of medicinal plants: Ehinacea purpurea, E. Angustifolia, Hypericum perforatum, H. barbatum, Plantago major, Saponaria officinalis, Digitalis purpurea, Origanum vulgare, Levisticum officina­le, Carum carvi, Trigonella foenum greacum, Melisa officinalis, Petroselinum sativum, Apium graveolens, Valeriana officinalis, Rubus fruticosus, Vaccinium myrtillus, Arnica montana, Calendula officinalis, Cichorium intybus, Salix alba and Chamomilla recutita. The presence of phytoplasma was detected using electron microscopy (TEM) in 5 species of medicinal plants in Serbia, and using molecular identification in order to identify phyto­plasma in other species. Two types of phytoplasma were identified on more than 20 species of the medicinal plants in Serbia: Stolbur phytoplasma (16SrXII group) and Clover yellow edge (16SrIII-B). There are very few qualitative and quantitative data on the changes in secondary metabolites af­fected by the phytoplasma and these data should be improved.Lečenje lekovitim biljem staro je koliko i čovečanstvo. Čak i danas, lečenje biljem ima svoju primenu i neprestano se razvija. Lekovite biljke predstavljaju skupoceno blago prirode kao sirovina za lečenje, kao hrana i predmet trgovine. U oblasti proučavanja prirodnih lekovitih sirovina postignuti su, do sada, veoma značajni rezultati, koji su uticali na povećanje interesovanja njihovog korišćenja u proizvodnji lekova. Gotovo da nema oblasti u savremenoj terapiji gde fitofarmaka nema primenu. Fitoterapija u širem smislu reci podrazumeva terapiju svim preparatima na bazi bilja. To mogu biti razni ekstraktivni preparati ili drugi galenski oblici definisanog sastava: kapsule, tablete, masti, sirupi i dr. Zastupljenost vrsta lekovitog bilja u Srbiji čini oko 700 vrsta, što predtavlja preko 19 % od ukupne flore Srbije. Zvanično je registrovano oko 420 vrsta lekovitog bilja, a u prometu se nalazi oko 300 vrsta, od kojih najveći deo raste spontano u prirodi, a manji broj se gaji plantažno. Vrednost proizvodnje lekovitog i aromatičnog bilja procenjuje se na oko sedam miliona, a izvoz na oko četiri miliona dolara. Raznovrsnost, brojnost i sve veći ekonomski značaj lekovitih biljaka, nameće potrebu proučavanja njihovih bolesti, među kojima fitopatogene gljive zauzimaju značajno mesto, a poslednjih desetak godina sve veći značaj preuzimaju fitoplazmoze. Fitoplazme su obligatni intracelularni mikroorganizmi koji nastanjuju floem i to ćelije sitastih cevi različitih biljnih vrsta. U prirodi ih prenose insekti, vektori iz grupe cikada na perzistentan način. Fitoplazme su uglavnom okruglastog, ali promenljivog oblika i veličine (50-1000 nm u prečniku), koja im omogućava prolaz kroz sitaste ploče floema. Vidljive su pod elektronskim mikroskopom. Predstavljaju najsitnije prokariotske mikroorganizme, bez ćelijskog zida, a obavijene su omotačem, po čemu se i razlikuju od bakterija. Sadrže ribozome sa ribonukleinskim kiselinama i dvospiralnu dezoksiribonukleinsku kiselinu. Imaju najmanji genom, koji je poznat, kod prokariotskih organizama (680-1600 kb). Ni jedna fitoplazma nije, do sada, odgajena kao čista kultura na veštačkoj podlozi, pa je zbog toga njihova identifikacija još uvek nesigurna i neprihvaćena. Najviše citiran i široko prihvaćen je sistem na osnovu sličnosti u sekvencama njihovog 16S ribozomalnog gena i bioloških osobina. Fitoplazmoze karakteriše niz patoloških promena, a mogu se ispoljiti kroz četiri tipična tipa simptoma: (1) filodija, (2) žutilo i crvenilo, (3) ozelenjavanje ili virescencija i (4) proliferacije vršnih pupoljaka ili 'veštičine metle'. Na lekovitim vrstama u Srbiji tipični fitoplazmozni simptomi utvrđeni su na: Ehinacea purpurea, E. Angustifolia, Hypericum perforatum, H. barbatum, Plantago major, Sapona­ria officinalis, Digitalis purpurea, Origanum vulgare, Levisticum officinale, Carum carvi, Trigonella foenum greacum, Melisa officinalis, Petroselinum sativum, Apium graveolens, Valeriana officinalis, Rubus fruticosus, Vaccinium myrtillus, Arnica montana, Calendula officinalis, Cichorium intybus, Salix alba i Chamomilla recutita. Elektronskom mikroskopijom utvrđeno je prisusvo fitoplazmi u 5 vrsta lekovitih biljaka, a u ostalim vrstama primenom tehnika molekularne identifikacije. Dve vrste fitoplazmi su utvrđene na lekovitim biljkama u Srbiji: Stolbur fitoplazma (16SrXII grupa) i Clover yellow edge (16SrIII-B), na više od dvadeset vrsta lekovitih biljaka. Podaci o kvantitativnim i kvalitativnim promenama sekundarnih metabolita fitoplazmoznih lekovitih biljaka su oskudni, pa ih treba podspešiti

Akumulacija teških metala i mikroelemenata u lucerki (Medicago sativa L.) gajenoj uz deonicu autoputa E75 Beograd-Leskovac

The contents of heavy metals and trace elements and their accumulation in Medicago sativa L., cultivated on Eutric cambisol along the E75 route section Belgrade-Leskovac, were examined in order to assess the health and safety of animal feed. The samples of soil and aerial parts of the plant material were collected from both sides of lanes at 10, 30, 50 and 400 m perpendicular to the direction of the highway. Soil and plant analyses of the metals content were done according to ICP methodology. The results showed that at the locality L 14, a distance of 30 and 50 meters away from the lanes, the content of total forms of Cr, Ni and Pb in soil was above the maximum permissible concentration. In the plant biomass it was determined the following: in a sample from the location L 14 at a distance of 50 meters from the lanes concentrations of Ni and Co were higher than normal values, and concentrations of Fe and Pb were above toxic levels or maximum tolerance levels for animal feed; determined Fe content in the sample of alfalfa at location L 11, 400 m away from the lanes, and Ni in the sample from the site D 12 at a distance of 50 m from the lanes, was above the normal values, while in the sample from D12 location, at a distance of 30 m from the lanes, the content of Pb was above the toxic levels or maximum tolerance levels for animal feed. The results suggest a caution in the use of alfalfa, grown near the highway route, for animal feed because of the potential entry of heavy metals into the food chain.U deset uzoraka zemljišnog i biljnog materijala duž trase autoputa E 75 kroz Republiku Srbiju, na deonici od Beograda do Leskovca, ispitan je sadržaj teških metala i mikroelemenata i njihova akumulacija u Medicago sativa L. gajenoj na eutričnom kambisolu, radi ocene zdravstvene ispravnosti stočne hrane. Uzorci zemljišta i nadzemnog dela biljnog materijala uzorkovani su sa obe strane kolovoznih traka i to na 10, 30, 50 i 400 m upravno na pravac autoputa. Analiza zemljišnih uzoraka pokazala je da je na lokalitetu L 14, na udaljenosti 30 i 50 metara od kolovoznih traka sadržaj ukupnih formi Cr, Ni i Pb bio iznad maksimalno dozvoljenih koncentracija. U biljnoj masi u uzorku sa lokacije L14 na udaljenosti 50 metara od kolovoznih traka koncentracije Ni i Co su bile više od normalnih vrednosti, a koncentracije Fe i Pb bile su iznad toksičnih vrednosti odnosno maksimalno tolerantnog nivoa za ishranu životinja. Utvrđeni sadržaj Fe u uzorku lucerke na lokaciji L11 udaljenoj 400 m od kolovoznih traka, kao i Ni u uzorku sa lokacije D12 na udaljenosti 50 m od kolovoznih traka, bio je iznad normalnih vrednosti, dok je u uzorku D12 na udaljenosti 30 m od kolovoznih traka sadržaj Pb, bio iznad toksičnih vrednosti, odnosno maksimalno tolerantnih nivoa za ishranu životinja. Dobijeni rezultati upućuju na oprez pri korišćenju lucerke gajene pored trase autoputa za ishranu životinja zbog mogućeg ulaska teških metala u lanac ishrane