Main conclusionThe present study showed all the 16 strains isolated and identified from the alfalfa rhizosphere and nodules, and registered in GenBank, to be good candidates for targeted use in studies addressing the rather weak known mechanism of plant growth promotion, including that ofMedicago truncatula,a molecular crop model.Based on physiological, biochemical and molecular analysis, the 16 isolates obtained were ascribed to the following five families: Bacillaceae, Rhizobiaceae, Xantomonadaceae, Enterobacteriaceae and Pseudomonadaceae, within which 9 genera and 16 species were identified. All these bacteria were found to significantly enhance fresh and dry weight of root, shoots and whole 5-week-old seedlings. The bacteria were capable of the in vitro use of tryptophan to produce indolic compounds at various concentrations. The ability of almost all the strains to enhance growth of seedlings and individual roots was positively correlated with the production of the indolic compounds (r = 0.69; P = 0.0001), but not with the 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity (no correlation). For some strains, it was difficult to conclude whether the growth promotion was related to the production of indolic compounds or to the ACCD activity. It is likely that promotion of M. truncatula root development involves also root interaction with pseudomonads, known to produce 2,4-diacetylphloroglucinol (DAPG), a secondary metabolite reported to alter the root architecture by interacting with an auxin-dependent signaling pathway. Inoculation of seedlings with Pseudomonas brassicacearum KK 5, a bacterium known for its lowest ability to produce indolic compounds, the highest ACCD activity and the presence of the phlD gene responsible for DAPG precursor synthesis, resulted in a substantial promotion of root development. Inoculation with the strain increased the endogenous IAA level in M. truncatula leaves after inoculation of 5-week-old seedlings. Three other strains examined in this study also increased the IAA level in the leaves upon inoculation. Moreover, several other factors such as mobilization of phosphorus and zinc to make them available to plants, iron sequestration by siderophore production and the ability to ammonia production also contributed substantially to the phytostimulatory biofertilizing potential of isolated strains. There is, thus, evidence that Medicago truncatula growth promotion by rhizobacteria involves more than one mechanism.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-016-2469-7) contains supplementary material, which is available to authorized users.
The Internet of Things (IoT) has become widespread. Mainly used in industry, it already penetrates into every sphere of private life. It is often associated with complex sensors and very complicated technology. IoT in life sciences has gained a lot of importance because it allows one to minimize the costs associated with field research, expeditions, and the transport of the many sensors necessary for physical and chemical measurements. In the literature, we can find many sensational ideas regarding the use of remote collection of environmental research. However, can we fully say that IoT is well established in the natural sciences?
Wpłynęło w styczniu 2017 r. Zaakceptowano w marcu 2017 r. 1. Wprowadzenie. 2. Źródła chityny i jej struktura. 3. Chitynazy-budowa i działanie. 4. Bakterie produkujące chitynazy. 5. Rola chitynaz bakteryjnych w biotechnologii zielonej. 6. Wykorzystanie chitynaz w biotechnologii białej. 7. Wykorzystanie chitynaz w biotechnologii czerwonej. 8. Podsumowanie Bacterial chitinases and their application in biotechnology Abstract: Chitin, an insoluble linear β-1,4-linked polymer of N-acetylglucosamine, is the second most abundant polysaccharide in nature after cellulose. It is present in cell walls of several fungi, exoskeletons of insects and crustacean shells. Enzymatic hydrolysis of this polysaccharide is carried out in the presence of glycoside hydrolases-chitinases. They are produced by microorganisms, insects, plants, and animal, but it is the bacterial chitinases which play a fundamental role in degradation of the chitin. Chitinases and their products, chito-oligomers, have been of interest in recent years due to their wide range of applications in agriculture, medicine and industry. This review focuses on the enzymatic properties of the bacterial chitinases and their potential applications in various kinds of biotechnology. 1. Introduction. 2. Sources of chitin and its structure. 3. Chitinases-structure and function. 4. Chitinase-producing bacteria. 5. The role of bacterial chitinases in green biotechnology. 6. Application of chitinases in white biotechnology. 7. Application of chitinases in red biotechnology. 8. Summary
One of the main causes of climate change is the emission of GHGs, and one of the sources for the generation of such gasses is agriculture via plant production. Considering the foregoing, a study was conducted to assess PGPRs in strawberry cultivation which were able to limit GHG emissions. The first experimental factor was the inoculation of plant roots with the Bacillus sp. strains DLGB3, DKB26, DKB58, and DKB 84; the Pantoea sp. strains DKB63, DKB64, DKB65, and DKB68; Azotobacter sp. AJ 1.2; and Pseudomonas sp. PJ 1.1. The second experimental factor constituted the different moisture levels of the growth substrate. In the experiment, emissions of NH3, CO2, N2O, and CH4 were measured. In light of the conducted research, five strains were selected (Azotobacter sp. AJ 1.2; Pantoea sp. DKB64, DKB63, and DKB68; and Pseudomonas sp. strain PJ 1.1) that showed the greatest potential for reducing GHG emissions depending on the prevailing environmental conditions. The application of the tested bacterial strains under different moisture conditions in the substrate either reduced or did not affect GWP. This research on PGPR, which was conducted to select strains of rhizosphere bacteria that would be able to reduce GHG emissions, may form the basis for creating an inoculum and can be employed as an effective strategy for mitigating certain abiotic stresses.
Streszczenie: Chityna jest głównym składnikiem strukturalnym komórek grzybów i egzoszkieletów owadów. Komórki roślinne i bakteryjne są wyposażone w chitynazy, enzymy zdolne do hydrolizy chityny. Uczestniczą one w wielu interakcjach między organizmami, w tym w symbiozie i antagonizmie. Te interakcje są istotnymi czynnikami wielu funkcji ekosystemów i są ważne dla zdrowia roślin i zwierząt. Ponadto, ze względu na wspólne zajęcie siedlisk, grzyby i bakterie angażują się w złożone interakcje, które prowadzą do krytycznych zmian w zachowaniu mikroorganizmów, przykładem czego są bakterie endosymbiotyczne grzybów mikoryzowych. Chitynazy są przedmiotem zainteresowania w dziedzinie nauk o środowisku, medycynie i biotechnologii. Niniejszy przegląd opisuje rolę chitynaz roślinnych i bakteryjnych we wzajemnych interakcjach. 1. Wprowadzenie. 2. Zróżnicowanie chitynaz. 3. Chitynazy w interakcjach ze środowiskiem. 3.1. Chitynazy roślinne w interakcjach z mikroorganizmami. 3.2. Chitynazy bakteryjne w interakcjach z innymi mikroorganizmami. 4. Praktyczne zastosowanie chitynaz.
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