Browsing tag: bakterie endofityczne

BAKTERIE ENDOFITYCZNE W FITODEGRADACJI TOKSYCZNYCH ZANIECZYSZCZEŃ ORGANICZNYCH

ENDOPHYTIC BACTERIA IN PHYTODEGRADATION OF PERSISTENT ORGANIC POLLUTANTS
Daria Chlebek, Katarzyna Hupert-Kocurek

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Streszczenie: Fitodegradacja to przyjazna dla środowiska technologia, opierająca się na zdolności roślin do transformacji pobranych przez korzenie zanieczyszczeń organicznych. Istotną rolę we wspomaganiu procesów fitodegradacji mogą pełnić, budzące coraz większe zainteresowanie, bakterie endofityczne, kolonizujące wewnętrzne tkanki roślin bez wywoływania objawów chorobowych. Bakterie endofityczne wyposażone w odpowiednie szlaki metaboliczne, przyczyniają się do degradacji wielu różnych klas związków organicznych, w tym: wielopierścieniowych węglowodorów aromatycznych, lotnych i monopierścieniowych związków organicznych, materiałów wybuchowych czy pestycydów. Mogą również wspomagać bioremediację gazów cieplarnianych, takich jak metan i dwutlenek węgla. Ponadto, bakterie endofityczne mogą wspierać wzrost i rozwój roślin poprzez szeroki zakres bezpośrednich i pośrednich mechanizmów, co również wpływa na efektywność procesów fitodegradacji.

1. Wprowadzenie. 2. Fitodegradacja zanieczyszczeń organicznych. 3. Źródła bakterii endofitycznych wspomagających procesy fitodegradacji. 4. Zanieczyszczenia organiczne degradowane przez bakterie endofityczne. 5. Genetyczne uwarunkowania degradacji ksenobiotyków przez endofity. 6. Mechanizmy wpływające na efektywność fitodegradacji wspomaganej przez endofity bakteryjne. 7. Podsumowanie

Abstract: Organic pollutants are released into the environment as a result of various human activities. Traditional physical and chemical methods for the clean-up of soil and water polluted with these pollutants are often costly and invasive. A good alternative to above methods is bacteria assisted phytodegradation. Recently, the particular attention is focused on endophytic bacteria equipped with appropriate metabolic pathways, increasing the efficiency of organic compound degradation, and promoting plant growth. Endophytic bacteria are known to degrade various classes of organic compounds, such as: polycyclic aromatic hydrocarbons (PAHs); volatile and monocyclic organic compounds; explosives as well as pesticides. They may also assist bioremediation of greenhouse gases such as methan and carbon dioxide. Additionally, endophytic bacteria can promote the growth and development of plants through a wide range of direct and indirect mechanisms, which also affects the effectiveness of phytoremediation processes.

1. Introduction. 2. Phytodegradation of organic pollutants. 3. Sources of endophytic bacteria enchancing phytodegradation. 4. Organic pollutants degraded by endophytic bacteria. 5. Genetic basis of xenobiotics degradation in endophytic bacteria. 6. Mechanisms enhancing microbe-assisted phytodegradation. 7. Summary

Bakterie endofityczne i ich znaczenie w mikrobiologii środowiskowej, medycynie i przemyśle

Endophytic bacteria and their role in environmental microbiology, medicine and industry
M. Pawlik, T. Płociniczak, Z. Piotrowska-Seget

1. Wstęp. 2. Bakterie endofityczne – charakterystyka. 3. Kolonizacja tkanek roślinnych. 4. Endofity promujące wzrost roślin (PGPE). 5. Rola endofitów w fitodegradacji. 6. Rola endofitów w fitoekstrakcji. 7. Endofity w rolnictwie i ochronie roślin. 8. Metabolity endofitów w medycynie. 9. Produkcja bioplastiku. 10. Podsumowanie

Abstract: Endophytic bacteria have been known for more than 120 years. They live inside plant tissues without causing any apparent symptoms of disease or negative effects on the host. Each of the nearly 300 000 plant species that exist on the earth is host to one or more endophytes. Only a few of these plants have ever been completely studied relative to their endophytic biology. Consequently, the opportunity to find new and beneficial endophytic microorganisms among the diversity of plants in different ecosystems is considerable. During the long co-evolutionary process with their hosts, endophytes have developed many significant and novel characteristics. The relationships between plants and endophytic bacteria are very close. The endophytes which reside inside plant tissues can be classified as ‘obligate’ or ‘facultative’. The first group is strictly dependent on the host plant for their growth and survival and transmission to other plants. The second group has a stage in their life cycle in which they are able to exist outside the host plant. Recent studies have shown that endophytes accelerate the adaptation of plants to unbalanced environmental conditions such as saline soil, drought, stress caused by pesticides, heavy metals or hydrocarbons. Therefore, the exploitation of the interaction of plant endophytes for the remediation of contaminated soils is a promising area; however, role of these microorganisms is still unclear.

1. Introduction. 2. Characterization of endophytic bacteria. 3. Colonization of plant tissues. 4. Plant growth-promoting endophytes (PGPE). 5. The role of endophytes in phytodegradation 6. The role of endophytes in phytoextraction 7. Endophytes in agriculture and plant protection. 8. Endophytic metabolites in medicine. 9. Bioplastic production. 10. Summary

Genetyczne podłoże oddziaływań bakterii endofitycznych z roślinami

Genetic basis of endophytic bacteria-plant interactions
A. Piński, K. Hupert - Kocurek

1. Wprowadzenie. 2. Genetyczne uwarunkowania kolonizacji rośliny przez endofity bakteryjne. 3. Genetyczne podłoże odporności bakterii endofitycznych na stres oksydacyjny i osmotyczny. 4. Mechanizmy sekrecji i translokacji białek efektorowych. 5. Czynniki transkrypcyjne zaangażowane w interakcje endofit bakteryjny-gospodarz. 6. Zmiany w ekspresji genów w interakcji endofit bakteryjny-roślina. 7. Podsumowanie

Abstract: Bacterial endophytes promote plant growth through colonization of the internal tissues of the plant without external signs of infection or negative effects on their host. Although endophytic bacteria enter the plant through the primary and lateral root hair cells, root cracks and wounds, they are found at many sites in the plants, such as stems, leaves, seeds, and xylem. The colonization of plant tissues comprises: host recognition, chemotactic migration of endophyte towards root exudates, adhesion to the surface of the root, penetration of the epidermidis and finally adaptation to a new environment. The distinctive features of endophytic bacteria are their flagellar motility, secretion of the cell-wall degrading enzymes (CWDEs) and biofilm-forming ability. It is postulated that endophytic bacteria capable of colonizing plants should contain at least a minimum set of genes responsible for their endophytic behavior. Among them, genes involved in chemotaxis and adhesion processes, secretion and translocation of effector proteins as well as genes which facilitate survival in reactive-oxygen rich environment can be distinguished. An important group of genes are the ones which encode regulatory proteins involved in the control of gene expression at the transcriptional level. However, in establishing an endophytic association with plants, species-specific gene-functions seem to be involved. Identification of genes responsible for endophytic behavior will increase our knowledge about the genetic aspects of plant-endophyte interactions and enable to fully exploit their potential.

1. Introduction. 2. Genetic determinants of plant colonization by bacterial endophytes. 3. The genetic basis of endophytic bacteria resistance to oxidative and osmotic stress. 4. Mechanisms of secretion and translocation of effector proteins. 5. Transcription factors involved in the interactions of bacterial endophytes with the host. 6. Changes in gene expression in the plant-endophyte interactions. 7. Summary