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BATYR, Ludmila; SLĂNINĂ, Valerina. Inhibition of fungus induced by bacteria. In: Microbial Biotechnology. Ediția 4, 11-12 octombrie 2018, Chișinău. Chișinău, Republica Moldova: Institutul de Microbiologie şi Biotehnologie, 2018, p. 115. ISBN 978-9975-3178-8-7.
Ediția 4, 2018
Conferința "Microbial Biotechnology" |
Chișinău, Moldova, 11-12 octombrie 2018
Antifungal activity is a relatively common characteristic among bacteria, conferring an ecological advantage in environments which support the growth of a mixed bacterial and fungal flora. This activity has been detected by using a variety of in vitro methods, but not in all cases the chemical basis for this activity has been elucidated. This activity has significance in four areas: 1)development of therapeutic antifungal drugs, 2) development of plant protection agents, 3)suppression of fungal colonization: proliferation within the human body resulting in modification of the pattern of certain human clinical infections, and 4)reduction in the efficiency of isolation of fungal pathogens from clinical specimens. In this regard, the strains of microorganisms that are used in biotechnology present a commercial value and the problem of maintaining as longer as possible of their valuable biosynthetic proprieties is permanently in the attention of scientists. The conservation of microorganisms and of their properties requires the use of efficient methods of preservation and a continuous monitoring of the effectiveness of these methods. In our study, the antifungal activity of the strains of Pseudomonas aurantiaca CNMNPsB- 08, Pseudomonas aureofaciens CNMN-PsB-07 and Bacillus cereus var. fluorescens CNMNBB- 07 against the strains of fungal pathogens was evaluated, after their freeze-drying storage in the protective environment of Na succinate + 12% sucrose during the 3 and 6 years. The obtained results proved that the antifungal activity increased with the extension of the storage period. Thus, the collected data have demonstrated that after 6 years of conservation of Pseudomonas aurantiaca CNMN-PsB-08 and Bacillus cereus var. fluorescens CNMN-BB-07 strains, their antifungal activity against micromycetes Fusarium oxysporum and Fusarium solani increased: the diameter of the inhibition zone was larger by 5.0 – 4.7 mm and 6.3 – 7.7 mm, respectively, comparing with preservation period of 3 years. The antifungal activity of all isolates has enhanced during the storage period of 3 to 6 years against the micromycetes Alternaria alternata and Botrytis cinerea which also are active pathogens of crop plants. In this case, we can observe that the diameter of the inhibition zone of the strain Pseudomonas aurantiaca CNMN-PsB-08 against Alternaria alternata and Botrytis cinerea was growing by 8.6 and 5.3 mm, respectively. The strains Pseudomonas aureofaciens CNMN-PsB-07 and Bacillus cereus var. fluorescens CNMN-BB-07 have manifested antifungal activity against Aspergillus niger, with the increasing of the inhibition zone diameter from 12.3 to 19.0 mm and from 14.3 to 15.0 mm, respectively. The most significant increase of the antifungal activity was determined at the strain Pseudomonas aureofaciens CNMN-PsB-07 over the micromycetes Botrytis cinerea, with the inhibition zone increasing 2.03 times during the storage period from 3 to 6 years. The use of these bacterial species in biological control would allow increasing the plant resistance to pathogens. Thus, the efficient conservation methods allowing the maintenance or the increase of antifungal properties are an important step in the biotechnological production of efficient fungicide alternatives for plant protection.