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5 International Scientific Online Conference DOI: https://doi.org/10.15414/2021.9788055224015

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STUDY OF FUSARIUM EQUISETI METAL RESISTANCE TO CHROME AND COPPER
Irina Bukharina, Nadezhda Islamova

Udmurt State University, Izhevsk, Russian Federation; E-mail.: buharin@udmlink.ru
Soil pollution with heavy metals (HM) changes the composition and nature of the life of
microbial communities, disrupts metabolism and reduces the growth and reproduction of
plants. Hence, the issue of restoring disturbed lands becomes relevant, and phytoremediation
is the most promising in this regard. However, the efficiency of phytoremediation is largely
increased due to the interaction of plants with microorganisms that are beneficial to them
(especially endophytes), which allow them to change the absorption, mobility and
bioavailability of metal ions. It is known that some endophytic fungi isolated in media with an
increased HM content have increased metal resistance and are able to increase the resistance
to metals of host plants.
Purpose: to study the endurance limits of endophytic fungi isolated from the root system
of woody plants growing in conditions of technogenic pollution to the action of copper and
chromium.
The endophytic fungus Fusarium equiseti isolated from the root system of tree plantations
growing on the territory of the sanitary protection zone of the "Izhstal" industrial enterprise,
which is one of the main pollutants in the city of Izhevsk (the Udmurt Republic), was chosen as
the object of the study. F. equiseti is a naturally occurring root endophyte that is cosmopolitan
and has the ability to colonize the roots of non-host plants. The fungus has been long considered
pathogenic, but has recently attracted attention for its ability to acts as a biocontroller in the
fight against root pathogens. The species of the fungus was established by molecular DNA
analysis in the laboratory of the Leibniz Institute for Vegetable and Ornamental Crops (Berlin).
The mushrooms were cultivated on an agar medium consisting of dextrose broth, agar-agar and
distilled water, with the addition of different concentrations of copper and chromium: Cu – 50;
100; 150 mg/l; Cr – 2.5; 5; 10 mg/l. There was also a test case. The diameter of the colonies of
filamentous fungi and their growth rate were measured. The peculiarities of the response of
fungi to stress conditions were assessed by the content of malondialdehyde (MDA), which is a
product of lipid oxidation. The content of MDA was estimated by the degree of accumulation of
the product of its reaction with thiobarbituric acid (TBA), determining the optical density of the
solution on a spectrophotometer at a wavelength of 532 nm.
The chromium content in the medium influenced the growth of F. equiseti. The mushroom
showed great resistance to copper. The diameter of its colony in the variants Cu 50 and Cu 100
mg/l exceeded the values of the control. Nevertheless, at all studied concentrations of metals,
the growth of the fungus continued.
The MDA content in many variants significantly exceeded the control values. However,
when F. equiseti was grown on a substrate with chromium, the excess of MDA content was not
as significant as when copper was applied.
Fusarium equiseti has a high metal resistance to chromium and copper. The synthesis of
MDA and an increase in its concentration in the mycelium of the fungus is a response to an
increase in the concentration of HM ions in the substrate. These results also show the possibility
of using F. equiseti endophyte in bioremediation technologies for soils contaminated with HM
salts.
Keywords: metal resistance, endophytes, micromycetes, resistance, inoculation.
Acknowledgments
This work was supported by the RFBR grant "Postgraduates" № 19-316-90003.

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Spiritual Human Development
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