Page 93 - Book of Abstracts

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

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POSSIBLE MECHANISMS OF BACILLUS SUBTILIS AND SALICYLIC ACID-MEDIATED
REDUCTION OF POSTHARVEST DISEASES IN TUBERS OF SOLANUM TUBEROSUM L.
Oksana Lastochkina , Darya Garshina , Irina Shpirnaya , Almaz Ibragimov
1
2
3
3
1 Institute of Biochemistry and Genetics – Subdivision of the Ufa Federal Research Centre of the Russian
Academy of Sciences, Ufa, Russian Federation; E-mail.: oksanaibg@gmail.com
2 Bashkir Research Institute of Agriculture – Subdivision of the Ufa Federal Research Centre of the
Russian Academy of Sciences, Ufa, Russian Federation
3 Bashkir State University, Ufa, Russian Federation
Potato (Solanum tuberosum L.) is a major food crop worldwide due to its nutritional value
and health-promoting properties. Postharvest diseases lead to significant food and economic
losses. The application of eco-friendly and bio-safe approaches plays an important role in the
control of postharvest decay. Earlier we demonstrated that endobacteria Bacillus subtilis
(strains 104, 26D) and their compositions with natural signal molecule salicylic acid (SA)
reduced (up to 30–50 %) the incidence of dry rot and late blight in stored potatoes, caused by
Fusarium oxysporum and Phytophthora infestans, respectively. It was suggested that such action
of B. subtilis may be linked to their ability to produce compounds with antifungal activity
including lipopeptides (LPs).
In this study, we isolated and identified metabolites produced by B. subtilis 104 and 26D,
grown in Luria-Bertani broth (LB) and Medium Optimal for Lipopeptide Production (MOLP), as
well as assess their antifungal activity using classical and modern methods of microbiological
and biochemical analysis.
The obtained results of in vitro assays showed B. subtilis 10-4 and 26D exerts antagonistic
activity against phytopathogenic fungus F. oxysporum and Ph. infestans. The microscopic
observation showed the mycelia structure was well organized in the absence of the bacterial
cells, while numerous gaps of mycelia appeared in the presence of the B. subtilis. The results
showed the efficiency of the extracts of B. subtilis 104 and 26D metabolites for the inhibition of
F. oxysporum and Ph. infestans growth in Petry dishes. It was identified that tested strains B.
subtilis 104 and 26D produce LPs surfactins C13, C14, and C15, as well as bacillomicin D (С16)
for B. subtilis 26D was detected. Obviously, produced LPs make an important contribution to B.
subtilis (104, 26D)-induced suppressing of F. oxysporum and Ph. infestans growth as well as in
potatoes’ systemic resistance induction. With that, likely the spectrum of synthesized
metabolites is not limited only to detected LPs and may exist other components with antifungal
activity, for example, such as hydrolases capable to induce potatoes defense mechanisms. Also,
it was revealed B. subtilis (104, 26D) and especially compositions of B. subtilis (strain 104)+SA
contribute to the reduction of pathogens (F. oxysporum and Ph. infestans) – caused vitamin C
and starch destruction in stored potatoes. Thus, obtained results indicate that the detected LPs
produced by B. subtilis 104 and 26D can contribute to the formation of resistance of potato
tubers to dry rot and late blight diseases during long-time storage while maintaining their
quality and appearance.
Keywords: Solanum tuberosum, postharvest diseases, Bacillus subtilis, salicylic acid, antifungal activity.

Acknowledgments
The research was supported by the grant of the Russian Science Foundation (№ 18-76-00031) and
partially carried out within the framework of the state assignment of Russia (registration number AAAA-
A21-121011990120-7) with using the instrument park of the RCCU "Agidel" and "KODINK" of the UFRC
RAS.

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Spiritual Human Development
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