Biomics

Bacillus thuringiensis are the most common biological insect pest control agents. Some strains of B. thuringiensis are capable of endophytic existence, but the mechanisms of their interaction with plants and the role of phytohormones in this, for example, salicylic acid, which plays a key role in the development of plant immune responses against pathogenic microorganisms, have not been studied. When potato plants were treated with the endophytic strain B. thuringiensis B-5351 and salicylic acid simultaneously, an increase in the number of living bacterial cells in the internal tissues and a more than two-fold reduction in the area affected by late blight on the leaves was observed, relative to the control and action of B. thuringiensis B-5351 separately. The increase in plant resistance was accompanied by the accumulation of transcripts of the gene AY089962encoding the proteinase inhibitor and the activation of its protein product, which was more significant than after individual treatments. Under the field conditions (2020-2021), the treatment of plots with B. thuringiensis B-5351 alone did not reduce the degree of leaf spots infestation, however, in combination with salicylic acid, this indicator decreased by 20-25%. In 2020, the joint treatment of plants led to an increase in the total yield by an average of 20% relative to the control plots, as well as the yield of marketable tubers of the >80 g fraction. In 2021, only the treatment with salicylic acid led to an increase of total yield, but when combined with B. thuringiensis B-5351, the mass of large tubers increased. 

Bacillus thuringiensis, salicylic acid, potato, late blight, proteinase inhibitor, yield

1. Bagautdinova Z.Z., Omelyanchuk N., Tyapkin A.V., Kovrizhnykh V.V., Lavrekha V.V., Zemlyanskaya E.V.
Salicylic acid in root growth and development. International Journal of Molecular Sciences. 2022. V. 23(4). P. 2228-2237. doi: 10.3390/ijms23042228

2. Kudriavtseva N.N., Sofin A.V., Revina T.A., Gvozdeva E.L., Ievleva E.V., Valueva T.A. Secretion of proteolytic enzymes by three phytopathogenic microorganisms. Applied Biochemistry and Microbiology. 2013. V. 49(5). P. 513–521. doi: 10.1134/S0003683813050074

3. Kumar, P., Kamle, M., Borah, R. Bacillus thuringiensis as microbial biopesticide: uses and application for
sustainable agriculture. Egyptian Journal of Biological Pest Control. 2021. V. 31. P. 95-102. doi:10.1186/s41938-021-00440-3

4. Praca L.B., Gomes A.C.M.M., Cabral G., Martins E.S., Sujii E.H., Monnerat R.G. Entophytic colonization by brazilian strains of Bacillus thuringiensis on cabbage seedlings grown in vitro. Bt Research. 2012. V.3. P. 11–19. doi: 10.5376/BT.2012.03.0003

5. Raju S., Jayalakshmi S.K., Sreeramulu K. Differential elicitation of proteases and protease inhibitors in two different genotypes of chickpea (Cicer arietinum) by salicylic acid and spermine. J Plant Physiology. 2009. V. 166(10). P. 1015-1022. doi: 10.1016/j.jplph.2008.12.005

6. Sorokan A.V., Benkovskaya G.V., Burkhanova G.F., Blagova D.K., Maksimov I.V. Endophytic strain Bacillus subtilis 26DCryChS producing Cry1Ia toxin from Bacillus thuringiensis promotes multifaceted potato defense against Phytophthora infestans (Mont.) de Bary and pest Leptinotarsa decemlineata Say. Plants. 2020. V. 9. P. 1115–1123. doi: 10.3390/plants9091115

7. Takahashi H, Nakaho K, Ishihara T, Ando S, Wada T, Kanayama Y, Asano S, Yoshida S, Tsushima S, Hyakumachi M. Transcriptional profile of tomato roots exhibiting Bacillus thuringiensis–induced resistance to
Ralstonia solanacearum. Plant Cell Reports. 2014. V. 33(1). P. 99–110. doi: 10.1007/s00299-013-1515-1

8. Tao A., Panga F., Huang S., Yu G., Li B., Wang T. Characterization of endophytic Bacillus thuringiensis strains isolated from wheat plants as biocontrol agents against wheat flag smut. Biocontrol Science and Technology. 2014. V. 24(8). P. 901–924. doi: 10.1080/09583157.2014.904502

9. Yousefi H., Sanebani N., Mirabolfathy M. The effect of salicylic acid and Bacillus subtilis on cucumber root and stem rot, caused by Fusarium oxysporum f. sp. Radices cucumerinum. Iranian Journal of Plant Pathology. 2011. V.46(4). P.293-308. Available at: https://www.sid.ir/en/journal/ViewPaper.aspx?id=216346 (accessed 24.10.2022)

10. Zhang Q, Li W, Yang J, Xu J, Meng Y, Shan W. Two Phytophthora parasitica cysteine protease genes, PpCys44 and PpCys45, trigger cell death in various Nicotiana spp. and act as virulence factors. Molecular Plant Pathology. 2020. V. 21 (4). P. 541–554. doi: 10.1111/mpp.12915