EFFICIENCY OF SYMBIOTIC APPARATUS FUNCTIONING AND CELLULOLYTIC MICROBIOTA ACTIVITY IN SOYBEAN CULTIVARS FOLLOWING ENDOPHYTIC–RHIZOBIAL SEED INOCULATION
DOI:
https://doi.org/10.37406/2706-9052-2026-2-17Keywords:
soybean cultivars, pre-sowing inoculation, endophytic bacteria, root nodules, cellulose-degrading microorganismsAbstract
In Ukraine, the issue of biologization of nitrogen nutrition of soybeans and reduction of mineral fertilizer consumption is the subject of long-term research. However, for the conditions of the Black Sea region of Ukraine, the complex effect of combinations of RhizobinK with B. velezensis IMV B-8134, Pseudomonas sp. 6 and B. megaterium UKM B-5724 on the formation of the nodule apparatus of varieties of different early maturity and the seasonal dynamics of cellulose-destructive microbiota in different soil layers has not been sufficiently clarified. The aim: to determine the effects of pre-sowing seed inoculation with a rhizobial preparation and its combinations with endophytic bacteria on the formation of the symbiotic apparatus and the abundance of cellulolytic microorganisms in the rhizosphere of soybean cultivars Sofiia and Monarkh. Field experiments were conducted in Kherson Oblast, Ukraine, during 2023–2025. The treatments included an uninoculated control, RhizobinK, and its combinations with Bacillus velezensis IMV B-8134, Pseudomonas sp. 6, and Bacillus megaterium UCM B-5724. The number and fresh weight of nodules were determined at the branching and pod formation stages of soybean development. The abundance of cellulolytic microorganisms was assessed in the 0–20 and 20–40 cm soil layers during three interphase periods. The highest biological efficiency was achieved with the RhizobinK + B. velezensis IMV B-8134 treatment. At the branching stage, this combination promoted the formation of 26–27 nodules with a fresh weight of 0.34–0.39 g per plant, while at the pod formation stage it produced 41–49 nodules with a fresh weight of 1.21–1.45 g per plant. The average abundance of cellulolytic microorganisms under this treatment reached 2.93 million CFU g⁻¹ in the rhizosphere of cultivar Sofiia and 2.94 million CFU g⁻¹ in cultivar Monarkh, exceeding the control by 6.1% and 11.6%, respectively. The combination with B. megaterium was particularly effective for cultivar Monarkh, resulting in 47 nodules with a total fresh weight of 1.43 g per plant. Co-inoculation with rhizobial and endophytic bacteria enhanced the development of the soybean symbiotic apparatus and increased the biological activity of the rhizosphere. The RhizobinK + B. velezensis IMV B-8134 combination was identified as the most effective treatment for both soybean cultivars studied.
References
Вожегова Р. А., Боровик В. О., Рубцов Д. К., Біднина І. О., Клубук В. В. Сучасні аспекти вирішення проблеми економії азотних добрив під час вирощування сої в умовах зрошення. Аграрні інновації. 2020. № 1. С. 11–16. DOI: 10.32848/agrar.innov.2020.1.2
Ушкаренко В. О., Вожегова Р. А., Голобородько С. П., Коковіхін С. В. Методика польового досліду (зрошуване землеробство) : навчальний посібник. Херсон : Грінь Д. С., 2014. 445 с.
Barbosa J. Z., Hungria M., Sena J. V. S., Poggere G. C., Reis A. R. dos, Corrêa R. S. Meta-analysis reveals benefits of co-inoculation of soybean with Azospirillum brasilense and Bradyrhizobium spp. in Brazil. Applied Soil Ecology. 2021. Vol. 163. Art. 103913. DOI: 10.1016/j.apsoil.2021.103913.
Hnini M., Aurag J. Prevalence, diversity and applications potential of nodules endophytic bacteria: a systematic review. Frontiers in Microbiology. 2024. Vol. 15. Art. 1386742. DOI: 10.3389/fmicb.2024.1386742.
Kumawat K. C., Singh I., Nagpal S., Sharma P., Gupta R. K., Sirari A. Co-inoculation of indigenous Pseudomonas oryzihabitans and Bradyrhizobium sp. modulates the growth, symbiotic efficacy, nutrient acquisition, and grain yield of soybean. Pedosphere. 2022. Vol. 32, No. 3. P. 438–451. DOI: 10.1016/S1002-0160(21)60085-1.
Marchão R. L., Silva G. C. da, Andrade S. R. M. de, Reis Junior F. B. dos, Barros Júnior M. P. de, Haphonsso R. H., Carvalho A. M. de. Improving Soybean Development and Grain Yield by Complementary Inoculation with Growth-Promoting Bacteria Azospirillum, Pseudomonas, Priestia, and Bacillus. Plants. 2025. Vol. 14, No. 3. Art. 402. DOI: 10.3390/plants14030402.
Nakei M. D., Venkataramana P. B., Ndakidemi P. A. Soybean-Nodulating Rhizobia: Ecology, Characterization, Diversity, and Growth Promoting Functions. Frontiers in Sustainable Food Systems. 2022. Vol. 6. Art. 824444. DOI: 10.3389/fsufs.2022.824444.
Prando A. M., Barbosa J. Z., Oliveira A. B. de, Nogueira M. A., Possamai E. J., Hungria M. Benefits of soybean co-inoculation with Bradyrhizobium spp. and Azospirillum brasilense: Large-scale validation with farmers in Brazil. European Journal of Agronomy. 2024. Vol. 155. Art. 127112. DOI: 10.1016/j.eja.2024.127112.
Sibponkrung S., Kondo T., Tanaka K., Tittabutr P., Boonkerd N., Yoshida K., Teaumroong N. Co-Inoculation of Bacillus velezensis Strain S141 and Bradyrhizobium Strains Promotes Nodule Growth and Nitrogen Fixation. Microorganisms. 2020. Vol. 8, No. 5. Art. 678. DOI: 10.3390/microorganisms8050678.
Szczerba A., Płażek A., Kopeć P., Wójcik-Jagła M., Dubert F. Effect of different Bradyrhizobium japonicum inoculants on physiological and agronomic traits of soybean (Glycine max (L.) Merr.) associated with different expression of nodulation genes. BMC Plant Biology. 2024. Vol. 24. Art. 1201. DOI: 10.1186/s12870-024-05911-x.
Tu T.-C., Lin S.-H., Shen F.-T. Enhancing Symbiotic Nitrogen Fixation and Soybean Growth through Co-Inoculation with Bradyrhizobium and Pseudomonas Isolates. Sustainability. 2021. Vol. 13, No. 20. Art. 11539. DOI: 10.3390/su132011539.
Xing P., Zhao Y., Guan D., Li L., Zhao B., Ma M., Jiang X., Tian C., Cao F., Li J. Effects of Bradyrhizobium Co-Inoculated with Bacillus and Paenibacillus on the Structure and Functional Genes of Soybean Rhizobacteria Community. Genes. 2022. Vol. 13, No. 11. Art. 1922. DOI: 10.3390/genes13111922.
