The germination vigor of soybean seeds, seedlings weight, and nodulation activity during the development of soybean-rhizobia symbiosis at the vegetative stages of plant growth under the influence of the exopolysaccharides (EPS) of nodule bacteria Bradyrhizobium japonicum 634b (microsymbiont of soybean), Bradyrhizobium japonicum 631 (microsymbiont of both soybean and lupine) and Bradyrhizobium sp. (Lupinus) 359a, 400 (microsymbionts of lupine, with different nitrogen-fixing activities) were evaluated in laboratory and pot experiments. It was shown that microbe EPS had no significant stimulative effect on soybean seed germination and seedling development. The tendency of increasing germination vigor and seedling dry weight was observed while the EPS400 at concentration of 0.100 mg/ml was used. This may be due to carbohydrate biopolymer properties. The decrease in the amount of the extracellular polysaccharides to 0.025 mg/ml resulted in a reduction in the soybean seedling weight but it was not reliable. Rhizobial EPS stimulated nodulation of soybean at the two trifoliate leaf stage (V2) when they were applied to seedlings before inoculation with B. japonicum 634b. There was a tendency towards an increasing the number of root nodules at the three trifoliate leaf stage (V3) and also when the soybean seedlings were incubated with EPS and then inoculated with B. japonicum 631. Early root nodule formation was observed when soybean plants were treated by the EPS634 and EPS631 and then inoculated respectively with B. japonicum 634б and B. japonicum 631. There was no clear relationship between the specificity of rhizobial polysaccharides action on seed germination, seedlings development, nodule formation in the soybean—B. japonicum symbiosis and symbiotic properties of the strains, from what the EPS were obtained. However, there was some difference between the carbohydrate biopolymers in their action.
Keywords: nodule bacteria, soybean, exopolysaccharides, seed germination, symbiosis, nodulation
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1. Brewin, N.J. (1991). Development of the legume root nodule. Annu. Rev. Cell Biol., 7, pp. 191-226. doi: https://doi.org/10.1146/annurev.cb.07.110191.001203
2. Ghosh, P.K. & Maiti, T.K. (2016). Structure of extracellular exopolysaccharides (EPS) produced by rhizobia and their functions in legume-bacteria symbiosis: a review. Achievements in the Life Sciences, 10, pp. 136-143. https://doi.org/10.1016/j.als.2016.11.003
3. Marczak, M., Mazur, A., Koper, P., Zebracki, K. & Skorupska, A. (2017). Synthesis of rhizobial exopolysaccharides and their importance for symbiosis with legume plants. Genes, 8(12), p. 360. https://doi.org/10.3390/genes8120360
4. Mort, A.J. & Bauer, W.D. (1980). Composition of the capsular and extracellular polysaccharides of Rhizobium japonicum. Plant Physiol., 66, No. 1, pp. 158-163. https://doi.org/10.1104/pp.66.1.158
5. Leigh, J., Singner, E.R. & Walker, G.C. (1985). Exopolysaccharide-deficient mutants of Rhizobium meliloti that form ineffective nodules. Proc. Natl. Acad. Sci. USA, 82, pp. 6231-6235. https://doi.org/10.1073/pnas.82.18.6231
6. van Workum, W.A.T., van Slageren, S., van Brussel, A.A.N. & Kijne, J.W. (1998). Role of exopolysaccharides of Rhizobium leguminosarum bv. viciae as host plant-specific molecules required for infection thread formation during nodulation of Vicia sativa. Mol. Plant Microbe Interact., 11, No. 12, pp. 1233-1241. https://doi.org/10.1094/MPMI.1918.104.22.1683
7. Skorupska, A., Janczarek, M., Marczak, M., Mazur, A. & Kryl, J. (2006). Rhizobial exopolysaccharides: genetic control and symbiotic functions. Microbial. Cell Factories, 5, p.7. https://doi.org/10.1186/1475-2859-5-7
8. Kelly, S.J., Muszynski, A., Kawaharada, Y., Hubber, A.M., Sullivan, J.T., Sandal, N., Carlson, R.W., Stougaard, J. & Ronson, C.W. (2013). Conditional requirement for exopolysaccharide in the Mezorhizobium-Lotus symbiosis. Mol. Plant Microbe Interact., 26, pp. 319-329. https://doi.org/10.1094/MPMI-09-12-0227-R
9. Lopez-Baena, F.J., Ruiz-Sainz, J.E., Rodriguez-Carvajal, M.A. & Vinardell, J.M. (2016). Bacterial molecular signals in the Sinorhizobium fredii-soybean symbiosis. Int. J. Mol. Sci., 17, 755 p. https://doi.org/10.3390/ijms17050755
10. Qurashi, A.W. & Sabri, A.N. (2012). Bacterial exopolysaccharide and biofilm formation stimulate chickpea growth and soil aggregation under salt stress. Braz. J. Microbiol., 43, No. 3, pp. 1183-1191. https://doi.org/10.1590/S1517-83822012000300046
11. Alami, Y., Achouak, W., Marol, C. & Heulin, T. (2000). Rhizosphere soil aggregation and plant growth promotion of sunflowers by an exopolysaccharide-producing Rhizobium sp. strain isolated from sunflower roots. Appl. Environ. Microbiol., 66, No. 8, pp. 3393-3398. https://doi.org/10.1128/AEM.66.8.3393-3398.2000
12. Naseem, H. & Bano, A. (2014). Role of plant growth-promoting rhizobacteria and their exopolysaccharide in drought tolerance of maize. J. Plant Interact., 9, No. 1, pp. 689-701. https://doi.org/10.1080/17429145.2014.902125
13. Vanderlinde, E.M., Harrison, J.J., Muszynski, A., Carlson, R.W., Turner, R.J. & Yost, C.K. (2010). Identification of a novel ABC transporter required for desiccation tolerance, and biofilm formation in Rhizobium leguminosarum bv. viciae 3841. FEMS Microbiol. Ecol., 71, No. 3, pp. 327-340. https://doi.org/10.1111/j.1574-6941.2009.00824.x
14. Leschenko, A.K., Sichkar, V.I., Mikhailov, B.G. & Mar'yushkin, V.F. (1987). Soya. Kyiv: Naukova dumka [in Russian].
15. Kots, S.Ya., Beregovenko, S.K., Kirichenko, E.V. & Melnykova, N.N. (2007). Features of interaction between plants and nitrogen-fixing microorganisms. Kyiv: Naukova dumka [in Russian].
16. Melnykova, N.M., Malichenko, S.M. & Datsenko, V.K. (1998). Study of competitiveness of lupine nodule bacteria under the inoculation by active and inactive strains. Fiziologiya i Biokhimiya Kult. Rastenii, 30, No. 1. pp. 49-53 [in Ukrainian].
17. Grodzinskiy, A.M. & Grodzinskiy, D.M. (1964). Quick reference guide for plant physiology. Kyiv: Naukova dumka [in Russian].
18. Fomkina, M.M. & Ibragimova, S.A. (2016). Using of microbial polysaccharides for seed treatment. Ogarev-online. Biological Sci. 24. URL: http://journal.mrsu.ru/arts/ispolzovanie-mikrobnyx-polisaxaridov-dlya-obrabotki-semyan [in Russian].
19. Kosenko, L.V., Khailova, G.F. & Korelov, V.E. (2001). Effect exopolysaccharides of Rhizobium leguminosarum bv. viciae on nodulation and rhizogenesis of pea plants. Fiziologiya i Biokhimiya Kult. Rastenii, 33, No. 4, pp. 347-354 [in Russian].
20. Laus, M.C., van Brussel, A.A. & Kijne, J.W. (2005). Exopolysaccharide structure is not a determinant of host-plant specificity in nodulation of Vicia sativa roots. Mol. Plant Microbe Interact., 18, pp. 1123-1129. https://doi.org/10.1094/MPMI-18-1123
21. Rodrigues, A.C., Vendruscolo, C.T., da Silveira Moreira, A., Santana, M.V.S, de Paula Oliveira, J.P., Bonifacio, A. & Figueiredo, M.A.D.V.B. (2015). Rhizobium tropici exopolysaccharides as carriers improve the symbiosis of cowpea-Bradyrhizobium-Paenibacillus. Afr. J. Microbiol. Res., 9, pp. 2037-2050. https://doi.org/10.5897/AJMR2015.7592
22. Skorupska, A., Derylo, M. & Lorkiewicz, Z. (1985). Role of noncarbohydrate substitutions of Rhizobium exopolysaccharide in nodulation process. Arch. Microbiol., 143, No. 3, pp. 307-331. https://doi.org/10.1007/BF00411255