GRAIN-RESIDING ENDOPHYTIC BACTERIUM Paenibacillus polymyxa P 6.3 POSSESSES GROWTH-PROMOTING ACTIVITY AND PROTECT WHEAT GRAIN FROM PATHOGENIC EFFECT OF Pseudomonas syringae

Aim. To examine the effect of endophytic bacteria Paenibacillus polymyxa P 6.3, which was isolated from grains of winter wheat variety Podolyanka, on the germination of wheat grains after the exposure Pseudomonas syringae. Methods. Growth-promoting and biocontrol activity of P. polymyxa P 6.3 were examined using roll method. Standardized wheat grains were soaked in a suspension of 24 h culture of P. polymyxa P 6.3 for 12 h, control grains were soaked in sterile distilled H2O. After soaking, both pre-treated and control grains (of 25 pcs) were put into rolls. In three days, half of both pre-treated and control grains were exposed to phytopathogen P. sуringae, and germination was continued. The lengths of coleoptile and main root were measured on the 7th day of the experiment. Results were expressed as M ± m. Differences were considered significant at P ? 0.05. Results. Treatment wheat grains with P. polymyxa P 6.3 resulted in increased growth of coleoptile and main root in all three varieties. Most prominent effect was registered in Favorytka variety. After the exposure to phytopathogenic pseudomonads, slowing down of the growth of coleoptile and main root occurred in all wheat varieties. Highest susceptibility to P. syringae pathogenic effect was registered in Holikovska variety. Pre-treatment of wheat grains with endophytic bacteria abrogated growth-inhibiting effects of P.syringae. Conclusion. Endophytic bacteria P. polymyxa P 6.3 exerts a growth-stimulating effect on wheat germination and a protective effect against P. syringae. The plant growth promoting potential and antagonistic activity make strain P 6.3 a promising biocontrol agent and growth stimulator as a biofertilizer.