Bacteriophage Preparation Engineering for Biocontrol of Pseudomonas Syringae in Crop Science

Abstract

Phytopathogenic bacteria Pseudomonas syringae cause diseases of many cultivated plants, causing tumor neoformation, rot, chlorosis, necrosis, etc . The advanced biological mean to control bacteriosis in crop science is bacteriophages. In this work full biological characteristic of 8 bacteriophages is shown, active according to Pseudomonas syringae. The studied phages formed similar negative colonies- clear, rounded, in diameter of 5-9 mm. Lytic actifity of phages Pseudomonas syringae by Appelman from 10-4 to 10-8; by Gratia from 1,0±0,1×106 to 2,0±0,1×109 (BFU/ml). Bacteriophages Ps.s-7 UlGAU, Ps.s-13 UlGAU and Ps.s-27 UlGAU did not change lytic activity when storing in fridge during 12 months. Lytic activity of phages Ps.s-1 UlGAU, Ps.s-8, Ps.s-15 UlGAU, Ps.s-30 UlGAU, Ps.s-77 UlGAU in the same conditions fell within 1-2 orders. Spectrum of lytic activity of phages varied from 21,4% (Ps.s-13 UlGAU) to 85,7% (Ps.s-7 UlGAU, Ps.s-27 UlGAU). The study of phage specificity on 15 species og heterologous cultures showed that phages are specific for Pseudomonas syringae. Phages are moderately stable to heating and lose activity during 30 –minute temperature effect above 62°С. The optimal way to relieve phage lysate from living cells of Pseudomonas syringae was thrichloromethane at a ratio of 10:1and temporal exposition 45 minutes. On the basis of obtained data we determined capacity of each bacteriophage for the use as biocontrol agent. For further research for the study of molecular genetic characteristics we selected advanced strains of phages Pseudomonas syringae - Ps.s-7 UlGAU и Ps.s-27 UlGAU.