Based on changes of microbial community structure to analyze inhibitory parasitism ability of B. velezensis JTB8-2 to Orobanche aegyptiaca

Objective Investigating the relationship between the impact of B. velezensis JTB8-2 on soil microbial community structure and the decrease in Eguptian broomrape parasite population can provide a scientific basis for utilizing this strain effectively.

Methods Potted plants, high-throughput sequencing, and soil microbial isolation techniques were employed to analyze the effects of changes in microbial community structure on cuculla parasitism.

Results The population of viable bacteria in the rhizosphere soil and roots of tomatoes was 2.85×10⁷ and 2.32×10⁶ CFU/g, respectively, on the same day and after 3 days of application. After 39 days, the population of viable bacteria in the tomato rhizosphere soil and root decreased to 2.01×10⁷ and 1.35×10³ CFU/g, respectively. Furthermore, after 20 and 30 d, Pseudomonas spp. were found to be dominant in the tomato rhizosphere soil treated with bacterial solution and NB medium compared to the water control group. The abundance of Pseudomonas spp. was significantly higher than that observed in the water control group. Moreover, it was observed that Pseudomonas spp. isolated from tomato rhizosphere soil treated with bacterial solution exhibited biofilm production capability. Additionally, after both a duration of 20 days and a duration of 30 days, there was a significant reduction in Eguptian broomrape parasitism within the tomato rhizosphere compared to the water control group.

Conclusion B. velezensis JTB8-2 can colonize and survive in the rhizosphere soil of tomato plants, while attracting bacteria belonging to the Pseudomonas genus in the tomato rhizosphere soil to achieve antagonistic effects against Eguptian broomrape parasitism.