Abstract:

To screen the biocontrol bacteria of Salvia miltiorrhiza root rot, the infected S. miltiorrhiza and rhizosphere soil from healthy S. miltiorrhiza in Rizhao, Linyi, and Tai'an cities of Shandong Province were used as test materials. The tissue separation method was used to isolate the root rot pathogen from infected S. miltiorrhiza. The gradient dilution plate method and disk diffusion method were used to screen biocontrol bacteria from rhizosphere soil. Identification was achieved through the use of morphological characteristics and 16S rRNA, and control effect testing was carried out on the detached S. miltiorrhiza. The results showed that the pathogen RBT-2-1 isolated from infected S. miltiorrhiza was Fusarium equiseti, and the biocontrol bacterium i screened from rhizosphere soil was Pseudomonas chloriraphis subsp. aurantiaca. The antibacterial rate of i against TBG-2-1 was 66.67%. The control effect of i against TBG-2-1 on the detached S. miltiorrhiza in the prevention group was higher than in the treatment group. Furthermore, the addition of i in the prevention group resulted in the best control effect, reaching 44.45%. The prevention group of adding i was 1.6 times higher than the prevention group without addition, and 7.0 times higher than the treatment group. It can be concluded that the sequence and frequency of inoculation with i will affect the prevention efficacy of TBG-2-1. This study serves as a guide for future field experiments.

Key words: root rot of Salvia miltiorrhiza, Fusarium equiseti, Pseudomonas chlororaphis subsp. aurantiaca, biocontrol bacterium, disk diffusion method, prevention and control effect, vaccination sequence, usage frequency