2026-10-15T05:19:49Z https://www.scidb.cn/oai

10.57760/sciencedb.nprd.00102 2026-02-25T14:32:51Z

2026-02-25 1.The effects of thyme essential oil at different concentrations on the inhibition rates of three main pathogenic bacteria causing root rot of Astragalus mongholicus 2.Data related to pathogen identification doi:10.57760/sciencedb.nprd.00102 en 1.The mycelial discs with a diameter of 6 mm were inoculated in PDA medium with thyme essential oil concentrations of 0.5, 1.0, and 1.5 μL/mL respectively, and the antibacterial effects of the essential oil at different concentrations were analyzed (see Figure 6). After 72 h of in vitro contact, when the thyme essential oil concentration was 0.5 μL/mL, the average inhibition rates of the three pathogenic fungi from high to low were: Penicillium chrysogenum (35.2%) > Fusarium solani (30.1%) > Fusarium oxysporum (28.4%). When the concentration was 1.5 μL/mL, the inhibition rate against Penicillium chrysogenum reached the highest (72.1%), indicating that the inhibitory effect on Penicillium chrysogenum was stronger at this concentration. After 120 h of in vitro contact, when the concentration was 1.5 μL/mL, the average inhibition rate of the three pathogenic fungi was 82.67%. After 168 h of in vitro contact, when the thyme essential oil concentration was 0.5 μL/mL, the inhibition rate against Fusarium oxysporum was the lowest at 35.4%. When the concentration was 1.5 μL/mL, the average inhibition rates of the three pathogenic fungi were Penicillium chrysogenum (88.3%) > Fusarium solani (78.1%) > Fusarium oxysporum (73.5%).2.Isolation and purification of pathogenic bacteriaThe treated lesion tissue was placed on a sterilized PDA medium and incubated in a constant temperature incubator at 28°C for 48 hours. The colony morphology was observed on the plate, and colonies with distinct morphological differences, neat edges, and rapid growth were selected for re-isolation and repeated purification. The selected colonies were separated on a new agar plate using the streaking method until a single colony was obtained [15].Observation of pathogenic bacteria morphologyA 6 mm fungal colony was taken from the edge of the purified fungal plate and placed on a new PDA medium, and then incubated in the dark at 27°C for observing the colony and conidial characteristics. A fluorescence microscope was used for observation and photography. The fungi were identified according to the "Manual of Fungal Identification" [16].Molecular identification of pathogenic bacteriaDNA was extracted from the mycelium cultured for 6 days. Using DNA as the template, PCR amplification was performed with the fungal identification primers ITS1: 5'-TCCGTAGGTGAACCTGCGG-3' and ITS4: 5'-TCCTCCGCTTATTGATATGC-3'. The reaction process was as follows: pre-denaturation at 96°C for 2.5 min; denaturation at 96°C for 30 sec; annealing at 55°C for 30 sec; extension at 72°C for 1 min 30 sec; 30 cycles; extension at 72°C for 5 min. The products were detected by 1.5% agarose gel electrophoresis, and the target fragment was observed under blue light and purified from the gel. Then, DNA sequencing was performed using a sequencer, and the spliced sequence file was compared with the database using the NCBI Blast program to obtain the comparison results. Finally, a phylogenetic tree was constructed using MEGA7.0 software [17]. Thyme essential oil; root rot; Astragalus membranaceus var. mongholicus; root rot feng han RESTRICTED dataset Science Data Bank