基于高通量测序分析芽孢杆菌Bam22防治油菜根肿病的机制OA

[Objective]The study evaluated the control effect of Bacillus amyloliquefaciens Bam22 on clubroot disease of oilseed rape and as-sessed its impacts on soil microbial community structure and physicochemical properties,so as to explore its application potential in sustain-able agriculture.[Method]The inhibition rate of B.amyloliquefaciens Bam22 on the germination of Plasmodiophora brassicae resting spores was determined using a co-culture experiment of the Bam22 and the pathogen.Meanwhile,pot experiments were conducted to assess its con-trol effect on rape clubroot.High-throughput sequencing technology was used to analyze differences in the diversity and community structure of rhizosphere soil microorganisms under different treatments(BS:Bam22 treatment;CS:Control treatment).Combined with the contents of soil physicochemical properties,the correlations between changes in rhizosphere microbial abundance of rhizosphere soil microbial communi-ties and soil nutrient content were analyzed.[Result]Bam22 exhibited significant inhibitory effects on the germination of P.brassicae resting spores and demonstrated effective disease control,achieving a spore germination inhibition rate of 50.60％and a clubroot control efficacy of 80.96％.BS significantly elevated the levels of soil total phosphorus(TP),available phosphorus(AP),ammonium nitrogen(NH4+-N),and available potassium(AK),with increases of 0.07 g/kg,3.51 mg/kg,0.40 mg/kg and 60.66 mg/kg,respectively,compared to the control soil(CS).Concurrently,BS significantly reduced the concentrations of total potassium(TK)and nitrate nitrogen(NO3--N),which were 0.46 g/kg and 3.05 mg/kg lower than that of CS,respectively.BS significantly enhanced the richness and diversity of rhizosphere soil micro-bial communities,which was evidenced by substantially higher values of the ACE index,Chao1 index and Shannon index in BS compared to CS.Regarding microbial community composition,BS demonstrated a statistically significant elevation in the relative abundances of Bacillus(10.14％vs.5.45％)and Burkholderia(3.73％vs.3.09％).Analysis of the relative abundance of the top 10 genera revealed that the Myxococcus had a strong positive correlation with soil total potassium(TK)and alkaline-hydrolyzable nitrogen(AN).Nitrososphaera displayed an extremely significant negative correlation with soil total nitrogen(TN),available phosphorus(AP),available potassium(AK),and nitrate nitrogen(NO3--N),along with a significant negative correlation with exchangeable calcium(Ex-Ca).Allomyces showed a significant positive correlation with soil total nitrogen(TN),available phosphorus(AP),nitrate nitrogen(NO3--N),and an extremely significant positive correla-tion with available potassium(AK).Additionally,Heterotypic bacteria demonstrated a significant negative correlation with soil pH.In the BS-treated soil,the abundances of Bacillus and Flavobacterium,both known as biocontrol or plant growth promoting properties,were significantly elevated,with relative abundances of 10.14％and 3.44％,respectively.Conversely,the relative abundance of Fusarium,a pathogen associat-ed with disease induction,was markedly reduced to 30.71％,significantly lower than CS.[Conclusion]B.amyloliquefaciens Bam22 markedly elevates soil total phosphorus(TP),available phosphorus(AP),ammonium nitrogen(NH4+-N)and available potassium(AK)levels,thereby substantially improving soil fertility.Concurrently,it significantly enhances soil microbial richness and diversity,elevating the relative abun-dances of biocontrol-associated genera(e.g.,Bacillus and Flavobacterium)while suppressing pathogenic taxa such as Fusarium.This dual regulatory mechanism effectively synergizes to maintain a balanced and healthy soil microbial community structure,ultimately conferring ro-bust suppression of clubroot disease of oilseed rape.