绿农林®41复合微生物肥料改善根际土壤微生物群落缓解胡椒连作障碍的机制研究OA

This study investigated the mechanism by which Lvnonglin® 41 compound microbial fertilizer alleviating the continuous cropping obstacle in black pepper from the perspectives of bacterial and fungal community assembly and the potential functions in the rhizosphere soil,aiming to provide technical and theoretical guidance for healthy pepper cul-tivation.A field with a history of severe continuous cropping obstacle was selected for the experiment.Four treatments were established,water control(CK),Lvnonglin® 41 composite microbial fertilizer(LV41),composite microorganisms(CM),and nutrient substrate(NS).The incidence of Fusarium wilt was determined,and high-throughput sequencing was employed to analyze the community structure,diversity,and functional characteristics of bacteria and fungi.The results showed that compared with CK,all treatments exhibited some mitigating effects,with the LV41 treatment showing the most significant effect.The control efficacy of LV41 against Fusarium wilt incidence across different growth stages of pepper reached 83.01%to 86.50%.CM had the highest number of unique bacterial OTUs,while NS had the highest number of unique fungal OTUs.For bacterial communities,both Chao1 and Shannon indices followed the order CM>LV41>NS>CK.For fungal communities,the Chao1 index followed CM>LV41>NS>CK,whereas the Shannon index followed CK>NS>LV41>CM.PCoA results indicated distinct separations in both bacterial and fungal communities among the treatments.Treatment LV41 enriched beneficial bacteria Bacillus and Nitrospira,as well as beneficial fungus Chaetomium,with relative abundances of 2.09%,1.74%and 18.40%respectively,which were mark-edly higher than those in other treatments.The relative abundances of potential pathogen Fusarium and beneficial fun-gus Trichoderma were 1.92%and 0.33%,obviously lower than other groups.LEfSe analysis revealed that differentially abundant species in the LV41 treatment included 4 bacterial and 5 fungal taxa.Co-occurrence network analysis indi-cated that LV41 increased the complexity of the bacterial network and the clustering coefficient of the fungal network.Functional prediction showed that in LV41,the bacterial group Gram negative increased most significantly,while stress tolerant decreased most significantly.Fungal functional groups such as animal pathogen‒dung saprotroph‒endophyte‒epiphyte‒plant saprotroph‒wood saprotroph showed the most pronounced increase.The bacterial community assembly in LV41 was dominated by deterministic processes,whereas the fungal community assembly remained primarily sto-chastic.In conclusion,Lvnonglin® 41 composite microbial fertilizer reduced the incidence of Fusarium wilt in con-tinuously cropped pepper by improving bacterial and fungal community structure,network complexity and stability,functional composition,and assembly processes,demonstrating good potential for alleviating the continuous cropping obstacle in pepper.