| Lactiplantibacillus plantarum P9 was isolated from sour porridge samples in Bayannaoer City,Inner Mongolia.This study found that L.plantarum P9 also had good inhibitory activity against Aspergillus flavus through preliminary experiments.However,the current research on the antifungal properties of L.plantarum is still at the physiological and biochemical level,and the key factors for the antifungal activity of L.plantarum are still unclear.Therefore,this study took L.plantarum P9 as the research object.According to the difference in the number of viable bacteria in co-cultivation with A.flavus,samples were taken at 9 h and 14 h of co-cultivation,using SMRT sequencing technology and transcriptome sequencing technology,from the perspective of methylation and Transcriptome level exploration of L.plantarum P9 inhibition of A.flavus and to understand related important functional genes.The main findings are as follows:(1)Two methylation sites,m4 C and m6 A,were mainly identified in L.plantarum P9.Compared with 14 h,the methylation levels of m4 C and m6 A were higher after 9h of culture,with an average of 65.56% and 39.48%.A total of 2578 differentially methylated genes were identified between the experimental group and the control group,and the differentially methylated genes in the 9-h co-culture treatment were mainly enriched in metabolic pathways such as glycolysis/gluconeogenesis,pyruvate metabolism,and purine metabolism,14 h no significant enrichment pathway.It was shown that L.plantarum P9 mainly enhanced energy metabolism in the early stage of interaction,and it was speculated that energy metabolism was the key factor regulating the antifungal effect of L.plantarum.(2)Compared with the control group,a total of 938 differentially expressed genes were obtained after co-culturing for 9 hours,including 377up-regulated genes and 561 down-regulated genes.These differential genes were mainly enriched in metabolic pathways,biosynthesis of secondary metabolites.There are four pathways of microbial metabolism and biosynthesis of amino acids in different environments;only 30 differentially expressed genes were obtained after co-cultivation for 14 h,including 28up-regulated genes and 2 down-regulated genes,with no significantly enriched pathways.(3)Through the correlation analysis between methylation and gene expression,it was found that the level of gene methylation and expression were negatively correlated at 9h and 14 h of co-culture,and did not reach a significant level,indicating that the expression of L.plantarum P9 gene was regulated by methylation in co-culture.The effect of chemical regulation was not significant.By further intersecting the differentially methylated genes and differentially expressed genes,five genes related to lipid metabolism were obtained,namely: fab H,fab D,acc C,fab I and psf-1,which may play an antifungal role for L.plantarum key factor.In conclusion,this study revealed the correlation between the molecular level and antifungal properties of L.plantarum P9 from the perspective of methylation and transcriptomics,and the results showed that the genes regulating energy metabolism and lipid metabolism play a major role.This study will help to deeply analyze the antifungal mechanism of L.plantarum P9,and provide reference for the utilization and development of L.plantarum P9 in agriculture and food. |
