Study On The Antibacterial Mechanism Of Carvacrol On Storage Pathogenic Bacteria Of Garlic Sprout

During the storage period of garlic sprouts,they are infected by fungal diseases,leading to their decay and the formation of harmful toxins,resulting in significant loss of garlic sprouts and serious economic losses.At present,research on the prevention and control of plant fungal diseases mainly focuses on preservatives.Plant essential oils are natural preservatives with broad-spectrum and efficient antifungusl properties,and can be used as substitutes for chemical preservatives.This paper focuses on the natural preservative carvacrol as the main research object,exploring the antifungusl effect of carvacrol on garlic sprout storage pathogens,revealing the antifungusl mechanism of carvacrol at the molecular level,in order to study the use effect and principle of action of carvacrol in garlic sprout storage and preservation from the perspective of antifungusl activity.The main research content of the paper includes two parts:1.Screening of pathogenic fungus from garlic sprouts and the antifungusl effect of carvacrol: Through traditional microbiological isolation and identification and r DNAITS cloning and sequencing technology,the main pathogenic fungal species of garlic sprouts during cold storage and market sales were identified,and 8 strains of fungus were isolated and purified,Two strains with pathogenicity to garlic moss were identified through pathogenicity backgrafting experiments: Fusarium Tubingensis(F strain)and Aspergillus Tubingensis(HQ strain).At the same time,through in vitro antifungusl experiments,the inhibitory effect of carvacrol on garlic sprout pathogenic fungus was investigated.The regression equation of mycelial expansion toxicity,concentration for 50% of maximum effect,spore germination rate,protein content,and mycelial morphology and ultrastructure were used as parameters to analyze the inhibitory effect of carvacrol at different concentrations on F and HQ fungus,The results showed that carvacrol significantly inhibited the growth of mycelium and spore germination of F and HQ fungus,which were the pathogens of garlic moss.Carvacrol treatment significantly increased the leakage of protein in the fungus.Further scanning electron microscopy observation confirmed that carvacrol treatment destroyed the cell membrane of the fungus,causing the leakage of intracellular protein components,thereby inhibiting the growth of pathogens.2.Research on the mechanism of carvacrol inhibiting the pathogenic fungus of garlic moss: The effect of carvacrol on the expression of F fungus and HQ fungus at the gene level was analyzed by high-throughput sequencing technology and transcriptome technology.The results showed that 14417 genes were detected in F fungus experimental group vs control group(FX vs FC),of which a total of 739 differentially expressed genes: 201 up-regulated genes and 538 down-regulated genes;A total of11809 genes were detected in the HQ fungusl experimental group compared to the control group(HX vs HC),including 1442 differentially expressed genes: 402 upregulated genes and 1040 downregulated genes.Through GO functional enrichment analysis,FX vs.FC differentially expressed genes were annotated to transport activity,transferase activity,and transmembrane transport protein activity related functions,as well as ion binding,indicating that the inhibitory effect of carvacrol on F fungus may be influenced by membrane transport and ion regulation of the strain;The differential expression genes of HX vs.HC were annotated on membrane and ion binding and anion coordination related functions,indicating that the inhibitory effect of carvacrol on HQ fungus may also be influenced by the membrane transport and ion regulation of the strain.Through KEGG pathway enrichment analysis,FX vs FC mainly enriched glycolysis,ergosterol biosynthesis,sphingomyelin metabolism,amino acid synthesis and other pathways in steroid biosynthesis;HX vs.HC mainly enriches the biosynthesis pathway of ergosterol,MAPK signal transduction,and cell cycle pathways in steroid biosynthesis.The differentially expressed genes of F fungus and HQ fungus are enriched in the steroid biosynthesis pathway,and some differentially expressed genes are significantly upregulated or downregulated,affecting normal steroid biosynthesis,mainly affecting the synthesis of fungal ergosterol.This indicates that carvol inhibits carvol by inhibiting the synthesis of ergosterol,the main component of the cell membrane of pathogenic fungus,which leads to cell abnormalities and the growth and development of mycelium are blocked.The related genes in the biosynthesis pathway of ergosterol may be the antifungusl target of carvol.In addition,differential genes enrich the expression of enzyme genes related to cell walls,and the effect of celery phenol leads to the formation of chitin synthase andβ-The expression of 1,3-glucan synthase genes was significantly downregulated,and the cell wall structure was disrupted,promoting the interaction between carvacrol and fungal cell membranes,which may be another reason for cell abnormalities and hindered mycelial growth and development.