Screening Of Antibacterial Active Strains In Marine Fungi And Overexpression Of EqxR Gene In Fusarium Equiseti

Marine-derived fungi are grown in high-pressure,low-nutrient,low-temperature,salt-containing seawater environments,forming unique ecological characteristics and adaptation mechanisms that are resistant to hunger,salt,and alkali,and produce metabolites different from terrestrial microbial production.Marine-derived fungi have attracted the attention of pharmacologists due to their large-scale culture.The types of secondary metabolites of marine fungi mainly include alkaloids,polyketones,peptides,steroids,mites,and the like.Most compounds exhibit anti-inflammatory,antibacterial,antiviral and anti-tumor biological activities.The unreasonable use of antibacterial drugs worldwide has accelerated the emergence of super-resistant bacteria,and the development of a new generation of antibiotics is imminent.Most of the existing antibiotics are screened from soil-derived microorganisms.In order to obtain new antibiotics,marine-derived antibiotics have attracted great interest.The natural products of marine origin are more novel and more robust than terrestrial sources.Activity provides a material basis for the discovery of more desirable antimicrobial lead compounds.A rapid screening method for fungi with antibacterial activity was established.A double-layer agar plate rapid screening method was designed and improved.A modified double-layer agar plate screening method was used to rapidly screen a strain of 20 marine-derived fungi to obtain a significant antibacterial activity.The active strain WZXY-33-10,by identifying the active strain as Fusarium equisetin and separating and identifying two antibacterial active compounds equalitin(1)and epi-equisetin(2)by its modern chromatography and spectroscopy methods Specifically killing a variety of multi-drug resistant Gram-positive bacteria,and modifying the equisetin synthetic gene cluster to obtain equicetin high-yield strains.With the development of DNA sequencing technology,many new synthetic gene clusters have been discovered.Among the secondary metabolic related genes of these microorganisms,mainly include genes encoding secondary metabolic pathways and regulatory genes.According to genomic sequence analysis,genes encoded by genes can be identified.The catalyzed chemical reactions are genetically modified for our purpose.The whole genome sequencing of this Fusarium equiseti Fusarium oxysporum was carried out by second-generation sequencing technology to obtain detailed information of the equisetin biosynthesis gene cluster in the strain;the function of each gene or domain in the synthesis of equisetin was analyzed,according to literature reports.The over-expression of the regulatory factor eqxR of the synthetic gene cluster was carried out,and the eqxR gene was transformed and transformed by PEG/CaCl2-mediated protoplast genetic transformation technology to obtain a mutant strain.