Studies On Transgenic LL37 Gene And Ginsenoside Synthesis Related Genes Of Maize

The widespread application of antibiotic in feed additives would disrupt the balance of microbial colonies in poultry and livestock,seriously affecting the yield and quality of poultry and livestock products,and restricting the development of animal husbandry.In addition,some antibiotics remain in poultry and livestock feces and are released into the soil through feces,causing environmental pollution.Producing antimicrobial peptides and ginsenosides in crops such as corn and directly using them as feed can effectively reduce the use of antibiotic feed additives.In this thesis,we generated transgenic maize expressing LL37 gene or ginsenoside synthesis related genes.The main results are as follows:（1）Plasmid p3301-M6-LL37 was constructed,in which the ear-specific promoter OsMads6 drives the human antibacterial peptide gene LL37.The expression vector and the previously constructed p3301-35S-LL37 vector in the laboratory and p3301-M6-LL37 vector were transformed into maize through Agrobacterium-mediated method,respectively.LL37 protein contents were measured through ELISA method,and the highest expression levels of LL37 protein in p3301-35S-LL37 maize leaves was 21.72ng/g·FW and the highest expression levels of LL37 protein was 11.26 ng/g·FW in p3301-M6-LL37 maize ears.The results of bacteriostatic experiments showed that transgenic maize had significant bacteriostatic effects on Rhizoctonia solani,Fusarium graminearum,Fusarium oxysporum,and Ascomycetes,The antibacterial effect of human antimicrobial peptide LL37 in transgenic corn material created in this study was consistent with previous studies.（2）The vector containing six ginsenoside synthesis related genes was previously constructed in the laboratory,which was transformed into maize through Agrobacterium-mediated technology,and T₀ transgenic maize plants containing all genes were identified.Using UPLC-Q-TOF-MS technology,ginsenoside components were detected in the leaves of T₀ transgenic maize newly obtained in this study and the T₁ generation seeds of the transgenic maize generated previously,however,no ginsenoside components were detected in transgenic maize.The reason may be that the transferred gene is regulated by other genes in maize,or that the promoter-terminator combination used by the expression vector may cause gene silencing.In this thesis,we created transgenic maize containing LL37 gene or ginsenoside synthesis related genes,and investigated the antibacterial effect of antibacterial peptide and the content of ginsenoside components,providing experience for the large-scale application of antibacterial peptide and ginsenoside as feed additives.