Biosynthetic Regulation,chemical Modification And Plant Parasite Nematode Inhibitiory Activity Assays Of Beauvericin

Plant nematodes cause great loss to food production every year,but the kinds of nematicide which can control it are far from enough.The researh previously shows that Avermectin and Emodepside which belong to macrolide and cyclopeptide compound respectively can control the nematodes efficiently.Beauvericin has special mechanism and broad bioactivity.Cordyceps bassiana?Bb2860?and Isaria fumosorosea?ISF2679?which both are insecticidal fungi can biosynthesize Beauvericin.The study in this article is mostly about the biosynthesis regulation,chemical modification and nematocidal activity of Beauvericin.The research of biosynthesis regulation on Beauvericin is based on the Cordyceps bassiana?Bb2860?and Isaria fumosorosea?ISF2679?.The gene BBA₀9723 of Cordyceps bassiana,ISF₀0192 and ISF₀4479 of Isaria fumosorosea were knocked out respectively.BBA₀9723 and ISF₀0192 are speculated to be gene of C6 transcription factor repectively,and ISF₀4479 is the gene of histone acetylation enzyme.Beauviricin biosynthesis ability of the three deletion mutant,the BBA₀9723 overexpression mutant and the wild type of Cordyceps bassiana and Isaria fumosorosea were compared.The toxicity of these fungi to G mellonella were tested too.The result show that ISF₀0192 and BBA₀9723 negatively control the Beauvericin biosynthesis,and the deletion of ISF₀4479 causes it obsolutely losed.The mutations'toxicity against G.mellonella are better than the relating wild type respectively,and this shows that the genes all above can effect the toxicity of fungi.Beauvericin is a promising drug lead,and its biosynthesis and extraction is the key process.In the part,we studied the fermentation of Isaria fumosorosea,extraction and purification of Beauvericin.Beauvericin was chemical modificated by chemical synthesis method,and morpholinyl was introducted into the structure.At last,bioassay was done to compared the inhibitory bioactivity against with nematode in vitro and in vivo.The bioassay results showed that the introdution of morpholinyl can increase the inhibition activity of the compound.The inhibition index of the separation 3 of the derivative is 1.5 which is better than that of the Beauvericin.And this indicated that the chemical modefication need further exploration.