The Regulatory Mechanism Of Rab7 On The Biosynthesis Of DON In Fusarium Graminearum

Fusarium graminearum is one of the main pathogens of Wheat Scab. It can secrete DON toxin in wheat and infect with Fusarium head blight, which can affect the quality of agricultural products and food safety. There have been a lot of studies on the synthesis pathway of DON toxin produced by Fusarium graminearum, but the regulation mechanism of DON toxin synthesis is still not very clear, which is the main problem of the prevention and control of DON toxin pollution. Therefore, it is significant to study the regulation mechanism of DON toxin, which is very important for the effective control of DON toxin pollution. The subject select FgRab7 as the factor in controlling Fusarium graminearm toxin-producing, study of DON toxin biosynthesis regulatory mechanism designed to cut DON toxin levels through gene regulation for agriculture, theoretical basis for the disease control.Phenotype analysis was performed on the wild type PH-1 and FgRab7 knockout mutants of Fusarium, found that missing FgRab7 slow growth and sporulation decreased significantly. Detection of DON toxin accumulation in wild type PH-1 and FgRab7 knockout mutants and FgRab7 mutants by Elsia method, we found FgRab7 strains of DON toxins synthesis volume significantly reduced, 35 d of produced DON volume and wild type compared reduced near 11 times. The test of the production of complementary FgRab7 strains showed that 35 d produced DON volume is 6.9 times increased than knockout strains, so FgRab7 has play an important role on Fusarium graminearum produced DON toxinsIn order to clarify Rab7 regulatory molecular mechanisms, used the yeast two-hybrid system, successfully built decoy carrier pGADT7-Tri3 and pGBKT7-Rab7, then converted to AH109. Yeast transformants can grow on the culture medium(without SD/-Ade-/ Leu-/ Trp-/ His), Colonies shows blue on the SD/-Ade/-Leu/-Trp/-His/X-α-Gal plate, Proved that FgRab7 interacts with Tri3.Fluorescence quantitative PCR method was used to study the expression of FgRab7 on Tri gene, and the expression of Tri3, Tri4, Tri5, Tri6 and Tri101 genes in wild type strain PH-1 and FgRab7 knockout mutant were analyzed in different stages. Results show that in wild type strains and FgRab7 knockout mutant strains, with the prolongation of culture time, each tri gene expression increased gradually, 35 d expression amount reaches the maximum; but in tri gene in the mutant express knocking the same culture time FgRab7 its amount of was significantly lower than that of the wild type, inferred FgRab7 through regulation of tri gene expression reduced toxin synthesis.In summary, this paper prove Fusarium graminearum FgRab7 in toxin synthesis has an important role and found clear interaction between FgRab7 and tri3 gene. FgRab7 through synthesis of tri genes associated with regulation effect on expression of the toxin.