The Pathway And Biochemical Mechanism Of Fusarium Proliferatum Infecting Corn Sheath

Fusarium proliferatum is the main pathogen of corn sheath rot, which is able to secretcell wall degrading enzymes and toxins to infect the hosts. In order to explore themechanism of pathogen infection, we analyzed the paths of F. proliferatum infection ofhost, observed the changes of host cell ultrastructure in different infection periods anddeterminated the physiological and biochemical indexes during pathogen-host interaction.The main results were summarized as follows:1. In this study, the green fluorescent protein (GFP) gene was integrated into F.proliferatum genome via Agrobacterium tumefaciens-mediated transformation (ATMT).Ten mutants with green fluorescent marker were obtained.2. The results of scanning electron microscopy, fluorescent microscopy and placentablue staining analysis showed that the F. proliferatum could infect directly and indirectlyby stomata, although infection via stomata is the main pathway. The pathogen recognizedthe host after inoculation12to24h, then invaded the host cell after inoculation48h, andcolonized the host cells after inoculation72h in corn sheath.3. Transmission electron microscope observations showed that F. proliferatum mainlydamaged the host cell wall in latent period. The pathogen mainly damaged hostchloroplasts and nuclei after symptomatic period.4. The cellulase and pectinase activity began to rise after inoculation, and thiscorresponds to the cellulose and pectin content of corn sheath began to decline. Comparedwith the cellulose activity, pectinase activity was increased a greater degree. The resultindicated that the pectinase played a major role in the process of host infected by F.proliferatum.5. By analyzing the lignin content of different resistant materials, we found the lignincontent were gradually increased from latent period to invasion stage, then the lignincontent began to decrease. And the lignin content of mild-resistant varietie was lower thanhigh-resistant one.6. By analyzing the soluble sugar content of different resistant materials, we found thesoluble sugar content increased during latent period. But with the symptoms aggravate, the soluble sugar content decreased gradually. The soluble sugar content of mild-resistantvarieties reduced severely at late-onset.7. The soluble protein content of different resistant materials declined gradually afterinoculated. The soluble protein content of mild-resistant varietie was lower thanhigh-resistant one.