| In recent years, corn sheath rot occurred in national-wide corn production areas, and the trend of the disease increased year by year. But there were a few reports upon the occurrence and management of corn sheath rot all over the world till now. This study investigated the corn stem lodging-resistant and yield at different levels of corn sheath rot, and studied the infecting mechanism of Fusarium proliferatum against maize. Obtaining the reduced form of emerge spore conversion unit will lay a solid foundation for the further researching about infection mechanism and disease control of corn sheath rot. The main results were as follows:(1)At the beginning of the corn flower field of corn hybrids Zhengdan 958, inbred lines Zheng58 and OH43Ht1, corns with different diseased-degree were obtained by inoculating different concentration of spore suspension of Fusarium proliferatum in the field. We investigated the disease degree at the milk stage of corn, then the lodgingresistance of corn was measured by the YYD-1B digital display plant stems intensity detector, and the yield was determined after harvest. The stem lodging-resistance of inbred lines OH43Ht1, Zheng 58 and hybrid variety Zhengdan 958 were decreased with the diseased-degree of corn sheath rot increased. Data analysis showed that the yield of Zheng 58 and Zhengdan 958 decreased while the corn sheath rot disease level increased. The yield reduction of inbred lines Zheng 58 was increased from 13.84% to 29.53% per hectare, while it was increased from 3.99% to 16.72% per hectare of hybrid Zhengdan 958. The above results suggested that it could reduce the lodging-resistance, and then reduce the yield when corn sheath rot occurred seriously. In addition, the effect on inbred lines was greater than hybrids.(2)Using Agrobacterium tumefaciens-mediated transformation(ATMT) to transform F. proliferatum, the mutant library was built. Then we analyzed the phenotypes of 100 transformants, and measured their pathogenicity. We obtained a strain FP106, whose pathogenicity was obviously increased and two strains FP62 and FP80, whose pathogenicity were obviously decreased, then tested the cell wall degradation enzymes and crude toxin of the three mutants. The results showed that the cell wall degradation enzymes and crude toxin which were secreted by strains were positively correlated with the pathogenicity of strains. The research results could lay preliminary foundation for acquiring pathogenic gene of F. proliferatum and providing reference for effective prevention. |
