The Function Of Autophagy In Process Of Leaf Rust Fungus Infecting The Wheat

Autophagy is a kind of important biological defense and protection mechanisms that itdigests aging long life protein and injured cell structure and organelles in the condition ofnutritional deficiencies and environmental stresses to provide the necessary raw materialfor cells’ rebuilding, regeneration and repair, in order to achieve the cells’ recycle andreuse. Cell autophagy plays an important role in such as adaptation to the environmentchanges, the process of development and differentiation of cells, the decision of cells’lifetime, and a series of biological events. With the deepening of the research, the functionof autophagy in pathogen to the role of development, differentiation and disease also beganto be revealed. Recent studies indicate that autophagy affects appressorium’s turgor, andthus plays an important role in the pathogenicity of the rice blast fungus. With thecontinuous expansion of the autophagy, the research of pathogen infection structure lead toboom again. Leaf rust fungus is one of the main pathogens that causes the disease of leafrust and it is biotrophic fungus which has strong specialty. The mode of the leaf rustfungus infecting the wheat is different from the rice blast fungus. In this research, we usedwheat Lovrin10and leaf rust fungus165as the compatible interaction to carry on theexperiment. We systematically studied the feature of autophagy when is formed and thefunction of it by specific staining techniques and laser scanning confocal microscopy,transmission electron microscopy and drug test. We acquired the main results as follow:1The leaf rust fungus had differentiated germ tube and appressorium after8hinfecting. We didn’t find autophgosome in these two structures after MDC (autophagyspecific marker) staining and confocal observation.2Let the leaf rust fungus summer spores being cultured in the ordinary MS mediumuntil it germinated and sprouted, then using the inoculating needle gently to pick sporesinto a small centrifuge with glutaraldehyde under the dissecting microscope andproduced electron microscopy embedded block. Autophagic structures could not befound in summer spores and germ tubes after observing under the transmissionmicroscopy.3We took wheat leaves at different time point after infected with leaf rust fungusand made them into transmission electron microscopy embedded block. We determinedthe different infection structure by semi-thin positioning and observed them by confocal. We didn’t find autophgosome in appressorium, stomatal vesicle, intercellular hypha andhaustorium except haustorial mother cell, which has numbers of autophgosome.4We used pressure injection technique to inject autophagy inhibitor3-MA intowheat leaves after16h infected with leaf rust fungus and the CK is injected with PBS.After HR staining and observed by fluorescence microscopy, we found that3-MA couldinhibit the expanding size of mycelium mission and the ability of spores formation.The results above indicated that in the process of leaf rust infection, the leaf rustfungus structure haustorial mother cell has a lot of autophagosome. Autophagy involved inthe infection process of leaf rust fungus. After autophagy inhibitor3-MA inhibiting theformation of autophgosome in haustorial mother cell, leaf rust fungus’s colonies growthrate became slower and the ability of spores formation declined. The autophagy inhaustorial mother cell played an significant role in leaf rust fungus pathogenicity. Theresults of this study will help us better understand the role of autophagy in filamentousfungi, expanding people’s understanding of the physiological functions of organismsconservative intracellular substances high efficiency degradation pathway. It can provideeffective target sites to fight against leaf rust, and also provide a scientific theoretical andexperiment basis for breeding for disease resistance.