?. The Effector Protein Uv2169 Of Aspergillus Oryzae Is Involved In The Study Of Pathogenic Mechanism.?. The Carbohydrate Preference Of Aspergillus Oryzae

Rice false smut?RFS?is a fungal disease caused by Ustilaginoidea virens.This disease has been recorded in the world's major rice producing areas.U.virens not only affects rice production,but also causes toxic reaction in both men and livestock eating contaminated food.Although recent reports of RFS are increasing,most of them focus on the disease cycle,biological characteristics and infection process in rice.The molecular mechanism of U.virens infecting rice is not clear,and the formation of RFS balls is still a puzzle.An enormous amount of research is yet to be carried out.Previously,comparative trancriptome analysis revealed that the expression of Uv2169 was up-regulated after infection in rice.Uv2169 was a typical effector,which could induce cell death and inhibit ROS burst.On the basis of previous study,the function of Uv2169 gene was further studied.The formation of RFS balls requires a large amount of nutrients.In order to understand the formation of RFS balls,the sugar preference for U.virens was also studied.The main results are as following:?1?The addition of Uv2169 siRNA to the culture medium of U.virens showed that the wet weight of Uv2169 interfered mycelium was about half of that of the control,and the pathogenicity of the pathogen was decreased,and gene silencing and over-expression transformants of Uv2169 were obtained successfully.The data demonstrated that the morphology of hyphae changed greatly after Uv2169 silenced or over-expressed,and the pathogenicity of transformants silencing Uv2169 was lost.?2?The yeast two hybrid cDNA library of U.virens infected rice spikelets was successfully constructed.The quality of the cDNA library was good,and 56 candidate interacting proteins were screened by Uv2169.Many candidate interacting proteins were found to be involved in ribosome construction by GO annotation,and some candidate interacting proteins from U.virens could regulate the growth and development of U.virens.Compared with U.virens,more interacting proteins in rice are responsive to microorganisms.?3?By using a variety of different sugars to culture the U.virens strain P4,it was found that stachyose could promote the mycelial growth and spore germination.?4?The differential expressed genes were detected by transcriptome sequencing of U.virens cultured by stachyose compared to sucrose.It was found that stachyose can regulate the differential expression of 89 genes?58 up-regulated and 31 down-regulated?,of which there are about 23 transporter related proteins,and there are 4 MFS family genes in the transporter related proteins were induced by stachyose.?5?qRT-PCR was performed to detect the expression of several candidate stachyose transporter genes under the condition of different sugar-containing PSA?Potato-Sucrose-Agar?medium and CB?Czapek-sucrose-broth?/CStB?Czapek-stachyose-broth?.The data showed that Uv8b₆977 is a potential stachyose transporter.?6?The addition of stachyose to culture several other fungi showed that stachyose can not only promote the growth of U.virens,but also can be used for the culture of other fungi.This information is useful for optimizing the culture medium of many fungi.In summary,RNA interference and over-expression of Uv2169 in PJ52-2-5 showed that Uv2169 could affect the development and pathogenicity of the U.virens.And the yeast two hybrid library screening identified many Uv2169 candidate interacting proteins,further validation is in progress.In addition,we found that stachyose can promote the growth of many fungi,and thus stachyose can be used as a medium additive to optimize the culture conditions of fungi.We also identified a candidate stachyose transporter Uv8b₆977.On the one hand,this study laid the foundation for the study of the molecular mechanism of the interaction between U.virens and rice.On the other hand,it could provide clues for the study on the sugar utilization strategies of U.virens.