| Wheat stripe rust is a major disease of wheat,which caused by Puccinia striiformis f.sp.tritici(Pst).It can infect wheat in seedling stage and adult stage,resulting in great losses in production.Therefore,it is of great concern to know more biological and molecular knowledge of Pst in the control of wheat stripe rust.During infection,Pst can produce specialized organization-haustoria,which is crucial to the survival of Pst.It can not only absorb nutrients from wheat for pathogen surviving,but also secrete effectors which are deemed to regulate the physiological and defensive processes of the host.Nevertheless the mechanisms how effectors regulate host immunity,and effector functions in wheat-Pst interacton are still unknown.In this study,we found two effectors which can enhance Pst virulence and defensive to wheat immunity.We also screened the targets of this two effectors in wheat.The main results are as follows:(1)Pst64 and Pst21918 both contain a signal peptide,they have no transmembrane region and no functional annotation,the latter contains a nuclear localization signal(NLS);These two effectors are all Pst specific and have low polymorphism among Pst races;The q RT-PCR showed that Pst64 was almost down-regulated during the Pst infection phase,while Pst21918 was firstly down-regulated and then up-regulated and finally touched a lowest ebb in Pst infectation stage,which indicated that different effectors may have different expression pattern and their functions may different;Tobacco infiltration showed that both Pst64 and Pst21918 can inhibit BAX-induced cell necrosis;and wheat overexpression implied that Pst64 and Pst21918 can inhibit wheat PTI.(2)Using the Y2 H system,we screened two candidate targets of Pst64,which are magnesium transporter Mgt E isoform X1 and methionine-R-sulfoxide reductase;Pst21918 also had two targets,they are chloroplast-localized Ptr Tox A-Binding protein1 and mitogen-activated protein kinase 6. |
