Investigation of the role of a candidate effector of wheat stripe rust pathogen in plant immunity

Dagvadorj, Bayantes
The advanced plant molecular biology and plant biotechnology tools were employed in this thesis, in order to understand the role of a candidate effector, PstSCR1, of Puccinia striiformis f. sp. tritici (Pst) causing yellow rust disease in wheat. The homologues proteins of PstSCR1 were found to be only conserved in Pst, and in its closest relative, Puccinia graminis f. sp. tritici (Pgt). When PstSCR1 was expressed in Nicotiana benthamiana with its signal peptide (SP), it provoked the plant defense, whereas no such effect observed when it is expressed without SP, since SP facilitates crossing of proteins through cellular membranes, it is predicted that the effector is only functional (in triggering plant immune response) if secreted into plant apoplast. The subcellular localization of PstSCR1 was also investigated by microscopic analysis; the effector was indeed secreted to apoplast as the same as apoplastic marker C14 protein. It was also observed that the expression of the effector lowered the pathogenicity of Phythophtora infestans and Peronospora tabacina on N. benthamiana leaves, respectively. Moreover, when PstSCR1 was overexpressed, it triggered cell death. Brassinosteroid insensitive 1-Associated Kinase 1 (BAK1/SERK3) silenced N. benthamiana, cell death was remarkably abated, indicating BAK1 dependent function. Although SCR1-purified treatment on N. benthamiana showed a lack of cell death, it resulted in induction of defense genes NbCYP71D20 and NbACRE31, of which are induced in BAK1 dependent immune response. Based on our results, Pst-secreted protein, SCR1 can activate PAMP-triggered immunity on non-adapted hosts and contribute to non-host resistance.  


Kocabıyık, Semra (Elsevier BV, 1989-07-01)
The genetics of ANT(2″) and AAC(3)-II mediated gentamicin resistance in Gram-negative bacteria obtained from Hacettepe University Hospital in Turkey, was studied. The plasmid DNA analyzed by agarose gel electrophoresis revealed a heterogeneous plasmid population. Conjugal transfer appeared to be an efficient mechanism for the dissemination of resistance to gentamicin/tobramycin/kanamycin/streptomycin/chloramphenicol/cephalothin, which was the common resistance pattern in the population. Plasmids of 46, 60, ...
Cutting edge: Role of toll-like receptor 9 in CpG DNA-induced activation of human cells
Takeshita, F; Leifer, CA; Gursel, I; Ishii, KJ; Takeshita, S; Gürsel, Mayda; Klinman, DM (The American Association of Immunologists, 2001-10-01)
Unmethylated CpG motifs present in bacterial DNA stimulate a rapid and robust innate immune response. Human cell lines and PBMC that recognize CpG DNA express membrane-bound human Toll-like receptor 9 (hTLR9). Cells that are not responsive to CpG DNA become responsive when transfected with hTLR9. Expression of hTLR9 dramatically increases uptake of CpG (but not control) DNA into endocytic vesicles. Upon cell stimulation, hTLR9 and CpG DNA are found in the same endocytic vesicles. Cells expressing hTLR9 are ...
Detection and characterization of plant genes involved in various biotic and abiotic stress conditions using ddrt-pcr and isolation of interacting proteins
Ünver, Turgay; Akkaya, Mahinur S.; Department of Biotechnology (2008)
The main objective of this thesis dissertation is functionally characterizing the genes involved in biotic and abiotic stresses of plants at molecular level. Previously, upon pathogen attack Rad6 gene expression was found to be changed in wheat and barley plants. To functionally characterize the Rad6 gene, VIGS (Virus induced gene silencing) system was used. HR (Hypersensitive response) like symptoms was detected in every silenced barley and wheat plants. To figure out, transcriptomes and proteomes of Rad6 ...
Potential role of phosphatidylinositol 3 kinase, rather than DNA-dependent protein kinase, in CpG DNA-induced immune activation.
Ishii, KJ; Takeshita, F; Gursel, I; Gürsel, Mayda; Conover, J; Nussenzweig, A; Klinman, DM (Rockefeller University Press, 2002-07-15)
Unmethylated CpG motifs present in bacterial DNA stimulate a strong innate immune response. There is evidence that DNA-dependent protein kinase (DNA-PK) mediates CpG signaling. Specifically, wortmannin (an inhibitor of phosphatidylinositol 3 kinase [PI3]-kinases including DNA-PK) interferes with CpG-dependent cell activation, and DNA-PK knockout (KO) mice fail to respond to CpG stimulation. Current studies establish that wortmannin actually inhibits the uptake and colocalization of CpG DNA with toll-like re...
CpG RNA: identification of novel single-stranded RNA that stimulates human CD14+CD11c+ monocytes.
Sugiyama, T; Gürsel, Mayda; Takeshita, F; Coban, C; Conover, J; Kaisho, T; Akira, S; Klinman, DM; Ishii, KJ (The American Association of Immunologists, 2005-02-15)
Synthetic immunostimulatory nucleic acids such as CpG DNA are being harnessed therapeutically as vaccine adjuvants, anticancer or antiallergic agents. Efforts to identify nucleic acid-based agents capable of more specifically modulating the immune system are being developed. The current study identifies a novel class of single-stranded oligoribonucleotides (ORN) containing unmethylated CpG motifs and a poly(G) run at the 3 end (CpG ORN) that directly stimulate human CD14 CD11c monocytes but not dendritic ...
Citation Formats
B. Dagvadorj, “Investigation of the role of a candidate effector of wheat stripe rust pathogen in plant immunity,” Ph.D. - Doctoral Program, Middle East Technical University, 2016.