Gerüstproteine der Gerste in der Aktinreorganisation und Krankheitsentwicklung

• Applicants: Dr. Götz Hensel; Professor Dr. Ralph Hückelhoven
• Subject Area: Plant Breeding and Plant Pathology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 493803847

The mechanisms of plant disease susceptibility are of increasing interest to the cscientific community and to plant breeding. In barley, the small ROP (RHO of Plants) GTPase RACB is a susceptibility factor in interaction with the powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh). Genetic evidence suggests that Bgh addresses the barley cytoskeleton by manipulating functions of RACB. However, the exact mechanisms of ROP functions exploited by the fungus are not comprehensively understood. The new annotations of the barley genome and experimental evidence suggest that barley expresses five scaffold proteins expressed in the leaf (RICs for: ROP-Interactive and CRIB motif-containing protein) that interact directly with RACB. Distantly related RIC proteins in dicotyledonous plants, together with ROPs, affect the cytoskeleton. The aim of this project is to analyse the function of barley RIC proteins and to understand their contribution to RACB- and Bgh-mediated reorganization of the barley cytoskeleton. Experimentally, we are going to show the interaction of RACB with individual RIC proteins and with RIC-containing protein complexes in yeast and barley. Transient and stable overexpression of the proteins in barley show the contribution to cell autonomous and whole plant resistance or susceptibility to Bgh. Complementary transient gene silencing and stable RNA-guided endonuclease-mediated loss of gene function are induced and investigated for their effect on the host-parasite interaction. In addition, cell biological markers of the filamentous actin cytoskeleton, which are newly established for barley, will be used to study the influence of genetic factors on the cytoskeleton in living cells. Beyond this, new components of the RACB-RIC complexes will be biochemically identified and tested for function. The combination of genetic and cell biological approaches will further elucidate the mechanisms of RACB-mediated susceptibility in barley, thereby systematically assessing the function of leaf-expressed RICs in susceptibility and cytoskeletal organization.

• DFG Programme: Research Grants