Characterization of Blumeria graminis peptides as potential effectors targeting barley RAC/ROP proteins

小分子单体RAC/ROP GTP酶是细胞极性和植物防御反应的分子开关。在大麦中，RACB和相关的RAC/ROPS在对生态子囊菌Blumeria graminis f.sp.的敏感性中起作用。霍尔迪(BGH)。为了鉴定RACB相互作用蛋白，我们对感染病毒的大麦进行了酵母双杂交筛选。这鉴定了六个真菌克隆，它们编码同一类小肽。在独立的检测中证实了蛋白质-蛋白质的相互作用，真菌RACB相互作用肽的GFP-融合蛋白标记了细胞质和细胞皮质中的小结构，并在病原体进入的位置积累。两个BGH多肽的过度表达或宿主诱导的基因沉默，分别增强或降低了对真菌进入的敏感性。通过使用细胞生物学和遗传学工具，我们现在希望提供证据，证明这些多肽代表真菌毒力效应物，针对大麦RAC/Rop进行效应器触发的敏感性。

Small monomeric RAC/ROP GTPases are molecular switches in cell polarity and plant defence responses. In barley RACB and related RAC/ROPs function in susceptibility to the biotrophic ascomycete pathogen Blumeria graminis f.sp. hordei (Bgh). To identify RACBinteracting proteins, we have carried out yeast two hybrid screenings of a cDNA library from infected barley. This identified six fungal clones coding for to the same class of small peptides. Protein-protein interaction was confirmed in independent assays, and a GFP-fusion protein of a fungal RACB-interacting peptide labelled small structures in the cytoplasm and cell cortex and accumulated at the site of pathogen entry. Over-expression or host-induced gene silencing of two Bgh-peptides, enhanced or reduced susceptibility to fungal entry, respectively. By the use of cell-biological and genetic tools, we would like now to provide evidence that the peptides represent fungal virulence effectors that target barley RAC/ROPs for effector-triggered susceptibility.