P-161 - Exploring the Pathosystem Ramularia collo-cygni in Barley

Ramularia leaf spot disease has become one of the most important diseases in barley (Hordeum vulgare) cultivation, reducing grain quality and yield. Biotic cause of the disease is the hemibiotrophic fungus Ramularia collo-cygni (Rcc). Seed- and air-transmitted, Rcc initially establishes asymptomatically, followed by transition to a necrotic phase during the onset of leaf senescence. Control of Rcc in the field is hampered by the lack of resistant barley varieties and the decreasing efficiency of common fungicide classes. An alternative way to increase plant resilience to a broad spectrum of pathogens and pests are beneficial rhizobacteria, such as Bacillus spp., which can confer induced systemic resistance (ISR). Two consecutive years of field trials will reveal the influence of Bacillus spp. on the natural infection dynamics, analysed by Rcc-specific qPCR. To explore the plant-pathogen system, first, a reliable protocol for conidiospore production was established, to serve as inoculum for infection under greenhouse conditions. An artificial infection system was set up to study the influence of abiotic factors such as drought and light stress. For detailed analysis of fungus-plant interaction, Rcc was labeled with eGFP, to track the infection process by CLSM. Specific staining of fungal cell wall components indicates uneven distribution of chitin during infection establishment.