Dissecting the virulence components of two important barley pathogens

• Applicant: Dr. Fluturë Novakazi
• Subject Area: Plant Breeding and Plant Pathology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 557171467

Plant genetics associated with disease resistance is thoroughly studied and many resistance genes have been identified for essentially any pathosystem. To understand the interaction between the host and the respective pathogen, it is necessary to understand pathogen genetics and factors influencing virulence. Different genotypes of the same pathogen can differ greatly in their virulence spectrum, i.e. their ability to induce disease symptoms on a given host genotype. Virulence is governed by avirulence/ virulence factors, which in turn interact with the host’s resistance or susceptibility genes. Barley is an important cereal crop in many parts of the world. Two of the most important fungal diseases on barley are Pyrenophora teres and Rhynchosporium commune, the causal agents of net blotch and scald blotch, respectively. Numerous resistance genes and loci have been identified in barley against both pathogens, but only a handful of virulence factors in the pathogens have been described. However, with the abundance of resistance and susceptibility genes present in barley, many more avirulence/ virulence loci can be expected to be present in P. teres and R. commune. To understand the host-pathogen interaction of these pathosystems it is necessary to identify these underlying genetic regions and genes in the pathogens and investigate their interaction with their counterparts in the host. In the last decade the progress in sequencing platforms has been enormous leading to a substantial decline in labor and costs. Whole genome sequencing (WGS) is now affordable for many organisms, especially if genome sizes are small. With WGS, gene sequences of candidate genes and their variants in different individuals can be discovered. Leaf samples from all over Germany infected with P. teres or R. commune will be collected in two consecutive years. From those samples about 200 isolates for each pathogen will be tested in greenhouse trials and genotyped with WGS with the aims (i) to determine the prevalence of P. teres and R. commune in Germany, (ii) to assess the spatial distribution of P. teres f. teres and P. teres f. maculata, (iii) to assess the number of pathotypes and their distribution, (iv) to analyze the population structure and genetic diversity of German P. teres and R. commune populations and (vi) to identify QTL associated with virulence factors and the underlying genes.

• DFG Programme: Research Grants