Functional analysis of the Arabidopsis thaliana Mlo (AtMlo) gene family

• Applicant: Professor Dr. Ralph Panstruga
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2004 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5446497

MLO proteins constitute a family of plant-specific, heptahelical, plasma membrane-localized integral membrane proteins. Barley MLO, the "founder" of the protein family, serves a role as modulator of pathogen defence and cell death and is assumed to regulate a SNARE protein-dependent and vesicle-associated defence pathway at the cell periphery. We tested T-DNA insertion mutants in Arabidopsis Mlo genes for altered infection phenotypes upon challenge with a range of phytopathogens. We found that the AtMlo2 mu tant is allelic to the previously described pmr2 mutant and that AtMlo2 mutant alleles phenocopy the broad-spectrum powdery-mildew resistant phenotype of barley mlo mutants. This finding suggests a conserved role for MLO proteins in monocot and dicot plants and indicates that the ability of powdery mildew fungi to manipulate the MLO pathway has been retained for at least 150 million years. We will exploit this novel discovery to unravel the molecular basis of MLO function in Arabidopsis by various approache s including analysis of mlo signaling requirements, Atmlo2 suppressor mutagenesis, and comparative transcript profiling.

• DFG Programme: Research Grants