Evidence for Allele-Specific Levels of Enhanced Susceptibility of Wheat Mutants to the Hemibiotrophic Fungal Pathogen pv. .

Barley mutants are well known for their profound resistance against powdery mildew disease. Recently, mutant plants were generated in hexaploid bread wheat () with the help of transgenic (transcription-activator-like nuclease, TALEN) and non-transgenic (targeted induced local lesions in genomes, TILLING) biotechnological approaches. While full-gene knockouts in the three wheat () homoeologs, created via TALEN, confer full resistance to the wheat powdery mildew pathogen ( f.sp. ), the currently available TILLING-derived missense mutants provide only partial protection against powdery mildew attack. Here, we studied the infection phenotypes of TALEN- and TILLING-derived plants to the two hemibiotrophic pathogens , causing Septoria leaf blotch in wheat, and pv. (), the causal agent of wheat blast disease. While plants showed unaltered outcomes upon challenge with , we found evidence for allele-specific levels of enhanced susceptibility to , with stronger powdery mildew resistance correlated with more invasive growth by the blast pathogen. Surprisingly, unlike barley mutants, young wheat mutant plants do not show undesired pleiotropic phenotypes such as spontaneous callose deposits in leaf mesophyll cells or signs of early leaf senescence. In conclusion, our study provides evidence for allele-specific levels of enhanced susceptibility of plants to the hemibiotrophic wheat pathogen .