TILLING for effective powdery mildew resistance: A non-transgenic approach aimed at the generation of hexaploid wheat mlo mutants
R. PANSTRUGA (1), J. Acevedo (1), H. Thieron (1), D. Spencer (1), A. Phillips (2), K. Hammond-Kosack (2) (1) RWTH Aachen University, Germany; (2) Rothamsted Research, United Kingdom

Durable broad-spectrum powdery mildew resistance on the basis of a defective (mutated) Mlo gene is known for a long time in diploid barley and respective mlo mutants have been used successfully in barley breeding and agriculture for more than 35 years. Owing to its hexaploid genome, the creation of corresponding mlo mutants in bread wheat represents a major challenge. The deployment of transgenic plants (including those resulting from genome editing approaches) is a major concern in European agriculture. We therefore used the non-transgenic TILLING (Targeted Induced Local Lesions in Genomes) technology to select wheat lines (spring wheat cultivar Cadenza) that carry ethane methylsulfonate (EMS)-induced mutations in Mlo genes of the A, B and D genome. Selected single amino acid substitution mutations in the Mlo genes were tested for (partial) loss-of-function by transient expression analysis. We combined suitable mutant alleles via intermutant crosses, and marker-based selection of respective homozygous progeny led to various double and triple mutant combinations. The resulting lines provide sufficient powdery mildew resistance, possibly without the in part severe pleiotropic effects that are known to accompany mlo null mutants in barley.

Abstract Number: C3-4, P19-712
Session Type: Concurrent