A Barley Root Mutant Collection for Fast Forward Genetics

Recently, the interest in producing and exploiting mutant collections has increased due to the availability of new genomics-assisted mapping and cloning approaches. We are performing a forward-genetics screening of a barley mutagenized population (cv. Morex background) formerly produced for TILLING purposes (Talamè et al. 2008, Plant Biotechnol J. 6:477-485), to identify root morphology mutants. We have already analysed >3,000 M5 mutant families at the seedling stage and several tens of root mutants have been identified and confirmed. The mutants were grouped in three categories: root growth rate/length (short and long, 77%), root morphology (coiling, geotropic, etc., 15%) and root hairs (hairless, shorthairs, etc., 8%). Four randomly chosen mutants were utilized in experimental crosses and their Mendelian inheritance was confirmed. As a first step towards mapping and cloning the described mutants, a barley SNP array (Illumina 9K)-based bulk-segregant analysis was applied and shown to enable quickly and inexpensive mapping at cM-range interval.  Additional NGS-based approaches are being tested in order to streamline the process linking a mutant with the underlying gene, thus making our population a generally useful resource for functional genomics in cereals.