Whole exome sequencing-based identification of HvCSLC1 gene involved in root hair development in barley

The study was aimed on the identification of a gene responsible for abnormal root hair phenotype in barley, characterized by the inhibition of root hair tip growth at the very early stage of root hair development, right after the bulge formation. For this purpose whole-exome sequencing (WES) of two allelic barley mutants were used to identify mutations underlying the root hair phenotype: a rhp1.e mutant derived from chemically mutagenized spring cultivar Sebastian and rhp1.b mutant developed by chemical mutagenesis from Dema variety. Using WES approach we identified a G1674A substitution in rhp1.e mutant within HORVU1Hr1G077230 gene located on chromosome 1HL and encoding a cellulose synthase-like C1 protein (HvCSLC1) that is involved in the xyloglucan (XyG) synthesis. The mutation led to the retention of the second intron and premature termination of the HvCSLC1 protein. This substitution co-segregated with the abnormal root hair phenotype in the F2 progeny of rhp1.e mutant and its wild-type parent Sebastian. Different substitution, T1827C, was found within the same gene in rhp1.b mutant comparing to its parent variety Dema. Based on subsequent analysis we conclude that disruption of HvCSLC1 protein sequence leads to the root hair tip growth arrest at the stage of bulge formation.