Phenotypic characterization of point mutations spanning FHA domain and C-terminal region of Dawdle gene in Arabidopsis

The screening analysis of loss-of-function alleles in Arabidopsis thaliana revealed a mutation in the At3G20550 gene, called DAWDLE (DDL). The mutation in the DDL gene causes pleiotropic phenotypes and reduced the levels of several microRNAs. The DAWDLE gene encodes a protein with a Fork Head-Associated (FHA) domain, found in large range of proteins with significant cellular processes in prokaryotes and eukaryotes. However, it is not completely known whether the FHA domain and C-terminal region of the DDL are necessary for its function. The aim of this study was to determine the function of both regions by conducting a phenotypic analysis of point mutations spanning the FHA domain and C-terminal region in DDL Targeted Induced Local Lesions IN Genome (Tilling) screen was performed in the Columbia erecta-105 background of Arabidopsis resulting in point mutations spanning both regions of DDL. The mutants were phenotypically characterized. Height of the plant, hypocotyl and root length, and fertility were measured. Phenotypic analyses of the mutants revealed ddl phenotypes of varying degrees in different organs. Reduction in fertility and shortening in root, hypocotyl and stem lengths of the Tiller mutant lines suggest that the FHA domain and C-terminal region may require for DDL function in Arabidopsis. Key words: Dawdle, Fork Head-Associated Domain, Targeted Induced Local Lesions in Genome, Ethyl Methane Sulfonate, Arabidopsis