Morphological Research Of Rice Root Hair Mutants By Cryo-SEM And Map-based Cloning Of Mutant Genes

Root hairs are long tubular outgrowths that form on the surface of specialized epidermal cells.Their development occurs in three phases:cell fate specification, initiation and subsequent tip growth.The process of root hair formation is well characterized in Arabidopsis(Arabidopsis thaliana);however,only few mutants have been characterized at the molecular level in monocots,including barley(Hordeum vulgare),rice(Oryza sativa)and maize(Zea mays).In this paper,three mutants related to root hair initiation or tip growth in rice (Oryza sativa),were investigated by Cryo-Scanning Electron Microscopy (Cryo-SEM).The mutants,designated as Ossrh1,Ossrh2 and Ossrh3,were analysed according to epidermal cell phenotypes of primary roots.Ossrh1 shows wavy and branched hairs with swellings at base.Ossrh2's root hairs have swellings on the basal or along the hairs.Ossrh3 shows short root hairs.Ossrh1 and Ossrh3 develop short root hairs and have less root hairs than the wild type plants.Ossrh2 shows shorter root hairs,less root hairs' amount,shorter seedling height,shorter primary root and abnormal lateral roots compared to the wild type,which accords with pleiotropism.By using map-based cloning strategy,the genes of OsSRH1,OsSRH2 and OsSRH3 were mapped on Chromosome10 within 304Kb region,Chromosomel within 38Kb region and Chromosome6 within 56Kb region,respectively.