Abstract
In Arabidopsis, the root of a light-grown plant has a higher density of root hairs than that of a dark-grown plant. Root hair formation is regulated by various factors such as phytochrome and hormone. To understand the molecular mechanism of light promoted root hair formation, we screened Arabidopsis activation tagging lines and isolated a new light-promoted root-hair development mutant, lrh1. By comparing root hair densities of the wild type and the lrh1 mutant under continuous light conditions, it was suspected that a mutated gene might induce root hair formation. Mutant seedlings also had shorter roots than wild type, and reduced numbers of lateral roots. A database search revealed that an 11-kilobase sequence adjacent to the location of T-DNA insertion contained two repeated sequences, hundreds of small RNAs, and several proproteins. We expect that lrh1 will be a useful tool for discovering novel factors to regulate root hair formation.
