TY - JOUR UR - https://doi.org/10.7287/peerj.preprints.2267v1 DO - 10.7287/peerj.preprints.2267v1 TI - Increased root hair density by loss of WRKY6 in Arabidopsis thaliana AU - Stetter,Markus G AU - Benz,Martin AU - Ludewig,Uwe DA - 2016/07/08 PY - 2016 KW - Arabidopsis KW - root hair KW - ecotypes KW - genome wide association KW - mixed model KW - nutrition KW - phosphorus KW - inorganic phosphate KW - cortex KW - epidermis AB - Root hairs are unicellular elongations of certain rhizodermal cells that improve the uptake of sparingly soluble and immobile soil nutrients. Among different Arabidopsis thaliana genotypes, root hair density, length and the local acclimation to low inorganic phosphate (Pi) differs considerably, when analyzed on split agar plates. Here, genome-wide association fine mapping identified significant single nucleotide polymorphisms associated with the increased root hair density in the absence of local phosphate on chromosome 1. A loss-of-function mutant of the candidate transcription factor gene WRKY6, which is involved in the acclimation of plants to low phosphorus, had increased root hair density. This is partially explained by a reduced cortical cell diameter in wrky6-3, reducing the rhizodermal cell numbers adjacent to the cortical cells. As a consequence, rhizodermal cells in positions that are in contact with two cortical cells are found more often, leading to higher hair density. Distinct cortical cell diameters and epidermal cell lengths distinguish other Arabidopsis accessions with distinct root hair density and -Pi response from diploid Col-0, while tetraploid Col-0 had generally larger root cell sizes, which explain longer hairs. A distinct radial root morphology within Arabidopsis accessions and wrky6-3 explains some, but not all, differences in the root hair acclimation to –Pi. VL - 4 SP - e2267v1 T2 - PeerJ Preprints JO - PeerJ Preprints J2 - PeerJ Preprints SN - 2167-9843 ER -