Epidermal expression of a sterol biosynthesis gene regulates root growth by a non-cell-autonomous mechanism in Arabidopsis (Development)

The HYDRA1 (HYD1) gene is primarily expressed in the root epidermis and encodes a sterol Δ8-Δ7 isomerase. The hyd1 mutant has defects in growth and radial patterning of root development. Short et al. showed that although HYD1 is not expressed in the vascular cells, PIN1 localization and vascular patterning are abnormal in the hyd1 mutant. This observation suggests that a non-cell-autonomous signal is transferred from HYD1-expressing cells to non-expressing cells to maintain regular tissue patterning. The authors expressed the HYD1 gene solely in the root epidermis, which restored primary root length to ~60-80% of that of wild-type. This suggests that sterols are functioning in a non-autonomous manner to maintain root growth and development, possibly with auxin as the mobile signal. (Summary by Arif Ashraf) Development: 10.1242/dev.16057