Local brassinosteroid biosynthesis enables optimal root growth

作者：Nemanja Vukašinović, Yaowei Wang, Isabelle Vanhoutte, Matyáš Fendrych, Boyu Guo, Miroslav Kvasnica, Petra Jiroutová, Jana Oklešťková, Miroslav Strnad, Eugenia Russinova · 发表于：bioRxiv (Cold Spring Harbor Laboratory) · 年份：2020 · DOI：10.1101/2020.11.23.391474 · 被引用次数：16 · 研究领域：Plant Molecular Biology Research、Plant nutrient uptake and metabolism、Plant Stress Responses and Tolerance

Abstract Brassinosteroid hormones are indispensable for root growth and they control both cell division and cell elongation through the establishment of an increasing signaling gradient along the longitudinal root axis. Because of their limited mobility, the importance of brassinosteroid distribution for achieving the signaling maximum is largely overlooked. Expression pattern analysis of all known brassinosteroid biosynthetic enzymes revealed that not all cells in the Arabidopsis thaliana root possess full biosynthetic machinery and completion of biosynthesis relies on cell-to-cell movement of the hormone precursors. We demonstrate that brassinosteroid biosynthesis is largely restricted to the root elongation zone where it overlaps with brassinosteroid signaling maxima. Moreover, optimal root growth requires hormone concentrations, low in the meristem and high in the root elongation zone attributable to an increased biosynthesis. Our finding that spatiotemporal regulation of hormone synthesis results in a local hormone accumulation provides a paradigm for hormone-driven organ growth in the absence of long-distance hormone transport in plants.