Rice auxin influx carrier OsAUX1 facilitates root hair elongation in response to low external phosphate

First author: Jitender Giri; Affiliations: University of Nottingham (诺丁汉大学): Nottingham, UK

Corresponding author: Malcolm J. Bennett

Root traits such as root angle and hair length influence resource acquisition particularly for immobile nutrients like phosphorus (P). Here, we attempted to modify root angle in rice by disrupting the OsAUX1 auxin influx transporter gene (生长素输入转运基因) in an effort to improve rice P acquisition efficiency. We show by X-ray microCT imaging (X射线显微CT成像) that root angle is altered in the osaux1 mutant, causing preferential foraging (觅食) in the top soil (表层土壤) where P normally accumulates, yet surprisingly, P acquisition efficiency does not improve. Through closer investigation, we reveal that OsAUX1 also promotes root hair elongation in response to P limitation. Reporter studies reveal that auxin response increases in the root hair zone in low P environments. We demonstrate that OsAUX1 functions to mobilize auxin from the root apex (根尖) to the differentiation zone (分生区) where this signal promotes hair elongation when roots encounter (遭遇) low external P. We conclude that auxin and OsAUX1 play key roles in promoting root foraging for P in rice.

根的一些性状，如根角度和根毛长度会影响植物对于土壤中营养元素的摄取，尤其是一些固定在土壤中的营养元素，如磷元素。本文作者通过扰乱生长素输入转运基因改变水稻根角度以期望能够增强水稻对于磷元素的吸收效率。X射线显微CT成像显示在osaux1突变体中根角度发生变化，导致了根首先在磷优先积累的表层土壤中觅食磷元素，然而磷元素的吸收效率并未获得提升。通过进一步的调查，作者发现OsAUX1基因还能够响应磷缺乏的条件促进根毛的伸长。报告试验显示在低磷环境中，根毛区对于生长素的响应增强。本文研究显示OsAUX1蛋白会在根遭遇低磷条件时将生长素从根尖部位移动到根的分生区，进而促进根毛的伸长。综上，生长素和OsAUX1在水稻中促进根对于磷元素的吸收。

通讯：Malcolm J. Bennett (https://www.nottingham.ac.uk/biosciences/people/malcolm.bennett)

研究方向：植物根生长和发育的分子调控信号、基因及机制。

doi: 10.1038/s41467-018-03850-4

Journal: Nature Communications

Published online: 12 April, 2018

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