Centre for Plant Integrative Biology (CPIB), School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
National Institute of Plant Genome Research (NIPGR), New Delhi, India.
Nat Commun. 2018 Apr 12;9(1):1408. doi: 10.1038/s41467-018-03850-4.
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 in an effort to improve rice P acquisition efficiency. We show by X-ray microCT imaging that root angle is altered in the osaux1 mutant, causing preferential foraging in the top soil 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 to the differentiation zone where this signal promotes hair elongation when roots encounter low external P. We conclude that auxin and OsAUX1 play key roles in promoting root foraging for P in rice.
根特性，如根角和毛长，影响资源获取，特别是对磷（P）等不移动的养分。在这里，我们试图通过破坏生长素流入转运蛋白基因 OsAUX1 来改变水稻的根角，以提高水稻对 P 的获取效率。我们通过 X 射线微计算机断层扫描成像表明，根角在 osaux1 突变体中发生改变，导致在 P 通常积累的表土中优先觅食，然而令人惊讶的是，P 的获取效率并没有提高。通过更深入的研究，我们揭示出 OsAUX1 也响应 P 限制促进根毛伸长。报告基因研究表明，在低 P 环境中，生长素响应增加在根毛区。我们证明，OsAUX1 从根尖向分化区动员生长素，当根遇到低外部 P 时，这个信号促进毛伸长。我们得出结论，生长素和 OsAUX1 在促进水稻对 P 的根觅食中起着关键作用。
