College of Plant Protection, Yunnan Agricultural University, Kunming, China.
State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China.
Plant Cell Environ. 2021 Jun;44(6):1846-1857. doi: 10.1111/pce.14029. Epub 2021 Mar 5.
Transposable elements exist widely throughout plant genomes and play important roles in plant evolution. Auxin is an important regulator that is traditionally associated with root development and drought stress adaptation. The DEEPER ROOTING 1 (DRO1) gene is a key component of rice drought avoidance. Here, we identified a transposon that acts as an autonomous auxin-responsive promoter and its presence at specific genome positions conveys physiological adaptations related to drought avoidance. Rice varieties with a high and auxin-mediated transcription of DRO1 in the root tip show deeper and longer root phenotypes and are thus better adapted to drought. The INDITTO2 transposon contains an auxin response element and displays auxin-responsive promoter activity; it is thus able to convey auxin regulation of transcription to genes in its proximity. In the rice Acuce, which displays DRO1-mediated drought adaptation, the INDITTO2 transposon was found to be inserted at the promoter region of the DRO1 locus. Transgenesis-based insertion of the INDITTO2 transposon into the DRO1 promoter of the non-adapted rice variety Nipponbare was sufficient to promote its drought avoidance. Our data identify an example of how transposons can act as promoters and convey hormonal regulation to nearby loci, improving plant fitness in response to different abiotic stresses.
转座元件广泛存在于植物基因组中，在植物进化中发挥着重要作用。生长素是一种重要的调节剂，传统上与根发育和干旱胁迫适应有关。DEEPER ROOTING 1（DRO1）基因是水稻避旱的关键组成部分。在这里，我们鉴定了一个转座子，它作为一个自主的生长素响应启动子发挥作用，其在特定基因组位置的存在赋予了与避旱相关的生理适应。在根端具有高 DRO1 和生长素介导的转录的水稻品种表现出更深和更长的根表型，因此更好地适应干旱。INDITTO2 转座子含有生长素反应元件，并表现出生长素响应启动子活性；因此，它能够将生长素对转录的调控传递到其附近的基因。在表现出 DRO1 介导的干旱适应的水稻 Acuce 中，发现 INDITTO2 转座子插入到 DRO1 基因座的启动子区域。通过将 INDITTO2 转座子插入到非适应品种 Nipponbare 的 DRO1 启动子中的基于转基因的插入足以促进其避旱。我们的数据确定了一个转座子如何作为启动子发挥作用并将激素调节传递到附近基因座的例子，从而提高植物对不同非生物胁迫的适应能力。
