Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183 Umea, Sweden.
Plant Cell. 2012 Jun;24(6):2515-27. doi: 10.1105/tpc.112.099119. Epub 2012 Jun 22.
Vegetative shoot-based propagation of plants, including mass propagation of elite genotypes, is dependent on the development of shoot-borne roots, which are also called adventitious roots. Multiple endogenous and environmental factors control the complex process of adventitious rooting. In the past few years, we have shown that the auxin response factors ARF6 and ARF8, targets of the microRNA miR167, are positive regulators of adventitious rooting, whereas ARF17, a target of miR160, is a negative regulator. We showed that these genes have overlapping expression profiles during adventitious rooting and that they regulate each other's expression at the transcriptional and posttranscriptional levels by modulating the homeostasis of miR160 and miR167. We demonstrate here that this complex network of transcription factors regulates the expression of three auxin-inducible Gretchen Hagen3 (GH3) genes, GH3.3, GH3.5, and GH3.6, encoding acyl-acid-amido synthetases. We show that these three GH3 genes are required for fine-tuning adventitious root initiation in the Arabidopsis thaliana hypocotyl, and we demonstrate that they act by modulating jasmonic acid homeostasis. We propose a model in which adventitious rooting is an adaptive developmental response involving crosstalk between the auxin and jasmonate regulatory pathways.
植物的营养体无性繁殖，包括优良基因型的大规模繁殖，依赖于茎生根的发育，茎生根也称为不定根。多种内源性和环境因素控制不定根发生的复杂过程。在过去的几年中，我们已经表明，生长素响应因子 ARF6 和 ARF8 是 microRNA miR167 的靶标，是不定根发生的正调节剂，而 ARF17 是 miR160 的靶标，是负调节剂。我们表明，这些基因在不定根发生过程中有重叠的表达谱，并且它们通过调节 miR160 和 miR167 的内稳态在转录和转录后水平上相互调节彼此的表达。我们在这里证明，这个复杂的转录因子网络调节三个生长素诱导的 Gretchen Hagen3（GH3）基因，GH3.3、GH3.5 和 GH3.6 的表达，这些基因编码酰基-酰基-酰胺合成酶。我们表明，这三个 GH3 基因对于拟南芥下胚轴中不定根起始的微调是必需的，我们证明它们通过调节茉莉酸的稳态起作用。我们提出了一个模型，其中不定根发生是一种适应性发育反应，涉及生长素和茉莉酸调节途径之间的串扰。
