Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0116, USA.
Mol Plant. 2011 Jan;4(1):171-9. doi: 10.1093/mp/ssq052. Epub 2010 Sep 10.
Plants can sense the direction of gravity and orient their growth to ensure that roots are anchored in soil and that shoots grow upward. Gravitropism has been studied extensively using Arabidopsis genetics, but the exact mechanisms for gravitropism are not fully understood. Here, we demonstrate that five NPY genes play a key role in Arabidopsis root gravitropism. NPY genes were previously identified as regulators of auxin-mediated organogenesis in a genetic pathway with the AGC kinases PID, PID2, WAG1, and WAG2. We show that all five NPY genes are highly expressed in primary root tips. The single npy mutants do not display obvious gravitropism defects, but the npy1 npy2 npy3 npy4 npy5 quintuple mutants show dramatic gravitropic phenotypes. Systematic analysis of all the npy double, triple, and quadruple combinations demonstrates that the five NPY genes all contribute to gravitropism. Our work indicates that gravitropism, phototropism, and organogenesis use analogous mechanisms in which at least one AGC kinase, one NPH3/NPY gene, and one ARF are required.
植物可以感知重力的方向，并调整其生长方向，以确保根固定在土壤中，而芽向上生长。利用拟南芥遗传学，已对向重力性进行了广泛研究，但向重力性的确切机制尚未完全了解。在这里，我们证明了五个 NPY 基因在拟南芥根向重力性中起关键作用。NPY 基因先前被鉴定为 AGC 激酶 PID、PID2、WAG1 和 WAG2 遗传途径中生长素介导的器官发生的调节剂。我们表明，所有五个 NPY 基因在主根尖端都高度表达。单个 npy 突变体没有表现出明显的向重力性缺陷，但 npy1 npy2 npy3 npy4 npy5 五突变体表现出明显的向重力性表型。对所有 npy 双、三、四突变体组合的系统分析表明，这五个 NPY 基因都参与向重力性。我们的工作表明，向重力性、向光性和器官发生使用类似的机制，至少需要一个 AGC 激酶、一个 NPH3/NPY 基因和一个 ARF。
