PDF(Pubmed)
Abstract：
Terrestrial plants respond to and resist gravitational force. The response is termed \"gravity resistance\", and centrifugal hypergravity conditions are efficient for investigating its nature and mechanism. A functional screening of Arabidopsis T-DNA insertion lines for the suppression rate of elongation growth of hypocotyls under hypergravity conditions was performed in this study to identify the genes required for gravity resistance. As a result, we identified PEPTIDYL-tRNA HYDROLASE II (PTH2). In the wild type, elongation growth was suppressed by hypergravity, but this did not happen in the pth2 mutant. Lateral growth, dynamics of cortical microtubules, mechanical properties of cell walls, or cell wall thickness were also not affected by hypergravity in the pth2 mutant. In other words, the pth2 mutant did not show any significant hypergravity responses. However, the gravitropic curvature of hypocotyls of the pth2 mutant was almost equal to that of the wild type, indicating that the PTH2 gene is not required for gravitropism. It is suggested by these results that PTH2 is responsible for the critical processes of gravity resistance in Arabidopsis hypocotyls.
摘要：
陆地植物响应并抵抗重力。这种反应被称为“重力阻力”，离心超重力条件对研究其性质和机理是有效的。在这项研究中，对拟南芥T-DNA插入系进行了功能性筛选，以确定在超重力条件下下胚轴伸长生长的抑制率，以鉴定重力抗性所需的基因。因此,我们鉴定了肽-tRNA水解酶II（PTH2）。在野生型中,伸长生长被超重力抑制，但这并没有发生在pth2突变体。横向生长,皮质微管的动力学，细胞壁的机械性能，或pth2突变体的细胞壁厚度也不受超重力影响。换句话说,pth2突变体没有显示任何显著的超重力反应。然而,pth2突变体下胚轴的重力曲率几乎等于野生型，表明PTH2基因不是引力作用所必需的。这些结果表明，PTH2是拟南芥下胚轴重力抗性的关键过程。
