Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio A-1', CP 58030 Morelia, Michoacán, Mexico.
J Plant Physiol. 2012 Sep 15;169(14):1348-58. doi: 10.1016/j.jplph.2012.05.002. Epub 2012 Jun 1.
Jasmonic acid (JA) regulates a broad range of plant defense and developmental responses. COI1 has been recently found to act as JA receptor. In this report, we show that low micromolar concentrations of JA inhibited primary root (PR) growth and promoted lateral root (LR) formation in Arabidopsis wild-type (WT) seedlings. It was observed that the coi1-1 mutant was less sensitive to JA on pericycle cell activation to induce lateral root primordia (LRP) formation and presented alterations in lateral root positioning and lateral root emergence on bends. To investigate JA-auxin interactions important for remodeling of root system (RS) architecture, we tested the expression of auxin-inducible markers DR5:uidA and BA3:uidA in WT and coi1-1 seedlings in response to indole-3-acetic acid (IAA) and JA and analyzed the RS architecture of a suite of auxin-related mutants under JA treatments. We found that JA did not affect DR5:uidA and BA3:uidA expression in WT and coi1-1 seedlings. Our data also showed that PR growth inhibition in response to JA was likely independent of auxin signaling and that the induction of LRP required ARF7, ARF19, SLR, TIR1, AFB2, AFB3 and AXR1 loci. We conclude that JA regulation of postembryonic root development involves both auxin-dependent and independent mechanisms.
茉莉酸（JA）调节广泛的植物防御和发育反应。最近发现 COI1 作为 JA 受体起作用。在本报告中，我们表明，低微摩尔浓度的 JA 抑制拟南芥野生型（WT）幼苗的主根（PR）生长并促进侧根（LR）形成。观察到 coi1-1 突变体对周鞘细胞激活的 JA 反应不敏感，无法诱导侧根原基（LRP）形成，并且在弯曲处侧根定位和侧根出现发生改变。为了研究 JA-生长素相互作用对根系（RS）结构重塑的重要性，我们测试了生长素诱导标记物 DR5:uidA 和 BA3:uidA 在 WT 和 coi1-1 幼苗中对吲哚-3-乙酸（IAA）和 JA 的响应，并分析了 JA 处理下一系列生长素相关突变体的 RS 结构。我们发现 JA 对 WT 和 coi1-1 幼苗中的 DR5:uidA 和 BA3:uidA 表达没有影响。我们的数据还表明，JA 对 PR 生长的抑制作用可能独立于生长素信号转导，而 LRP 的诱导需要 ARF7、ARF19、SLR、TIR1、AFB2、AFB3 和 AXR1 基因座。我们得出结论，JA 对胚胎后根发育的调节涉及依赖和不依赖生长素的机制。
