Guseman Jessica M, Hellmuth Antje, Lanctot Amy, Feldman Tamar P, Moss Britney L, Klavins Eric, Calderón Villalobos Luz Irina A, Nemhauser Jennifer L
Department of Biology, University of Washington, Seattle, WA 98195, USA.
Leibniz Institute of Plant Biochemistry, Halle (Saale) 06120, Germany.
Development. 2015 Mar 1;142(5):905-9. doi: 10.1242/dev.117234. Epub 2015 Jan 29.
Auxin elicits diverse cell behaviors through a simple nuclear signaling pathway initiated by degradation of Aux/IAA co-repressors. Our previous work revealed that members of the large Arabidopsis Aux/IAA family exhibit a range of degradation rates in synthetic contexts. However, it remained an unresolved issue whether differences in Aux/IAA turnover rates played a significant role in plant responses to auxin. Here, we use the well-established model of lateral root development to directly test the hypothesis that the rate of auxin-induced Aux/IAA turnover sets the pace for auxin-regulated developmental events. We did this by generating transgenic plants expressing degradation rate variants of IAA14, a crucial determinant of lateral root initiation. Progression through the well-established stages of lateral root development was strongly correlated with the engineered rates of IAA14 turnover, leading to the conclusion that Aux/IAAs are auxin-initiated timers that synchronize developmental transitions.
生长素通过由Aux/IAA共抑制因子降解引发的简单核信号通路引发多种细胞行为。我们之前的研究表明，拟南芥大型Aux/IAA家族的成员在合成环境中表现出一系列降解速率。然而，Aux/IAA周转速率的差异是否在植物对生长素的反应中起重要作用仍是一个未解决的问题。在这里，我们使用成熟的侧根发育模型直接测试以下假设：生长素诱导的Aux/IAA周转速率为生长素调节的发育事件设定了节奏。我们通过生成表达IAA14降解速率变体的转基因植物来实现这一点，IAA14是侧根起始的关键决定因素。侧根发育既定阶段的进展与IAA14的工程周转速率密切相关，得出的结论是Aux/IAAs是生长素启动的定时器，可同步发育转变。
