Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California, San Diego, La Jolla CA., 92093, USA.
Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
Nat Commun. 2019 Sep 6;10(1):4021. doi: 10.1038/s41467-019-12002-1.
A detailed understanding of abiotic stress tolerance in plants is essential to provide food security in the face of increasingly harsh climatic conditions. Glucosinolates (GLSs) are secondary metabolites found in the Brassicaceae that protect plants from herbivory and pathogen attack. Here we report that in Arabidopsis, aliphatic GLS levels are regulated by the auxin-sensitive Aux/IAA repressors IAA5, IAA6, and IAA19. These proteins act in a transcriptional cascade that maintains expression of GLS levels when plants are exposed to drought conditions. Loss of IAA5/6/19 results in reduced GLS levels and decreased drought tolerance. Further, we show that this phenotype is associated with a defect in stomatal regulation. Application of GLS to the iaa5,6,19 mutants restores stomatal regulation and normal drought tolerance. GLS action is dependent on the receptor kinase GHR1, suggesting that GLS may signal via reactive oxygen species. These results provide a novel connection between auxin signaling, GLS levels and drought response.
深入了解植物的非生物胁迫耐受性对于在日益恶劣的气候条件下保障粮食安全至关重要。硫代葡萄糖苷（GLS）是十字花科植物中的次生代谢物，可保护植物免受草食动物和病原体的侵害。在这里，我们报告说在拟南芥中，脂肪族 GLS 水平受生长素敏感的Aux/IAA 抑制剂 IAA5、IAA6 和 IAA19 调控。这些蛋白在转录级联中发挥作用，当植物暴露于干旱条件下时，维持 GLS 水平的表达。缺失 IAA5/6/19 会导致 GLS 水平降低和耐旱性降低。此外，我们表明这种表型与气孔调节缺陷有关。将 GLS 应用于 iaa5、6、19 突变体可恢复气孔调节和正常的耐旱性。GLS 的作用依赖于受体激酶 GHR1，表明 GLS 可能通过活性氧信号传递。这些结果为生长素信号、GLS 水平和干旱响应之间提供了新的联系。
