Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China.
Vegetable Germplasm Innovation and Variety Improvement Key Laboratory of Sichuan Province, Horticulture Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China.
J Plant Physiol. 2022 Oct;277:153805. doi: 10.1016/j.jplph.2022.153805. Epub 2022 Sep 3.
Arabidopsis abscisic acid ABA-Insensitive RING Proteins (AtAIRP1-4) are RING E3s that play significant roles in ABA-signaling pathways. However, it is still unclear whether they have other functions. Here, AtAIRP4 was determined to play a role in response to gibberellin A3 (GA) in Arabidopsis thaliana. After proAtAIRP4::GUS transgenic lines were treated with GA, the GUS activity decreased in hypocotyls. Increased hypocotyl elongation in response to GA seen in WT was not observed in the AtAIRP4-overexpression lines, whereas AtAIRP4-overexpression lines were hypersensitive to Paclobutrazol (PAC, an inhibitor of GA biosynthesis) during the seed germination stage. Additionally, AtAIRP4-overexpressing lines showed the lowest level of primary root elongation in the presence of GA. The levels of endogenous GA in 35S::AtAIRP4 lines were lower than those in wild-type. In addition, among the plants, the mRNA levels of the GA synthetic gene GIBBERELLIN 20-OXIDASE1 (GA20ox1) was the lowest in overexpressing line. However, the expression of the response gene DELLA RGA-LIKE3 (RGL3) was the highest in overexpressing lines after treatment with GA. Thus, AtAIRP4 plays a negative role in GA-mediated hypocotyl elongation and root growth, and it inhibits the synthesis of endogenous biologically active GA to some extent.
拟南芥脱落酸 ABA 不敏感 RING 蛋白（AtAIRP1-4）是 RING E3，它们在 ABA 信号通路中发挥重要作用。然而，目前尚不清楚它们是否具有其他功能。在这里，确定 AtAIRP4 在拟南芥对赤霉素 A3（GA）的反应中起作用。在用 GA 处理 proAtAIRP4::GUS 转基因系后，下胚轴中的 GUS 活性降低。在 WT 中观察到的对 GA 的下胚轴伸长增加在 AtAIRP4 过表达系中没有观察到，而 AtAIRP4 过表达系在种子萌发阶段对多效唑（PAC，GA 生物合成的抑制剂）敏感。此外，在存在 GA 的情况下，AtAIRP4 过表达系的主根伸长率最低。35S::AtAIRP4 系中的内源 GA 水平低于野生型。此外，在这些植物中，GA 合成基因 GIBBERELLIN 20-OXIDASE1（GA20ox1）的 mRNA 水平在过表达系中最低。然而，在用 GA 处理后，响应基因 DELLA RGA-LIKE3（RGL3）的表达在过表达系中最高。因此，AtAIRP4 在 GA 介导的下胚轴伸长和根生长中起负作用，并在某种程度上抑制内源生物活性 GA 的合成。
