State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Department of Chemistry, Wuhan University, Wuhan 430072, China.
Plant Sci. 2022 Oct;323:111369. doi: 10.1016/j.plantsci.2022.111369. Epub 2022 Jul 9.
To bear harsh environmental threats, plants have developed complex protection mechanisms involving phytohormones, counting abscisic acid (ABA). The function of the F-Box family containing the Domain of Unknown Function 295 (DUF295) has not yet been comprehensively characterized in Arabidopsis (Arabidopsis thaliana). In this study, we evaluated the function of a putative member of the F-Box/DUF295 family in Arabidopsis, F-box/DUF295 Brassiceae specific 2 (FDB2). We found that FDB2 expression was suppressed by ABA and abiotic stresses. FDB2 overexpression (OE) reduced ABA sensitivity during seed germination and seedling growth, but enhanced ABA-sensitivity of seed germination and seedling growth in fdb2 mutants was scored. When treated with ABA, expressions of ABI3, ABI4 and ABI5 showed decreased in OE lines but increased in fdb2 mutants. In addition, ABA-induced FDB2 degradation exhibited sensitive to MG132, suggesting that FDB2 degradation by ABA might be mediated by the ubiquitin-26S proteasome system. Moreover, ABA-induced significant over-accumulation of reactive oxygen species (ROS) at the root tips of fdb2 mutants was observed, this phenomenon was correlated to reduced activities of a set of ROS scavengers in fdb2 mutants relative to Col-0. In summary, our results suggest that Arabidopsis FDB2 is involved in ABA-mediated inhibition of seed germination, seedling growth including modulation of ROS homeostasis in roots.
为了承受恶劣的环境威胁，植物已经发展出涉及植物激素的复杂保护机制，包括脱落酸（ABA）。含有未知功能域 295（DUF295）的 F-Box 家族的功能在拟南芥（Arabidopsis thaliana）中尚未得到全面描述。在这项研究中，我们评估了拟南芥中一个假定的 F-Box/ DUF295 家族成员 F-Box/ DUF295 芸薹属特异性 2（FDB2）的功能。我们发现 FDB2 的表达受到 ABA 和非生物胁迫的抑制。FDB2 过表达（OE）降低了种子萌发和幼苗生长过程中的 ABA 敏感性，但增强了 fdb2 突变体中种子萌发和幼苗生长的 ABA 敏感性。当用 ABA 处理时，ABI3、ABI4 和 ABI5 的表达在 OE 系中降低，但在 fdb2 突变体中增加。此外，ABA 诱导的 FDB2 降解对 MG132 敏感，表明 ABA 诱导的 FDB2 降解可能是由泛素-26S 蛋白酶体系统介导的。此外，在 fdb2 突变体根尖观察到 ABA 诱导的活性氧（ROS）显著积累，这一现象与 fdb2 突变体中一组 ROS 清除剂的活性相对于 Col-0 降低有关。总之，我们的结果表明，拟南芥 FDB2 参与 ABA 介导的种子萌发抑制、幼苗生长，包括调节根中的 ROS 稳态。
