Skubacz Anna, Daszkowska-Golec Agata, Szarejko Iwona
Department of Genetics, Faculty of Biology and Environmental Protection, University of Silesia Katowice, Poland.
Front Plant Sci. 2016 Dec 16;7:1884. doi: 10.3389/fpls.2016.01884. eCollection 2016.
ABA Insensitive 5 (ABI5) is a basic leucine zipper transcription factor that plays a key role in the regulation of seed germination and early seedling growth in the presence of ABA and abiotic stresses. ABI5 functions in the core ABA signaling, which is composed of PYR/PYL/RCAR receptors, PP2C phosphatases and SnRK2 kinases, through the regulation of the expression of genes that contain the ABSCISIC ACID RESPONSE ELEMENT (ABRE) motif within their promoter region. The regulated targets include stress adaptation genes, e.g., LEA proteins. However, the expression and activation of is not only dependent on the core ABA signaling. Many transcription factors such as ABI3, ABI4, MYB7 and WRKYs play either a positive or a negative role in the regulation of expression. Additionally, the stability and activity of ABI5 are also regulated by other proteins through post-translational modifications such as phosphorylation, ubiquitination, sumoylation and -nitrosylation. Moreover, ABI5 also acts as an ABA and other phytohormone signaling integrator. Components of auxin, cytokinin, gibberellic acid, jasmonate and brassinosteroid signaling and metabolism pathways were shown to take part in regulation and/or to be regulated by ABI5. Monocot orthologs of have been identified. Although their roles in the molecular and physiological adaptations during abiotic stress have been elucidated, knowledge about their detailed action still remains elusive. Here, we describe the recent advances in understanding the action of ABI5 in early developmental processes and the adaptation of plants to unfavorable environmental conditions. We also focus on ABI5 relation to other phytohormones in the abiotic stress response of plants.
ABA不敏感5（ABI5）是一种碱性亮氨酸拉链转录因子，在脱落酸（ABA）和非生物胁迫存在的情况下，对种子萌发和幼苗早期生长的调控起着关键作用。ABI5在核心ABA信号传导中发挥作用，该信号传导由PYR/PYL/RCAR受体、PP2C磷酸酶和SnRK2激酶组成，通过调控其启动子区域含有脱落酸响应元件（ABRE）基序的基因的表达来实现。受调控的靶标包括胁迫适应基因，例如胚胎发育晚期丰富蛋白（LEA）。然而，ABI5的表达和激活不仅依赖于核心ABA信号传导。许多转录因子，如ABI3、ABI4、MYB7和WRKYs，在ABI5表达的调控中发挥着正向或负向作用。此外，ABI5的稳定性和活性也受到其他蛋白质通过翻译后修饰，如磷酸化、泛素化、SUMO化和亚硝基化的调控。此外，ABI5还作为ABA和其他植物激素信号的整合因子。生长素、细胞分裂素、赤霉素、茉莉酸和油菜素内酯信号传导及代谢途径的组分已被证明参与ABI5的调控和/或受ABI5调控。已鉴定出ABI5的单子叶直系同源物。尽管它们在非生物胁迫期间的分子和生理适应中的作用已得到阐明，但关于它们详细作用的知识仍然难以捉摸。在这里，我们描述了在理解ABI5在早期发育过程中的作用以及植物对不利环境条件的适应方面的最新进展。我们还关注了在植物非生物胁迫响应中ABI5与其他植物激素的关系。
