Vishal Bhushan, Kumar Prakash P
Department of Biological Sciences, National University of Singapore, Singapore, Singapore.
Front Plant Sci. 2018 Jun 20;9:838. doi: 10.3389/fpls.2018.00838. eCollection 2018.
Overall growth and development of a plant is regulated by complex interactions among various hormones, which is critical at different developmental stages. Some of the key aspects of plant growth include seed development, germination and plant survival under unfavorable conditions. Two of the key phytohormones regulating the associated physiological processes are gibberellins (GA) and abscisic acid (ABA). GAs participate in numerous developmental processes, including, seed development and seed germination, seedling growth, root proliferation, determination of leaf size and shape, flower induction and development, pollination and fruit expansion. Despite the association with abiotic stresses, ABA is essential for normal plant growth and development. It plays a critical role in different abiotic stresses by regulating various downstream ABA-dependent stress responses. Plants maintain a balance between GA and ABA levels constantly throughout the developmental processes at different tissues and organs, including under unfavorable environmental or physiological conditions. Here, we will review the literature on how GA and ABA control different stages of plant development, with focus on seed germination and selected abiotic stresses. The possible crosstalk of ABA and GA in specific events of the above processes will also be discussed, with emphasis on downstream stress signaling components, kinases and transcription factors (TFs). The importance of several key ABA and GA signaling intermediates will be illustrated. The knowledge gained from such studies will also help to establish a solid foundation to develop future crop improvement strategies.
植物的整体生长和发育受多种激素之间复杂相互作用的调节，这在不同发育阶段至关重要。植物生长的一些关键方面包括种子发育、萌发以及在不利条件下的植株存活。调节相关生理过程的两种关键植物激素是赤霉素（GA）和脱落酸（ABA）。赤霉素参与众多发育过程，包括种子发育、种子萌发、幼苗生长、根系增殖、叶片大小和形状的确定、花的诱导和发育、授粉以及果实膨大。尽管与非生物胁迫有关，但脱落酸对植物的正常生长和发育至关重要。它通过调节各种下游依赖脱落酸的胁迫反应，在不同的非生物胁迫中发挥关键作用。在不同组织和器官的整个发育过程中，包括在不利的环境或生理条件下，植物不断维持赤霉素和脱落酸水平之间的平衡。在此，我们将综述关于赤霉素和脱落酸如何控制植物发育不同阶段的文献，重点是种子萌发和特定的非生物胁迫。还将讨论脱落酸和赤霉素在上述过程特定事件中的可能相互作用，重点是下游胁迫信号成分、激酶和转录因子。将说明几种关键的脱落酸和赤霉素信号中间体的重要性。从这些研究中获得的知识也将有助于为制定未来的作物改良策略奠定坚实基础。
