APETALA 2‐domain‐containing transcription factors: focusing on abscisic acid and gibberellins antagonism

Abstract

Summary The phytohormones abscisic acid (ABA) and gibberellin (GA) antagonistically mediate diverse plant developmental processes including seed dormancy and germination, root development, and flowering time control, and thus the optimal balance between ABA and GA is essential for plant growth and development. Although more than a half and one century have passed since the initial discoveries of ABA and GA, respectively, the precise mechanisms underlying ABA–GA antagonism still need further investigation. Emerging evidence indicates that two APETALA 2 (AP2)‐domain‐containing transcription factors (ATFs), ABI4 in Arabidopsis and OsAP2‐39 in rice, play key roles in ABA and GA antagonism. These two transcription factors precisely regulate the transcription pattern of ABA and GA biosynthesis or inactivation genes, mediating ABA and GA levels. In this Viewpoint article, we try to shed light on the effects of ATFs on ABA–GA antagonism, and summarize the overlapping but distinct biological functions of these ATFs in the antagonism between ABA and GA. Finally, we strongly propose that further research is needed into the detailed roles of additional numerous ATFs in ABA and GA crosstalk, which will improve our understanding of the antagonism between these two phytohormones.

A matter of life and death: Molecular, physiological, and environmental regulation of seed longevity

“…Over the past decades, numerous investigations have identified intrinsic genetic and physiological factors involved in the regulation of seed longevity. For instance, ROS production and elimination (Rajjou et al, ; Rajjou & Debeaujon, ; Wiebach, Nagel, Börner, Altmann, & Riewe, ), the concentrations of plant hormones (Shu et al, ; Shu, Zhou, & Yang, ), repair and maintenance systems for nucleic acids and proteins (Chen et al, ; Fleming, Richards, & Walters, ; Petla et al, ; Waterworth et al, ), and the presence of several storage compounds (Li et al, ; Zhou et al, ) play important roles, via complex pathways or networks, in controlling seed longevity (Figure ).…”

“…Phytohormones play key and distinct roles throughout the lifecycle, including seed dormancy, germination, and abiotic stress responses (Liu et al, ; Liu & Hou, ; Shu et al, ; Shu, Liu, Xie, & He, ; Shu, Zhou, Cheng, Luo, & Yang, ). It is widely recognized that ABA and GAs mediate seed dormancy and germination antagonistically (El‐Maarouf‐Bouteau & Bailly, ; Jeevan Kumar et al, ; Shu et al, ; Shu, Zhou, & Yang, ). ABA accumulates in seeds, inducing and maintaining dormancy during seed maturation, and the ABA concentration decreases during germination (Shu et al, ).…”

Genome-Wide Characterization and Expression Profiling of Squamosa Promoter Binding Protein-Like (SBP) Transcription Factors in Wheat (Triticum aestivum L.)

“…Throughout the entire lifespan of a plant, plant-specific transcription factors (TFs) play key roles in regulating the expression of downstream genes in a temporal and spatial manner by specifically binding cis-acting elements of gene promoter regions, and thereby regulate plant growth and development processes [1,2]. For example, in rice, Rice Starch Regulator1 (RSR1) from APETALA2/ethylene responsive factor (AP2/ERF) TFs negatively regulates the expression of type I starch synthesis genes, and RSR1 deficiency results in enhanced expression of starch synthesis genes in seeds and facilitates the improvement of rice quality and nutrition value [3].…”

SlHY5 Integrates Temperature, Light, and Hormone Signaling to Balance Plant Growth and Cold Tolerance

“…ABA and GA are classic phytohormones, which antagonistically control diverse aspects of plant development and abiotic stress response (Razem et al, 2006;Shu et al, 2013Shu et al, , 2018a. It has been proposed that several key transcription factors, including AtABI4 and OsAP2-39, directly or indirectly control the transcription pattern of ABA and GA biosynthetic genes to regulate the balance between ABA and GA (Yaish et al, 2010;Shu et al, 2013Shu et al, , 2018b. GAs play a positive role in plant growth and a negative role in plant cold tolerance (Achard et al, 2008;Sun, 2011;Zhou et al, 2017).…”