Two Faces of One Seed: Hormonal Regulation of Dormancy and Germination.
Seed plants have evolved to maintain the dormancy of freshly matured seeds until the appropriate time for germination. Seed dormancy and germination are distinct physiological processes, and the transition from dormancy to germination is not only a critical developmental step in the life cycle of plants but is also important for agricultural production. These processes are precisely regulated by diverse endogenous hormones and environmental cues. Although ABA (abscisic acid) and GAs (gibberellins) are known to be the primary phytohormones that antagonistically regulate seed dormancy, recent findings demonstrate that another phytohormone, auxin, is also critical for inducing and maintaining seed dormancy, and therefore might act as a key protector of seed dormancy. In this review, we summarize our current understanding of the sophisticated molecular networks involving the critical roles of phytohormones in regulating seed dormancy and germination, in which AP2-domain-containing transcription factors play key roles. We also discuss the interactions (crosstalk) of diverse hormonal signals in seed dormancy and germination, focusing on the ABA/GA balance that constitutes the central node.
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Institute of Ecological Agriculture, Sichuan Agricultural University, Chengdu 611130, China.
Kai
K
Shu
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; College of Agronomy, Xinjiang Agricultural University, Urumqi, Xinjiang 830052, China.
Xiao-Dong
XD
Liu
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: qxie@genetics.ac.cn.
Qi
Q
Xie
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China. Electronic address: zhhe@sibs.ac.cn.
Zu-Hua
ZH
He
D018525:Germination / Q000502:physiology*; D057445:Plant Dormancy; D010937:Plant Growth Regulators / Q000502:physiology*; D018521:Plant Physiological Phenomena; D010944:Plants; D012639:Seeds / Q000254:growth & development*; D015398:Signal Transduction
D010937:Plant Growth Regulators
ABA; GA; auxin; crosstalk; germination; seed dormancy