Abscisic acid and the control of seed dormancy and germination

Abstract

Abscisic acid (ABA) is a plant hormone that regulates seed dormancy and germination. Seeds undergo changes in both ABA content and sensitivity during seed development and germination in response to internal and external cues. Recent advances in functional genomics have revealed the integral components involved in ABA metabolism (biosynthesis and catabolism) and perception, the core signalling pathway, as well as the factors that trigger ABA-mediated transcription. These allow for comparative studies to be conducted on seeds under different environmental conditions and from different genetic backgrounds. This review summarizes our understanding of the control of ABA content and the responsiveness of seeds to afterripening, light, high temperature and nitrate, with a focus on which tissues are involved in its metabolism and signalling. Also described are the regulators of ABA metabolism and signalling, which potentially act as the node for hormone crosstalk. Integration of such knowledge into the complex and diverse events occurring during seed germination will be the next challenge, which will allow for a clearer understanding of the role of ABA.

A Co-Opted Hormonal Cascade Activates Dormant Adventitious Root Primordia upon Flooding in Solanum dulcamara

“…In rice, ABA treatment hampers flooding-induced AR emergence by preventing epidermal cell death (Steffens and Sauter, 2005), but it has not been reported whether ABA levels actually go down at the site of the preformed AR primordia and whether this is sufficient to mimic the flooding and ethylene responses. ABA also has a prominent role in dormancy initiation and maintenance in seeds and vegetative organ buds (Arend et al, 2009;Nambara et al, 2010;Reddy et al, 2013). Interestingly, a (transient) dormancy phenotype has been reported for LR primordia in Arabidopsis and is thought to occur in situations where LR emergence is not required (e.g.…”

Do the seeds of Solidago gigantea Aiton have physiological determinants of invasiveness?

“…Temperature is a key environmental factor regulating dormancy and germination. During seed maturation, temperature influences innate dormancy, and when seeds become a part of the soil seed bank, temperature and moisture content are the key factors that regulate and synchronize the dormancy cycle across seasons (Kendall and Penfield 2012;Kundel et al 2014;Nambara et al 2010).…”

Identification of an abscisic acid transporter by functional screening using the receptor complex as a sensor

“…In plants, the hormone abscisic acid (ABA) plays crucial roles in the responses to abiotic and biotic stresses, as well as in the induction and maintenance of seed dormancy (3)(4)(5)(6). Long-distance transport of ABA from roots to leaves has been extensively discussed in relation to stomatal closure in response to water deficit (7)(8)(9)(10)(11).…”