From the Outside to the Inside: New Insights on the Main Factors That Guide Seed Dormancy and Germination

Abstract

The transition from a dormant to a germinating seed represents a crucial developmental switch in the life cycle of a plant. Subsequent transition from a germinating seed to an autotrophic organism also requires a robust and multi-layered control. Seed germination and seedling growth are multistep processes, involving both internal and external signals, which lead to a fine-tuning control network. In recent years, numerous studies have contributed to elucidate the molecular mechanisms underlying these processes: from light signaling and light-hormone crosstalk to the effects of abiotic stresses, from epigenetic regulation to translational control. However, there are still many open questions and molecular elements to be identified. This review will focus on the different aspects of the molecular control of seed dormancy and germination, pointing out new molecular elements and how these integrate in the signaling pathways already known.

Transcriptome and Metabolite Conjoint Analysis Reveals the Seed Dormancy Release Process in Callery Pear

“…Here, a homologous of ABI4 (Chr1.g57127) was identified with down-regulated expression profiles during seed cold stratification, indicating its potential role in regulating the seed dormancy release of callery pear (Figure 8). Additionally, activator-and repressortype bHLH, bZIP, NAC, WRKY, and MYB genes affect the seed chilling response and the seed dormancy status [35,71]. ICE1, a bHLH TF with a master role in modulating the plant cold response, physically interacts with a bZIP-type TF ABI5 to fine-turn ABA signaling and suppress seed germination [72].…”

The bHLH transcription factor MpHYPNOS regulates gemma dormancy in the liverwort Marchantia polymorpha

“…On the other hand, ethylene plays opposite roles in dormancy regulation of seed and gemmae. While ethylene and its signaling factors promote release of seed dormancy in dicot species [reviewed in (Longo et al ., 2020)], ethylene application enhances gemma dormancy in gemma cup (Li et al ., 2020).…”

“…Mutants defective in auxin biosynthesis and signaling produce germinated gemmae inside of gemma cups (Eklund et al ., 2015; Kato et al ., 2017). Notably, ethylene plays opposite roles in regulating the dormancy of seeds vs. gemmae: While ethylene and its signaling factors promote the release of seed dormancy in dicot species [reviewed in (Longo et al ., 2020)], ethylene treatment enhances the dormancy of gemmae in the gemma cup (Li et al ., 2020).…”

Developmental Signals in the 21st Century; New Tools and Advances in Plant Signaling

“…This issue also includes an interesting review on reproductive development [7]. The authors focused on the seed-to-seedling transition, which is a key step in plant life, strictly controlled by both endogenous and environmental cues.…”

“…The molecular networks that control these developmental steps have been deeply investigated. The review by Longo et al, 2021 [7], focuses on new molecular elements in the transcriptional, translational, and epigenetic regulatory mechanisms, pointing out how these networks integrate the response to environmental and hormonal signals [7]. Attempting to provide a more complex view of the different developmental processes affecting plants, this issue includes an excellent research paper focused on the process of differentiation of functional chloroplasts [8].…”