Hormonal and molecular events during seed dormancy release and germination.

AbstractSeed dormancy and timing of its release is important developmental transition determining the survival of individual as well as population and species. We used Medicago truncatula as model to study legume seed dormancy in ecological and genomics context. The effect of oscillating temperatures as one of the dormancy release factor was tested over the period of 88 days on the set of 178 accessions originating from variable environmental conditions of Mediterranean basin. Phenotypic plasticity of final dormancy was significantly correlated with increased aridity, suggesting that plastic responses to external stimuli provide seeds with strong bet-hedging capacity and the potential to cope with high levels of environmental heterogeneity. Genome-wide association analysis identified candidate genes associated with dormancy release related to secondary metabolites synthesis, hormone regulation and modification of the cell wall likely mediating seed coat permeability and ultimately imbibition and germination.HighlightMedicago seed dormancy was correlated with increased aridity of the environment, suggesting that plastic responses provide seeds with a bet-hedging capacity. Genome-wide association analysis identified candidate genes associated with release from dormancy.

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Transcriptome profiles revealed molecular mechanisms of alternating temperatures in breaking the epicotyl morphophysiological dormancy of Polygonatum sibiricum seeds

BMC Plant Biology ◽

10.1186/s12870-021-03147-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Dengqun Liao ◽

Ruipeng An ◽

Jianhe Wei ◽

Dongmei Wang ◽

Xianen Li ◽

...

Keyword(s):

Seed Dormancy ◽

Seedling Establishment ◽

Large Scale ◽

Molecular Mechanisms ◽

Seedling Emergence ◽

Differentially Expressed ◽

Natural Environments ◽

Sequencing Analysis ◽

Dormancy Release ◽

Morphophysiological Dormancy

Abstract Background To adapt seasonal climate changes under natural environments, Polygonatum sibiricum seeds have a long period of epicotyl morphophysiological dormancy, which limits their wide-utilization in the large-scale plant progeny propagation. It has been proven that the controlled consecutive warm and cold temperature treatments can effectively break and shorten this seed dormancy status to promote its successful underdeveloped embryo growth, radicle emergence and shoot emergence. To uncover the molecular basis of seed dormancy release and seedling establishment, a SMRT full-length sequencing analysis and an Illumina sequencing-based comparison of P. sibiricum seed transcriptomes were combined to investigate transcriptional changes during warm and cold stratifications. Results A total of 87,251 unigenes, including 46,255 complete sequences, were obtained and 77,148 unigenes (88.42%) were annotated. Gene expression analyses at four stratification stages identified a total of 27,059 DEGs in six pairwise comparisons and revealed that more differentially expressed genes were altered at the Corm stage than at the other stages, especially Str_S and Eme. The expression of 475 hormone metabolism genes and 510 hormone signaling genes was modulated during P. sibiricum seed dormancy release and seedling emergence. One thousand eighteen transcription factors and five hundred nineteen transcription regulators were detected differentially expressed during stratification and germination especially at Corm and Str_S stages. Of 1246 seed dormancy/germination known DEGs, 378, 790, and 199 DEGs were associated with P. sibiricum MD release (Corm vs Seed), epicotyl dormancy release (Str_S vs Corm), and the seedling establishment after the MPD release (Eme vs Str_S). Conclusions A comparison with dormancy- and germination-related genes in Arabidopsis thaliana seeds revealed that genes related to multiple plant hormones, chromatin modifiers and remodelers, DNA methylation, mRNA degradation, endosperm weakening, and cell wall structures coordinately mediate P. sibiricum seed germination, epicotyl dormancy release, and seedling establishment. These results provided the first insights into molecular regulation of P. sibiricum seed epicotyl morphophysiological dormancy release and seedling emergence. They may form the foundation of future studies regarding gene interaction and the specific roles of individual tissues (endosperm, newly-formed corm) in P. sibiricum bulk seed dormancy.

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Commercial Seed Lots Exhibit Reduced Seed Dormancy in Comparison to Wild Seed Lots of Echinacea purpurea

HortScience ◽

10.21273/hortsci.40.6.1843 ◽

2005 ◽

Vol 40 (6) ◽

pp. 1843-1845 ◽

Cited By ~ 4

Author(s):

Luping Qu ◽

Xiping Wang ◽

Ying Chen ◽

Richard Scalzo ◽

Mark P. Widrlechner ◽

...

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Echinacea Purpurea ◽

Seed Source ◽

Ex Situ ◽

Growth Chamber ◽

Dormancy Release ◽

Wild Populations ◽

Group Of Seven ◽

Cultivated Populations

Seed germination patterns were studied in Echinacea purpurea (L.) Moench grouped by seed source, one group of seven lots from commercially cultivated populations and a second group of nine lots regenerated from ex situ conserved wild populations. Germination tests were conducted in a growth chamber in light (40 μmol·m–2·s–1) or darkness at 25 °C for 20 days after soaking the seeds in water for 10 minutes. Except for two seed lots from wild populations, better germination was observed for commercially cultivated populations in light (90% mean among seed lots, ranging from 82% to 95%) and in darkness (88% mean among seed lots, ranging from 82% to 97%) than for wild populations in light (56% mean among seed lots, ranging from 9% to 92%) or in darkness (37% mean among seed lots, ranging from 4% to 78%). No germination difference was measured between treatments in light and darkness in the commercially cultivated populations, but significant differences were noted for treatments among wild populations. These results suggest that repeated cycles of sowing seeds during cultivation without treatments for dormancy release resulted in reduced seed dormancy in E. purpurea.

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Functional Identification of 9-cis-epoxycarotenoid Dioxygenase Genes in Double Dormant Plant-herbaceous Peony

10.21203/rs.3.rs-1176350/v1 ◽

2021 ◽

Author(s):

Riwen Fei ◽

Siyang Duan ◽

Jiayuan Ge ◽

Tianyi Sun ◽

Xiaomei Sun

Keyword(s):

Seed Dormancy ◽

Dormancy Release ◽

Transcriptome Data ◽

Functional Identification ◽

Internal Factors ◽

Herbaceous Peony ◽

Aba Metabolism ◽

Complex Process ◽

Aba Content ◽

Endogenous Aba

Abstract Seed dormancy and germination is a complex process, which is affected by external environmental conditions and internal factors independently or mutually. Phytohormones play an important regulatory role in this process. ABA was the main phytohormone affecting herbaceous peony seed dormancy release. However, the mechanism of ABA in the dormancy release of herbaceous peony needs to be further explored. Here, transcriptome data was screened from the perspective of ABA metabolism, and significantly differentially expressed PlNCED1 and PlNCED2 were obtained. We found that their expression trends were positively correlated with ABA content. Among them, PlNCED2 had a stronger regulatory effect on ABA content and was more sensitive to exogenous ABA. Overexpression and silencing of PlNCEDs in callus could affect the expression of PlCYP707As and the content of endogenous ABA. Through the observation of seed germination of Arabidopsis thaliana (A. thaliana), we found PlNCED1 and PlNCED2 promoted seed dormancy, and the promotion effect of PlNCED2 was more obvious. In general, PlNCED1 and PlNCED2 participated in the dormancy release of herbaceous peony seeds by regulating the accumulation of endogenous ABA. Our work can reveal the molecular mechanism and related theories of ABA involved in herbaceous peony seed dormancy release.

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Physiological characteristics of cold stratification on seed dormancy release in rice

Plant Growth Regulation ◽

10.1007/s10725-019-00516-z ◽

2019 ◽

Vol 89 (2) ◽

pp. 131-141

Author(s):

Bin Yang ◽

Jinping Cheng ◽

Jiankang Wang ◽

Yanhao Cheng ◽

Yongqi He ◽

...

Keyword(s):

Seed Dormancy ◽

Physiological Characteristics ◽

Cold Stratification ◽

Dormancy Release

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Seed dormancy release of Halenia elliptica in response to stratification temperature, duration and soil moisture content

BMC Plant Biology ◽

10.1186/s12870-020-02560-8 ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Da Li Chen ◽

Xin Ping Luo ◽

Zhen Yuan ◽

Meng Jie Bai ◽

Xiao Wen Hu

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Seed Dormancy ◽

Soil Moisture Content ◽

Dormancy Release ◽

Halenia Elliptica

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A repressor complex silencing ABA signaling in seeds?

Journal of Experimental Botany ◽

10.1093/jxb/eraa062 ◽

2020 ◽

Vol 71 (10) ◽

pp. 2847-2853 ◽

Cited By ~ 1

Author(s):

Hiroyuki Nonogaki

Keyword(s):

Seed Germination ◽

Seed Dormancy ◽

Transcriptional Repression ◽

Target Genes ◽

Aba Signaling ◽

Molecular Events ◽

Aba Sensitivity ◽

Repressor Complex ◽

Transcription Factor Target ◽

Signaling Components

Abstract Seed dormancy is induced primarily by abscisic acid (ABA) and maintained through elevated levels of ABA sensitivity in seeds. The core mechanisms of ABA-imposed seed dormancy are emerging, but it is still unclear how these blockages in seeds are eliminated during after-ripening, or what molecular events in imbibed seeds are responsible for the initial stages of germination induction. Some pieces of evidence suggest that a repressor complex, which potentially triggers seed germination through the suppression of ABA signaling components, might be present in seeds. The usual suspect, protein phosphatase 2C, which inactivates kinases and shuts down ABA signaling in the major dormancy pathway, is possibly associated with this complex. Other members, such as WD40 proteins and histone deacetylase subunits, homologs of which are found in the flowering repressor complex, perhaps constitute this complex in seeds. The repressor activity could counteract the dormancy mechanisms in an overwhelming manner, through well-coordinated inactivation and turnover of germination-suppressing transcription factors, which is probably accompanied by chromatin silencing and transcriptional repression of the transcription factor target genes. This review provides a perspective on a putative seed germination-inducing repressor complex, including its possible modes of action and upstream regulators.

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