A Perspective on Secondary Seed Dormancy in Arabidopsis thaliana

Primary seed dormancy is the phenomenon whereby seeds newly shed by the mother plant are unable to germinate under otherwise favorable conditions for germination. Primary dormancy is released during dry seed storage (after-ripening), and the seeds acquire the capacity to germinate upon imbibition under favorable conditions, i.e., they become non-dormant. Primary dormancy can also be released from the seed by various treatments, for example, by cold imbibition (stratification). Non-dormant seeds can temporarily block their germination if exposed to unfavorable conditions upon seed imbibition until favorable conditions are available. Nevertheless, prolonged unfavorable conditions will re-induce dormancy, i.e., germination will be blocked upon exposure to favorable conditions. This phenomenon is referred to as secondary dormancy. Relative to primary dormancy, the mechanisms underlying secondary dormancy remain understudied in Arabidopsis thaliana and largely unknown. This is partly due to the experimental difficulty in observing secondary dormancy in the laboratory and the absence of established experimental protocols. Here, an overview is provided of the current knowledge on secondary dormancy focusing on A. thaliana, and a working model describing secondary dormancy is proposed, focusing on the interaction of primary and secondary dormancy.

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Secondary dormancy inBrassica napusis correlated with enhancedBnaDOG1transcript levels

Seed Science Research ◽

10.1017/s0960258514000427 ◽

2015 ◽

Vol 25 (2) ◽

pp. 221-229 ◽

Cited By ~ 7

Author(s):

Guillaume Née ◽

Evelyn Obeng-Hinneh ◽

Pourya Sarvari ◽

Kazumi Nakabayashi ◽

Wim J.J. Soppe

Keyword(s):

Arabidopsis Thaliana ◽

Seed Dormancy ◽

Seed Quality ◽

High Homology ◽

Transcript Levels ◽

Secondary Dormancy ◽

Similar Expression Pattern ◽

Low Levels ◽

Selection For ◽

Conserved Gene

AbstractDormancy has evolved in plants to restrict germination to favourable growth seasons. Seeds from most crop plants have low dormancy levels due to selection for immediate germination during domestication. Seed dormancy is usually not completely lost and low levels are required to maintain sufficient seed quality.Brassica napuscultivars show low levels of primary seed dormancy. However,B. napusseeds are prone to the induction of secondary dormancy, which can lead to the occurrence of volunteers in the field in subsequent years after cultivation. TheDELAY OF GERMINATION 1(DOG1) gene has been identified as a major dormancy gene in the model plantArabidopsis thaliana.DOG1is a conserved gene and has been shown to be required for seed dormancy in various monocot and dicot plant species. We have identified threeB. napusgenes with high homology toAtDOG1, which we namedBnaA.DOG1.a,BnaC.DOG1.aandBnaC.DOG1.b. The transcripts of these genes could only be detected in seeds and showed a similar expression pattern during seed maturation asAtDOG1. In addition, theBnaDOG1genes showed enhanced transcript levels after the induction of secondary dormancy. These results suggest a role forDOG1in the induction of secondary dormancy inB. napus.

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Effect of FLOWERING LOCUS C on seed germination depends on dormancy

Functional Plant Biology ◽

10.1071/fp16368 ◽

2017 ◽

Vol 44 (5) ◽

pp. 493 ◽

Cited By ~ 10

Author(s):

Logan Blair ◽

Gabriela Auge ◽

Kathleen Donohue

Keyword(s):

Arabidopsis Thaliana ◽

Seed Germination ◽

Genetic Pathway ◽

Flowering Locus C ◽

Primary Dormancy ◽

Seed Imbibition ◽

Secondary Dormancy ◽

Germination Temperature ◽

Flowering Locus ◽

Dormancy Induction

FLOWERING LOCUS C (FLC) has a major regulatory role in the timing of flowering in Arabidopsis thaliana (L.) Heynh. and has more recently been shown to influence germination. Here, we investigated the conditions under which FLC influences germination, and demonstrated that its effect depends on the level of primary and secondary dormancy and the temperature of seed imbibition. We tested the germination response of genotypes with different degrees of FLC activity over the course of after-ripening and after secondary dormancy induction by hot stratification. Genotypes with high FLC-activity showed higher germination; this response was greatest when seeds exhibited primary dormancy or were induced into secondary dormancy by hot stratification. In this study, which used less dormant seeds, the effect of FLC was more evident at 22°C, the less permissive germination temperature, than at 10°C, in contrast to prior published results that used more dormant seeds. Thus, because effects of FLC variation depend on dormancy, and because the range of temperature that permits germination also depends on dormancy, the temperature at which FLC affects germination can also vary with dormancy. Finally, we document that the effect of FLC can depend on FRIGIDA and that FRIGIDA itself appears to influence germination. Thus, pleiotropy between germination and flowering pathways in A. thaliana extends beyond FLC and involves other genes in the FLC genetic pathway.

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Secondary dormancy dynamics depends on primary dormancy status inArabidopsis thaliana

Seed Science Research ◽

10.1017/s0960258514000440 ◽

2015 ◽

Vol 25 (2) ◽

pp. 230-246 ◽

Cited By ~ 24

Author(s):

Gabriela A. Auge ◽

Logan K. Blair ◽

Liana T. Burghardt ◽

Jennifer Coughlan ◽

Brianne Edwards ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Seedling Survival ◽

Seed Maturation ◽

Maternal Plant ◽

Primary Dormancy ◽

Secondary Dormancy ◽

Different Temperatures ◽

Time Of Year ◽

Dormancy Induction ◽

Different Levels

AbstractSeed dormancy can prevent germination under unfavourable conditions that reduce the chances of seedling survival. Freshly harvested seeds often have strong primary dormancy that depends on the temperature experienced by the maternal plant and which is gradually released through afterripening. However, seeds can be induced into secondary dormancy if they experience conditions or cues of future unfavourable conditions. Whether this secondary dormancy induction is influenced by seed-maturation conditions and primary dormancy has not been explored in depth. In this study, we examined secondary dormancy induction in seeds ofArabidopsis thalianamatured under different temperatures and with different levels of afterripening. We found that low water potential and a range of temperatures, from 8°C to 35°C, induced secondary dormancy. Secondary dormancy induction was affected by the state of primary dormancy of the seeds. Specifically, afterripening had a non-monotonic effect on the ability to be induced into secondary dormancy by stratification; first increasing in sensitivity as afterripening proceeded, then declining in sensitivity after 5 months of afterripening, finally increasing again by 18 months of afterripening. Seed-maturation temperature sometimes had effects that were independent of expressed primary dormancy, such that seeds that had matured at low temperature, but which had comparable germination proportions as seeds matured at warmer temperatures, were more easily induced into secondary dormancy. Because seed-maturation temperature is a cue of when seeds were matured and dispersed, these results suggest that the interaction of seed-maturation temperature, afterripening and post-dispersal conditions all combine to regulate the time of year of seed germination.

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Effect of Harvest Timing on Dormancy Induction in Canola Seeds

Weed Science ◽

10.1614/ws-d-13-00178.1 ◽

2014 ◽

Vol 62 (3) ◽

pp. 548-554 ◽

Cited By ~ 7

Author(s):

Teketel A. Haile ◽

Steven J. Shirtliffe

Keyword(s):

Early Development ◽

Seed Dormancy ◽

Color Change ◽

Main Stem ◽

Seed Color ◽

Primary Dormancy ◽

Secondary Dormancy ◽

Harvest Timing ◽

Soil Seedbank ◽

Dormancy Induction

Seedbank persistence in canola seeds is related to their potential to develop secondary dormancy. This can result in volunteer weed problems many years after canola production. The potential to be induced into secondary dormancy is controlled by both the canola genetics and the environment of the mother plant. However, the effect of time of harvesting on secondary dormancy potential is not known. The objective of this study was to determine the effect of harvest timing on potential to develop seed dormancy in canola. Six harvest samples were collected weekly from two canola genotypes (5440 and 5020) starting from 10 to 20% seed color change on the main stem until they were fully ripened. Freshly harvested seeds of 5440 and 5020 showed 13 and 16% primary dormancy at 32 and 33 d after flowering (DAF), respectively, but dormancy decreased with harvest timings and no dormancy was observed when seeds were fully mature (78 DAF). After dormancy induction, 10% of 5440 seeds were dormant at 32 DAF, but 94% of seeds were dormant at 78 DAF. Similarly, 70% of 5020 seeds were dormant at 33 DAF, but 90% of seeds were dormant at 68 DAF. Thus, seeds had lower potential to secondary dormancy at early development but have a high potential to secondary dormancy induction at full maturity. This study suggests that windrowing these canola genotypes at the recommended time (60% seed color change on the main stem) may reduce ability of the seed to develop secondary dormancy and thus reduce the persistence of seeds in the soil seedbank.

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ABA Metabolism and Homeostasis in Seed Dormancy and Germination

International Journal of Molecular Sciences ◽

10.3390/ijms22105069 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5069

Author(s):

Naoto Sano ◽

Annie Marion-Poll

Keyword(s):

Seed Dormancy ◽

Current Knowledge ◽

Fine Tuning ◽

Environmental Signals ◽

Hormone Synthesis ◽

Control Seed ◽

Functional Relationships ◽

Aba Metabolism ◽

Natural Variations ◽

Germinating Seeds

Abscisic acid (ABA) is a key hormone that promotes dormancy during seed development on the mother plant and after seed dispersal participates in the control of dormancy release and germination in response to environmental signals. The modulation of ABA endogenous levels is largely achieved by fine-tuning, in the different seed tissues, hormone synthesis by cleavage of carotenoid precursors and inactivation by 8′-hydroxylation. In this review, we provide an overview of the current knowledge on ABA metabolism in developing and germinating seeds; notably, how environmental signals such as light, temperature and nitrate control seed dormancy through the adjustment of hormone levels. A number of regulatory factors have been recently identified which functional relationships with major transcription factors, such as ABA INSENSITIVE3 (ABI3), ABI4 and ABI5, have an essential role in the control of seed ABA levels. The increasing importance of epigenetic mechanisms in the regulation of ABA metabolism gene expression is also described. In the last section, we give an overview of natural variations of ABA metabolism genes and their effects on seed germination, which could be useful both in future studies to better understand the regulation of ABA metabolism and to identify candidates as breeding materials for improving germination properties.

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An Analysis of Microsatellite Loci in Arabidopsis thaliana: Mutational Dynamics and Application

Genetics ◽

10.1093/genetics/165.3.1475 ◽

2003 ◽

Vol 165 (3) ◽

pp. 1475-1488

Author(s):

V Vaughan Symonds ◽

Alan M Lloyd

Keyword(s):

Arabidopsis Thaliana ◽

Microsatellite Loci ◽

Current Knowledge ◽

Flowering Plant ◽

Allele Frequency Distribution ◽

Strongly Correlated ◽

Microsatellite Evolution ◽

Stepwise Mutation ◽

Mutation Pattern ◽

Infinite Alleles Model

Abstract Microsatellite loci are among the most commonly used molecular markers. These loci typically exhibit variation for allele frequency distribution within a species. However, the factors contributing to this variation are not well understood. To expand on the current knowledge of microsatellite evolution, 20 microsatellite loci were examined for 126 accessions of the flowering plant, Arabidopsis thaliana. Substantial variability in mutation pattern among loci was found, most of which cannot be explained by the assumptions of the traditional stepwise mutation model or infinite alleles model. Here it is shown that the degree of locus diversity is strongly correlated with the number of contiguous repeats, more so than with the total number of repeats. These findings support a strong role for repeat disruptions in stabilizing microsatellite loci by reducing the substrate for polymerase slippage and recombination. Results of cluster analyses are also presented, demonstrating the potential of microsatellite loci for resolving relationships among accessions of A. thaliana.

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Roles of Glutathione in Mediating Abscisic Acid Signaling and Its Regulation of Seed Dormancy and Drought Tolerance

Genes ◽

10.3390/genes12101620 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1620

Author(s):

Murali Krishna Koramutla ◽

Manisha Negi ◽

Belay T. Ayele

Keyword(s):

Signal Transduction ◽

Abscisic Acid ◽

Seed Dormancy ◽

Growth And Development ◽

Current Knowledge ◽

Stomatal Closure ◽

Redox Homeostasis ◽

Critical Role ◽

Stress Conditions ◽

Signal Perception

Plant growth and development and interactions with the environment are regulated by phytohormones and other signaling molecules. During their evolution, plants have developed strategies for efficient signal perception and for the activation of signal transduction cascades to maintain proper growth and development, in particular under adverse environmental conditions. Abscisic acid (ABA) is one of the phytohormones known to regulate plant developmental events and tolerance to environmental stresses. The role of ABA is mediated by both its accumulated level, which is regulated by its biosynthesis and catabolism, and signaling, all of which are influenced by complex regulatory mechanisms. Under stress conditions, plants employ enzymatic and non-enzymatic antioxidant strategies to scavenge excess reactive oxygen species (ROS) and mitigate the negative effects of oxidative stress. Glutathione (GSH) is one of the main antioxidant molecules playing a critical role in plant survival under stress conditions through the detoxification of excess ROS, maintaining cellular redox homeostasis and regulating protein functions. GSH has recently emerged as an important signaling molecule regulating ABA signal transduction and associated developmental events, and response to stressors. This review highlights the current knowledge on the interplay between ABA and GSH in regulating seed dormancy, germination, stomatal closure and tolerance to drought.

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