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Special Issue "Seed Dormancy: Molecular Control of Its Induction and Alleviation"
Deadline for manuscript submissions: 31 March 2020.
The seed, a key entity in the life cycle of higher plants, allows and ensures its survival by acquiring primary dormancy, which is hormonally induced and then maintained and strictly regulated by the modulation of a suitable hormonal signaling network. The dormancy of some seeds can be relieved through a tightly regulated process called after-ripening (AR) that occurs in dry, mature, and viable seeds stored in dry conditions. As a result of AR, abundant changes of transcripts take place and the window of environmental conditions that allow seed germination widens. The events occurring during this loss of dormancy are of significant functional, ecological, and agricultural interest. Genetic, –omics, and physiological studies about AR have shown the key role of the balance between gibberellins (GAs) and abscisic acid (ABA) metabolism and sensitivity. Recent evidence also supports a possible role of ethylene in AR execution and modulation. However, hormone-independent signals (e.g., reactive oxygen species (ROS) and nitrate) also appear to be involved in the triggering and maintenance of AR. The way in which hormone- and non-hormone-signaling pathways affect each other is still scarcely known. With all these aforementioned factors put together, the implementation of AR involves genes associated with the completion of germination. Nevertheless, the complexity and diversity of mechanisms that trigger and control AR is a great puzzle, with the majority of its pieces still missing.
Prof. Angel J. Matilla
Manuscript Submission Information
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Plants is an international peer-reviewed open access monthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.
- AR mutants
- cell wall degradation
- monocot- and dicot-seeds
- RBOHD genes
- ROS homeostasis mutants
- seed pathogenesis
- specific regulators of AR
- tissue specificity of gene expression
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
Authors: Raquel Iglesias Fernández et al
Affiliation: Centro de Biotecnología y Genómica de Plantas (CBGP)-Severo Ochoa, Universidad Politécnica de Madrid (UPM), Campus de Montegancedo, Km-38, M40, 28223, Pozuelo de Alarcón, Madrid (Spain)
Abstract: The seed is the propagule of higher plants that allows their dissemination and the survival of the specie. Seed dormancy prevents a premature germination under favourable conditions. When dormancy pathways are activated, seeds are able to germinate in a narrow range of conditions. The molecular mechanisms inducing seed dormancy are classically related with the abscisic acid (ABA) and gibberellins (GAs) perception and metabolism. Novel players have been recently described to be involved in seed dormancy establishment, maintenance and release such as reactive oxygen species (ROS), epigenetic modifications and translational regulation of stored mRNAs. This review is an update of the state of the art in these emerging mechanisms underlying seed dormancy.
Title: The Auxin, a New Affiliated to Seed Dormancy
Authors: Angel J. Matilla
Affiliation: Department of Functional Biology, Life Campus, Faculty of Pharmacy, University of Santiago de Compostela (USC), 15782 Santiago de Compostela, Spain
Abstract: Seed dormancy is a relevant adaptative trait that ensures the germination at the appropriate time. Abscisic acid (ABA), synthesized during seed development, induces and maintains seed dormancy. ABA acts through the PYR/RCAR-PP2C-SnRK2 signaling cascade, and ABA-response transcription factors such as ABI3, ABI4 and ABI5 are known to affect seed dormancy. The auxin (indol-3-acetic acid; IAA) is involved in almost all aspects of plant development. Recent biochemical and genetic evidences have suggested the very likely involvement of IAA in seed dormancy. Among which ABI3 is required for IAA-mediated seed dormancy. This and other facts indicate that IAA affects to the ABA signaling to achieve their physiological effect. Likewise, IAA plays an essential role during seed-coat development and its transport from endosperm is regulated by AGAMOUS-LIKE62 (AGL62) whose transcript is specifically expressed in the endosperm. This update shows why auxin is considered a new hormonal signaling directly involved in seed development and dormancy.
Title: Decay of messenger RNA during after-ripening in barley grains
Authors: José M. Barrero
Affiliation: The Commonwealth Scientific and Industrial Research Organisation
Abstract: Commercial cereals suffer a problem known as pre-harvest sprouting (PHS), which is the early germination of the mature grains in the mother plant in wet conditions. Lack of grain dormancy is the main reason for PHS. Dormancy acquisition during grain maturation has been studied, but the mechanism by which dormancy is gradually lost after maturation is unknown. Using barley, we find that the RNA stored in the grain has a principal role in determining grain dormancy, and that its decay during grain storage is correlated with dormancy lost. We first observed that ribosomal RNA degrades during grain storage. Then, using a new RNA-seq approach, we demonstrate that the messenger RNA (mRNA) also decays, although some species appear to be stable. Given its high abundance in grains, mRNA that is related to the hormone ABA is predominately impacted. This shifts the mRNA population from an ABA-dominated transcriptomic environment to a germination-permissive situation. We propose that variability in RNA stability could be exploited for developing cereal varieties resistant to PHS.
Title: The intervention of DOG1 in the primary seed dormancy
Authors: Carrillo-Barral1, N., Matilla2, A.J., Rodríguez-Gacio2, M.C.
Affiliation: 1Departamento de Biología, Facultad de Ciencias, Universidad de A Coruña, Campus Zapateira, 15071-A Coruña, Spain. 2Departamento de Biología Funcional (Área Fisiología Vegetal), Facultad de Farmacia, Universidad de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
Abstract: DELAY OF GERMINATION 1 (DOG1) has been identified as one of the major regulator of primary seed dormancy (PSD) together with abscisic acid (ABA). Thus, DOG1 and ABA need to be present to execute PSD. DOG1 was the first QTL identified for natural variations of seed dormancy among A. thaliana accessions. DOG1 is highly conserved in both dicot and monocot species and its function in PSD is too. DOG1 active protein levels accumulating during seed maturation are correlating with the level of PSD. DOG1 protein may be modified (i.e. inactive) during after-ripening (AR). Mutation in DOG1 (e.g. dog1 which possesses scarce endogenous ABA and enhanced GAs content) can completely remove dormancy. DOG1 promotes PSD during seed development; but how it does so remains unknown. The function of DOG1 appears to be tightly regulated by a complex array of mechanisms that include alternative splicing, alternative polyadenylation, regulation of miRNA156 expression and a cis-acting antisense non-coding transcript (asDOG1). Furthermore, DOG1 has been shown to physically interact with two phosphatases (ABA‐HYPERSENSITIVE GERMINATION 1 and 3; AHG1 and AHG3) to functionally block their essential downstream roles in the release of PSD. A further phosphatase, PROTEIN PHOSPHATASE 2A SUBUNIT A2 (PP2AA/PDF1), also physically interacts with DOG1, but acts upstream to have a negative role in PSD. Interestingly, the transcription factor bZIP67 binds to the DOG1 promotor and is required for DOG expression and DOG accumulation. Together, DOG1 function is not strictly limited to seed dormancy, but that it is required for many facets of seed maturation, in part by interfering with ABA and ethylene signaling components.
Title: A perspective on secondary dormancy
Authors: Gonda Buijs and Luis Lopez-Molina
Affiliation: Department of Botany and Plant Biology, University of Geneva, Genève, Switzerland
Abstract: Seed dormancy is the phenomenon whereby viable seeds are unable to germinate under otherwise favorable conditions for germination. Primary dormancy is the dormancy present in seeds newly shed from the mother plant. After the release of primary dormancy, e.g. during seed after-ripening, seeds become non-dormant, i.e. they acquire the capacity to germinate under favorable conditions. However, when non-dormant seeds are exposed to prolonged conditions unfavourable for germination they can regain the inability to germinate under favorable conditions. This is termed secondary dormancy. Compared to primary dormancy, the mechanisms behind secondary dormancy remain understudied and virtually unknown. The main reason for this is practical: it is difficult to study in the laboratory. Additionally, there’s no clear consensus in protocols used. Recently, some field experiments have been performed with the model organism Arabidopsis thaliana. In this short review, we provide an overview of the current knowledge and provide a practical perspective for future research.
Title: Seed transcriptome annotation reveals new insights on the effect of alternating temperature on ROS homeostasis and Ethylene metabolism in wild cardoon
Authors: H.R. Huarte1, G.D. Puglia2,*, A.D. Prjibelski3, S.A. Raccuia2
Affiliation: 1 CONICET/Facultad de Ciencias Agrarias, Universidad Nacional de Lomas de Zamora, Llavallol, Argentina. 2 Consiglio Nazionale delle Ricerche, Istituto per i Sistemi Agricoli e Forestali del Mediterraneo (CNR-ISAFOM) U.O.S. Catania, Via Empedocle, 58, 95128 Catania, Italy; 3 Center for Algorithmic Biotechnology, Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; *Corresponding author. E-mail: [email protected]; Telephone number: +390956139914
Abstract: Alternating temperatures are widely recognized as signals promoting the relief of seed dormancy for many species. At molecular level, the ethylene signalling pathways counteracting ABA effects are triggered by reactive oxygen species (ROS) which homeostasis is influenced by temperatures fluctuation. Wild cardoon achenes poorly germinated at constant temperature of 20, 15 or 10 °C, whereas germination was substantially improved at alternating temperatures of 20/10 °C (above 80%). Using a RNA-seq approach, we annotated 14,710 gene transcripts expressed in achenes exposed to constant or alternating temperatures. Among them we identified transcripts homologous to key-genes involved in the regulation of dormancy relief. Alternating temperatures sharply increased the expression of ACO1, ETR1, RBOH, genes related to ethylene synthesis and signalling and ROS synthesis, respectively, which was confirmed via gas chromatography, whereas CAT gene expression (associated with ROS degradation) was reduced suggesting a precise equilibrium among ROS synthesis and degradation. Use of ethylene inhibitors, NAD(P)H oxidase inhibitor and ROS scavengers reduced germination at 20/10 °C. Conversely, the presence of a peroxidase inhibitor increased germination at constant temperatures. Taken together, these results evidence that exposure to alternating temperatures elicits a specific ROS amount production and the activation of ethylene metabolism that may promote dormancy relief.