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Seed Development, Dormancy and Germination

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Plant Sciences".

Deadline for manuscript submissions: closed (31 December 2018) | Viewed by 119115

Special Issue Editor

Ben-Gurion University of the Negev, Beer Sheba, Israel
Interests: seed development; seed germination; seed metabolism; network analysis

Special Issue Information

Dear Colleagues,

Seeds play a major role in ecosystems and agriculture as plant propagation units and products for human food and animal and insect feed. Seed propagation is determined by the seed potential to germinate and produce viable and robust seedlings. Thus uniformity and rate of germination are important traits in agriculture, especially in crops that are sown directly in the field. In contrast, seeds in the wild are characterised by large differences in rates of development and germination likely to enhance seedling establishment. The molecular mechanisms modulating germination traits are complex, integrating information (i) from the mother plant during development and stored in the seed maternal tissues, in their structure, composition and biochemistry, (ii) from the surrounding environment and (iii) from the embryo own genetic makeup. The output of this interplay will define the length of primary and secondary dormancy.

Eventually, radicle protrusion will bring germination to its end and seedling establishment will begin. The present issue collects original works related to molecular processes occurring during, and likely mediating, seed development, dormancy and germination with the aim to elucidate the fascinating relation between a seed and its environment; a relation fundamental to life on the planet.

Prof. Aaron Fait
Guest Editor

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Keywords

  • seed development
  • seed ecology
  • seed germination
  • seed dormancy
  • seed radicle protrusion
  • seed bank
  • seed metabolism

Published Papers (23 papers)

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16 pages, 4079 KiB  
Article
Seed Treatment with Trichoderma longibrachiatum T6 Promotes Wheat Seedling Growth under NaCl Stress Through Activating the Enzymatic and Nonenzymatic Antioxidant Defense Systems
by Shuwu Zhang, Bingliang Xu and Yantai Gan
Int. J. Mol. Sci. 2019, 20(15), 3729; https://doi.org/10.3390/ijms20153729 - 30 Jul 2019
Cited by 34 | Viewed by 4259
Abstract
Salt stress is one of the major abiotic stresses limiting crop growth and productivity worldwide. Species of Trichoderma are widely recognized for their bio-control abilities, but little information is regarding to the ability and mechanisms of their promoting plant growth and enhancing plant [...] Read more.
Salt stress is one of the major abiotic stresses limiting crop growth and productivity worldwide. Species of Trichoderma are widely recognized for their bio-control abilities, but little information is regarding to the ability and mechanisms of their promoting plant growth and enhancing plant tolerance to different levels of salt stress. Hence, we determined (i) the role of Trichoderma longibrachiatum T6 (TL-6) in promoting wheat (Triticum aestivum L.) seed germination and seedling growth under different levels of salt stress, and (ii) the mechanisms responsible for the enhanced tolerance of wheat to salt stress by TL-6. Wheat seeds treated with or without TL-6 were grown under different levels of salt stress in controlled environmental conditions. As such, the TL-6 treatments promoted seed germination and increased the shoot and root weights of wheat seedlings under both non-stress and salt-stress conditions. Wheat seedlings with TL-6 treatments under different levels of NaCl stress increased proline content by an average of 11%, ascorbate 15%, and glutathione 28%; and decreased the contents of malondialdehyde (MDA) by an average of 19% and hydrogen peroxide (H2O2) 13%. The TL-6 treatments induced the transcriptional level of reactive oxygen species (ROS) scavenging enzymes, leading to the increases of glutathione s-transferase (GST) by an average of 17%, glutathione peroxidase (GPX) 16%, ascorbate peroxidase (APX) 17%, glutathione reductase (GR) 18%, dehydroascorbate reductase (DHAR) 5%. Our results indicate that the beneficial strain of TL-6 effectively scavenged ROS under NaCl stress through modulating the activity of ROS scavenging enzymes, regulating the transcriptional levels of ROS scavenging enzyme gene expression, and enhancing the nonenzymatic antioxidants in wheat seedling in response to salt stress. Our present study provides a new insight into the mechanisms of TL-6 can activate the enzymatic and nonenzymatic antioxidant defense systems and enhance wheat seedling tolerance to different levels of salt stress at physiological, biochemical and molecular levels. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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17 pages, 6901 KiB  
Article
Map-Based Cloning, Phylogenetic, and Microsynteny Analyses of ZmMs20 Gene Regulating Male Fertility in Maize
by Yanbo Wang, Dongcheng Liu, Youhui Tian, Suowei Wu, Xueli An, Zhenying Dong, Simiao Zhang, Jianxi Bao, Ziwen Li, Jinping Li and Xiangyuan Wan
Int. J. Mol. Sci. 2019, 20(6), 1411; https://doi.org/10.3390/ijms20061411 - 20 Mar 2019
Cited by 21 | Viewed by 3616
Abstract
Genic male sterility (GMS) mutant is a useful germplasm resource for both theory research and production practice. The identification and characterization of GMS genes, and assessment of male-sterility stability of GMS mutant under different genetic backgrounds in Zea may (maize) have (1) deepened [...] Read more.
Genic male sterility (GMS) mutant is a useful germplasm resource for both theory research and production practice. The identification and characterization of GMS genes, and assessment of male-sterility stability of GMS mutant under different genetic backgrounds in Zea may (maize) have (1) deepened our understanding of the molecular mechanisms controlling anther and pollen development, and (2) enabled the development and efficient use of many biotechnology-based male-sterility (BMS) systems for hybrid breeding. Here, we reported a complete GMS mutant (ms20), which displays abnormal anther cuticle and pollen development. Its fertility restorer gene ZmMs20 was found to be a new allele of IPE1 encoding a glucose methanol choline (GMC) oxidoreductase involved in lipid metabolism in anther. Phylogenetic and microsynteny analyses showed that ZmMs20 was conserved among gramineous species, which provide clues for creating GMS materials in other crops. Additionally, among the 17 maize cloned GMS genes, ZmMs20 was found to be similar to the expression patterns of Ms7, Ms26, Ms6021, APV1, and IG1 genes, which will give some clues for deciphering their functional relationships in regulating male fertility. Finally, two functional markers of ZmMs20/ms20 were developed and tested for creating maize ms20 male-sterility lines in 353 genetic backgrounds, and then an artificial maintainer line of ms20 GMS mutation was created by using ZmMs20 gene, ms20 mutant, and BMS system. This work will promote our understanding of functional mechanisms of male fertility and facilitate molecular breeding of ms20 male-sterility lines for hybrid seed production in maize. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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21 pages, 3149 KiB  
Article
Global Gene Expression of Seed Coat Tissues Reveals a Potential Mechanism of Regulating Seed Size Formation in Castor Bean
by Anmin Yu, Zaiqing Wang, Yang Zhang, Fei Li and Aizhong Liu
Int. J. Mol. Sci. 2019, 20(6), 1282; https://doi.org/10.3390/ijms20061282 - 14 Mar 2019
Cited by 8 | Viewed by 5112
Abstract
The physiological and molecular basis of seed size formation is complex, and the development of seed coat (derived from integument cells) might be a critical factor that determines seed size formation for many endospermic seeds. Castor bean (Ricinus communis L.), a model [...] Read more.
The physiological and molecular basis of seed size formation is complex, and the development of seed coat (derived from integument cells) might be a critical factor that determines seed size formation for many endospermic seeds. Castor bean (Ricinus communis L.), a model system of studying seed biology, has large and persistent endosperm with a hard seed coat at maturity. Here, we investigated the potential molecular mechanisms underlying seed size formation in castor bean by comparing the difference between global gene expression within developing seed coat tissues between the large-seed ZB107 and small-seed ZB306. First, we observed the cell size of seed coat and concluded that the large seed coat area of ZB107 resulted from more cell numbers (rather than cell size). Furthermore, we found that the lignin proportion of seed coat was higher in ZB306. An investigation into global gene expression of developing seed coat tissues revealed that 815 genes were up-regulated and 813 were down-regulated in ZB306 relative to ZB107. Interestingly, we found that many genes involved in regulating cell division were up-regulated in ZB107, whereas many genes involved in regulating lignin biosynthesis (including several NAC members, as well as MYB46/83 and MYB58/63) and in mediating programmed cell death (such as CysEP1 and βVPE) were up-regulated in ZB306. Furthermore, the expression patterns of the genes mentioned above indicated that the lignification of seed coat tissues was enhanced and occurred earlier in the developing seeds of ZB306. Taken together, we tentatively proposed a potential scenario for explaining the molecular mechanisms of seed coat governing seed size formation in castor bean by increasing the cell number and delaying the onset of lignification in seed coat tissues in large-seed ZB107. This study not only presents new information for possible modulation of seed coat related genes to improve castor seed yield, but also provides new insights into understanding the molecular basis of seed size formation in endospermic seeds with hard seed coat. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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17 pages, 1212 KiB  
Article
Nitric Oxide-Induced Dormancy Removal of Apple Embryos Is Linked to Alterations in Expression of Genes Encoding ABA and JA Biosynthetic or Transduction Pathways and RNA Nitration
by Paulina Andryka-Dudek, Katarzyna Ciacka, Anita Wiśniewska, Renata Bogatek and Agnieszka Gniazdowska
Int. J. Mol. Sci. 2019, 20(5), 1007; https://doi.org/10.3390/ijms20051007 - 26 Feb 2019
Cited by 15 | Viewed by 3527
Abstract
Short-term (3 h) treatment of embryos isolated from dormant apple (Malus domestica Borkh.) seeds with NO donors stimulates their transition from dormancy to germination. Seed dormancy is maintained by ABA, while germination is controlled mainly by gibberellins (GAs) and jasmonic acid (JA). [...] Read more.
Short-term (3 h) treatment of embryos isolated from dormant apple (Malus domestica Borkh.) seeds with NO donors stimulates their transition from dormancy to germination. Seed dormancy is maintained by ABA, while germination is controlled mainly by gibberellins (GAs) and jasmonic acid (JA). NO-induced dormancy removal correlates with low ABA concentration in embryonic axes and reduced embryo sensitivity to ABA. We analyzed the expression of genes encoding key enzymes of ABA degradation (CYP707A1, CYP707A2), biosynthesis (NCED3, NCED9), and elements of the ABA transduction pathway (PYL1, PYL2, RCAR1, RCAR3, PP2CA, ABI1, ABI2, SNRK2, ABI5, AREB3, ABF). A role for JA in the regulation of germination led us to investigate the expression of genes encoding enzymes of JA biosynthesis (AOS1, JMT, JAR1) and the transduction pathway (COI1, MYC2, JAZ3, JAZ12). The expression profiles of the genes were estimated in embryonic axes isolated from dormant or NO fumigated apple embryos. The analyzed genes were differentially regulated during dormancy alleviation, the main modifications in the transcription level were detected for NCED3, NCED9, CYP707A2, RCAR1, ABF, AOS1, JMT, JAR1 and JAZ3. A regulatory role of NO in the removal of seed dormancy is associated with the stimulation of expression of genes related to ABA degradation, down-regulation of genes responsible for ABA synthesis, an increase of expression level of genes engaged in JA synthesis and modification of the expression of genes engaged in signaling pathways of the hormones. To confirm a signaling role of NO during dormancy breakage, an increased RNA nitration level in embryonic axes was demonstrated. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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21 pages, 760 KiB  
Article
Genome-Wide Detection of Major and Epistatic Effect QTLs for Seed Protein and Oil Content in Soybean Under Multiple Environments Using High-Density Bin Map
by Benjamin Karikari, Shuguang Li, Javaid Akhter Bhat, Yongce Cao, Jiejie Kong, Jiayin Yang, Junyi Gai and Tuanjie Zhao
Int. J. Mol. Sci. 2019, 20(4), 979; https://doi.org/10.3390/ijms20040979 - 23 Feb 2019
Cited by 28 | Viewed by 5937
Abstract
Seed protein and oil content are the two important traits determining the quality and value of soybean. Development of improved cultivars requires detailed understanding of the genetic basis underlying the trait of interest. However, it is prerequisite to have a high-density linkage map [...] Read more.
Seed protein and oil content are the two important traits determining the quality and value of soybean. Development of improved cultivars requires detailed understanding of the genetic basis underlying the trait of interest. However, it is prerequisite to have a high-density linkage map for precisely mapping genomic regions, and therefore the present study used high-density genetic map containing 2267 recombination bin markers distributed on 20 chromosomes and spanned 2453.79 cM with an average distance of 1.08 cM between markers using restriction-site-associated DNA sequencing (RAD-seq) approach. A recombinant inbred line (RIL) population of 104 lines derived from a cross between Linhefenqingdou and Meng 8206 cultivars was evaluated in six different environments to identify main- and epistatic-effect quantitative trait loci (QTLs)as well as their interaction with environments. A total of 44 main-effect QTLs for protein and oil content were found to be distributed on 17 chromosomes, and 15 novel QTL were identified for the first time. Out of these QTLs, four were major and stable QTLs, viz., qPro-7-1, qOil-8-3, qOil-10-2 and qOil-10-4, detected in at least two environments plus combined environment with R2 values >10%. Within the physical intervals of these four QTLs, 111 candidate genes were screened for their direct or indirect involvement in seed protein and oil biosynthesis/metabolism processes based on gene ontology and annotation information. Based on RNA sequencing (RNA-seq) data analysis, 15 of the 111 genes were highly expressed during seed development stage and root nodules that might be considered as the potential candidate genes. Seven QTLs associated with protein and oil content exhibited significant additive and additive × environment interaction effects, and environment-independent QTLs revealed higher additive effects. Moreover, three digenic epistatic QTLs pairs were identified, and no main-effect QTLs showed epistasis. In conclusion, the use of a high-density map identified closely linked flanking markers, provided better understanding of genetic architecture and candidate gene information, and revealed the scope available for improvement of soybean quality through marker assisted selection (MAS). Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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24 pages, 4220 KiB  
Article
New Insight on Water Status in Germinating Brassica napus Seeds in Relation to Priming-Improved Germination
by Katarzyna Lechowska, Szymon Kubala, Łukasz Wojtyla, Grzegorz Nowaczyk, Muriel Quinet, Stanley Lutts and Małgorzata Garnczarska
Int. J. Mol. Sci. 2019, 20(3), 540; https://doi.org/10.3390/ijms20030540 - 28 Jan 2019
Cited by 38 | Viewed by 6386
Abstract
Seed priming is a pre-sowing method successfully used to improve seed germination. Since water plays a crucial role in germination, the aim of this study was to investigate the relationship between better germination performances of osmoprimed Brassica napus seeds and seed water status [...] Read more.
Seed priming is a pre-sowing method successfully used to improve seed germination. Since water plays a crucial role in germination, the aim of this study was to investigate the relationship between better germination performances of osmoprimed Brassica napus seeds and seed water status during germination. To achieve this goal, a combination of different kinds of approaches was used, including nuclear magnetic resonance (NMR) spectroscopy, TEM, and SEM as well as semi-quantitative PCR (semi-qPCR). The results of this study showed that osmopriming enhanced the kinetics of water uptake and the total amount of absorbed water during both the early imbibition stage and in the later phases of seed germination. The spin–spin relaxation time (T2) measurement suggests that osmopriming causes faster water penetration into the seed and more efficient tissue hydration. Moreover, factors potentially affecting water relations in germinating primed seeds were also identified. It was shown that osmopriming (i) changes the microstructural features of the seed coat, e.g., leads to the formation of microcracks, (ii) alters the internal structure of the seed by the induction of additional void spaces in the seed, (iii) increases cotyledons cells vacuolization, and (iv) modifies the expression pattern of aquaporin genes. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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10 pages, 1300 KiB  
Article
Variations in Accumulation of Lignin and Cellulose and Metabolic Changes in Seed Hull Provide Insight into Dehulling Characteristic of Tartary Buckwheat Seeds
by Chao Song, Chengrui Ma and Dabing Xiang
Int. J. Mol. Sci. 2019, 20(3), 524; https://doi.org/10.3390/ijms20030524 - 26 Jan 2019
Cited by 13 | Viewed by 3353
Abstract
Tartary buckwheat (Fagopyrum tataricum) is considered a profitable crop that possesses medicinal properties, because of its flavonoid compounds. However, the dehulling issue is becoming the bottleneck for consumption of Tartary buckwheat seed. In this study, we investigated the relation between dehulling [...] Read more.
Tartary buckwheat (Fagopyrum tataricum) is considered a profitable crop that possesses medicinal properties, because of its flavonoid compounds. However, the dehulling issue is becoming the bottleneck for consumption of Tartary buckwheat seed. In this study, we investigated the relation between dehulling efficiency and content of lignin and cellulose in the seed hull. Moreover, the untargeted metabolomics analysis, including partial least squares discriminant analysis (PLS-DA) and principal component analysis (PCA), were performed to examine the pattern of metabolic changes in the hull of Tartary buckwheat seeds, XQ 1 and MQ 1, during seed development using gas chromatography mass spectrometry (GC-MS). In mature seed hull the accumulation of highest lignin and lowest cellulose were observed in the hull of MQ 1 seed, a dehulling-friendly variety with highest dehulling efficiency (93%), than that in other dehulling recalcitrant varieties, such as XQ 1 with a range of dehulling efficiency from 2% to 6%. During seed development, the total content of lignin and cellulose increased. MQ 1 and XQ 1 displayed a similar trend in the change of lignin and cellulose that the content was decreased in lignin and increased in cellulose. PCA result showed the metabolic differentiations between MQ 1 and XQ 1 during seed development. The results of our study suggest the compensatory regulation of lignin and cellulose deposition in the hull of mature and developing seed, and deviation of MQ 1 from the ratio of lignin to cellulose of other dehulling recalcitrant varieties may have been a contributing factor that resulted in the dehulling differentia. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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22 pages, 2075 KiB  
Article
Combined Proteomic and Metabolomic Profiling of the Arabidopsis thaliana vps29 Mutant Reveals Pleiotropic Functions of the Retromer in Seed Development
by Thomas C Durand, Gwendal Cueff, Béatrice Godin, Benoît Valot, Gilles Clément, Thierry Gaude and Loïc Rajjou
Int. J. Mol. Sci. 2019, 20(2), 362; https://doi.org/10.3390/ijms20020362 - 16 Jan 2019
Cited by 12 | Viewed by 6117
Abstract
The retromer is a multiprotein complex conserved from yeast to humans, which is involved in intracellular protein trafficking and protein recycling. Selection of cargo proteins transported by the retromer depends on the core retromer subunit composed of the three vacuolar protein sorting (VPS) [...] Read more.
The retromer is a multiprotein complex conserved from yeast to humans, which is involved in intracellular protein trafficking and protein recycling. Selection of cargo proteins transported by the retromer depends on the core retromer subunit composed of the three vacuolar protein sorting (VPS) proteins, namely VPS26, VPS29, and VPS35. To gain a better knowledge of the importance of the plant retromer in protein sorting, we carried out a comparative proteomic and metabolomic analysis of Arabidopsis thaliana seeds from the wild-type and the null-retromer mutant vps29. Here, we report that the retromer mutant displays major alterations in the maturation of seed storage proteins and synthesis of lipid reserves, which are accompanied by severely impaired seed vigor and longevity. We also show that the lack of retromer components is counterbalanced by an increase in proteins involved in intracellular trafficking, notably members of the Ras-related proteins in brain (RAB) family proteins. Our study suggests that loss of the retromer stimulates energy metabolism, affects many metabolic pathways, including that of cell wall biogenesis, and triggers an osmotic stress response, underlining the importance of retromer function in seed biology. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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21 pages, 2748 KiB  
Article
Comparative Transcriptome Analysis Reveals an Efficient Mechanism for α -Linolenic Acid Synthesis in Tree Peony Seeds
by Qingyu Zhang, Rui Yu, Daoyang Sun, Md Mahbubur Rahman, Lihang Xie, Jiayuan Hu, Lixia He, Aruna Kilaru, Lixin Niu and Yanlong Zhang
Int. J. Mol. Sci. 2019, 20(1), 65; https://doi.org/10.3390/ijms20010065 - 24 Dec 2018
Cited by 27 | Viewed by 4248
Abstract
Tree peony (Paeonia section Moutan DC.) species are woody oil crops with high unsaturated fatty acid content, including α-linolenic acid (ALA/18:3; >40% of the total fatty acid). Comparative transcriptome analyses were carried out to uncover the underlying mechanisms responsible for high and [...] Read more.
Tree peony (Paeonia section Moutan DC.) species are woody oil crops with high unsaturated fatty acid content, including α-linolenic acid (ALA/18:3; >40% of the total fatty acid). Comparative transcriptome analyses were carried out to uncover the underlying mechanisms responsible for high and low ALA content in the developing seeds of P. rockii and P. lutea, respectively. Expression analysis of acyl lipid metabolism genes revealed upregulation of select genes involved in plastidial fatty acid synthesis, acyl editing, desaturation, and triacylglycerol assembly in seeds of P. rockii relative to P. lutea. Also, in association with ALA content in seeds, transcript levels for fatty acid desaturases (SAD, FAD2, and FAD3), which encode enzymes necessary for polyunsaturated fatty acid synthesis, were higher in P. rockii compared to P. lutea. Furthermore, the overexpression of PrFAD2 and PrFAD3 in Arabidopsis increased linoleic and ALA content, respectively, and modulated the final ratio 18:2/18:3 in the seed oil. In conclusion, we identified the key steps and validated the necessary desaturases that contribute to efficient ALA synthesis in a woody oil crop. Together, these results will aid to increase essential fatty acid content in seeds of tree peonies and other crops of agronomic interest. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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9 pages, 2201 KiB  
Communication
Notched Belly Grain 4, a Novel Allele of Dwarf 11, Regulates Grain Shape and Seed Germination in Rice (Oryza sativa L.)
by Xiaohong Tong, Yifeng Wang, Aiqun Sun, Babatunde Kazeem Bello, Shen Ni and Jian Zhang
Int. J. Mol. Sci. 2018, 19(12), 4069; https://doi.org/10.3390/ijms19124069 - 16 Dec 2018
Cited by 18 | Viewed by 4671
Abstract
Notched belly grain (NBG) is a type of deformed grain shape that has been associated with inferior appearance and tastes in rice. NBG is coordinated by both environments and genetics. In this study, we report on the first map-based cloning of an NBG [...] Read more.
Notched belly grain (NBG) is a type of deformed grain shape that has been associated with inferior appearance and tastes in rice. NBG is coordinated by both environments and genetics. In this study, we report on the first map-based cloning of an NBG gene on chromosome 4, denoted NBG4, which is a novel allele of Dwarf 11 encoding a cytochrome P450 (CYP724B1) involved in brassinosteroid (BR) biosynthesis. A 10-bp deletion in the 7th exon knocked down the level of the NBG4 transcript and shifted the reading frame of the resulting protein. In addition to the dwarf and clustered panicle as previously reported in the allelic mutants, nbg4 grains also displayed retarded germination and NBG due to the physical constraint of deformed hulls caused by abnormal hull elongation. NBG4 is constitutively expressed with the highest level of expression in immature inflorescences. In all, 2294 genes were differentially expressed in nbg4 and wild-type (WT), and evidence is presented that NBG4 regulates OsPPS-2, OsPRA2, OsYUCCA1, sped1-D, and Dwarf that play critical roles in determining plant architecture, panicle development, and seed germination. This study demonstrated that NBG4 is a key node in the brassinosteroid-mediated regulation of rice grain shape. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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13 pages, 1455 KiB  
Article
Revisiting the Role of Ethylene and N-End Rule Pathway on Chilling-Induced Dormancy Release in Arabidopsis Seeds
by Xu Wang, Zhazira Yesbergenova-Cuny, Catherine Biniek, Christophe Bailly, Hayat El-Maarouf-Bouteau and Françoise Corbineau
Int. J. Mol. Sci. 2018, 19(11), 3577; https://doi.org/10.3390/ijms19113577 - 13 Nov 2018
Cited by 16 | Viewed by 4248
Abstract
Dormant Arabidopsis (Arabidopsis thaliana) seeds do not germinate easily at temperatures higher than 10–15 °C. Using mutants affected in ethylene signaling (etr1, ein2 and ein4) and in the N-end-rule pathway of the proteolysis (prt6 and ate1-ate2) [...] Read more.
Dormant Arabidopsis (Arabidopsis thaliana) seeds do not germinate easily at temperatures higher than 10–15 °C. Using mutants affected in ethylene signaling (etr1, ein2 and ein4) and in the N-end-rule pathway of the proteolysis (prt6 and ate1-ate2) we have investigated the effects of cold and ethylene on dormancy alleviation. Ethylene (10–100 ppm) and 2–4 days chilling (4 °C) strongly stimulate the germination of wild type (Col-0) seeds at 25 °C. Two to four days of chilling promote the germination at 25 °C of all the mutants suggesting that release of dormancy by cold did not require ethylene and did not require the N-end-rule pathway. One mutant (etr1) that did not respond to ethylene did not respond to GA3 either. Mutants affected in the N-end rule (prt6 and ate1-ate2) did not respond to ethylene indicating that also this pathway is required for dormancy alleviation by ethylene; they germinated after chilling and in the presence of GA3. Cold can activate the ethylene signaling pathway since it induced an accumulation of ETR1, EINI4, and EIN2 transcripts, the expression of which was not affected by ethylene and GA3. Both cold followed by 10 h at 25 °C and ethylene downregulated the expression of PRT6, ATE1, ATE2, and of ABI5 involved in ABA signaling as compared to dormant seeds incubated at 25 °C. In opposite, the expression of RGA, GAI, and RGL2 encoding three DELLAs was induced at 4 °C but downregulated in the presence of ethylene. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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15 pages, 4865 KiB  
Article
Pretreatment with NaCl Promotes the Seed Germination of White Clover by Affecting Endogenous Phytohormones, Metabolic Regulation, and Dehydrin-Encoded Genes Expression under Water Stress
by Yiqin Cao, Linlin Liang, Bizhen Cheng, Yue Dong, Jiaqi Wei, Xiaolan Tian, Yan Peng and Zhou Li
Int. J. Mol. Sci. 2018, 19(11), 3570; https://doi.org/10.3390/ijms19113570 - 12 Nov 2018
Cited by 17 | Viewed by 3405
Abstract
This study was designed to examine the effects of NaCl pretreatment on the seed germination of white clover (Trifolium repens cv. Ladino) under water stress induced by 19% polyethylene glycol (PEG) 6000. Lower concentrations of NaCl (0.5, 1, and 2.5 mM) pretreatment [...] Read more.
This study was designed to examine the effects of NaCl pretreatment on the seed germination of white clover (Trifolium repens cv. Ladino) under water stress induced by 19% polyethylene glycol (PEG) 6000. Lower concentrations of NaCl (0.5, 1, and 2.5 mM) pretreatment significantly alleviated stress-induced decreases in germination percentage, germination vigor, germination index, and radicle length of seedlings after seven days of germination under water stress. The soaking with 1 mM of NaCl exhibited most the pronounced effects on improving seed germination and alleviating stress damage. NaCl-induced seeds germination and growth could be associated with the increases in endogenous gibberellic acid (GA) and indole-3-acetic acid (IAA) levels through activating amylases leading to improved amylolysis under water stress. Seedlings pretreated with NaCl had a significantly lower osmotic potential than untreated seedlings during seed germination, which could be related to significantly higher soluble sugars and free proline content in NaCl-treated seedlings under water stress. For antioxidant metabolism, NaCl pretreatment mainly improved superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione reductase activities, transcript levels of FeSOD, APX, and DHAR, and the content of ascorbic acid, reduced glutathione, and oxidized glutathione during seed germination under water stress. The results indicated that seeds soaking with NaCl could remarkably enhance antioxidant metabolism, thereby decreasing the accumulation of reactive oxygen species and membrane lipid peroxidation during germination under water stress. In addition, NaCl-upregulated dehydrin-encoded genes SK2 expression could be another important mechanism of drought tolerance during seeds germination of white clover in response to water stress. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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14 pages, 3839 KiB  
Article
Effects of Nitrogen Level during Seed Production on Wheat Seed Vigor and Seedling Establishment at the Transcriptome Level
by Daxing Wen, Haicheng Xu, Liuyong Xie, Mingrong He, Hongcun Hou, Chenglai Wu, Yan Li and Chunqing Zhang
Int. J. Mol. Sci. 2018, 19(11), 3417; https://doi.org/10.3390/ijms19113417 - 31 Oct 2018
Cited by 12 | Viewed by 4569
Abstract
Nitrogen fertilizer is a critical determinant of grain yield and seed quality in wheat. However, the mechanism of nitrogen level during seed production affecting wheat seed vigor and seedling establishment at the transcriptome level remains unknown. Here, we report that wheat seeds produced [...] Read more.
Nitrogen fertilizer is a critical determinant of grain yield and seed quality in wheat. However, the mechanism of nitrogen level during seed production affecting wheat seed vigor and seedling establishment at the transcriptome level remains unknown. Here, we report that wheat seeds produced under different nitrogen levels (N0, N168, N240, and N300) showed significant differences in seed vigor and seedling establishment. In grain yield and seed vigor, N0 and N240 treatments showed the minimum and maximum, respectively. Subsequently, we used RNA-seq to analyze the transcriptomes of seeds and seedlings under N0 and N240 at the early stage of seedling establishment. Gene Ontology (GO) term enrichment analysis revealed that dioxygenase-activity-related genes were dramatically upregulated in faster growing seedlings. Among these genes, the top three involved linoleate 9S-lipoxygenase (Traes_2DL_D4BCDAA76, Traes_2DL_CE85DC5C0, and Traes_2DL_B5B62EE11). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that pathways involved in nutrient mobilization and the antioxidant system showed enhanced expression under N240. Moreover, seeds with faster growing seedlings had a higher gene expression level of α-amylase, which was consistent with α-amylase activity. Taken together, we propose a model for seedling establishment and seed vigor in response to nitrogen level during seed production. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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15 pages, 7590 KiB  
Article
In situ Degradation and Characterization of Endosperm Starch in Waxy Rice with the Inhibition of Starch Branching Enzymes during Seedling Growth
by Ting Pan, Lingshang Lin, Qiaoquan Liu and Cunxu Wei
Int. J. Mol. Sci. 2018, 19(11), 3397; https://doi.org/10.3390/ijms19113397 - 30 Oct 2018
Cited by 2 | Viewed by 2585
Abstract
High-resistant starch cereal crops with the inhibition of the starch branching enzyme (SBE) have been widely studied. However, the effects of the inhibition of SBE on waxy cereal crops are unclear. A transgenic rice line (GTR) derived from a japonica waxy rice cultivar [...] Read more.
High-resistant starch cereal crops with the inhibition of the starch branching enzyme (SBE) have been widely studied. However, the effects of the inhibition of SBE on waxy cereal crops are unclear. A transgenic rice line (GTR) derived from a japonica waxy rice cultivar Guang-ling-xiang-nuo (GLXN) has been developed through antisense RNA inhibition of both SBEI and SBEIIb. In this study, GLXN and GTR were cultivated in the dark only in deionized H2O, and their shoot and root growth, starch in situ degradation, and starch property changes were investigated during seedling growth. Compared with GLXN, GTR showed a significantly slow seedling growth, which was not due to the embryo size and vitality. The slow degradation of starch in the seed restrained the seedling growth. GLXN starch was completely degraded gradually from the proximal to distal region of the embryo and from the outer to inner region in the endosperm, but GTR starch in the peripheral region of the endosperm was not completely degraded, and the starch residual was located in the outside of the compound starch though its degradation pattern was similar to GLXN. During seedling growth, GLXN starch had the same A-type crystallinity and a similar ordered structure, but the crystallinity changed from the CA-type to B-type and the ordered structure gradually increased in the GTR starch. The above results indicated that GTR had a heterogeneous starch distributed regionally in the endosperm. The starch in the peripheral region of the endosperm had a B-type crystallinity, which was located in the outside of the compound starch and significantly increased the resistance to in situ degradation, leading to the seedling slow growth. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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14 pages, 2251 KiB  
Article
Germination and the Early Stages of Seedling Development in Brachypodium distachyon
by Elzbieta Wolny, Alexander Betekhtin, Magdalena Rojek, Agnieszka Braszewska-Zalewska, Joanna Lusinska and Robert Hasterok
Int. J. Mol. Sci. 2018, 19(10), 2916; https://doi.org/10.3390/ijms19102916 - 25 Sep 2018
Cited by 56 | Viewed by 6325
Abstract
Successful germination and seedling development are crucial steps in the growth of a new plant. In this study, we investigated the course of the cell cycle during germination in relation to grain hydration in the model grass Brachypodium distachyon (Brachypodium) for the first [...] Read more.
Successful germination and seedling development are crucial steps in the growth of a new plant. In this study, we investigated the course of the cell cycle during germination in relation to grain hydration in the model grass Brachypodium distachyon (Brachypodium) for the first time. Flow cytometry was performed to monitor the cell cycle progression during germination and to estimate DNA content in embryo tissues. The analyses of whole zygotic embryos revealed that the relative DNA content was 2C, 4C, 8C, and 16C. Endoreplicated nuclei were detected in the scutellum and coleorhiza cells, whereas the rest of the embryo tissues only had nuclei with a 2C and 4C DNA content. This study was accompanied by a spatiotemporal profile analysis of the DNA synthetic activity in the organs of Brachypodium embryos during germination using EdU labelling. Upon imbibition, nuclear DNA replication was initiated in the radicle within 11 h and subsequently spread towards the plumule. The first EdU-labelled prophases were observed after 14 h of imbibition. Analysis of selected genes that are involved in the regulation of the cell cycle, such as those encoding cyclin-dependent kinases and cyclins, demonstrated an increase in their expression profiles. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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19 pages, 4017 KiB  
Article
The Potential Role of Auxin and Abscisic Acid Balance and FtARF2 in the Final Size Determination of Tartary Buckwheat Fruit
by Moyang Liu, Zhaotang Ma, Tianrun Zheng, Jing Wang, Li Huang, Wenjun Sun, Yanjun Zhang, Weiqiong Jin, Junyi Zhan, Yuntao Cai, Yujia Tang, Qi Wu, Zizhong Tang, Tongliang Bu, Chenglei Li, Hui Chen and Gang Zhao
Int. J. Mol. Sci. 2018, 19(9), 2755; https://doi.org/10.3390/ijms19092755 - 13 Sep 2018
Cited by 24 | Viewed by 3801
Abstract
Tartary buckwheat is a type of cultivated medicinal and edible crop with good economic and nutritional value. Knowledge of the final fruit size of buckwheat is critical to its yield increase. In this study, the fruit development of two species of Tartary buckwheat [...] Read more.
Tartary buckwheat is a type of cultivated medicinal and edible crop with good economic and nutritional value. Knowledge of the final fruit size of buckwheat is critical to its yield increase. In this study, the fruit development of two species of Tartary buckwheat in the Polygonaceae was analyzed. During fruit development, the size/weight, the contents of auxin (AUX)/abscisic acid (ABA), the number of cells, and the changes of embryo were measured and observed; and the two fruit materials were compared to determine the related mechanisms that affected fruit size and the potential factors that regulated the final fruit size. The early events during embryogenesis greatly influenced the final fruit size, and the difference in fruit growth was primarily due to the difference in the number of cells, implicating the effect of cell division rate. Based on our observations and recent reports, the balance of AUX and ABA might be the key factor that regulated the cell division rate. They induced the response of auxin response factor 2 (FtARF2) and downstream small auxin upstream RNA (FtSAURs) through hormone signaling pathway to regulate the fruit size of Tartary buckwheat. Further, through the induction of fruit expansion by exogenous auxin, FtARF2b was significantly downregulated. The FtARF2b is a potential target for molecular breeding or gene editing. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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17 pages, 1864 KiB  
Article
The γ-Aminobutyric Acid (GABA) Alleviates Salt Stress Damage during Seeds Germination of White Clover Associated with Na+/K+ Transportation, Dehydrins Accumulation, and Stress-Related Genes Expression in White Clover
by Bizhen Cheng, Zhou Li, Linlin Liang, Yiqin Cao, Weihang Zeng, Xinquan Zhang, Xiao Ma, Linkai Huang, Gang Nie, Wei Liu and Yan Peng
Int. J. Mol. Sci. 2018, 19(9), 2520; https://doi.org/10.3390/ijms19092520 - 25 Aug 2018
Cited by 101 | Viewed by 6364
Abstract
The objective of this study was to determine the effect of soaking with γ-aminobutyric acid (GABA) on white clover (Trifolium repens cv. Haifa) seed germination under salt stress induced by 100 mM NaCl. Seeds soaking with GABA (1 μM) significantly alleviated salt-induced [...] Read more.
The objective of this study was to determine the effect of soaking with γ-aminobutyric acid (GABA) on white clover (Trifolium repens cv. Haifa) seed germination under salt stress induced by 100 mM NaCl. Seeds soaking with GABA (1 μM) significantly alleviated salt-induced decreases in endogenous GABA content, germination percentage, germination vigor, germination index, shoot and root length, fresh and dry weight, and root activity of seedling during seven days of germination. Exogenous application of GABA accelerated starch catabolism via the activation of amylase and also significantly reduced water-soluble carbohydrate, free amino acid, and free proline content in seedlings under salt stress. In addition, improved antioxidant enzyme activities (SOD, GPOX, CAT, APX, DHAR, GR and MDHR) and gene transcript levels (Cu/ZnSOD, FeSOD, MnSOD, CAT, GPOX, APX, MDHR, GPX and GST) was induced by seeds soaking with GABA, followed by decreases in O2∙−, H2O2, and MDA accumulation during germination under salt stress. Seeds soaking with GABA could also significantly improve Na+/K+ content and transcript levels of genes encoding Na+/K+ transportation (HKT1, HKT8, HAL2, H+-ATPase and SOS1) in seedlings of white clover. Moreover, exogenous GABA significantly induced the accumulation of dehydrins and expression of genes encoding dehydrins (SK2, Y2K, Y2SK, and dehydrin b) in seedlings under salt stress. These results indicate that GABA mitigates the salt damage during seeds germination through enhancing starch catabolism and the utilization of sugar and amino acids for the maintenance of growth, improving the antioxidant defense for the alleviation of oxidative damage, increasing Na+/K+ transportation for the osmotic adjustment, and promoting dehydrins accumulation for antioxidant and osmotic adjustment under salt stress. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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17 pages, 1526 KiB  
Article
One Way to Achieve Germination: Common Molecular Mechanism Induced by Ethylene and After-Ripening in Sunflower Seeds
by Qiong Xia, Marine Saux, Maharajah Ponnaiah, Françoise Gilard, François Perreau, Stéphanie Huguet, Sandrine Balzergue, Nicolas Langlade, Christophe Bailly, Patrice Meimoun, Françoise Corbineau and Hayat El-Maarouf-Bouteau
Int. J. Mol. Sci. 2018, 19(8), 2464; https://doi.org/10.3390/ijms19082464 - 20 Aug 2018
Cited by 14 | Viewed by 5352
Abstract
Dormancy is an adaptive trait that blocks seed germination until the environmental conditions become favorable for subsequent vegetative plant growth. Seed dormancy is defined as the inability to germinate in favorable conditions. Dormancy is alleviated during after-ripening, a dry storage period, during which [...] Read more.
Dormancy is an adaptive trait that blocks seed germination until the environmental conditions become favorable for subsequent vegetative plant growth. Seed dormancy is defined as the inability to germinate in favorable conditions. Dormancy is alleviated during after-ripening, a dry storage period, during which dormant (D) seeds unable to germinate become non-dormant (ND), able to germinate in a wide range of environmental conditions. The treatment of dormant seeds with ethylene (D/ET) promotes seed germination, and abscisic acid (ABA) treatment reduces non-dormant (ND/ABA) seed germination in sunflowers (Helianthus annuus). Metabolomic and transcriptomic studies have been performed during imbibition to compare germinating seeds (ND and D/ET) and low-germinating seeds (D and ND/ABA). A PCA analysis of the metabolites content showed that imbibition did not trigger a significant change during the first hours (3 and 15 h). The metabolic changes associated with germination capacity occurred at 24 h and were related to hexoses, as their content was higher in ND and D/ET and was reduced by ABA treatment. At the transcriptional level, a large number of genes were altered oppositely in germinating, compared to the low-germinating seeds. The metabolomic and transcriptomic results were integrated in the interpretation of the processes involved in germination. Our results show that ethylene treatment triggers molecular changes comparable to that of after-ripening treatment, concerning sugar metabolism and ABA signaling inhibition. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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25 pages, 2586 KiB  
Article
Long-Term Effects of Cold on Growth, Development and Yield of Narrow-Leaf Lupine May Be Alleviated by Seed Hydropriming or Butenolide
by Agnieszka Płażek, Franciszek Dubert, Przemysław Kopeć, Michał Dziurka, Agnieszka Kalandyk, Jakub Pastuszak, Piotr Waligórski and Bogdan Wolko
Int. J. Mol. Sci. 2018, 19(8), 2416; https://doi.org/10.3390/ijms19082416 - 16 Aug 2018
Cited by 13 | Viewed by 3680
Abstract
In this article, the effects of cold on the development of Lupine angustifolius and the possibility of mitigating it, via seed hydropriming or pre-treatment with butenolide (10−6 M–10−4 M), are investigated in two cultivars, differing in their ability to germinate at [...] Read more.
In this article, the effects of cold on the development of Lupine angustifolius and the possibility of mitigating it, via seed hydropriming or pre-treatment with butenolide (10−6 M–10−4 M), are investigated in two cultivars, differing in their ability to germinate at low temperature. Physiological background of plant development after cold stress was investigated in imbibed seeds. For the first four weeks, the seedlings grew at 7 °C or 13 °C. Seeds well germinating at 7 °C demonstrated higher activity of α-amylase and higher levels of gibberellins, IAA and kinetin. Germination ability at low temperature correlated with dehydrogenase activity and membrane permeability. Seed pre-treatment improved germination at low temperature by decreasing abscisic acid content. Seed hydropriming alleviated cold effects on plant development rate and yield, while butenolide accelerated vegetative development but delayed the generative phase. Potential seed yield may be predicted based on the seed germination vigour and the photosynthetic efficiency measured before flowering. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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15 pages, 5212 KiB  
Article
A Novel Mutation of OsPPDKB, Encoding Pyruvate Orthophosphate Dikinase, Affects Metabolism and Structure of Starch in the Rice Endosperm
by Long Zhang, Linglong Zhao, Lingshang Lin, Lingxiao Zhao, Qiaoquan Liu and Cunxu Wei
Int. J. Mol. Sci. 2018, 19(8), 2268; https://doi.org/10.3390/ijms19082268 - 02 Aug 2018
Cited by 24 | Viewed by 4422
Abstract
Starch, as a main energy storage substance, plays an important role in plant growth and human life. Despite the fact that several enzymes and regulators involved in starch biosynthesis have been identified, the regulating mechanism of starch synthesis is still unclear. In this [...] Read more.
Starch, as a main energy storage substance, plays an important role in plant growth and human life. Despite the fact that several enzymes and regulators involved in starch biosynthesis have been identified, the regulating mechanism of starch synthesis is still unclear. In this study, we isolated a rice floury endosperm mutant M14 from a mutant pool induced by 60Co. Both total starch content and amylose content in M14 seeds significantly decreased, and starch thermal and pasting properties changed. Compound starch granules were defected in the floury endosperm of M14 seeds. Map-based cloning and a complementation test showed that the floury endosperm phenotype was determined by a gene of OsPPDKB, which encodes pyruvate orthophosphate dikinase (PPDK, EC 2.7.9.1). Subcellular localization analysis demonstrated that PPDK was localized in chloroplast and cytoplasm, the chOsPPDKB highly expressed in leaf and leaf sheath, and the cyOsPPDKB constitutively expressed with a high expression in developing endosperm. Moreover, the expression of starch synthesis-related genes was also obviously altered in M14 developing endosperm. The above results indicated that PPDK played an important role in starch metabolism and structure in rice endosperm. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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12 pages, 2378 KiB  
Article
GW2 Functions as an E3 Ubiquitin Ligase for Rice Expansin-Like 1
by Beom Seok Choi, Yeon Jeong Kim, Kesavan Markkandan, Yeon Jong Koo, Jong Tae Song and Hak Soo Seo
Int. J. Mol. Sci. 2018, 19(7), 1904; https://doi.org/10.3390/ijms19071904 - 28 Jun 2018
Cited by 53 | Viewed by 5285
Abstract
Seed size is one of the most important traits determining the yield of cereal crops. Many studies have been performed to uncover the mechanism of seed development. However, much remains to be understood, especially at the molecular level, although several genes involved in [...] Read more.
Seed size is one of the most important traits determining the yield of cereal crops. Many studies have been performed to uncover the mechanism of seed development. However, much remains to be understood, especially at the molecular level, although several genes involved in seed size have been identified. Here, we show that rice Grain Width 2 (GW2), a RING-type E3 ubiquitin ligase, can control seed development by catalyzing the ubiquitination of expansin-like 1 (EXPLA1), a cell wall-loosening protein that increases cell growth. Microscopic examination revealed that a GW2 mutant had a chalky endosperm due to the presence of loosely packed, spherical starch granules, although the grain shape was normal. Yeast two-hybrid and in vitro pull-down assays showed a strong interaction between GW2 and EXPLA1. In vitro ubiquitination analysis demonstrated that EXPLA1 was ubiquitinated by GW2 at lysine 279 (K279). GW2 and EXPLA1 colocalized to the nucleus when expressed simultaneously. These results suggest that GW2 negatively regulates seed size by targeting EXPLA1 for degradation through its E3 ubiquitin ligase activity. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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Review

Jump to: Research

17 pages, 2249 KiB  
Review
The Rice Alpha-Amylase, Conserved Regulator of Seed Maturation and Germination
by Rebecca Njeri Damaris, Zhongyuan Lin, Pingfang Yang and Dongli He
Int. J. Mol. Sci. 2019, 20(2), 450; https://doi.org/10.3390/ijms20020450 - 21 Jan 2019
Cited by 94 | Viewed by 15552
Abstract
Alpha-amylase, the major form of amylase with secondary carbohydrate binding sites, is a crucial enzyme throughout the growth period and life cycle of angiosperm. In rice, alpha-amylase isozymes are critical for the formation of the storage starch granule during seed maturation and motivate [...] Read more.
Alpha-amylase, the major form of amylase with secondary carbohydrate binding sites, is a crucial enzyme throughout the growth period and life cycle of angiosperm. In rice, alpha-amylase isozymes are critical for the formation of the storage starch granule during seed maturation and motivate the stored starch to nourish the developing seedling during seed germination which will directly affect the plant growth and field yield. Alpha-amylase has not yet been studied intensely to understand its classification, structure, expression trait, and expression regulation in rice and other crops. Among the 10-rice alpha-amylases, most were exclusively expressed in the developing seed embryo and induced in the seed germination process. During rice seed germination, the expression of alpha-amylase genes is known to be regulated negatively by sugar in embryos, however positively by gibberellin (GA) in endosperm through competitively binding to the specific promoter domain; besides, it is also controlled by a series of other abiotic or biotic factors, such as salinity. In this review, we overviewed the research progress of alpha-amylase with focus on seed germination and reflected on how in-depth work might elucidate its regulation and facilitate crop breeding as an efficient biomarker. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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12 pages, 2438 KiB  
Review
The Dead Can Nurture: Novel Insights into the Function of Dead Organs Enclosing Embryos
by Buzi Raviv, James Godwin, Gila Granot and Gideon Grafi
Int. J. Mol. Sci. 2018, 19(8), 2455; https://doi.org/10.3390/ijms19082455 - 19 Aug 2018
Cited by 17 | Viewed by 5000
Abstract
Plants have evolved a variety of dispersal units whereby the embryo is enclosed by various dead protective layers derived from maternal organs of the reproductive system including seed coats (integuments), pericarps (ovary wall, e.g., indehiscent dry fruits) as well as floral bracts (e.g., [...] Read more.
Plants have evolved a variety of dispersal units whereby the embryo is enclosed by various dead protective layers derived from maternal organs of the reproductive system including seed coats (integuments), pericarps (ovary wall, e.g., indehiscent dry fruits) as well as floral bracts (e.g., glumes) in grasses. Commonly, dead organs enclosing embryos (DOEEs) are assumed to provide a physical shield for embryo protection and means for dispersal in the ecosystem. In this review article, we highlight recent studies showing that DOEEs of various species across families also have the capability for long-term storage of various substances including active proteins (hydrolases and ROS detoxifying enzymes), nutrients and metabolites that have the potential to support the embryo during storage in the soil and assist in germination and seedling establishment. We discuss a possible role for DOEEs as natural coatings capable of “engineering” the seed microenvironment for the benefit of the embryo, the seedling and the growing plant. Full article
(This article belongs to the Special Issue Seed Development, Dormancy and Germination)
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