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Zhang X, Liang X, He S, Tian H, Liu W, Jia Y, Zhang L, Zhang W, Kuang H, Chen J. Seed color in lettuce is determined by the LsTT2, LsCHS, and Ls2OGD genes from the flavonoid biosynthesis pathway. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2023; 136:241. [PMID: 37930450 DOI: 10.1007/s00122-023-04491-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023]
Abstract
KEY MESSAGE The mutated LsTT2 and Ls2OGD genes are responsible for white seeds and yellow seeds in lettuce, respectively. Three LsCHS genes are involved in the biosynthesis of flavonoid in seed coats. Lettuce seeds have several different colors, including black, yellow, and white. The genetic mechanisms underlying color variations of lettuce seeds remain unknown. We used genome-wide association studies (GWAS) and map-based cloning approaches to clone genes controlling the color of lettuce seeds. LsTT2, which encodes an R2R3-MYB transcription factor and is homologous to the TT2 gene in Arabidopsis, was shown to be the causal gene for the variation of black and white seeds in lettuce. A point mutation leads to the lack of stop codon in the LsTT2 transcript, resulting in white seeds. Knockout of the LsTT2 gene converted black seeds to white seeds. The locus controlling yellow seeds was mapped to Chromosome 2. Knockout of two 2-oxoglutarate-dependent dioxygenases (2OGD) genes from the candidate region converted black seeds to yellow seeds, suggesting that these two 2OGD proteins catalyze the conversion of yellow metabolites to black metabolites. We also showed that three LsCHS genes from the candidate region are associated with flavonoid biosynthesis in seeds. Knockout mutants of the three LsCHS genes decreased color intensity. This study provides new insights into the regulation of flavonoid biosynthesis in plants.
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Affiliation(s)
- Xiaoyan Zhang
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Xiaoli Liang
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Shuping He
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Hao Tian
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Wenye Liu
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Yue Jia
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Lei Zhang
- Jiangsu Key Laboratory of Phylogenomics and Comparative Genomics, School of Life Sciences, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, People's Republic of China
| | - Weiyi Zhang
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Hanhui Kuang
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Jiongjiong Chen
- National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
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Seed germination and vigor: ensuring crop sustainability in a changing climate. Heredity (Edinb) 2022; 128:450-459. [PMID: 35013549 DOI: 10.1038/s41437-022-00497-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/29/2021] [Accepted: 01/02/2022] [Indexed: 11/08/2022] Open
Abstract
In the coming decades, maintaining a steady food supply for the increasing world population will require high-yielding crop plants which can be productive under increasingly variable conditions. Maintaining high yields will require the successful and uniform establishment of plants in the field under altered environmental conditions. Seed vigor, a complex agronomic trait that includes seed longevity, germination speed, seedling growth, and early stress tolerance, determines the duration and success of this establishment period. Elevated temperature during early seed development can decrease seed size, number, and fertility, delay germination and reduce seed vigor in crops such as cereals, legumes, and vegetable crops. Heat stress in mature seeds can reduce seed vigor in crops such as lettuce, oat, and chickpea. Warming trends and increasing temperature variability can increase seed dormancy and reduce germination rates, especially in crops that require lower temperatures for germination and seedling establishment. To improve seed germination speed and success, much research has focused on selecting quality seeds for replanting, priming seeds before sowing, and breeding varieties with improved seed performance. Recent strides in understanding the genetic basis of variation in seed vigor have used genomics and transcriptomics to identify candidate genes for improving germination, and several studies have explored the potential impact of climate change on the percentage and timing of germination. In this review, we discuss these recent advances in the genetic underpinnings of seed performance as well as how climate change is expected to affect vigor in current varieties of staple, vegetable, and other crops.
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Sano N, Marion-Poll A. ABA Metabolism and Homeostasis in Seed Dormancy and Germination. Int J Mol Sci 2021; 22:5069. [PMID: 34064729 PMCID: PMC8151144 DOI: 10.3390/ijms22105069] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 02/07/2023] Open
Abstract
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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Affiliation(s)
| | - Annie Marion-Poll
- IJPB Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France;
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Ghaleb W, Barre P, Teulat B, Ahmed LQ, Escobar-Gutiérrez AJ. Divergent Selection for Seed Ability to Germinate at Extreme Temperatures in Perennial Ryegrass ( Lolium perenne L.). FRONTIERS IN PLANT SCIENCE 2021; 12:794488. [PMID: 35173750 PMCID: PMC8841656 DOI: 10.3389/fpls.2021.794488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/14/2021] [Indexed: 05/03/2023]
Abstract
Various adaptive mechanisms can ensure that seedlings are established at the most favourable time and place. These mechanisms include seed dormancy i.e., incapacity to germinate in any environment without a specific environmental trigger and inhibition i.e., incapacity to germinate in an unfavourable environment (water availability, temperature: thermoinhibition and light). The objective of this research was to study in the temperate range for germination of forage and turf grass species perennial ryegrass, if the thermal requirements for germination are under genetic controlled and could be selectively bred. Two divergent selections of three cycles were realized on a natural population: one to select for the capacity to germinate at 10°C vs. the impossibility to germinate at 10°C, and one to select for the capacity to germinate at 32°C vs. the impossibility to germinate at 32°C. Seeds of all the lots obtained from the two divergent selections were then germinated at constant temperatures from 5 to 35°C to evaluate their germination ability. Concerning the positive selection, the first cycle of positive selection at 10°C was highly efficient with a very strong increase in the germination percentage. However, afterward no selection effect was observed during the next two cycles of positive selection. By contrast, the positive selection at 32°C was efficient during all cycles with a linear increase of the percentage of germination at 32°C. Concerning the negative selection, we observed only a large positive effect of the first cycle of selection at 10°C. These findings demonstrate that seed thermoinhibition at 10 and 32°C observed in a natural population of perennial ryegrass has a genetic basis and a single recessive gene seems to be involved at 10°C.
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Affiliation(s)
- Wagdi Ghaleb
- INRAE, URP3F, F-86600 Lusignan, France
- Biotechnology Research Center (BTRC), Tripoli, Libya
| | - Philippe Barre
- INRAE, URP3F, F-86600 Lusignan, France
- *Correspondence: Philippe Barre,
| | - Béatrice Teulat
- Univ. Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, F-49000 Angers, France
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Effects of Exogenous Abscisic Acid (ABA) on Carotenoids and Petal Color in Osmanthus fragrans 'Yanhonggui'. PLANTS 2020; 9:plants9040454. [PMID: 32260328 PMCID: PMC7238031 DOI: 10.3390/plants9040454] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/17/2020] [Accepted: 03/31/2020] [Indexed: 01/16/2023]
Abstract
Osmanthus fragrans is a well-known native plant in China, and carotenoids are the main group of pigments in the petals. Abscisic acid (ABA) is one of the products of the metabolic pathway of carotenoids. Application of ABA could affect pigmentation of flower petals by changing the carotenoid content. However, little is known about the effects of ABA treatment on carotenoid accumulation in O. fragrans. In this study, different concentrations of ABA (0, 150 and 200 mg/L) were spread on the petals of O. fragrans 'Yanhonggui'. The petal color of 'Yanhonggui' receiving every ABA treatment was deeper than that of the control. The content of total carotenoids in the petals significantly increased with 200 mg/L ABA treatment. In the petals, α-carotene and β-carotene were the predominant carotenoids. The expression of several genes involved in the metabolism of carotenoids increased with 200 mg/L ABA treatment, including PSY1, PDS1, Z-ISO1, ZDS1, CRTISO, NCED3 and CCD4. However, the transcription levels of the latter two carotenoid degradation-related genes were much lower than of the five former carotenoid biosynthesis-related genes; the finding would explain the significant increase in total carotenoids in 'Yanhonggui' petals receiving the 200 mg/L ABA treatment.
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6
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Sita K, Sehgal A, HanumanthaRao B, Nair RM, Vara Prasad PV, Kumar S, Gaur PM, Farooq M, Siddique KHM, Varshney RK, Nayyar H. Food Legumes and Rising Temperatures: Effects, Adaptive Functional Mechanisms Specific to Reproductive Growth Stage and Strategies to Improve Heat Tolerance. FRONTIERS IN PLANT SCIENCE 2017; 8:1658. [PMID: 29123532 PMCID: PMC5662899 DOI: 10.3389/fpls.2017.01658] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/08/2017] [Indexed: 05/20/2023]
Abstract
Ambient temperatures are predicted to rise in the future owing to several reasons associated with global climate changes. These temperature increases can result in heat stress- a severe threat to crop production in most countries. Legumes are well-known for their impact on agricultural sustainability as well as their nutritional and health benefits. Heat stress imposes challenges for legume crops and has deleterious effects on the morphology, physiology, and reproductive growth of plants. High-temperature stress at the time of the reproductive stage is becoming a severe limitation for production of grain legumes as their cultivation expands to warmer environments and temperature variability increases due to climate change. The reproductive period is vital in the life cycle of all plants and is susceptible to high-temperature stress as various metabolic processes are adversely impacted during this phase, which reduces crop yield. Food legumes exposed to high-temperature stress during reproduction show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to smaller seeds and poor yields. Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field. Omics approaches unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress.
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Affiliation(s)
- Kumari Sita
- Department of Botany, Panjab University, Chandigarh, India
| | | | | | | | - P. V. Vara Prasad
- Sustainable Intensification Innovation Lab, Kansas State University, Manhattan, KS, United States
| | - Shiv Kumar
- International Center for Agricultural Research in the Dry Areas, Rabat, Morocco
| | - Pooran M. Gaur
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
| | - Muhammad Farooq
- Department of Agronomy, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | | | - Rajeev K. Varshney
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
- The UWA Institute of Agriculture, University of Western Australia, Perth, WA, Australia
| | - Harsh Nayyar
- Department of Botany, Panjab University, Chandigarh, India
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Sita K, Sehgal A, HanumanthaRao B, Nair RM, Vara Prasad PV, Kumar S, Gaur PM, Farooq M, Siddique KHM, Varshney RK, Nayyar H. Food Legumes and Rising Temperatures: Effects, Adaptive Functional Mechanisms Specific to Reproductive Growth Stage and Strategies to Improve Heat Tolerance. FRONTIERS IN PLANT SCIENCE 2017. [PMID: 29123532 DOI: 10.3389/flps.2017.01658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ambient temperatures are predicted to rise in the future owing to several reasons associated with global climate changes. These temperature increases can result in heat stress- a severe threat to crop production in most countries. Legumes are well-known for their impact on agricultural sustainability as well as their nutritional and health benefits. Heat stress imposes challenges for legume crops and has deleterious effects on the morphology, physiology, and reproductive growth of plants. High-temperature stress at the time of the reproductive stage is becoming a severe limitation for production of grain legumes as their cultivation expands to warmer environments and temperature variability increases due to climate change. The reproductive period is vital in the life cycle of all plants and is susceptible to high-temperature stress as various metabolic processes are adversely impacted during this phase, which reduces crop yield. Food legumes exposed to high-temperature stress during reproduction show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to smaller seeds and poor yields. Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field. Omics approaches unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress.
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Affiliation(s)
- Kumari Sita
- Department of Botany, Panjab University, Chandigarh, India
| | | | | | | | - P V Vara Prasad
- Sustainable Intensification Innovation Lab, Kansas State University, Manhattan, KS, United States
| | - Shiv Kumar
- International Center for Agricultural Research in the Dry Areas, Rabat, Morocco
| | - Pooran M Gaur
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
| | - Muhammad Farooq
- Department of Agronomy, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Kadambot H M Siddique
- The UWA Institute of Agriculture, University of Western Australia, Perth, WA, Australia
| | - Rajeev K Varshney
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
- The UWA Institute of Agriculture, University of Western Australia, Perth, WA, Australia
| | - Harsh Nayyar
- Department of Botany, Panjab University, Chandigarh, India
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Huo H, Henry IM, Coppoolse ER, Verhoef-Post M, Schut JW, de Rooij H, Vogelaar A, Joosen RVL, Woudenberg L, Comai L, Bradford KJ. Rapid identification of lettuce seed germination mutants by bulked segregant analysis and whole genome sequencing. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:345-360. [PMID: 27406937 DOI: 10.1111/tpj.13267] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 05/07/2023]
Abstract
Lettuce (Lactuca sativa) seeds exhibit thermoinhibition, or failure to complete germination when imbibed at warm temperatures. Chemical mutagenesis was employed to develop lettuce lines that exhibit germination thermotolerance. Two independent thermotolerant lettuce seed mutant lines, TG01 and TG10, were generated through ethyl methanesulfonate mutagenesis. Genetic and physiological analyses indicated that these two mutations were allelic and recessive. To identify the causal gene(s), we applied bulked segregant analysis by whole genome sequencing. For each mutant, bulked DNA samples of segregating thermotolerant (mutant) seeds were sequenced and analyzed for homozygous single-nucleotide polymorphisms. Two independent candidate mutations were identified at different physical positions in the zeaxanthin epoxidase gene (ABSCISIC ACID DEFICIENT 1/ZEAXANTHIN EPOXIDASE, or ABA1/ZEP) in TG01 and TG10. The mutation in TG01 caused an amino acid replacement, whereas the mutation in TG10 resulted in alternative mRNA splicing. Endogenous abscisic acid contents were reduced in both mutants, and expression of the ABA1 gene from wild-type lettuce under its own promoter fully complemented the TG01 mutant. Conventional genetic mapping confirmed that the causal mutations were located near the ZEP/ABA1 gene, but the bulked segregant whole genome sequencing approach more efficiently identified the specific gene responsible for the phenotype.
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Affiliation(s)
- Heqiang Huo
- Seed Biotechnology Center, Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Isabelle M Henry
- Department of Plant Biology and Genome Center, University of California, Davis, CA, 95616, USA
| | | | | | - Johan W Schut
- Rijk Zwaan Breeding B.V., 2678, ZG De Lier, The Netherlands
| | - Han de Rooij
- Rijk Zwaan Breeding B.V., 2678, ZG De Lier, The Netherlands
| | - Aat Vogelaar
- Rijk Zwaan Breeding B.V., 2678, ZG De Lier, The Netherlands
| | | | - Leo Woudenberg
- Rijk Zwaan Breeding B.V., 2678, ZG De Lier, The Netherlands
| | - Luca Comai
- Department of Plant Biology and Genome Center, University of California, Davis, CA, 95616, USA
| | - Kent J Bradford
- Seed Biotechnology Center, Department of Plant Sciences, University of California, Davis, CA, 95616, USA
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10
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Driedonks N, Rieu I, Vriezen WH. Breeding for plant heat tolerance at vegetative and reproductive stages. PLANT REPRODUCTION 2016; 29:67-79. [PMID: 26874710 PMCID: PMC4909801 DOI: 10.1007/s00497-016-0275-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/21/2016] [Indexed: 05/19/2023]
Abstract
KEY MESSAGE Thermotolerant crop research. Global warming has become a serious worldwide threat. High temperature is a major environmental factor limiting crop productivity. Current adaptations to high temperature via alterations to technical and management systems are insufficient to sustain yield. For this reason, breeding for heat-tolerant crops is in high demand. This review provides an overview of the effects of high temperature on plant physiology, fertility and crop yield and discusses the strategies for breeding heat-tolerant cultivars. Generating thermotolerant crops seems to be a challenging task as heat sensitivity is highly variable across developmental stages and processes. In response to heat, plants trigger a cascade of events, switching on numerous genes. Although breeding has made substantial advances in developing heat-tolerant lines, the genetic basis and diversity of heat tolerance in plants remain largely unknown. The development of new varieties is expensive and time-consuming, and knowledge of heat tolerance mechanisms would aid the design of strategies to screen germplasm for heat tolerance traits. However, gains in heat tolerance are limited by the often narrow genetic diversity. Exploration and use of wild relatives and landraces in breeding can increase useful genetic diversity in current crops. Due to the complex nature of plant heat tolerance and its immediate global concern, it is essential to face this breeding challenge in a multidisciplinary holistic approach involving governmental agencies, private companies and academic institutions.
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Affiliation(s)
- Nicky Driedonks
- Department of Molecular Plant Physiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Ivo Rieu
- Department of Molecular Plant Physiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
| | - Wim H Vriezen
- Bayer CropScience Vegetable Seeds, PO Box 4005, 6080 AA, Haelen, The Netherlands
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Huo H, Wei S, Bradford KJ. DELAY OF GERMINATION1 (DOG1) regulates both seed dormancy and flowering time through microRNA pathways. Proc Natl Acad Sci U S A 2016; 113:E2199-206. [PMID: 27035986 PMCID: PMC4839450 DOI: 10.1073/pnas.1600558113] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Seed germination and flowering, two critical developmental transitions in plant life cycles, are coordinately regulated by genetic and environmental factors to match plant establishment and reproduction to seasonal cues. The DELAY OF GERMINATION1 (DOG1) gene is involved in regulating seed dormancy in response to temperature and has also been associated genetically with pleiotropic flowering phenotypes across diverse Arabidopsis thaliana accessions and locations. Here we show that DOG1 can regulate seed dormancy and flowering times in lettuce (Lactuca sativa, Ls) and Arabidopsis through an influence on levels of microRNAs (miRNAs) miR156 and miR172. In lettuce, suppression of LsDOG1 expression enabled seed germination at high temperature and promoted early flowering in association with reduced miR156 and increased miR172 levels. In Arabidopsis, higher miR156 levels resulting from overexpression of the MIR156 gene enhanced seed dormancy and delayed flowering. These phenotypic effects, as well as conversion of MIR156 transcripts to miR156, were compromised in DOG1 loss-of-function mutant plants, especially in seeds. Overexpression of MIR172 reduced seed dormancy and promoted early flowering in Arabidopsis, and the effect on flowering required functional DOG1 Transcript levels of several genes associated with miRNA processing were consistently lower in dry seeds of Arabidopsis and lettuce when DOG1 was mutated or its expression was reduced; in contrast, transcript levels of these genes were elevated in a DOG1 gain-of-function mutant. Our results reveal a previously unknown linkage between two critical developmental phase transitions in the plant life cycle through a DOG1-miR156-miR172 interaction.
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Affiliation(s)
- Heqiang Huo
- Department of Plant Sciences, Seed Biotechnology Center, University of California, Davis, CA 95616
| | - Shouhui Wei
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Kent J Bradford
- Department of Plant Sciences, Seed Biotechnology Center, University of California, Davis, CA 95616;
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Finch-Savage WE, Bassel GW. Seed vigour and crop establishment: extending performance beyond adaptation. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:567-91. [PMID: 26585226 DOI: 10.1093/jxb/erv490] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Seeds are central to crop production, human nutrition, and food security. A key component of the performance of crop seeds is the complex trait of seed vigour. Crop yield and resource use efficiency depend on successful plant establishment in the field, and it is the vigour of seeds that defines their ability to germinate and establish seedlings rapidly, uniformly, and robustly across diverse environmental conditions. Improving vigour to enhance the critical and yield-defining stage of crop establishment remains a primary objective of the agricultural industry and the seed/breeding companies that support it. Our knowledge of the regulation of seed germination has developed greatly in recent times, yet understanding of the basis of variation in vigour and therefore seed performance during the establishment of crops remains limited. Here we consider seed vigour at an ecophysiological, molecular, and biomechanical level. We discuss how some seed characteristics that serve as adaptive responses to the natural environment are not suitable for agriculture. Past domestication has provided incremental improvements, but further actively directed change is required to produce seeds with the characteristics required both now and in the future. We discuss ways in which basic plant science could be applied to enhance seed performance in crop production.
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Affiliation(s)
- W E Finch-Savage
- School of Life Sciences, Warwick University, Wellesbourne Campus, Warwick CV35 9EF, UK
| | - G W Bassel
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
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Yoong FY, O'Brien LK, Truco MJ, Huo H, Sideman R, Hayes R, Michelmore RW, Bradford KJ. Genetic Variation for Thermotolerance in Lettuce Seed Germination Is Associated with Temperature-Sensitive Regulation of ETHYLENE RESPONSE FACTOR1 (ERF1). PLANT PHYSIOLOGY 2016; 170:472-88. [PMID: 26574598 PMCID: PMC4704578 DOI: 10.1104/pp.15.01251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/10/2015] [Indexed: 05/20/2023]
Abstract
Seeds of most lettuce (Lactuca sativa) cultivars are susceptible to thermoinhibition, or failure to germinate at temperatures above approximately 28°C, creating problems for crop establishment in the field. Identifying genes controlling thermoinhibition would enable the development of cultivars lacking this trait and, therefore, being less sensitive to high temperatures during planting. Seeds of a primitive accession (PI251246) of lettuce exhibited high-temperature germination capacity up to 33°C. Screening a recombinant inbred line population developed from PI215246 and cv Salinas identified a major quantitative trait locus (Htg9.1) from PI251246 associated with the high-temperature germination phenotype. Further genetic analyses discovered a tight linkage of the Htg9.1 phenotype with a specific DNA marker (NM4182) located on a single genomic sequence scaffold. Expression analyses of the 44 genes encoded in this genomic region revealed that only a homolog of Arabidopsis (Arabidopsis thaliana) ETHYLENE RESPONSE FACTOR1 (termed LsERF1) was differentially expressed between PI251246 and cv Salinas seeds imbibed at high temperature (30°C). LsERF1 belongs to a large family of transcription factors associated with the ethylene-signaling pathway. Physiological assays of ethylene synthesis, response, and action in parental and near-isogenic Htg9.1 genotypes strongly implicate LsERF1 as the gene responsible for the Htg9.1 phenotype, consistent with the established role for ethylene in germination thermotolerance of Compositae seeds. Expression analyses of genes associated with the abscisic acid and gibberellin biosynthetic pathways and results of biosynthetic inhibitor and hormone response experiments also support the hypothesis that differential regulation of LsERF1 expression in PI251246 seeds elevates their upper temperature limit for germination through interactions among pathways regulated by these hormones. Our results support a model in which LsERF1 acts through the promotion of gibberellin biosynthesis to counter the inhibitory effects of abscisic acid and, therefore, promote germination at high temperatures.
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Affiliation(s)
- Fei-Yian Yoong
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
| | - Laurel K O'Brien
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
| | - Maria Jose Truco
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
| | - Heqiang Huo
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
| | - Rebecca Sideman
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
| | - Ryan Hayes
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
| | - Richard W Michelmore
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
| | - Kent J Bradford
- Department of Plant Sciences, Seed Biotechnology Center (F.-Y.Y., L.K.O., H.H., R.W.M., K.J.B.), and Genome Center (M.J.T., R.W.M.), University of California, Davis, California 95616;Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire 03824 (R.S.); andU.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, Salinas, California 93905 (R.H.)
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Zheng C, Halaly T, Acheampong AK, Takebayashi Y, Jikumaru Y, Kamiya Y, Or E. Abscisic acid (ABA) regulates grape bud dormancy, and dormancy release stimuli may act through modification of ABA metabolism. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1527-42. [PMID: 25560179 PMCID: PMC4339608 DOI: 10.1093/jxb/eru519] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In warm-winter regions, induction of dormancy release by hydrogen cyanamide (HC) is mandatory for commercial table grape production. Induction of respiratory stress by HC leads to dormancy release via an uncharacterized biochemical cascade that could reveal the mechanism underlying this phenomenon. Previous studies proposed a central role for abscisic acid (ABA) in the repression of bud meristem activity, and suggested its removal as a critical step in the HC-induced cascade. In the current study, support for these assumptions was sought. The data show that ABA indeed inhibits dormancy release in grape (Vitis vinifera) buds and attenuates the advancing effect of HC. However, HC-dependent recovery was detected, and was affected by dormancy status. HC reduced VvXERICO and VvNCED transcript levels and induced levels of VvABA8'OH homologues. Regulation of these central players in ABA metabolism correlated with decreased ABA and increased ABA catabolite levels in HC-treated buds. Interestingly, an inhibitor of ethylene signalling attenuated these effects of HC on ABA metabolism. HC also modulated the expression of ABA signalling regulators, in a manner that supports a decreased ABA level and response. Taken together, the data support HC-induced removal of ABA-mediated repression via regulation of ABA metabolism and signalling. Expression profiling during the natural dormancy cycle revealed that at maximal dormancy, the HC-regulated VvNCED1 transcript level starts to drop. In parallel, levels of VvA8H-CYP707A4 transcript and ABA catabolites increase sharply. This may provide initial support for the involvement of ABA metabolism also in the execution of natural dormancy.
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Affiliation(s)
- Chuanlin Zheng
- Institute of Plant Sciences, Department of Fruit Tree Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Institute of Plant Sciences and Genetics in Agriculture, The Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Tamar Halaly
- Institute of Plant Sciences, Department of Fruit Tree Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
| | - Atiako Kwame Acheampong
- Institute of Plant Sciences, Department of Fruit Tree Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Institute of Plant Sciences and Genetics in Agriculture, The Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | | | - Yusuke Jikumaru
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
| | - Yuji Kamiya
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
| | - Etti Or
- Institute of Plant Sciences, Department of Fruit Tree Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
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15
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Hoang HH, Sechet J, Bailly C, Leymarie J, Corbineau F. Inhibition of germination of dormant barley (Hordeum vulgare L.) grains by blue light as related to oxygen and hormonal regulation. PLANT, CELL & ENVIRONMENT 2014; 37:1393-403. [PMID: 24256416 DOI: 10.1111/pce.12239] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/13/2013] [Accepted: 11/13/2013] [Indexed: 05/24/2023]
Abstract
Germination of primary dormant barley grains is promoted by darkness and temperatures below 20 °C, but is strongly inhibited by blue light. Exposure under blue light at 10 °C for periods longer than five days, results in a progressive inability to germinate in the dark, considered as secondary dormancy. We demonstrate that the inhibitory effect of blue light is reinforced in hypoxia. The inhibitory effect of blue light is associated with an increase in embryo abscisic acid (ABA) content (by 3.5- to 3.8-fold) and embryo sensitivity to both ABA and hypoxia. Analysis of expression of ABA metabolism genes shows that increase in ABA mainly results in a strong increase in HvNCED1 and HvNCED2 expression, and a slight decrease in HvABA8'OH-1. Among the gibberellins (GA) metabolism genes examined, blue light decreases the expression of HvGA3ox2, involved in GA synthesis, increases that of GA2ox3 and GA2ox5, involved in GA catabolism, and reduces the GA signalling evaluated by the HvExpA11 expression. Expression of secondary dormancy is associated with maintenance of high embryo ABA content and a low HvExpA11 expression. The partial reversion of the inhibitory effect of blue light by green light also suggests that cryptochrome might be involved in this hormonal regulation.
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Affiliation(s)
- Hai Ha Hoang
- UR5-EAC 7180 CNRS, PCMP, UPMC Univ Paris 06, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005, Paris, France
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16
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Silva-Correia J, Freitas S, Tavares RM, Lino-Neto T, Azevedo H. Phenotypic analysis of the Arabidopsis heat stress response during germination and early seedling development. PLANT METHODS 2014; 10:7. [PMID: 24606772 PMCID: PMC3975293 DOI: 10.1186/1746-4811-10-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/26/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND Phenotypic characterization of Arabidopsis thaliana gain- and loss-of-function mutants is a delicate and meticulous task that often involves the analysis of multiple parameters. Arabidopsis heat tolerance has been evaluated based on direct assessments that include seed germination, seedling survival, hypocotyl and root elongation, or indirect measurements such as chlorophyll content or ion leakage. RESULTS In an attempt to simplify the detection of heat stress-associated phenotypes, a collection of protocols for analysis of seed germination and seedling survival to heat treatment is proposed. Temperatures and lengths of heat treatments were combined into several heat tolerance assays, to be used as a primary approach for the search and characterization of basal and acquired heat tolerance-associated phenotypes at early developmental stages. The usefulness of this methodology was illustrated through the characterization of heat-related phenotypes in different Arabidopsis ecotypes as well as in gain- and loss-of-function mutants. CONCLUSIONS The use of standardized experimental protocols designed to detect temperature-related phenotypes is proposed. The suggested plate-based assays provide an appropriate framework of experimental conditions for detection of variability amongst natural accessions or mutants lines. Functional studies could be facilitated by using this inexpensive and undemanding approach.
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Affiliation(s)
- Joana Silva-Correia
- Center for Biodiversity, Functional & Integrative Genomics (BioFIG), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- Present address: 3B’s Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909 Guimarães, Taipas, Portugal
| | - Sara Freitas
- Center for Biodiversity, Functional & Integrative Genomics (BioFIG), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Rui M Tavares
- Center for Biodiversity, Functional & Integrative Genomics (BioFIG), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Teresa Lino-Neto
- Center for Biodiversity, Functional & Integrative Genomics (BioFIG), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Herlânder Azevedo
- Center for Biodiversity, Functional & Integrative Genomics (BioFIG), Plant Functional Biology Center, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- Present address: CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
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17
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Nonogaki H. Seed dormancy and germination-emerging mechanisms and new hypotheses. FRONTIERS IN PLANT SCIENCE 2014; 5:233. [PMID: 24904627 PMCID: PMC4036127 DOI: 10.3389/fpls.2014.00233] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/10/2014] [Indexed: 05/18/2023]
Abstract
Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of "seed dormancy mutants." These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination studies with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible "mechanosensing" in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production.
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Affiliation(s)
- Hiroyuki Nonogaki
- *Correspondence: Hiroyuki Nonogaki, Department of Horticulture, Oregon State University, 4017 ALS Bldg., Corvallis OR 97331, USA e-mail:
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18
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Bita CE, Gerats T. Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress-tolerant crops. FRONTIERS IN PLANT SCIENCE 2013; 4:273. [PMID: 23914193 PMCID: PMC3728475 DOI: 10.3389/fpls.2013.00273] [Citation(s) in RCA: 621] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 07/03/2013] [Indexed: 05/17/2023]
Abstract
Global warming is predicted to have a general negative effect on plant growth due to the damaging effect of high temperatures on plant development. The increasing threat of climatological extremes including very high temperatures might lead to catastrophic loss of crop productivity and result in wide spread famine. In this review, we assess the impact of global climate change on the agricultural crop production. There is a differential effect of climate change both in terms of geographic location and the crops that will likely show the most extreme reductions in yield as a result of expected extreme fluctuations in temperature and global warming in general. High temperature stress has a wide range of effects on plants in terms of physiology, biochemistry and gene regulation pathways. However, strategies exist to crop improvement for heat stress tolerance. In this review, we present recent advances of research on all these levels of investigation and focus on potential leads that may help to understand more fully the mechanisms that make plants tolerant or susceptible to heat stress. Finally, we review possible procedures and methods which could lead to the generation of new varieties with sustainable yield production, in a world likely to be challenged both by increasing population, higher average temperatures and larger temperature fluctuations.
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Affiliation(s)
- Craita E. Bita
- Section Plant Sciences, Institute for Water and Wetland Research, Radboud University NijmegenNijmegen, Netherlands
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19
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Hoang HH, Sotta B, Gendreau E, Bailly C, Leymarie J, Corbineau F. Water content: a key factor of the induction of secondary dormancy in barley grains as related to ABA metabolism. PHYSIOLOGIA PLANTARUM 2013; 148:284-296. [PMID: 23061651 DOI: 10.1111/j.1399-3054.2012.01710.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/21/2012] [Accepted: 09/21/2012] [Indexed: 06/01/2023]
Abstract
Primary dormant barley (Hordeum vulgare) grains germinate at 10-15°C but not at 30°C, and there exist a positive correlation between embryo ABA content after 24 h on water and the depth of dormancy. Incubation at 30°C results in a progressive loss of the ability to germinate at 15°C. This induction of a secondary dormancy is optimal after 3 days and requires an embryo water content higher than 0.50 g H₂O g⁻¹ DW, this corresponding with activation of the cell cycle. There exists no correlation between ABA content after 3 days at 30°C and the induction of secondary dormancy. However, at high water content (1.60-1.87 g H₂O g⁻¹ DW), secondary dormancy is associated with an high embryo ABA content after transfer to 15°C, resulting from an increase in HvNCED1 and HvNCED2 expression and a decrease in HvABA8'OH-1. Such changes are not observed at 0.45 g H₂O g⁻¹ DW. Incubation at 30°C also results in an increase in expression of genes involved in GA catabolism (HvGA2ox1, HvGA2ox3 and HvGA2ox5) and synthesis (HvGA3ox2, HvGA20ox1 and HvGA20ox3). The HvGA3ox2/HvGA2ox3 transcript ratio remains low (0.27-0.37) at 30°C and after transfer to 15°C in secondary dormant seeds, but it is higher than two when secondary dormancy is not induced. Changes in HvExpA11 expression indicate that GA signaling decreases when a secondary dormancy is expressed. Our results clearly indicate that expression of genes involved in ABA and GA metabolism differs in primary and secondary dormancies and furthermore, their expression is related to embryo water content.
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Affiliation(s)
- Hai Ha Hoang
- UR5-EAC 7180 CNRS, Physiologie Cellulaire et Moléculaire des Plantes, Université Pierre et Marie Curie-Univ Paris 6, Boîte Courrier 156, Bat C, 4 Place Jussieu, F-75005, Paris, France
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20
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Truco MJ, Ashrafi H, Kozik A, van Leeuwen H, Bowers J, Wo SRC, Stoffel K, Xu H, Hill T, Van Deynze A, Michelmore RW. An Ultra-High-Density, Transcript-Based, Genetic Map of Lettuce. G3 (BETHESDA, MD.) 2013; 3:617-631. [PMID: 23550116 PMCID: PMC3618349 DOI: 10.1534/g3.112.004929] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/07/2013] [Indexed: 02/07/2023]
Abstract
We have generated an ultra-high-density genetic map for lettuce, an economically important member of the Compositae, consisting of 12,842 unigenes (13,943 markers) mapped in 3696 genetic bins distributed over nine chromosomal linkage groups. Genomic DNA was hybridized to a custom Affymetrix oligonucleotide array containing 6.4 million features representing 35,628 unigenes of Lactuca spp. Segregation of single-position polymorphisms was analyzed using 213 F7:8 recombinant inbred lines that had been generated by crossing cultivated Lactuca sativa cv. Salinas and L. serriola acc. US96UC23, the wild progenitor species of L. sativa The high level of replication of each allele in the recombinant inbred lines was exploited to identify single-position polymorphisms that were assigned to parental haplotypes. Marker information has been made available using GBrowse to facilitate access to the map. This map has been anchored to the previously published integrated map of lettuce providing candidate genes for multiple phenotypes. The high density of markers achieved in this ultradense map allowed syntenic studies between lettuce and Vitis vinifera as well as other plant species.
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Affiliation(s)
- Maria José Truco
- The Genome Center, University of California, Davis, California 95616
| | - Hamid Ashrafi
- Seed Biotechnology Center, University of California, Davis, California 95616
| | - Alexander Kozik
- The Genome Center, University of California, Davis, California 95616
| | - Hans van Leeuwen
- The Genome Center, University of California, Davis, California 95616
| | - John Bowers
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602
| | | | - Kevin Stoffel
- Seed Biotechnology Center, University of California, Davis, California 95616
| | - Huaqin Xu
- The Genome Center, University of California, Davis, California 95616
| | - Theresa Hill
- Seed Biotechnology Center, University of California, Davis, California 95616
| | - Allen Van Deynze
- Seed Biotechnology Center, University of California, Davis, California 95616
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Richard W Michelmore
- The Genome Center, University of California, Davis, California 95616
- Department of Plant Sciences, University of California, Davis, California 95616
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Arc E, Sechet J, Corbineau F, Rajjou L, Marion-Poll A. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination. FRONTIERS IN PLANT SCIENCE 2013; 4:63. [PMID: 23531630 PMCID: PMC3607800 DOI: 10.3389/fpls.2013.00063] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/05/2013] [Indexed: 05/18/2023]
Abstract
Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA) during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8'-hydroxylation. The hormonal balance between ABA and gibberellins (GAs) has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO) has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8'-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination.
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Affiliation(s)
- Erwann Arc
- Institut Jean-Pierre Bourgin (UMR1318 INRA – AgroParisTech), Institut National de la Recherche Agronomique, Saclay Plant ScienceVersailles, France
- UFR de Physiologie végétale, AgroParisTechParis, France
| | - Julien Sechet
- Institut Jean-Pierre Bourgin (UMR1318 INRA – AgroParisTech), Institut National de la Recherche Agronomique, Saclay Plant ScienceVersailles, France
| | - Françoise Corbineau
- Germination et Dormance des Semences, UR5 UPMC-EAC 7180 CNRS, Université Pierre et Marie Curie-Paris 6Paris, France
| | - Loïc Rajjou
- Institut Jean-Pierre Bourgin (UMR1318 INRA – AgroParisTech), Institut National de la Recherche Agronomique, Saclay Plant ScienceVersailles, France
- UFR de Physiologie végétale, AgroParisTechParis, France
| | - Annie Marion-Poll
- Institut Jean-Pierre Bourgin (UMR1318 INRA – AgroParisTech), Institut National de la Recherche Agronomique, Saclay Plant ScienceVersailles, France
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22
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Huo H, Dahal P, Kunusoth K, McCallum CM, Bradford KJ. Expression of 9-cis-EPOXYCAROTENOID DIOXYGENASE4 is essential for thermoinhibition of lettuce seed germination but not for seed development or stress tolerance. THE PLANT CELL 2013; 25:884-900. [PMID: 23503626 PMCID: PMC3634695 DOI: 10.1105/tpc.112.108902] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 02/10/2013] [Accepted: 02/25/2013] [Indexed: 05/18/2023]
Abstract
Thermoinhibition, or failure of seeds to germinate at warm temperatures, is common in lettuce (Lactuca sativa) cultivars. Using a recombinant inbred line population developed from a lettuce cultivar (Salinas) and thermotolerant Lactuca serriola accession UC96US23 (UC), we previously mapped a quantitative trait locus associated with thermoinhibition of germination to a genomic region containing a gene encoding a key regulated enzyme in abscisic acid (ABA) biosynthesis, 9-cis-EPOXYCAROTENOID DIOXYGENASE4 (NCED4). NCED4 from either Salinas or UC complements seeds of the Arabidopsis thaliana nced6-1 nced9-1 double mutant by restoring germination thermosensitivity, indicating that both NCED4 genes encode functional proteins. Transgenic expression of Salinas NCED4 in UC seeds resulted in thermoinhibition, whereas silencing of NCED4 in Salinas seeds led to loss of thermoinhibition. Mutations in NCED4 also alleviated thermoinhibition. NCED4 expression was elevated during late seed development but was not required for seed maturation. Heat but not water stress elevated NCED4 expression in leaves, while NCED2 and NCED3 exhibited the opposite responses. Silencing of NCED4 altered the expression of genes involved in ABA, gibberellin, and ethylene biosynthesis and signaling pathways. Together, these data demonstrate that NCED4 expression is required for thermoinhibition of lettuce seeds and that it may play additional roles in plant responses to elevated temperature.
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Affiliation(s)
- Heqiang Huo
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Peetambar Dahal
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Keshavulu Kunusoth
- Department of Seed Science and Technology, Acharya N.G. Ranga Agricultural University, Rajendranagar, Hyderabad 500030, Andhra Pradesh, India
| | | | - Kent J. Bradford
- Department of Plant Sciences, University of California, Davis, California 95616
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23
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Linkies A, Leubner-Metzger G. Beyond gibberellins and abscisic acid: how ethylene and jasmonates control seed germination. PLANT CELL REPORTS 2012; 31:253-70. [PMID: 22044964 DOI: 10.1007/s00299-011-1180-1] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 10/13/2011] [Accepted: 10/13/2011] [Indexed: 05/04/2023]
Abstract
Appropriate responses of seeds and fruits to environmental factors are key traits that control the establishment of a species in a particular ecosystem. Adaptation of germination to abiotic stresses and changing environmental conditions is decisive for fitness and survival of a species. Two opposing forces provide the basic physiological mechanism for the control of seed germination: the increasing growth potential of the embryo and the restraint weakening of the various covering layers (seed envelopes), including the endosperm which is present to a various extent in the mature seeds of most angiosperms. Gibberellins (GA), abscisic acid (ABA) and ethylene signaling and metabolism mediate environmental cues and in turn influence developmental processes like seed germination. Cross-species work has demonstrated that GA, ABA and ethylene interact during the regulation of endosperm weakening, which is at least partly based on evolutionarily conserved mechanisms. We summarize the recent progress made in unraveling how ethylene promotes germination and acts as an antagonist of ABA. Far less is known about jasmonates in seeds for which we summarize the current knowledge about their role in seeds. While it seems very clear that jasmonates inhibit germination, the results obtained so far are partly contradictory and depend on future research to reach final conclusions on the mode of jasmonate action during seed germination. Understanding the mechanisms underlying the control of seed germination and its hormonal regulation is not only of academic interest, but is also the ultimate basis for further improving crop establishment and yield, and is therefore of common importance.
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Affiliation(s)
- Ada Linkies
- Botany/Plant Physiology, Institute for Biology II, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104, Freiburg, Germany.
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24
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Martínez-Andújar C, Martin RC, Nonogaki H. Seed traits and genes important for translational biology--highlights from recent discoveries. PLANT & CELL PHYSIOLOGY 2012; 53:5-15. [PMID: 21849396 DOI: 10.1093/pcp/pcr112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Seeds provide food, feed, fiber and fuel. They are also an important delivery system of genetic information, which is essential for the survival of wild species in ecosystems and the production of agricultural crops. In this review, seed traits and genes that are potentially important for agricultural applications are discussed. Over the long period of crop domestication, seed traits have been modified through intentional or unintentional selections. While most selections have led to seed traits favorable for agricultural consumption, such as larger seeds with higher nutritional value than the wild type, other manipulations in modern breeding sometimes led to negative traits, such as vivipary, precocious germination on the maternal plant or reduced seed vigor, as a side effect during the improvement of other characteristics. Greater effort is needed to overcome these problems that have emerged as a consequence of crop improvement. Seed biology researchers have characterized the function of many genes in the last decade, including those associated with seed domestication, which may be useful in addressing critical issues in modern agriculture, such as the prevention of vivipary and seed shattering or the enhancement of yields. Recent discoveries in seed biology research are highlighted in this review, with an emphasis on their potential for translational biology.
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Kendall SL, Hellwege A, Marriot P, Whalley C, Graham IA, Penfield S. Induction of dormancy in Arabidopsis summer annuals requires parallel regulation of DOG1 and hormone metabolism by low temperature and CBF transcription factors. THE PLANT CELL 2011; 23:2568-80. [PMID: 21803937 PMCID: PMC3226211 DOI: 10.1105/tpc.111.087643] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 07/08/2011] [Accepted: 07/15/2011] [Indexed: 05/18/2023]
Abstract
Summer annuals overwinter as seeds in the soil seed bank. This is facilitated by a cold-induced increase in dormancy during seed maturation followed by a switch to a state during seed imbibition in which cold instead promotes germination. Here, we show that the seed maturation transcriptome in Arabidopsis thaliana is highly temperature sensitive and reveal that low temperature during seed maturation induces several genes associated with dormancy, including DELAY OF GERMINATION1 (DOG1), and influences gibberellin and abscisic acid levels in mature seeds. Mutants lacking DOG1, or with altered gibberellin or abscisic acid synthesis or signaling, in turn show reduced ability to enter the deeply dormant states in response to low seed maturation temperatures. In addition, we find that DOG1 promotes gibberellin catabolism during maturation. We show that C-REPEAT BINDING FACTORS (CBFs) are necessary for regulation of dormancy and of GA2OX6 and DOG1 expression caused by low temperatures. However, the temperature sensitivity of CBF transcription is markedly reduced in seeds and is absent in imbibed seeds. Our data demonstrate that inhibition of CBF expression is likely a critical feature allowing cold to promote rather than inhibit germination and support a model in which CBFs act in parallel to a low-temperature signaling pathway in the regulation of dormancy.
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Affiliation(s)
- Sarah L. Kendall
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Anja Hellwege
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Poppy Marriot
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Celina Whalley
- Technology Facility, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Ian A. Graham
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Steven Penfield
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom
- Address correspondence to
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Bahin E, Bailly C, Sotta B, Kranner I, Corbineau F, Leymarie J. Crosstalk between reactive oxygen species and hormonal signalling pathways regulates grain dormancy in barley. PLANT, CELL & ENVIRONMENT 2011; 34:980-993. [PMID: 21388415 DOI: 10.1111/j.1365-3040.2011.02298.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Seed dormancy, defined as the inability to germinate under favourable conditions, is controlled by abscisic acid (ABA) and gibberellins (GAs). Phytohormone signalling interacts with reactive oxygen species (ROS) signalling regarding diverse aspects of plant physiology and is assumed to be important in dormancy alleviation. Using dormant barley grains that do not germinate at 30 °C in darkness, we analysed ROS content and ROS-processing systems, ABA content and metabolism, GA-responsive genes and genes involved in GA metabolism in response to hydrogen peroxide (H₂O₂) treatment. During after-ripening, the ROS content in the embryo was not affected, while the antioxidant glutathione (GSH) was gradually converted to glutathione disulphide (GSSG). ABA treatment up-regulated catalase activity through transcriptional activation of HvCAT2. Exogenous H₂O₂ partially alleviated dormancy although it was associated with a small increase in embryonic ABA content related to a slight induction of HvNCED transcripts. H₂O₂ treatment did not affect ABA sensitivity but up-regulated the expression of HvExpA11 (GA-induced gene), inhibited the expression of HvGA2ox3 involved in GA catabolism and enhanced the expression of HvGA20ox1 implicated in GA synthesis. In barley, H₂O₂ could be implicated in dormancy alleviation through activation of GA signalling and synthesis rather than repression of ABA signalling.
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Affiliation(s)
- Emilie Bahin
- UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK
| | - Christophe Bailly
- UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK
| | - Bruno Sotta
- UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK
| | - Ilse Kranner
- UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK
| | - Françoise Corbineau
- UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK
| | - Juliette Leymarie
- UPMC Univ Paris 06, UR5 - EAC 7180 CNRS, PCMP, Boîte courrier 156, Bat C, 4 place Jussieu, F-75005 Paris, FranceSeed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, RH17 6TN, UK
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Ji X, Dong B, Shiran B, Talbot MJ, Edlington JE, Hughes T, White RG, Gubler F, Dolferus R. Control of abscisic acid catabolism and abscisic acid homeostasis is important for reproductive stage stress tolerance in cereals. PLANT PHYSIOLOGY 2011; 156:647-62. [PMID: 21502188 PMCID: PMC3177265 DOI: 10.1104/pp.111.176164] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 04/17/2011] [Indexed: 05/18/2023]
Abstract
Drought stress at the reproductive stage causes pollen sterility and grain loss in wheat (Triticum aestivum). Drought stress induces abscisic acid (ABA) biosynthesis genes in anthers and ABA accumulation in spikes of drought-sensitive wheat varieties. In contrast, drought-tolerant wheat accumulates lower ABA levels, which correlates with lower ABA biosynthesis and higher ABA catabolic gene expression (ABA 8'-hydroxylase). Wheat TaABA8'OH1 deletion lines accumulate higher spike ABA levels and are more drought sensitive. ABA treatment of the spike mimics the effect of drought, causing high levels of sterility. ABA treatment represses the anther cell wall invertase gene TaIVR1, and drought-tolerant lines appeared to be more sensitive to the effect of ABA. Drought-induced sterility shows similarity to cold-induced sterility in rice (Oryza sativa). In cold-stressed rice, the rate of ABA accumulation was similar in cold-sensitive and cold-tolerant lines during the first 8 h of cold treatment, but in the tolerant line, ABA catabolism reduced ABA levels between 8 and 16 h of cold treatment. The ABA biosynthesis gene encoding 9-cis-epoxycarotenoid dioxygenase in anthers is mainly expressed in parenchyma cells surrounding the vascular bundle of the anther. Transgenic rice lines expressing the wheat TaABA8'OH1 gene under the control of the OsG6B tapetum-specific promoter resulted in reduced anther ABA levels under cold conditions. The transgenic lines showed that anther sink strength (OsINV4) was maintained under cold conditions and that this correlated with improved cold stress tolerance. Our data indicate that ABA and ABA 8'-hydroxylase play an important role in controlling anther ABA homeostasis and reproductive stage abiotic stress tolerance in cereals.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Rudy Dolferus
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2601, Australia
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