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Vera Hernández PF, Mendoza Onofre LE, Rosas Cárdenas FDF. Responses of sorghum to cold stress: A review focused on molecular breeding. FRONTIERS IN PLANT SCIENCE 2023; 14:1124335. [PMID: 36909409 PMCID: PMC9996117 DOI: 10.3389/fpls.2023.1124335] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Climate change has led to the search for strategies to acclimatize plants to various abiotic stressors to ensure the production and quality of crops of commercial interest. Sorghum is the fifth most important cereal crop, providing several uses including human food, animal feed, bioenergy, or industrial applications. The crop has an excellent adaptation potential to different types of abiotic stresses, such as drought, high salinity, and high temperatures. However, it is susceptible to low temperatures compared with other monocotyledonous species. Here, we have reviewed and discussed some of the research results and advances that focused on the physiological, metabolic, and molecular mechanisms that determine sorghum cold tolerance to improve our understanding of the nature of such trait. Questions and opportunities for a comprehensive approach to clarify sorghum cold tolerance or susceptibility are also discussed.
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Affiliation(s)
- Pedro Fernando Vera Hernández
- Instituto Politécnico Nacional, Centro de Investigación en Biotecnología Aplicada, Ex-Hacienda San Juan Molino Carretera Estatal Tecuexcomac-Tepetitla, Tlaxcala, Mexico
| | | | - Flor de Fátima Rosas Cárdenas
- Instituto Politécnico Nacional, Centro de Investigación en Biotecnología Aplicada, Ex-Hacienda San Juan Molino Carretera Estatal Tecuexcomac-Tepetitla, Tlaxcala, Mexico
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Sorghum as a Novel Crop for Central Europe: Using a Broad Diversity Set to Dissect Temperate-Adaptation. AGRONOMY-BASEL 2019. [DOI: 10.3390/agronomy9090535] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sorghum (Sorghum bicolor L. Moench) is a promising novel crop for Central Europe. However, enhancements in cold tolerance and early maturity are essential for a successful adaptation to cooler climates. We scored a broad sorghum diversity set (n = 338) for early chilling tolerance, high-latitude adaptation, and bioenergy related agronomical traits in multi-environment trials. Our results show a high phenotypic variation and medium to high heritabilities for most traits, indicating that a robust breeding progress is feasible. Several public accessions with a good adaptation to cooler climates were identified, which can serve as valuable base material for sorghum breeding in temperate areas. Genome-wide association studies reveal a polygenic (quantitative) character for most of the traits, confirming previous studies. Hence, for practical breeding, it will be difficult to conduct efficient marker-assisted selection for temperate-adaptation traits in genetically diverse material.
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Moghimi N, Desai JS, Bheemanahalli R, Impa SM, Vennapusa AR, Sebela D, Perumal R, Doherty CJ, Jagadish SVK. New candidate loci and marker genes on chromosome 7 for improved chilling tolerance in sorghum. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3357-3371. [PMID: 30949711 DOI: 10.1093/jxb/erz143] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 03/20/2019] [Indexed: 06/09/2023]
Abstract
Sorghum is often exposed to suboptimal low temperature stress under field conditions, particularly at the seedling establishment stage. Enhancing chilling tolerance will facilitate earlier planting and so minimize the negative impacts of other stresses experienced at later growth stages. Genome-wide association mapping was performed on a sorghum association panel grown under control (30/20 °C; day/night) and chilling (20/10 °C) conditions. Genomic regions on chromosome 7, controlling the emergence index and seedling (root and shoot) vigor, were associated with increased chilling tolerance but they did not co-localize with undesirable tannin content quantitative trait loci (QTLs). Shoot and root samples from highly contrasting haplotype pairs expressing differential responses to chilling stress were used to identify candidate genes. Three candidate genes (an alpha/beta hydrolase domain protein, a DnaJ/Hsp40 motif-containing protein, and a YTH domain-containing RNA-binding protein) were expressed at significantly higher levels under chilling stress in the tolerant haplotype compared with the sensitive haplotype and BTx623. Moreover, two CBF/DREB1A transcription factors on chromosome 2 showed a divergent response to chilling in the contrasting haplotypes. These studies identify haplotype differences on chromosome 7 that modulate chilling tolerance by either regulating CBF or feeding back into this signaling pathway. We have identified new candidate genes that will be useful markers in ongoing efforts to develop tannin-free chilling-tolerant sorghum hybrids.
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Affiliation(s)
- Naghmeh Moghimi
- Department of Agronomy, Kansas State University, Manhattan, KS, USA
| | - Jigar S Desai
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, USA
| | | | - Somayanda M Impa
- Department of Agronomy, Kansas State University, Manhattan, KS, USA
| | | | - David Sebela
- Department of Agronomy, Kansas State University, Manhattan, KS, USA
| | - Ramasamy Perumal
- Agricultural Research Center, Kansas State University, Hays, KS, USA
| | - Colleen J Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC, USA
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Parra-Londono S, Fiedler K, Kavka M, Samans B, Wieckhorst S, Zacharias A, Uptmoor R. Genetic dissection of early-season cold tolerance in sorghum: genome-wide association studies for seedling emergence and survival under field and controlled environment conditions. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2018; 131:581-595. [PMID: 29147737 DOI: 10.1007/s00122-017-3021-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 11/10/2017] [Indexed: 05/20/2023]
Abstract
A QTL on sorghum chromosome SBI-06 putatively improves field emergence under low-temperature conditions. Low temperatures decisively limit seedling emergence and vigor during early growth of sorghum and, thus, strongly impair geographical expansion. To broaden sorghum cultivation to temperate regions, the establishment of cold-tolerant genotypes is a prioritized breeding goal. The present study aims at the quantification of seedling emergence and survival under chilling temperatures and the detection of marker-trait associations controlling temperature-related seedling establishment. A diversity set consisting of 194 biomass sorghum lines was subjected to extensive phenotyping comprising field trials and controlled environment experiments. The final emergence percentage (FEP) under field conditions was significantly reduced under cold stress. Broad-sense heritability was h 2 = 0.87 for FEP in the field and h 2 = 0.93 for seedling survival rate (SR) under controlled conditions. Correlations between FEP in the field and under controlled conditions were low; higher correlations were observed between field FEP and SR in controlled environments. Genome-wide association studies (GWAS) were conducted using 44,515 single nucleotide polymorphisms (SNPs) and revealed eight regions with suggestive marker-trait associations for FEP and SR on chromosomes SBI-01, -02, -03, -06, -09, and -10 (p < 5.7 × 10-5) and a significant association on SBI-06 for field FEP (p < 2.9 × 10-6). Although not significant under controlled conditions, SR of genotypes carrying the minor allele on the field FEP quantitative trait loci (QTL) on SBI-06 was on average 13.1% higher, while FEP under controlled conditions was on average 9.7% higher with a linearly decreasing effect with increasing temperatures (R 2 = 0.82). Promising candidate genes putatively conferring seedling cold tolerance were identified.
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Affiliation(s)
| | - Karin Fiedler
- KWS SAAT SE, Grimsehlstraße 31, 37555, Einbeck, Germany
| | - Mareike Kavka
- Chair of Agronomy, University of Rostock, Justus-von-Liebig-Weg 6, 18059, Rostock, Germany
| | - Birgit Samans
- Department of Plant Breeding, Justus Liebig University Gießen, Heinrich-Buff-Ring 26-32, 35392, Gießen, Germany
| | | | | | - Ralf Uptmoor
- Chair of Agronomy, University of Rostock, Justus-von-Liebig-Weg 6, 18059, Rostock, Germany.
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Parra-Londono S, Kavka M, Samans B, Snowdon R, Wieckhorst S, Uptmoor R. Sorghum root-system classification in contrasting P environments reveals three main rooting types and root-architecture-related marker-trait associations. ANNALS OF BOTANY 2018; 121:267-280. [PMID: 29351588 PMCID: PMC5808808 DOI: 10.1093/aob/mcx157] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 10/19/2017] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Roots facilitate acquisition of macro- and micronutrients, which are crucial for plant productivity and anchorage in the soil. Phosphorus (P) is rapidly immobilized in the soil and hardly available for plants. Adaptation to P scarcity relies on changes in root morphology towards rooting systems well suited for topsoil foraging. Root-system architecture (RSA) defines the spatial organization of the network comprising primary, lateral and stem-derived roots and is important for adaptation to stress conditions. RSA phenotyping is a challenging task and essential for understanding root development. METHODS In this study, 19 traits describing RSA were analysed in a diversity panel comprising 194 sorghum genotypes, fingerprinted with a 90-k single-nucleotide polymorphism (SNP) array and grown under low and high P availability. KEY RESULTS Multivariate analysis was conducted and revealed three different RSA types: (1) a small root system; (2) a compact and bushy rooting type; and (3) an exploratory root system, which might benefit plant growth and development if water, nitrogen (N) or P availability is limited. While several genotypes displayed similar rooting types in different environments, others responded to P scarcity positively by developing more exploratory root systems, or negatively with root growth suppression. Genome-wide association studies revealed significant quantitative trait loci (P < 2.9 × 10-6) on chromosomes SBI-02, SBI-03, SBI-05 and SBI-09. Co-localization of significant and suggestive (P < 5.7 × 10-5) associations for several traits indicated hotspots controlling root-system development on chromosomes SBI-02 and SBI-03. CONCLUSIONS Sorghum genotypes with a compact, bushy and shallow root system provide potential adaptation to P scarcity in the field by allowing thorough topsoil foraging, while genotypes with an exploratory root system may be advantageous if N or water is the limiting factor, although such genotypes showed highest P uptake levels under the artificial conditions of the present study.
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Affiliation(s)
| | - Mareike Kavka
- Chair of Agronomy, University of Rostock, Rostock, Germany
| | - Birgit Samans
- Department of Plant Breeding, Justus Liebig University Gießen, Gießen, Germany
| | - Rod Snowdon
- Department of Plant Breeding, Justus Liebig University Gießen, Gießen, Germany
| | | | - Ralf Uptmoor
- Chair of Agronomy, University of Rostock, Rostock, Germany
- For correspondence. E-mail:
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Ortiz D, Hu J, Salas Fernandez MG. Genetic architecture of photosynthesis in Sorghum bicolor under non-stress and cold stress conditions. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4545-4557. [PMID: 28981780 PMCID: PMC5853419 DOI: 10.1093/jxb/erx276] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/15/2017] [Indexed: 05/18/2023]
Abstract
Sorghum (Sorghum bicolor L. Moench) is a C4 species sensitive to the cold spring conditions that occur at northern latitudes, especially when coupled with excessive light, and that greatly affect the photosynthetic rate. The objective of this study was to discover genes/genomic regions that control the capacity to cope with excessive energy under low temperature conditions during the vegetative growth period. A genome-wide association study (GWAS) was conducted for seven photosynthetic gas exchange and chlorophyll fluorescence traits under three consecutive temperature treatments: control (28 °C/24 °C), cold (15 °C/15 °C), and recovery (28 °C/24 °C). Cold stress significantly reduced the rate of photosynthetic CO2 uptake of sorghum plants, and a total of 143 unique genomic regions were discovered associated with at least one trait in a particular treatment or with derived variables. Ten regions on chromosomes 3, 4, 6, 7, and 8 that harbor multiple significant markers in linkage disequilibrium (LD) were consistently identified in gas exchange and chlorophyll fluorescence traits. Several candidate genes within those intervals have predicted functions related to carotenoids, phytohormones, thioredoxin, components of PSI, and antioxidants. These regions represent the most promising results for future validation and with potential application for the improvement of crop productivity under cold stress.
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Affiliation(s)
- Diego Ortiz
- Department of Agronomy, Iowa State University, Ames, IA, USA
| | - Jieyun Hu
- Department of Agronomy, Iowa State University, Ames, IA, USA
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Chopra R, Burow G, Burke JJ, Gladman N, Xin Z. Genome-wide association analysis of seedling traits in diverse Sorghum germplasm under thermal stress. BMC PLANT BIOLOGY 2017; 17:12. [PMID: 28086798 PMCID: PMC5237230 DOI: 10.1186/s12870-016-0966-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 12/23/2016] [Indexed: 05/20/2023]
Abstract
BACKGROUND Climate variability due to fluctuation in temperature is a worldwide concern that imperils crop production. The need to understand how the germplasm variation in major crops can be utilized to aid in discovering and developing breeding lines that can withstand and adapt to temperature fluctuations is more necessary than ever. Here, we analyzed the genetic variation associated with responses to thermal stresses in a sorghum association panel (SAP) representing major races and working groups to identify single nucleotide polymorphisms (SNPs) that are associated with resilience to temperature stress in a major cereal crop. RESULTS The SAP exhibited extensive variation for seedling traits under cold and heat stress. Genome-wide analyses identified 30 SNPs that were strongly associated with traits measured at seedling stage under cold stress and tagged genes that act as regulators of anthocyanin expression and soluble carbohydrate metabolism. Meanwhile, 12 SNPs were significantly associated with seedling traits under heat stress and these SNPs tagged genes that function in sugar metabolism, and ion transport pathways. Evaluation of co-expression networks for genes near the significantly associated SNPs indicated complex gene interactions for cold and heat stresses in sorghum. We focused and validated the expression of four genes in the network of Sb06g025040, a basic-helix-loop-helix (bHLH) transcription factor that was proposed to be involved in purple color pigmentation of leaf, and observed that genes in this network were upregulated during cold stress in a moderately tolerant line as compared to the more sensitive line. CONCLUSION This study facilitated the tagging of genome regions associated with variation in seedling traits of sorghum under cold and heat stress. These findings show the potential of genotype information for development of temperature resilient sorghum cultivars and further characterization of genes and their networks responsible for adaptation to thermal stresses. Knowledge on the gene networks from this research can be extended to the other cereal crops to better understand the genetic basis of resilience to temperature fluctuations during plant developmental stages.
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Affiliation(s)
- Ratan Chopra
- Plant Stress & Germplasm Development Unit, Cropping Systems Research Laboratory, USDA-ARS, Lubbock, TX, 79415, USA.
| | - Gloria Burow
- Plant Stress & Germplasm Development Unit, Cropping Systems Research Laboratory, USDA-ARS, Lubbock, TX, 79415, USA.
| | - John J Burke
- Plant Stress & Germplasm Development Unit, Cropping Systems Research Laboratory, USDA-ARS, Lubbock, TX, 79415, USA
| | - Nicholas Gladman
- Plant Stress & Germplasm Development Unit, Cropping Systems Research Laboratory, USDA-ARS, Lubbock, TX, 79415, USA
| | - Zhanguo Xin
- Plant Stress & Germplasm Development Unit, Cropping Systems Research Laboratory, USDA-ARS, Lubbock, TX, 79415, USA
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Jha UC, Bohra A, Jha R. Breeding approaches and genomics technologies to increase crop yield under low-temperature stress. PLANT CELL REPORTS 2017; 36:1-35. [PMID: 27878342 DOI: 10.1007/s00299-016-2073-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/04/2016] [Indexed: 05/11/2023]
Abstract
Improved knowledge about plant cold stress tolerance offered by modern omics technologies will greatly inform future crop improvement strategies that aim to breed cultivars yielding substantially high under low-temperature conditions. Alarmingly rising temperature extremities present a substantial impediment to the projected target of 70% more food production by 2050. Low-temperature (LT) stress severely constrains crop production worldwide, thereby demanding an urgent yet sustainable solution. Considerable research progress has been achieved on this front. Here, we review the crucial cellular and metabolic alterations in plants that follow LT stress along with the signal transduction and the regulatory network describing the plant cold tolerance. The significance of plant genetic resources to expand the genetic base of breeding programmes with regard to cold tolerance is highlighted. Also, the genetic architecture of cold tolerance trait as elucidated by conventional QTL mapping and genome-wide association mapping is described. Further, global expression profiling techniques including RNA-Seq along with diverse omics platforms are briefly discussed to better understand the underlying mechanism and prioritize the candidate gene (s) for downstream applications. These latest additions to breeders' toolbox hold immense potential to support plant breeding schemes that seek development of LT-tolerant cultivars. High-yielding cultivars endowed with greater cold tolerance are urgently required to sustain the crop yield under conditions severely challenged by low-temperature.
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Affiliation(s)
- Uday Chand Jha
- Indian Institute of Pulses Research, Kanpur, 208024, India.
| | - Abhishek Bohra
- Indian Institute of Pulses Research, Kanpur, 208024, India.
| | - Rintu Jha
- Indian Institute of Pulses Research, Kanpur, 208024, India
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Upadhyaya HD, Wang YH, Sastry DVSSR, Dwivedi SL, Prasad PVV, Burrell AM, Klein RR, Morris GP, Klein PE. Association mapping of germinability and seedling vigor in sorghum under controlled low-temperature conditions. Genome 2015; 59:137-45. [PMID: 26758024 DOI: 10.1139/gen-2015-0122] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sorghum is one of the world's most important food, feed, and fiber crops as well as a potential feedstock for lignocellulosic bioenergy. Early-season planting extends sorghum's growing season and increases yield in temperate regions. However, sorghum's sensitivity to low soil temperatures adversely impacts seed germination. In this study, we evaluated the 242 accessions of the ICRISAT sorghum mini core collection for seed germination and seedling vigor at 12 °C as a measure of cold tolerance. Genome-wide association analysis was performed with approximately 162,177 single nucleotide polymorphism markers. Only one marker locus (Locus 7-2) was significantly associated with low-temperature germination and none with vigor. The linkage of Locus 7-2 to low-temperature germination was supported by four lines of evidence: strong association in three independent experiments, co-localization with previously mapped cold tolerance quantitative trait loci (QTL) in sorghum, a candidate gene that increases cold tolerance and germination rate when its wheat homolog is overexpressed in tobacco, and its syntenic region in rice co-localized with two cold tolerance QTL in rice. This locus may be useful in developing tools for molecular breeding of sorghums with improved low-temperature germinability.
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Affiliation(s)
- Hari D Upadhyaya
- a International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Andhra Pradesh, India.,b Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA.,c UWA Institute of Agriculture, the University of Western Australia, Crawley WA 6009, Australia
| | - Yi-Hong Wang
- d Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - Dintyala V S S R Sastry
- a International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Andhra Pradesh, India
| | - Sangam L Dwivedi
- a International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Andhra Pradesh, India
| | - P V Vara Prasad
- b Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA
| | - A Millie Burrell
- e Department of Horticulture and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA
| | - Robert R Klein
- f USDA-ARS, Southern Plains Agricultural Research Center, College Station, TX 77845, USA
| | - Geoffrey P Morris
- b Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA
| | - Patricia E Klein
- e Department of Horticulture and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA
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Fiedler K, Bekele WA, Duensing R, Gründig S, Snowdon R, Stützel H, Zacharias A, Uptmoor R. Genetic dissection of temperature-dependent sorghum growth during juvenile development. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2014; 127:1935-48. [PMID: 25023408 DOI: 10.1007/s00122-014-2350-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 06/17/2014] [Indexed: 05/11/2023]
Abstract
Promising genome regions for improving cold tolerance of sorghum were identified on chromosomes SBI-01, SBI-03, SBI-07, and SBI-10. Chlorophyll fluorescence had no major effect on growth rates at low temperatures. Developing fast growing sorghum seedlings is an important breeding goal for temperate climates since low springtime temperatures are resulting in a prolonged juvenile development. The adaptation of sorghum to tropical and subtropical highlands gives hint for certain genetic variation. The goals of the present study were to detect marker-trait associations for leaf and dry matter growth rate and for chlorophyll fluorescence and content (SPAD) in relation to temperature. A diversity set comprising 194 genotypes was tested in eight controlled environments with temperatures ranging from 9.4 to 20.8 °C. Significant marker-trait associations (p < 0.05) were identified for each individual temperature regime and on the parameters of regression analyses describing the responses of growth or chlorophyll related traits to temperatures. The diversity set was fingerprinted with 171 diversity array technology (DArT) and 31 simple-sequence repeat (SSR) markers. SSRs were used to analyze the population structure while association studies were performed on DArT markers. Promising marker-trait associations for growth rates in relation to temperature were detected on chromosomes SBI-01, SBI-03, SBI-07, and SBI-10. Many promising loci were also significantly associated to the results obtained in individual low-temperature environments. Marker-trait associations for chlorophyll content and fluorescence did occasionally co-locate to those for growth during juvenile development but there was no evidence supporting our hypothesis that seedling growth at low temperatures is largely influenced by SPAD or fluorescence.
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Affiliation(s)
- Karin Fiedler
- Institute of Biological Production Systems, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419, Hannover, Germany
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Bekele WA, Fiedler K, Shiringani A, Schnaubelt D, Windpassinger S, Uptmoor R, Friedt W, Snowdon RJ. Unravelling the genetic complexity of sorghum seedling development under low-temperature conditions. PLANT, CELL & ENVIRONMENT 2014; 37:707-723. [PMID: 24033406 DOI: 10.1111/pce.12189] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 08/15/2013] [Accepted: 08/17/2013] [Indexed: 06/02/2023]
Abstract
Sorghum is a promising alternative to maize for bioenergy production in Europe; however, its use is currently limited by poor adaptation to low temperatures during and after germination. We collected multi-trait phenotype data under optimal and suboptimal temperatures in a genetically diverse recombinant inbred line (RIL) mapping population showing contrasting segregation patterns for pre- and post-emergence chilling tolerance. Germination, emergence, seedling development, root architecture and seedling survival were assessed in two different seedlots. Emergence and root establishment were found to be the key determinants of development and survival under chilling stress. Highly interactive epistatic quantitative trait loci (QTL) hotspots, including a previously unknown QTL on Sb06 with a significant effect on prolonged chilling survival, were found to regulate different physiological mechanisms contributing to maintenance of growth and development despite the chilling temperatures. The major QTL regions harbour promising candidate genes with known roles in abiotic stress tolerance. Identification of loci in the QTL hotspot regions conferring maintenance of cell division and growth under early chilling stress represents a promising step towards breeding for successful establishment of sorghum in temperate climates.
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Affiliation(s)
- Wubishet A Bekele
- Department of Plant Breeding, Justus Liebig University, Giessen, 35392, Giessen, Germany
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Bekele WA, Wieckhorst S, Friedt W, Snowdon RJ. High-throughput genomics in sorghum: from whole-genome resequencing to a SNP screening array. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:1112-25. [PMID: 23919585 DOI: 10.1111/pbi.12106] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/28/2013] [Accepted: 07/09/2013] [Indexed: 05/18/2023]
Abstract
With its small, diploid and completely sequenced genome, sorghum (Sorghum bicolor L. Moench) is highly amenable to genomics-based breeding approaches. Here, we describe the development and testing of a robust single-nucleotide polymorphism (SNP) array platform that enables polymorphism screening for genome-wide and trait-linked polymorphisms in genetically diverse S. bicolor populations. Whole-genome sequences with 6× to 12× coverage from five genetically diverse S. bicolor genotypes, including three sweet sorghums and two grain sorghums, were aligned to the sorghum reference genome. From over 1 million high-quality SNPs, we selected 2124 Infinium Type II SNPs that were informative in all six source genomes, gave an optimal Assay Design Tool (ADT) score, had allele frequencies of 50% in the six genotypes and were evenly spaced throughout the S. bicolor genome. Furthermore, by phenotype-based pool sequencing, we selected an additional 876 SNPs with a phenotypic association to early-stage chilling tolerance, a key trait for European sorghum breeding. The 3000 attempted bead types were used to populate half of a dual-species Illumina iSelect SNP array. The array was tested using 564 Sorghum spp. genotypes, including offspring from four unrelated recombinant inbred line (RIL) and F2 populations and a genetic diversity collection. A high call rate of over 80% enabled validation of 2620 robust and polymorphic sorghum SNPs, underlining the efficiency of the array development scheme for whole-genome SNP selection and screening, with diverse applications including genetic mapping, genome-wide association studies and genomic selection.
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Affiliation(s)
- Wubishet A Bekele
- Department of Plant Breeding, Justus Liebig University, Giessen, Germany
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