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Miller ME, Liberatore KL, Kianian SF. Optimization and Comparative Analysis of Plant Organellar DNA Enrichment Methods Suitable for Next-generation Sequencing. J Vis Exp 2017. [PMID: 28784941 DOI: 10.3791/55528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Plant organellar genomes contain large, repetitive elements that may undergo pairing or recombination to form complex structures and/or sub-genomic fragments. Organellar genomes also exist in admixtures within a given cell or tissue type (heteroplasmy), and an abundance of subtypes may change throughout development or when under stress (sub-stoichiometric shifting). Next-generation sequencing (NGS) technologies are required to obtain deeper understanding of organellar genome structure and function. Traditional sequencing studies use several methods to obtain organellar DNA: (1) If a large amount of starting tissue is used, it is homogenized and subjected to differential centrifugation and/or gradient purification. (2) If a smaller amount of tissue is used (i.e., if seeds, material, or space is limited), the same process is performed as in (1), followed by whole-genome amplification to obtain sufficient DNA. (3) Bioinformatics analysis can be used to sequence the total genomic DNA and to parse out organellar reads. All these methods have inherent challenges and tradeoffs. In (1), it may be difficult to obtain such a large amount of starting tissue; in (2), whole-genome amplification could introduce a sequencing bias; and in (3), homology between nuclear and organellar genomes could interfere with assembly and analysis. In plants with large nuclear genomes, it is advantageous to enrich for organellar DNA to reduce sequencing costs and sequence complexity for bioinformatics analyses. Here, we compare a traditional differential centrifugation method with a fourth method, an adapted CpG-methyl pulldown approach, to separate the total genomic DNA into nuclear and organellar fractions. Both methods yield sufficient DNA for NGS, DNA that is highly enriched for organellar sequences, albeit at different ratios in mitochondria and chloroplasts. We present the optimization of these methods for wheat leaf tissue and discuss major advantages and disadvantages of each approach in the context of sample input, protocol ease, and downstream application.
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Affiliation(s)
- Marisa E Miller
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Horticultural Science, University of Minnesota
| | - Katie L Liberatore
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Plant Pathology, University of Minnesota
| | - Shahryar F Kianian
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Plant Pathology, University of Minnesota;
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Soyk S, Lemmon ZH, Oved M, Fisher J, Liberatore KL, Park SJ, Goren A, Jiang K, Ramos A, van der Knaap E, Van Eck J, Zamir D, Eshed Y, Lippman ZB. Bypassing Negative Epistasis on Yield in Tomato Imposed by a Domestication Gene. Cell 2017; 169:1142-1155.e12. [PMID: 28528644 DOI: 10.1016/j.cell.2017.04.032] [Citation(s) in RCA: 183] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/13/2017] [Accepted: 04/24/2017] [Indexed: 02/03/2023]
Abstract
Selection for inflorescence architecture with improved flower production and yield is common to many domesticated crops. However, tomato inflorescences resemble wild ancestors, and breeders avoided excessive branching because of low fertility. We found branched variants carry mutations in two related transcription factors that were selected independently. One founder mutation enlarged the leaf-like organs on fruits and was selected as fruit size increased during domestication. The other mutation eliminated the flower abscission zone, providing "jointless" fruit stems that reduced fruit dropping and facilitated mechanical harvesting. Stacking both beneficial traits caused undesirable branching and sterility due to epistasis, which breeders overcame with suppressors. However, this suppression restricted the opportunity for productivity gains from weak branching. Exploiting natural and engineered alleles for multiple family members, we achieved a continuum of inflorescence complexity that allowed breeding of higher-yielding hybrids. Characterizing and neutralizing similar cases of negative epistasis could improve productivity in many agricultural organisms. VIDEO ABSTRACT.
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Affiliation(s)
- Sebastian Soyk
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Zachary H Lemmon
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Matan Oved
- Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Josef Fisher
- Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Katie L Liberatore
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Soon Ju Park
- Division of Biological Sciences and Research Institute for Basic Science, Wonkwang University, Iksan, Jeonbuk 54538, Rep. of Korea
| | - Anna Goren
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ke Jiang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Alexis Ramos
- Institute of Plant Breeding, Genetic & Genomics, University of Georgia, Athens, GA 30602, USA
| | - Esther van der Knaap
- Institute of Plant Breeding, Genetic & Genomics, University of Georgia, Athens, GA 30602, USA
| | | | - Dani Zamir
- Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Yuval Eshed
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Zachary B Lippman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA; Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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Liberatore KL, Dukowic-Schulze S, Miller ME, Chen C, Kianian SF. The role of mitochondria in plant development and stress tolerance. Free Radic Biol Med 2016; 100:238-256. [PMID: 27036362 DOI: 10.1016/j.freeradbiomed.2016.03.033] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 01/03/2023]
Abstract
Eukaryotic cells require orchestrated communication between nuclear and organellar genomes, perturbations in which are linked to stress response and disease in both animals and plants. In addition to mitochondria, which are found across eukaryotes, plant cells contain a second organelle, the plastid. Signaling both among the organelles (cytoplasmic) and between the cytoplasm and the nucleus (i.e. nuclear-cytoplasmic interactions (NCI)) is essential for proper cellular function. A deeper understanding of NCI and its impact on development, stress response, and long-term health is needed in both animal and plant systems. Here we focus on the role of plant mitochondria in development and stress response. We compare and contrast features of plant and animal mitochondrial genomes (mtDNA), particularly highlighting the large and highly dynamic nature of plant mtDNA. Plant-based tools are powerful, yet underutilized, resources for enhancing our fundamental understanding of NCI. These tools also have great potential for improving crop production. Across taxa, mitochondria are most abundant in cells that have high energy or nutrient demands as well as at key developmental time points. Although plant mitochondria act as integrators of signals involved in both development and stress response pathways, little is known about plant mtDNA diversity and its impact on these processes. In humans, there are strong correlations between particular mitotypes (and mtDNA mutations) and developmental differences (or disease). We propose that future work in plants should focus on defining mitotypes more carefully and investigating their functional implications as well as improving techniques to facilitate this research.
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Affiliation(s)
- Katie L Liberatore
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, United States.
| | | | - Marisa E Miller
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Horticultural Science, University of Minnesota, St. Paul, MN 55108, United States
| | - Changbin Chen
- Department of Horticultural Science, University of Minnesota, St. Paul, MN 55108, United States
| | - Shahryar F Kianian
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, United States
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Kianian PMA, Liberatore KL, Miller ME, Hegstad JB, Kianian SF. Dissecting Plant Chromosomes by the Use of Ionizing Radiation. Methods Mol Biol 2016; 1429:91-101. [PMID: 27511169 DOI: 10.1007/978-1-4939-3622-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Radiation treatment of genomes is used to generate chromosome breaks for numerous applications. This protocol describes the preparation of seeds and the determination of the optimal level of irradiation dosage for the creation of a radiation hybrid (RH) population. These RH lines can be used to generate high-resolution physical maps for the assembly of sequenced genomes as well as the fine mapping of genes. This procedure can also be used for mutation breeding and forward/reverse genetics.
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Affiliation(s)
- Penny M A Kianian
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Ave., St. Paul, MN, 55108, USA.
| | - Katie L Liberatore
- USDA-ARS, Cereal Disease Laboratory, Department of Plant Pathology, University of Minnesota, 1551 Lindig Ave., St. Paul, MN, 55108, USA
| | - Marisa E Miller
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Ave., St. Paul, MN, 55108, USA
| | - Justin B Hegstad
- Department of Plant Sciences, North Dakota State University, Fargo, ND, USA
| | - Shahryar F Kianian
- USDA-ARS, Cereal Disease Laboratory, Department of Plant Pathology, University of Minnesota, 1551 Lindig Ave., St. Paul, MN, 55108, USA.
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Jiang K, Liberatore KL, Park SJ, Alvarez JP, Lippman ZB. Tomato yield heterosis is triggered by a dosage sensitivity of the florigen pathway that fine-tunes shoot architecture. PLoS Genet 2013; 9:e1004043. [PMID: 24385931 PMCID: PMC3873276 DOI: 10.1371/journal.pgen.1004043] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 11/06/2013] [Indexed: 12/22/2022] Open
Abstract
The superiority of hybrids has long been exploited in agriculture, and although many models explaining "heterosis" have been put forth, direct empirical support is limited. Particularly elusive have been cases of heterozygosity for single gene mutations causing heterosis under a genetic model known as overdominance. In tomato (Solanum lycopersicum), plants carrying mutations in SINGLE FLOWER TRUSS (SFT) encoding the flowering hormone florigen are severely delayed in flowering, become extremely large, and produce few flowers and fruits, but when heterozygous, yields are dramatically increased. Curiously, this overdominance is evident only in the background of "determinate" plants, in which the continuous production of side shoots and inflorescences gradually halts due to a defect in the flowering repressor SELF PRUNING (SP). How sp facilitates sft overdominance is unclear, but is thought to relate to the opposing functions these genes have on flowering time and shoot architecture. We show that sft mutant heterozygosity (sft/+) causes weak semi-dominant delays in flowering of both primary and side shoots. Using transcriptome sequencing of shoot meristems, we demonstrate that this delay begins before seedling meristems become reproductive, followed by delays in subsequent side shoot meristems that, in turn, postpone the arrest of shoot and inflorescence production. Reducing SFT levels in sp plants by artificial microRNAs recapitulates the dose-dependent modification of shoot and inflorescence production of sft/+ heterozygotes, confirming that fine-tuning levels of functional SFT transcripts provides a foundation for higher yields. Finally, we show that although flowering delays by florigen mutant heterozygosity are conserved in Arabidopsis, increased yield is not, likely because cyclical flowering is absent. We suggest sft heterozygosity triggers a yield improvement by optimizing plant architecture via its dosage response in the florigen pathway. Exploiting dosage sensitivity of florigen and its family members therefore provides a path to enhance productivity in other crops, but species-specific tuning will be required.
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Affiliation(s)
- Ke Jiang
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Katie L. Liberatore
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Soon Ju Park
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - John P. Alvarez
- Monash University, School of Biological Sciences, Clayton Campus, Melbourne, Victoria, Australia
| | - Zachary B. Lippman
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
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Abstract
Cellular responses to DNA damage and inhibited replication are evolutionarily conserved sets of pathways that are critical to preserving genome stability. To identify new participants in these responses, we undertook a screen for regulators that, when present on a high-copy vector, alter expression of a DNA damage-inducible RNR3-lacZ reporter construct in Saccharomyces cerevisiae. From this screen we isolated a plasmid encoding two closely related paralogs, WTM1 and WTM2, that greatly increases constitutive expression of RNR3-lacZ. Moderate overexpression of both genes together, or high-level expression of WTM2 alone from a constitutive promoter, upregulates RNR3-lacZ in the absence of DNA damage. Overexpressed, tagged Wtm2p is associated with the RNR3 promoter, indicating that this effect is likely direct. Further investigation reveals that Wtm2p and Wtm1p, previously described as regulators of meiotic gene expression and transcriptional silencing, amplify transcriptional induction of RNR3 in response to replication stress and modulate expression of genes encoding other RNR subunits.
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Affiliation(s)
- Susannah Green Tringe
- Department of Molecular Genetics and Microbiology and Cancer Research and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA
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