51
|
Zemanová V, Popov M, Pavlíková D, Kotrba P, Hnilička F, Česká J, Pavlík M. Effect of arsenic stress on 5-methylcytosine, photosynthetic parameters and nutrient content in arsenic hyperaccumulator Pteris cretica (L.) var. Albo-lineata. BMC PLANT BIOLOGY 2020; 20:130. [PMID: 32228515 PMCID: PMC7106808 DOI: 10.1186/s12870-020-2325-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 02/28/2020] [Indexed: 05/15/2023]
Abstract
BACKGROUND Arsenic toxicity induces a range of metabolic responses in plants, including DNA methylation. The focus of this paper was on the relationship between As-induced stress and plant senescence in the hyperaccumulator Pteris cretica var. Albo-lineata (Pc-Al). We assume difference in physiological parameters and level of DNA methylation in young and old fronds as symptoms of As toxicity. RESULTS The As accumulation of Pc-Al fronds, grown in pots of haplic chernozem contaminated with 100 mg As kg- 1 for 122 days, decreased with age. Content of As was higher in young than old fronds for variants with 100 mg As kg- 1 (2800 and 2000 mg As kg- 1 dry matter, respectively). The highest As content was determined in old fronds of Pc-Al grown in pots with 250 mg As kg- 1. The increase with age was confirmed for determined nutrients - Cu, Mg, Mn, S and Zn. A significant elevation of all analysed nutrients was showed in old fronds. Arsenic accumulation affected DNA methylation status in fronds, but content of 5-methylcytosine (5mC) decreased only in old fronds of Pc-Al (from 25 to 12%). Determined photosynthetic processes showed a decrease of fluorescence, photosynthetic rate and chlorophylls of As treatments in young and old fronds. Water potential was decreased by As in both fronds. Thinning of the sclerenchymatous inner cortex and a reduction in average tracheid metaxylem in the vascular cylinder was showed in roots of As treatment. Irrespective to fronds age, physiological parameters positively correlated with a 5mC while negatively with direct As toxicity. Opposite results were found for contents of Cu, Mg, Mn, S and Zn. CONCLUSIONS The results of this paper point to changes in the metabolism of the hyperaccumulator plant Pc-Al, upon low and high exposure to As contamination. The significant impact of As on DNA methylation was found in old fronds. Irrespective to fronds age, significant correlations were confirmed for 5mC and As toxicity. Our analysis of the very low water potential values and lignification of cell walls in roots showed that transports of assimilated metabolites and water between roots and fronds were reduced. As was showed by our results, epigenetic changes could affect studied parameters of the As hyperaccumulator plant Pc-Al, especially in old fronds.
Collapse
Affiliation(s)
- Veronika Zemanová
- Isotope Laboratory, Institute of Experimental Botany, The Czech Academy of Sciences, Vídeňská 1083, 14220, Prague, Czech Republic
- Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 16500, Prague, Czech Republic
| | - Marek Popov
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Technická 5, 16628, Prague, Czech Republic
| | - Daniela Pavlíková
- Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 16500, Prague, Czech Republic
| | - Pavel Kotrba
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Technická 5, 16628, Prague, Czech Republic
| | - František Hnilička
- Department of Botany and Plant Physiology, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 16500, Prague, Czech Republic
| | - Jana Česká
- Department of Botany and Plant Physiology, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 16500, Prague, Czech Republic
| | - Milan Pavlík
- Isotope Laboratory, Institute of Experimental Botany, The Czech Academy of Sciences, Vídeňská 1083, 14220, Prague, Czech Republic.
| |
Collapse
|
52
|
Mehraj H, Kawanabe T, Shimizu M, Miyaji N, Akter A, Dennis ES, Fujimoto R. In Arabidopsis thaliana Heterosis Level Varies among Individuals in an F 1 Hybrid Population. PLANTS 2020; 9:plants9040414. [PMID: 32230994 PMCID: PMC7238264 DOI: 10.3390/plants9040414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/23/2020] [Accepted: 03/23/2020] [Indexed: 11/28/2022]
Abstract
Heterosis or hybrid vigour is a phenomenon in which hybrid progeny exhibit superior yield and biomass to parental lines and has been used to breed F1 hybrid cultivars in many crops. A similar level of heterosis in all F1 individuals is expected as they are genetically identical. However, we found variation in rosette size in individual F1 plants from a cross between C24 and Columbia-0 accessions of Arabidopsis thaliana. Big-sized F1 plants had 26.1% larger leaf area in the first and second leaves than medium-sized F1 plants at 14 days after sowing in spite of the identical genetic background. We identified differentially expressed genes between big- and medium-sized F1 plants by microarray; genes involved in the category of stress response were overrepresented. We made transgenic plants overexpressing 21 genes, which were differentially expressed between the two size classes, and some lines had increased plant size at 14 or 21 days after sowing but not at all time points during development. Change of expression levels in stress-responsive genes among individual F1 plants could generate the variation in plant size of individual F1 plants in A. thaliana.
Collapse
Affiliation(s)
- Hasan Mehraj
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
| | - Takahiro Kawanabe
- School of Agriculture, Tokai University, Toroku, Higashi-ku, Kumamoto 862-8652, Japan
- Correspondence: (T.K.); (R.F.)
| | - Motoki Shimizu
- Iwate Biotechnology Research Center, Narita, Kitakami, Iwate 024-0003, Japan;
| | - Naomi Miyaji
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
| | - Ayasha Akter
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
- Department of Horticulture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Elizabeth S. Dennis
- CSIRO Agriculture and Food, Canberra, ACT 2601, Australia;
- University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
- Correspondence: (T.K.); (R.F.)
| |
Collapse
|
53
|
Heterosis Breeding in Eggplant ( Solanum melongena L.): Gains and Provocations. PLANTS 2020; 9:plants9030403. [PMID: 32213925 PMCID: PMC7154857 DOI: 10.3390/plants9030403] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 01/15/2023]
Abstract
Heterosis (or hybrid vigor) results in a hybrid’s phenotypic superiority over its founder parents for quantitative and qualitative traits. Hybrid vigor is defined by mechanisms such as dominant complementation, over-dominance, and epistasis. Eggplant (Solanum melongena L.) is an essential vegetable crop and a good source of dietary minerals, vitamins, and anthocyanins, with a high oxygen radical absorbance capacity and low caloric value. Given the economic and nutritional significance of eggplants, breeding efforts focus on developing high-yielding varieties—mostly F1 hybrids—with important traits. Studies indicate the successful exploitation of heterosis in the eggplant for a considerable improvement with respect to quantitative traits. In this direction, estimating heterosis for yield-related traits could well be useful for examining the most beneficial hybrid mix with the exploitation of top-quality hybrid. This review examines the current perception of the breeding and molecular aspects of heterosis in eggplants and cites several studies describing the mechanisms. Rendering and combining recent genomics, epigenetic, proteomic, and metabolomics studies present new prospects towards the understanding of the regulatory events of heterosis involved in the evolution and the domestication of the eggplant ideotype.
Collapse
|
54
|
Liu J, Li M, Zhang Q, Wei X, Huang X. Exploring the molecular basis of heterosis for plant breeding. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:287-298. [PMID: 30916464 DOI: 10.1111/jipb.12804] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/13/2019] [Indexed: 05/18/2023]
Abstract
Since approximate a century ago, many hybrid crops have been continually developed by crossing two inbred varieties. Owing to heterosis (hybrid vigor) in plants, these hybrids often have superior agricultural performances in yield or disease resistance succeeding their inbred parental lines. Several classical hypotheses have been proposed to explain the genetic causes of heterosis. During recent years, many new genetics and genomics strategies have been developed and used for the identifications of heterotic genes in plants. Heterotic effects of the heterotic loci and molecular functions of the heterotic genes are being investigated in many plants such as rice, maize, sorghum, Arabidopsis and tomato. More and more data and knowledge coming from the molecular studies of heterotic loci and genes will serve as a valuable resource for hybrid breeding by molecular design in future. This review aims to address recent advances in our understanding of the genetic and molecular mechanisms of heterosis in plants. The remaining scientific questions on the molecular basis of heterosis and the potential applications in breeding are also proposed and discussed.
Collapse
Affiliation(s)
- Jie Liu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Mengjie Li
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Qi Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Xin Wei
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Xuehui Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| |
Collapse
|
55
|
Baldauf JA, Vedder L, Schoof H, Hochholdinger F. Robust non-syntenic gene expression patterns in diverse maize hybrids during root development. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:865-876. [PMID: 31638701 DOI: 10.1093/jxb/erz452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 09/30/2019] [Indexed: 06/10/2023]
Abstract
Distantly related maize (Zea mays L.) inbred lines exhibit an exceptional degree of structural genomic diversity, which is probably unique among plants. This study systematically investigated the developmental and genotype-dependent regulation of the primary root transcriptomes of a genetically diverse panel of maize F1-hybrids and their parental inbred lines. While we observed substantial transcriptomic changes during primary root development, we demonstrated that hybrid-associated gene expression patterns, including differential, non-additive, and allele-specific transcriptome profiles, are particularly robust to these developmental fluctuations. For instance, differentially expressed genes with preferential expression in hybrids were highly conserved during development in comparison to their parental counterparts. Similarly, in hybrids a major proportion of non-additively expressed genes with expression levels between the parental values were particularly conserved during development. Importantly, in these expression patterns non-syntenic genes that evolved after the separation of the maize and sorghum lineages were systemically enriched. Furthermore, non-syntenic genes were substantially linked to the conservation of all surveyed gene expression patterns during primary root development. Among all F1-hybrids, between ~40% of the non-syntenic genes with unexpected allelic expression ratios and ~60% of the non-syntenic differentially and non-additively expressed genes were conserved and therefore robust to developmental changes. Hence, the enrichment of non-syntenic genes during primary root development might be involved in the developmental adaptation of maize roots and thus the superior performance of hybrids.
Collapse
Affiliation(s)
- Jutta A Baldauf
- Institute for Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Bonn, Germany
| | - Lucia Vedder
- Institute for Crop Science and Resource Conservation, Crop Bioinformatics, University of Bonn, Bonn, Germany
| | - Heiko Schoof
- Institute for Crop Science and Resource Conservation, Crop Bioinformatics, University of Bonn, Bonn, Germany
| | - Frank Hochholdinger
- Institute for Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Bonn, Germany
| |
Collapse
|
56
|
Crisp PA, Hammond R, Zhou P, Vaillancourt B, Lipzen A, Daum C, Barry K, de Leon N, Buell CR, Kaeppler SM, Meyers BC, Hirsch CN, Springer NM. Variation and Inheritance of Small RNAs in Maize Inbreds and F1 Hybrids. PLANT PHYSIOLOGY 2020; 182:318-331. [PMID: 31575624 PMCID: PMC6945832 DOI: 10.1104/pp.19.00817] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/23/2019] [Indexed: 05/20/2023]
Abstract
Small RNAs (sRNAs) regulate gene expression, play important roles in epigenetic pathways, and are hypothesized to contribute to hybrid vigor in plants. Prior investigations have provided valuable insights into associations between sRNAs and heterosis, often using a single hybrid genotype or tissue, but our understanding of the role of sRNAs and their potential value to plant breeding are limited by an incomplete picture of sRNA variation between diverse genotypes and development stages. Here, we provide a deep exploration of sRNA variation and inheritance among a panel of 108 maize (Zea mays) samples spanning five tissues from eight inbred parents and 12 hybrid genotypes, covering a spectrum of heterotic groups, genetic variation, and levels of heterosis for various traits. We document substantial developmental and genotypic influences on sRNA expression, with varying patterns for 21-nucleotide (nt), 22-nt, and 24-nt sRNAs. We provide a detailed view of the distribution of sRNAs in the maize genome, revealing a complex makeup that also shows developmental plasticity, particularly for 22-nt sRNAs. sRNAs exhibited substantially more variation between inbreds as compared with observed variation for gene expression. In hybrids, we identify locus-specific examples of nonadditive inheritance, mostly characterized as partial or complete dominance, but rarely outside the parental range. However, the global abundance of 21-nt, 22-nt, and 24-nt sRNAs varies very little between inbreds and hybrids, suggesting that hybridization affects sRNA expression principally at specific loci rather than on a global scale. This study provides a valuable resource for understanding the potential role of sRNAs in hybrid vigor.
Collapse
Affiliation(s)
- Peter A Crisp
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Reza Hammond
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware 19711
| | - Peng Zhou
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Brieanne Vaillancourt
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Anna Lipzen
- United States Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Chris Daum
- United States Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Kerrie Barry
- United States Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Natalia de Leon
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706
| | - C Robin Buell
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Shawn M Kaeppler
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
- Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211
| | - Candice N Hirsch
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108
| | - Nathan M Springer
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
| |
Collapse
|
57
|
Vondras AM, Minio A, Blanco-Ulate B, Figueroa-Balderas R, Penn MA, Zhou Y, Seymour D, Ye Z, Liang D, Espinoza LK, Anderson MM, Walker MA, Gaut B, Cantu D. The genomic diversification of grapevine clones. BMC Genomics 2019; 20:972. [PMID: 31830913 PMCID: PMC6907202 DOI: 10.1186/s12864-019-6211-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 10/22/2019] [Indexed: 12/14/2022] Open
Abstract
Background Vegetatively propagated clones accumulate somatic mutations. The purpose of this study was to better appreciate clone diversity and involved defining the nature of somatic mutations throughout the genome. Fifteen Zinfandel winegrape clone genomes were sequenced and compared to one another using a highly contiguous genome reference produced from one of the clones, Zinfandel 03. Results Though most heterozygous variants were shared, somatic mutations accumulated in individual and subsets of clones. Overall, heterozygous mutations were most frequent in intergenic space and more frequent in introns than exons. A significantly larger percentage of CpG, CHG, and CHH sites in repetitive intergenic space experienced transition mutations than in genic and non-repetitive intergenic spaces, likely because of higher levels of methylation in the region and because methylated cytosines often spontaneously deaminate. Of the minority of mutations that occurred in exons, larger proportions of these were putatively deleterious when they occurred in relatively few clones. Conclusions These data support three major conclusions. First, repetitive intergenic space is a major driver of clone genome diversification. Second, clones accumulate putatively deleterious mutations. Third, the data suggest selection against deleterious variants in coding regions or some mechanism by which mutations are less frequent in coding than noncoding regions of the genome.
Collapse
Affiliation(s)
- Amanda M Vondras
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Andrea Minio
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Barbara Blanco-Ulate
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA.,Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Rosa Figueroa-Balderas
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Michael A Penn
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Yongfeng Zhou
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
| | - Danelle Seymour
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
| | - Zirou Ye
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Dingren Liang
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Lucero K Espinoza
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Michael M Anderson
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - M Andrew Walker
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA
| | - Brandon Gaut
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, 92617, USA
| | - Dario Cantu
- Department of Viticulture and Enology, University of California Davis, Davis, CA, 95616, USA.
| |
Collapse
|
58
|
He D, Xia B, Zhou Q, Wang L, Huang X. Rare earth elements regulate the endocytosis and DNA methylation in root cells of Arabidopsis thaliana. CHEMOSPHERE 2019; 227:522-532. [PMID: 31004819 DOI: 10.1016/j.chemosphere.2019.04.076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/30/2019] [Accepted: 04/10/2019] [Indexed: 06/09/2023]
Abstract
With increasing application of rare earth elements (REEs), the resulting environmental safety has attracted extensive attention. When REEs act on plant leaves, REEs can initiate endocytosis in leaf cells, causing more REEs enter plant cells and then severe damage to plants. But when REEs directly act on plant roots, whether and how REEs affect the endocytosis in root cells remain unknown. Here, we characterized effects of lanthanum [La(III)], a REE with high accumulation in environment, on the endocytosis in root cells of Arabidopsis thaliana, and revealed effect mechanism from the perspective of DNA methylation. We found that La(III) enhanced the endocytosis in root cells and the extent of enhancement depended on the dose and time of La(III) exposure: 160 μM > 80 μM >30 μM (12 h); 80 μM > 30 μM >160 μM (24 h); 24 h > 12 h. La(III)-enhanced endocytosis in root cells resulted from DNA methylation, which was closely related to the expression level of genes encoding DNA methylases/demethylases: CMT3, DRM2 and DNMT2 for 12 h, MET1, CMT1, CMT2, CMT3, DRM2, DNMT2, ROS1, DME, DML2, DML5a, and DML5b for 24 h. Conversely, enhanced endocytosis also promoted the expression level of genes encoding DNA methylases/demethylases. Our findings provide references for understanding the mechanisms by which REEs impact plants.
Collapse
Affiliation(s)
- Ding He
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China
| | - Binxin Xia
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China
| | - Qing Zhou
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China
| | - Lihong Wang
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China.
| | - Xiaohua Huang
- National and Local Joint Engineering Research Center of Biomedical Functional Materials, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, China.
| |
Collapse
|
59
|
Gonzalez-Bayon R, Shen Y, Groszmann M, Zhu A, Wang A, Allu AD, Dennis ES, Peacock WJ, Greaves IK. Senescence and Defense Pathways Contribute to Heterosis. PLANT PHYSIOLOGY 2019; 180:240-252. [PMID: 30710054 PMCID: PMC6501064 DOI: 10.1104/pp.18.01205] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/17/2019] [Indexed: 05/12/2023]
Abstract
Hybrids are used extensively in agriculture due to their superior performance in seed yield and plant growth, yet the molecular mechanisms underpinning hybrid performance are not well understood. Recent evidence has suggested that a decrease in basal defense response gene expression regulated by reduced levels of salicylic acid (SA) may be important for vigor in certain hybrid combinations. Decreasing levels of SA in the Arabidopsis (Arabidopsis thaliana) accession C24 through the introduction of the SA catabolic enzyme salicylate1 hydroxylase (NahG) increases plant size, phenocopying the large-sized C24/Landsberg erecta (Ler) F1 hybrids. C24♀ × Ler♂ F1 hybrids and C24 NahG lines shared differentially expressed genes and pathways associated with plant defense and leaf senescence including decreased expression of SA biosynthetic genes and SA response genes. The expression of TL1 BINDING TRANSCRIPTION FACTOR1, a key regulator in resource allocation between growth and defense, was decreased in both the F1 hybrid and the C24 NahG lines, which may promote growth. Both C24 NahG lines and the F1 hybrids showed decreased expression of the key senescence-associated transcription factors WRKY53, NAC-CONTAINING PROTEIN29, and ORESARA1 with a delayed onset of senescence compared to C24 plants. The delay in senescence resulted in an extension of the photosynthetic period in the leaves of F1 hybrids compared to the parental lines, potentially allowing each leaf to contribute more resources toward growth.
Collapse
Affiliation(s)
| | - Yifei Shen
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia
- Institute of Crop Science & Institute of Bioinformatics, Zhejiang University, Hangzhou 310058, China
| | - Michael Groszmann
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Anyu Zhu
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia
| | - Aihua Wang
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia
| | - Annapurna D Allu
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia
| | - Elizabeth S Dennis
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia
- University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - W James Peacock
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia
- University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Ian K Greaves
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia
| |
Collapse
|
60
|
Affiliation(s)
- Lisa M Smith
- Department of Animal and Plant Sciences and The Plant Production and Protection (P3) Centre, University of Sheffield, Sheffield S10 2TN, United Kingdom
| |
Collapse
|
61
|
Ng WL, Wu W, Zou P, Zhou R. Comparative transcriptomics sheds light on differential adaptation and species diversification between two Melastoma species and their F 1 hybrid. AOB PLANTS 2019; 11:plz019. [PMID: 31037213 PMCID: PMC6481908 DOI: 10.1093/aobpla/plz019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
Variation in gene expression has been shown to promote adaptive divergence, and can lead to speciation. The plant genus Melastoma, thought to have diversified through adaptive radiation, provides an excellent model for the study of gene expressional changes during adaptive differentiation and following interspecific hybridization. In this study, we performed RNA-seq on M. candidum, M. sanguineum and their F1 hybrid, to investigate the role of gene expression in species diversification within the genus. Reference transcriptomes were assembled using combined data from both parental species, resulting in 50 519 and 48 120 transcripts for the leaf and flower petal, after removing redundancy. Differential expression analysis uncovered 3793 and 2116 differentially expressed (DE) transcripts, most of which are between M. candidum and M. sanguineum. Differential expression was observed for genes related to light responses, as well as genes that regulate the development of leaf trichomes, a trait that among others is thought to protect plants against sunlight, suggesting the differential adaptation of the species to sunlight intensity. The analysis of positively selected genes between the two species also revealed possible differential adaptation to other abiotic stresses such as drought and temperature. In the hybrid, almost all possible modes of expression were observed at the DE transcripts, although at most transcripts, the expression levels were similar to that of either parent instead of being intermediate. A small number of transgressively expressed transcripts that matched genes known to promote plant growth and adaptation to stresses in new environments were also found, possibly explaining the vigour observed in the hybrid. The findings in this study provided insights into the role of gene expression in the diversification of Melastoma, which we believe is an important example for more cross-taxa comparisons in the future.
Collapse
Affiliation(s)
- Wei Lun Ng
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
- China-ASEAN College of Marine Sciences, Xiamen University Malaysia, Sepang, Selangor, Malaysia
| | - Wei Wu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Peishan Zou
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Renchao Zhou
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| |
Collapse
|
62
|
Heterotic patterns of primary and secondary metabolites in the oilseed crop Brassica juncea. Heredity (Edinb) 2019; 123:318-336. [PMID: 30911141 DOI: 10.1038/s41437-019-0213-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 02/23/2019] [Accepted: 03/11/2019] [Indexed: 02/01/2023] Open
Abstract
Heterosis refers to the superior performance of F1 hybrids over their respective parental inbred lines. Although the genetic and expression basis of heterosis have been previously investigated, the metabolic basis for this phenomenon is poorly understood. In a preliminary morphological study in Brassica juncea, we observed significant heterosis at the 50% flowering stage, wherein both the growth and reproduction of F1 reciprocal hybrids were greater than that of their parents. To identify the possible metabolic causes or consequences of this heterosis, we carried out targeted LC-MS analysis of 48 primary (amino acids and sugars) and secondary metabolites (phytohormones, glucosinolates, flavonoids, and phenolic esters) in five developmental tissues at 50% flowering in hybrids and inbred parents. Principal component analysis (PCA) of metabolites clearly separated inbred lines from their hybrids, particularly in the bud tissues. In general, secondary metabolites displayed more negative heterosis values in comparison to primary metabolites. The tested primary and secondary metabolites displayed both additive and non-additive modes of inheritance in F1 hybrids, wherein the number of metabolites showing an additive mode of inheritance were higher in buds and siliques (52.77-97.14%) compared to leaf tissues (47.37-80%). Partial least regression (PLS) analysis further showed that primary metabolites, in general, displayed higher association with morphological parameters in F1 hybrids. Overall, our results are consistent with a resource-cost model for heterosis in B. juncea, where metabolite allocation in hybrids appears to favor growth, at the expense of secondary metabolism.
Collapse
|
63
|
Liang L, Chang Y, Lu J, Wu X, Liu Q, Zhang W, Su X, Zhang B. Global Methylomic and Transcriptomic Analyses Reveal the Broad Participation of DNA Methylation in Daily Gene Expression Regulation of Populus trichocarpa. FRONTIERS IN PLANT SCIENCE 2019; 10:243. [PMID: 30873202 PMCID: PMC6403135 DOI: 10.3389/fpls.2019.00243] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 02/13/2019] [Indexed: 05/24/2023]
Abstract
Changes in DNA methylation patterns in different tissues, at various developmental stages, and under environmental stimuli have been investigated in plants. However, the involvement of DNA methylation in daily gene expression regulation and the plant circadian clock have not been reported. Here, we investigated DNA methylomes and mRNA transcriptomes from leaves of P. trichocarpa over 24 h by high-throughput sequencing. We found that approximately 15.63-19.50% of the genomic cytosine positions were methylated in mature poplar leaves, with approximately half being in the form of asymmetric CHH sites. Repetitive sequences and transposable elements (TEs) were heavily methylated, and the hAT and CMC-EnSpm transposons were more heavily methylated than other TEs. High methylation levels were observed upstream and downstream of the transcribed region, medium in exon and intron, low in untranslated region (5'-UTR and 3'-UTR) of genic regions. In total, about 53,689 differentially methylated regions (DMRs) were identified and CHH context was the most abundant type among daily DNA methylation changes. The DMRs overlapped with over one third of the total poplar genes, including plant defense genes. In addition, a positive correlation between expression levels and DNA methylation levels in the gene body region were observed in DMR overlapping genes. About 1,895 circadian regulated genes overlapped with DMRs, with 871 hypermethylated genes with down-regulated expression levels and 881 hypomethylated genes with up-regulated expression levels, indicating the possible regulation of DNA methylation on the daily rhythmic expression of these genes. But rhythmic DNA methylation changes were not detected in any oscillator component genes controlling the plant circadian clock. Our results suggest that DNA methylation participates widely in daily gene expression regulation, but is not the main mechanism modulating the plant circadian clock.
Collapse
Affiliation(s)
- Lixiong Liang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Yingying Chang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Junqian Lu
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Xiaojuan Wu
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Qi Liu
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Weixi Zhang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Xiaohua Su
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Bingyu Zhang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
- Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| |
Collapse
|
64
|
Nadir S, Li W, Zhu Q, Khan S, Zhang XL, Zhang H, Wei ZF, Li MT, Zhou L, Li CY, Chen LJ, Lee DS. A novel discovery of a long terminal repeat retrotransposon-induced hybrid weakness in rice. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1197-1207. [PMID: 30576523 PMCID: PMC6382335 DOI: 10.1093/jxb/ery442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/04/2018] [Indexed: 06/09/2023]
Abstract
Hybrid weakness is a post-zygotic hybridization barrier frequently observed in plants, including rice. In this study, we describe the genomic variation among three temperate japonica rice (Oryza sativa ssp. japonica) varieties 'Aranghyangchalbyeo' ('CH7'), 'Sanghaehyangheolua' ('CH8') and 'Shinseonchalbyeo' ('CH9'), carrying different hybrid weakness genes. The reciprocal progeny obtained from crossing any two varieties displayed characteristic hybrid weakness traits. We mapped and cloned a new locus, Hwc3 (hybrid weakness 3), on chromosome 4. Sequence analysis identified that a long terminal repeat (LTR) retrotransposon was inserted into the promoter region of the Hwc3 gene in 'CH7'. A 4-kb DNA fragment from 'CH7' containing the Hwc3 gene with the inserted LTR retrotransposon was able to induce hybrid weakness in hybrids with 'CH8' plants carrying the Hwc1 gene by genetic complementation. We investigated the differential gene expression profile of F1 plants exhibiting hybrid weakness and detected that the genes associated with energy metabolism were significantly down-regulated compared with the parents. Based on our results, we propose that LTR retrotransposons could be a potential cause of hybrid weakness in intrasubspecific hybrids in japonica rice. Understanding the molecular mechanisms underlying intrasubspecific hybrid weakness is important for increasing our knowledge on reproductive isolation and could have significant implications for rice improvement and hybrid breeding.
Collapse
Affiliation(s)
- Sadia Nadir
- Rice Research Institute, Yunnan Agriculture University, Kunming, Yunnan, China
- Department of Chemistry, University of Science and Technology, Bannu, KPK, Pakistan
- Centre for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Wei Li
- Rice Research Institute, Yunnan Agriculture University, Kunming, Yunnan, China
| | - Qian Zhu
- Rice Research Institute, Yunnan Agriculture University, Kunming, Yunnan, China
| | - Sehroon Khan
- Centre for Mountain Ecosystem Studies, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- World Agroforestry Centre, East and Central Asia, Kunming, Yunnan, China
| | - Xiao-Ling Zhang
- Agricultural College of Kunming University, Kunming, Yunnan, China
| | - Hui Zhang
- College of Agronomy and Biotechnology, Yunnan Agriculture University, Kunming, Yunnan, China
| | - Zhen-Fei Wei
- Maize Research Institute, Shanxi Academy of Agriculture Sciences, Xinzhou, Shanxi, China
| | - Meng-Ting Li
- Rice Research Institute, Yunnan Agriculture University, Kunming, Yunnan, China
| | - Li Zhou
- Rice Research Institute, Yunnan Agriculture University, Kunming, Yunnan, China
| | - Cheng-Yun Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Li-Juan Chen
- Rice Research Institute, Yunnan Agriculture University, Kunming, Yunnan, China
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
| | - Dong-Sun Lee
- Rice Research Institute, Yunnan Agriculture University, Kunming, Yunnan, China
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, Yunnan, China
| |
Collapse
|
65
|
Vaid N, Laitinen RAE. Diverse paths to hybrid incompatibility in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:199-213. [PMID: 30098060 DOI: 10.1111/tpj.14061] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/02/2018] [Accepted: 08/08/2018] [Indexed: 05/28/2023]
Abstract
One of the most essential questions of biology is to understand how different species have evolved. Hybrid incompatibility, a phenomenon in which hybrids show reduced fitness in comparison with their parents, can result in reproductive isolation and speciation. Therefore, studying hybrid incompatibility provides an entry point in understanding speciation. Hybrid incompatibilities are known throughout taxa, and the underlying mechanisms have mystified scientists since the theory of evolution by means of natural selection was introduced. In plants, it is only in recent years that the high-throughput genetic and molecular tools have become available for the Arabidopsis genus, thus helping to shed light on the different genes and molecular and evolutionary mechanisms that underlie hybrid incompatibilities. In this review, we highlight the current knowledge of diverse mechanisms that are known to contribute to hybrid incompatibility.
Collapse
Affiliation(s)
- Neha Vaid
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Roosa A E Laitinen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Germany
| |
Collapse
|
66
|
Kooke R, Morgado L, Becker F, van Eekelen H, Hazarika R, Zheng Q, de Vos RCH, Johannes F, Keurentjes JJB. Epigenetic mapping of the Arabidopsis metabolome reveals mediators of the epigenotype-phenotype map. Genome Res 2018; 29:96-106. [PMID: 30504416 PMCID: PMC6314165 DOI: 10.1101/gr.232371.117] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 11/27/2018] [Indexed: 11/24/2022]
Abstract
Identifying the sources of natural variation underlying metabolic differences between plants will enable a better understanding of plant metabolism and provide insights into the regulatory networks that govern plant growth and morphology. So far, however, the contribution of epigenetic variation to metabolic diversity has been largely ignored. In the present study, we utilized a panel of Arabidopsis thaliana epigenetic recombinant inbred lines (epiRILs) to assess the impact of epigenetic variation on the metabolic composition. Thirty epigenetic QTL (QTLepi) were detected, which partly overlap with QTLepi linked to growth and morphology. In an effort to identify causal candidate genes in the QTLepi regions and their putative trans-targets, we performed in silico small RNA and qPCR analyses. Differentially expressed genes were further studied by phenotypic and metabolic analyses of knockout mutants. Three genes were detected that recapitulated the detected QTLepi effects, providing evidence for epigenetic regulation in cis and in trans. These results indicate that epigenetic mechanisms impact metabolic diversity, possibly via small RNAs, and thus aid in further disentangling the complex epigenotype-phenotype map.
Collapse
Affiliation(s)
- Rik Kooke
- Laboratory of Genetics, Wageningen University and Research, 6708 PB Wageningen, The Netherlands.,Laboratory of Biometris, Wageningen University and Research, 6708 PB Wageningen, The Netherlands.,Centre for Biosystems Genomics, 6708 PB Wageningen, The Netherlands
| | - Lionel Morgado
- Groningen Bioinformatics Centre, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Frank Becker
- Laboratory of Genetics, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Henriëtte van Eekelen
- Business Unit Bioscience, Wageningen Plant Research, 6708 PB Wageningen, The Netherlands
| | - Rashmi Hazarika
- Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany
| | - Qunfeng Zheng
- Business Unit Bioscience, Wageningen Plant Research, 6708 PB Wageningen, The Netherlands.,Tea Research Institute, Chinese Academy of Agricultural Sciences, 310008 Hangzhou, P.R. China
| | - Ric C H de Vos
- Centre for Biosystems Genomics, 6708 PB Wageningen, The Netherlands.,Business Unit Bioscience, Wageningen Plant Research, 6708 PB Wageningen, The Netherlands.,Netherlands Metabolomics Centre, 2333 CC Leiden, The Netherlands
| | - Frank Johannes
- Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany.,Population Epigenetics and Epigenomics, Department of Plant Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Joost J B Keurentjes
- Laboratory of Genetics, Wageningen University and Research, 6708 PB Wageningen, The Netherlands.,Centre for Biosystems Genomics, 6708 PB Wageningen, The Netherlands
| |
Collapse
|
67
|
Yadav NS, Khadka J, Domb K, Zemach A, Grafi G. CMT3 and SUVH4/KYP silence the exonic Evelknievel retroelement to allow for reconstitution of CMT1 mRNA. Epigenetics Chromatin 2018; 11:69. [PMID: 30446008 PMCID: PMC6238269 DOI: 10.1186/s13072-018-0240-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 11/09/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The Chromomethylase 1 (CMT1) has long been considered a nonessential gene because, in certain Arabidopsis ecotypes, the CMT1 gene is disrupted by the Evelknievel (EK) retroelement, inserted within exon 13, or contains frameshift mutations, resulting in a truncated, non-functional protein. In contrast to other transposable elements, no transcriptional activation of EK was observed under stress conditions (e.g., protoplasting). RESULTS We wanted to explore the regulatory pathway responsible for EK silencing in the Ler ecotype and its effect on CMT1 transcription. Methylome databases confirmed that EK retroelement is heavily methylated and methylation is extended toward CMT1 downstream region. Strong transcriptional activation of EK accompanied by significant reduction in non-CG methylation was found in cmt3 and kyp2, but not in ddm1 or RdDM mutants. EK activation in cmt3 and kyp2 did not interfere with upstream CMT1 expression but abolish transcription through the EK. We identified, in wild-type Ler, three spliced variants in which the entire EK is spliced out; one variant (25% of splicing incidents) facilitates proper reconstitution of an intact CMT1 mRNA. We could recover very low amount of the full-length CMT1 mRNA from WT Ler and Col, but not from cmt3 mutant. CONCLUSIONS Our findings highlight CMT3-SUVH4/KYP as the major pathway silencing the intragenic EK via inducing non-CG methylation. Furthermore, retroelement insertion within exons (e.g., CMT1) may not lead to a complete abolishment of the gene product when the element is kept silent. Rather the element can be spliced out to bring about reconstruction of an intact, functional mRNA and possibly retrieval of an active protein.
Collapse
Affiliation(s)
- Narendra Singh Yadav
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben Gurion, Israel
| | - Janardan Khadka
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben Gurion, Israel
| | - Katherine Domb
- The School of Plant Sciences and Food Security, Tel-Aviv University, 69978, Tel Aviv, Israel
| | - Assaf Zemach
- The School of Plant Sciences and Food Security, Tel-Aviv University, 69978, Tel Aviv, Israel
| | - Gideon Grafi
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Midreshet Ben Gurion, Israel.
| |
Collapse
|
68
|
Zhao T, Tao X, Feng S, Wang L, Hong H, Ma W, Shang G, Guo S, He Y, Zhou B, Guan X. LncRNAs in polyploid cotton interspecific hybrids are derived from transposon neofunctionalization. Genome Biol 2018; 19:195. [PMID: 30419941 PMCID: PMC6233382 DOI: 10.1186/s13059-018-1574-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/23/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Interspecific hybridization and whole genome duplication are driving forces of genomic and organism diversification. But the effect of interspecific hybridization and whole genome duplication on the non-coding portion of the genome in particular remains largely unknown. In this study, we examine the profile of long non-coding RNAs (lncRNAs), comparing them with that of coding genes in allotetraploid cotton (Gossypium hirsutum), its putative diploid ancestors (G. arboreum; G. raimondii), and an F1 hybrid (G. arboreum × G. raimondii, AD). RESULTS We find that most lncRNAs (80%) that were allelic expressed in the allotetraploid genome. Moreover, the genome shock of hybridization reprograms the non-coding transcriptome in the F1 hybrid. Interestingly, the activated lncRNAs are predominantly transcribed from demethylated TE regions, especially from long interspersed nuclear elements (LINEs). The DNA methylation dynamics in the interspecies hybridization are predominantly associated with the drastic expression variation of lncRNAs. Similar trends of lncRNA bursting are also observed in the progress of polyploidization. Additionally, we find that a representative novel lncRNA XLOC_409583 activated after polyploidization from a LINE in the A subgenome of allotetraploid cotton was involved in control of cotton seedling height. CONCLUSION Our results reveal that the processes of hybridization and polyploidization enable the neofunctionalization of lncRNA transcripts, acting as important sources of increased plasticity for plants.
Collapse
Affiliation(s)
- Ting Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
- College of Agriculture and Biotechnology, Zhejiang University, Zhejiang, 210058, Hangzhou, China
| | - Xiaoyuan Tao
- College of Agriculture and Biotechnology, Zhejiang University, Zhejiang, 210058, Hangzhou, China
| | - Shouli Feng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Luyao Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Hui Hong
- National Key Laboratory of Plant Molecular Genetics, National Plant Gene Research Center, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Wei Ma
- College of Agriculture and Biotechnology, Zhejiang University, Zhejiang, 210058, Hangzhou, China
| | - Guandong Shang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Shisong Guo
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Yuxin He
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Baoliang Zhou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
| | - Xueying Guan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
- College of Agriculture and Biotechnology, Zhejiang University, Zhejiang, 210058, Hangzhou, China.
| |
Collapse
|
69
|
Shapturenko MN, Vakula SV, Tarutina LA, Nikitinskaya TV, Pechkovskaya TV, Mishin LA, Khotyleva LV. Allelic and epigenetic DNA variation in relation to F1 heterosis manifestation in F1 hybrids of Capsicum annuum L. Vavilovskii Zhurnal Genet Selektsii 2018. [DOI: 10.18699/vj18.425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Managing F1heterosis is one of the major objectives in hybrid crop breeding programs. The classical theory considers the heterozygosity in F1hybrids to be the main factor contributing to heterosis and therefore presumes a linear relationship between the value of genetic polymorphisms in parental lines and the heterotic response of their F1offspring. Therefore, the genetic diversity information is viewed as a tool for selection of promising cross-combinations, but results published by different researchers are inconsistent. In this work, we studied the contributions of structural and nonstructural DNA polymorphisms to F1heterosis manifestation. We used SSR and methyl-sensitive AFLP (MSAP with HpaII and MspI izoshisomers) protocols for obtaining specific patterns for heterotic and nonheterotic F1hybrids of sweet pepper (Capsicum annuum L.) from a Belarusian breeding program. We found out that a certain portion of heterosis for yield-related traits might be explained by the polymorphism revealed by SSR analysis. According to our data, the total number of polymorphic SSR loci and the ratio of polymorphic and nonpolymorphic loci demonstrate a significant predictive value and can serve as additional prognostic criteria for the selection of promising cross-combinations. From the MSAP assay, we found a relationship between heterosis and the numbers of methylated and nonmethylated DNA loci for yield traits. Our results indicate that cross-hybridization may favor epiallelic modifications in F1hybrids, presumably responsible for heterosis. Thus, epigenetic DNA variation may explain the absence of a linear relationship between the level of structural DNA divergence and F1heterosis, as well as the manifestation of heterosis in crosses of related (genetically similar) accessions.
Collapse
Affiliation(s)
- M. N. Shapturenko
- Institute of Genetics and Cytology of the National Academy of Sciences of Belarus
| | - S. V. Vakula
- Institute of Genetics and Cytology of the National Academy of Sciences of Belarus
| | - L. A. Tarutina
- Institute of Genetics and Cytology of the National Academy of Sciences of Belarus
| | - T. V. Nikitinskaya
- Institute of Genetics and Cytology of the National Academy of Sciences of Belarus
| | - T. V. Pechkovskaya
- Institute of Genetics and Cytology of the National Academy of Sciences of Belarus
| | | | - L. V. Khotyleva
- Institute of Genetics and Cytology of the National Academy of Sciences of Belarus
| |
Collapse
|
70
|
Quantification of DNA Methylation as Biomarker for Grain Quality. Methods Mol Biol 2018. [PMID: 30397813 DOI: 10.1007/978-1-4939-8914-0_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
DNA methylation is an important biomarker for gene activity. It contributes to gene silencing and is involved in regulating various seed developmental processes in plants. Many of these processes are involved in important traits associated with aspects of grain quality. A reliable, fast, and cheap method is the estimation of DNA methylation utilizing methylation sensitive restriction enzymes (MSRE) and quantitative real-time PCR (qPCR) for selected candidate regions. The presented method can be used to confirm an effect of RNAi constructs on their target genes or trans-activity. Analysis of promoter regions can contribute to estimation of gene activity and related traits.
Collapse
|
71
|
Duan CG, Zhu JK, Cao X. Retrospective and perspective of plant epigenetics in China. J Genet Genomics 2018; 45:621-638. [PMID: 30455036 DOI: 10.1016/j.jgg.2018.09.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/25/2018] [Accepted: 09/30/2018] [Indexed: 01/21/2023]
Abstract
Epigenetics refers to the study of heritable changes in gene function that do not involve changes in the DNA sequence. Such effects on cellular and physiological phenotypic traits may result from external or environmental factors or be part of normal developmental program. In eukaryotes, DNA wraps on a histone octamer (two copies of H2A, H2B, H3 and H4) to form nucleosome, the fundamental unit of chromatin. The structure of chromatin is subjected to a dynamic regulation through multiple epigenetic mechanisms, including DNA methylation, histone posttranslational modifications (PTMs), chromatin remodeling and noncoding RNAs. As conserved regulatory mechanisms in gene expression, epigenetic mechanisms participate in almost all the important biological processes ranging from basal development to environmental response. Importantly, all of the major epigenetic mechanisms in mammalians also occur in plants. Plant studies have provided numerous important contributions to the epigenetic research. For example, gene imprinting, a mechanism of parental allele-specific gene expression, was firstly observed in maize; evidence of paramutation, an epigenetic phenomenon that one allele acts in a single locus to induce a heritable change in the other allele, was firstly reported in maize and tomato. Moreover, some unique epigenetic mechanisms have been evolved in plants. For example, the 24-nt siRNA-involved RNA-directed DNA methylation (RdDM) pathway is plant-specific because of the involvements of two plant-specific DNA-dependent RNA polymerases, Pol IV and Pol V. A thorough study of epigenetic mechanisms is of great significance to improve crop agronomic traits and environmental adaptability. In this review, we make a brief summary of important progress achieved in plant epigenetics field in China over the past several decades and give a brief outlook on future research prospects. We focus our review on DNA methylation and histone PTMs, the two most important aspects of epigenetic mechanisms.
Collapse
Affiliation(s)
- Cheng-Guo Duan
- Shanghai Center for Plant Stress Biology and Center of Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology and Center of Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China; Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA.
| | - Xiaofeng Cao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
| |
Collapse
|
72
|
Schmid MW, Heichinger C, Coman Schmid D, Guthörl D, Gagliardini V, Bruggmann R, Aluri S, Aquino C, Schmid B, Turnbull LA, Grossniklaus U. Contribution of epigenetic variation to adaptation in Arabidopsis. Nat Commun 2018; 9:4446. [PMID: 30361538 PMCID: PMC6202389 DOI: 10.1038/s41467-018-06932-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 10/05/2018] [Indexed: 12/20/2022] Open
Abstract
In plants, transgenerational inheritance of some epialleles has been demonstrated but it remains controversial whether epigenetic variation is subject to selection and contributes to adaptation. Simulating selection in a rapidly changing environment, we compare phenotypic traits and epigenetic variation between Arabidopsis thaliana populations grown for five generations under selection and their genetically nearly identical ancestors. Selected populations of two distinct genotypes show significant differences in flowering time and plant architecture, which are maintained for at least 2–3 generations in the absence of selection. While we cannot detect consistent genetic changes, we observe a reduction of epigenetic diversity and changes in the methylation state of about 50,000 cytosines, some of which are associated with phenotypic changes. Thus, we propose that epigenetic variation is subject to selection and can contribute to rapid adaptive responses, although the extent to which epigenetics plays a role in adaptation is still unclear. Whether plant epigenetic variation is subject to selection and contributes to adaptation is under debate. Here, the authors compare DNA methylation and phenotypes of Arabidopsis lines subject to simulated selection and their nearly isogenic ancestors and provide evidence that epigenetic variation contributes to adaptive responses.
Collapse
Affiliation(s)
- Marc W Schmid
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.,Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland.,Service and Support for Science IT, University of Zurich, Stampfenbachstrasse 73, 8006, Zurich, Switzerland.,MWSchmid GmbH, Möhrlistrasse 25, 8006, Zurich, Switzerland
| | - Christian Heichinger
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.,Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland.,L. Hoffmann-La Roche AG, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Diana Coman Schmid
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.,Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland.,Scientific IT Services, ETH Zurich, Weinbergstrasse 11, 8092, Zurich, Switzerland
| | - Daniela Guthörl
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.,Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland
| | - Valeria Gagliardini
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.,Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland
| | - Rémy Bruggmann
- Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, Hochschulstrasse 6, 3012, Bern, Switzerland
| | - Sirisha Aluri
- Functional Genomics Center Zurich, ETH and University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Catharine Aquino
- Functional Genomics Center Zurich, ETH and University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Bernhard Schmid
- Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Lindsay A Turnbull
- Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland. .,Zurich-Basel Plant Science Center, University of Zurich, ETH Zurich and University of Basel, Tannenstrasse 1, 8092, Zurich, Switzerland.
| |
Collapse
|
73
|
van Hulten MHA, Paulo MJ, Kruijer W, Blankestijn-De Vries H, Kemperman B, Becker FFM, Yang J, Lauss K, Stam ME, van Eeuwijk FA, Keurentjes JJB. Assessment of heterosis in two Arabidopsis thaliana common-reference mapping populations. PLoS One 2018; 13:e0205564. [PMID: 30312352 PMCID: PMC6185836 DOI: 10.1371/journal.pone.0205564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 09/27/2018] [Indexed: 12/01/2022] Open
Abstract
Hybrid vigour, or heterosis, has been of tremendous importance in agriculture for the improvement of both crops and livestock. Notwithstanding large efforts to study the phenomenon of heterosis in the last decades, the identification of common molecular mechanisms underlying hybrid vigour remain rare. Here, we conducted a systematic survey of the degree of heterosis in Arabidopsis thaliana hybrids. For this purpose, two overlapping Arabidopsis hybrid populations were generated by crossing a large collection of naturally occurring accessions to two common reference lines. In these Arabidopsis hybrid populations the range of heterosis for several developmental and yield related traits was examined, and the relationship between them was studied. The traits under study were projected leaf area at 17 days after sowing, flowering time, height of the main inflorescence, number of side branches from the main stem or from the rosette base, total seed yield, seed weight, seed size and the estimated number of seeds per plant. Predominantly positive heterosis was observed for leaf area and height of the main inflorescence, whereas mainly negative heterosis was observed for rosette branching. For the other traits both positive and negative heterosis was observed in roughly equal amounts. For flowering time and seed size only low levels of heterosis were detected. In general the observed heterosis levels were highly trait specific. Furthermore, no correlation was observed between heterosis levels and the genetic distance between the parental lines. Since all selected lines were a part of the Arabidopsis genome wide association (GWA) mapping panel, a genetic mapping approach was applied to identify possible regions harbouring genetic factors causal for heterosis, with separate calculations for additive and dominance effects. Our study showed that the genetic mechanisms underlying heterosis were highly trait specific in our hybrid populations and greatly depended on the genetic background, confirming the elusive character of heterosis.
Collapse
Affiliation(s)
| | - Maria-Joāo Paulo
- Biometris, Wageningen University and Research, Wageningen, The Netherlands
| | - Willem Kruijer
- Biometris, Wageningen University and Research, Wageningen, The Netherlands
| | | | - Brend Kemperman
- Laboratory of Genetics, Wageningen University and Research, Wageningen, the Netherlands
| | - Frank F. M. Becker
- Laboratory of Genetics, Wageningen University and Research, Wageningen, the Netherlands
| | - Jiaming Yang
- Laboratory of Genetics, Wageningen University and Research, Wageningen, the Netherlands
| | - Kathrin Lauss
- Plant Development & (Epi)Genetics, Faculty of Science, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Amsterdam, The Netherlands
| | - Maike E. Stam
- Plant Development & (Epi)Genetics, Faculty of Science, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Amsterdam, The Netherlands
| | | | | |
Collapse
|
74
|
Yu N, Cao L, Yuan L, Zhi X, Chen Y, Gan S, Chen L. Maintenance of grafting-induced epigenetic variations in the asexual progeny of Brassica oleracea and B. juncea chimera. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:22-38. [PMID: 30086201 DOI: 10.1111/tpj.14058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/23/2018] [Accepted: 07/31/2018] [Indexed: 05/19/2023]
Abstract
Grafting-induced variations have been observed in many plant species, but the heritability of variation in progeny is not well understood. In our study, adventitious shoots from the C cell lineage of shoot apical meristem (SAM) grafting chimera TCC (where the origin of the outmost, middle and innermost cell layers, respectively, of SAM is designated by 'T' for tuber mustard and 'C' for red cabbage) were induced and identified as r-CCC (r = regenerated). To investigate the maintenance of grafting variations during cell propagation and regeneration, different generations of asexual progeny (r-CCCn, n = generation) were established through successive regeneration of axillary shoots from r-CCC. The fourth generation of r-CCC (r-CCC4) was selected to perform whole genome bisulfite sequencing for comparative analysis of hetero-grafting-induced global methylation changes relative to r-s-CCC4 (s = self-grafting). Increased CHH methylation levels and proportions were observed in r-CCC4, with substantial changes occurring in the repeat elements. Small RNA sequencing revealed 1135 specific small interfering RNA (siRNA) tags that were typically expressed in r-CCC, r-CCC2 and r-CCC4. Notably, 65% of these specific siRNAs were associated with repeat elements, termed RE siRNAs. Subsequent analysis revealed that the CHH methylation of RE siRNA-overlapping regions was mainly hypermethylation in r-CCC4, indicating that they were responsible for directing and maintaining grafting-induced CHH methylation. Moreover, the expression of 13 differentially methylated genes (DMGs) correlated with the phenotypic variation, showing differential expression levels between r-CCC4 and r-s-CCC4. These DMGs were predominantly CG hypermethylated, their methylation modifications corresponded to the transcription of relative methyltransferase.
Collapse
Affiliation(s)
- Ningning Yu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Liwen Cao
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Lu Yuan
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Xiao Zhi
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Yiqian Chen
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Susheng Gan
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Liping Chen
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| |
Collapse
|
75
|
Junaid A, Kumar H, Rao AR, Patil AN, Singh NK, Gaikwad K. Unravelling the epigenomic interactions between parental inbreds resulting in an altered hybrid methylome in pigeonpea. DNA Res 2018; 25:361-373. [PMID: 29566130 PMCID: PMC6105106 DOI: 10.1093/dnares/dsy008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 02/21/2018] [Indexed: 12/15/2022] Open
Abstract
DNA methylation is an important heritable landmark conferring epigenetic changes in hybrids and has fascinated biologists and plant-breeders over the years. Although epigenetic changes have been documented in rice and maize hybrids, such investigations have not been reported in pigeonpea. Here, we report genome-wide methylation profiles of pigeonpea sterile and fertile inbred lines and their fertile F1 hybrid at single base resolution. We found that pigeonpea genome is relatively enriched in CG methylation. Identification of differentially methylated regions (DMRs) in the sterile and fertile parent revealed remarkable differences between their methylation patterns. Investigation of methylation status of parental DMRs in hybrid revealed non-additive methylation patterns resulting from trans-chromosomal methylation and trans-chromosomal demethylation events. Furthermore, we discovered several DMRs negatively associated with gene expression in the hybrid and fertile parent. Interestingly, many of those DMRs belonged to transposable elements and genes encoding pentatricopeptide repeats associated proteins, which may mediate a role in modulating the genes impacting pollen fertility. Overall, our findings provide an understanding of two parental epigenomes interacting to give rise to an altered methylome in pigeonpea hybrids, from genome-wide point of view.
Collapse
Affiliation(s)
- Alim Junaid
- National Research Centre on Plant Biotechnology, LBS Centre, PUSA Campus, New Delhi, India
| | - Himanshu Kumar
- Indian Agricultural Statistics Research Institute, New Delhi, India
| | - A R Rao
- Indian Agricultural Statistics Research Institute, New Delhi, India
| | - A N Patil
- Pulse Reaserch Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, P.O. Krishi Nagar, Akola, Maharashtra, India
| | - N K Singh
- National Research Centre on Plant Biotechnology, LBS Centre, PUSA Campus, New Delhi, India
| | - Kishor Gaikwad
- National Research Centre on Plant Biotechnology, LBS Centre, PUSA Campus, New Delhi, India
| |
Collapse
|
76
|
Raza MA, Yu N, Wang D, Cao L, Gan S, Chen L. Differential DNA methylation and gene expression in reciprocal hybrids between Solanum lycopersicum and S. pimpinellifolium. DNA Res 2018; 24:597-607. [PMID: 28679169 PMCID: PMC5726463 DOI: 10.1093/dnares/dsx028] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/27/2017] [Indexed: 12/22/2022] Open
Abstract
Wide hybridization is a common and efficient breeding strategy for enhancing crop yield and quality. An interesting phenomenon is that the reciprocal hybrids usually show different phenotypes, and its underlying mechanism is not well understood. Here, we reported our comparative analysis of the DNA methylation patterns in Solanum lycopersicum, Solanum pimpinellifolium and their reciprocal hybrids by methylated DNA immunoprecipitation sequencing. The reciprocal hybrids had lower levels of DNA methylation in CpG islands and LTR retroelements when compared with those of their parents. Importantly, remarkable differences in DNA methylation patterns, mainly in introns and CDS regions, were revealed between the reciprocal hybrids. These different methylated regions were mapped to 79 genes, 14 of which were selected for analysis of gene expression levels. While there was an inverse correlation between DNA methylation and gene expression in promoter regions, the relationship was complicated in gene body regions. Further association analysis revealed that there were 15 differentially methylated genes associated with siRNAs, and that the methylation levels of these genes were inversely correlated with respective siRNAs. All these data raised the possibility that the direction of hybridization induced the divergent epigenomes leading to changes in the transcription levels of reciprocal hybrids.
Collapse
Affiliation(s)
- Muhammad Ammar Raza
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, P. R. China
| | - Ningning Yu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, P. R. China
| | - Dan Wang
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, P. R. China
| | - Liwen Cao
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, P. R. China
| | - Susheng Gan
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, P. R. China.,Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Liping Chen
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, P. R. China
| |
Collapse
|
77
|
Dwivedi SL, Siddique KHM, Farooq M, Thornton PK, Ortiz R. Using Biotechnology-Led Approaches to Uplift Cereal and Food Legume Yields in Dryland Environments. FRONTIERS IN PLANT SCIENCE 2018; 9:1249. [PMID: 30210519 PMCID: PMC6120061 DOI: 10.3389/fpls.2018.01249] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/06/2018] [Indexed: 05/29/2023]
Abstract
Drought and heat in dryland agriculture challenge the enhancement of crop productivity and threaten global food security. This review is centered on harnessing genetic variation through biotechnology-led approaches to select for increased productivity and stress tolerance that will enhance crop adaptation in dryland environments. Peer-reviewed literature, mostly from the last decade and involving experiments with at least two seasons' data, form the basis of this review. It begins by highlighting the adverse impact of the increasing intensity and duration of drought and heat stress due to global warming on crop productivity and its impact on food and nutritional security in dryland environments. This is followed by (1) an overview of the physiological and molecular basis of plant adaptation to elevated CO2 (eCO2), drought, and heat stress; (2) the critical role of high-throughput phenotyping platforms to study phenomes and genomes to increase breeding efficiency; (3) opportunities to enhance stress tolerance and productivity in food crops (cereals and grain legumes) by deploying biotechnology-led approaches [pyramiding quantitative trait loci (QTL), genomic selection, marker-assisted recurrent selection, epigenetic variation, genome editing, and transgene) and inducing flowering independent of environmental clues to match the length of growing season; (4) opportunities to increase productivity in C3 crops by harnessing novel variations (genes and network) in crops' (C3, C4) germplasm pools associated with increased photosynthesis; and (5) the adoption, impact, risk assessment, and enabling policy environments to scale up the adoption of seed-technology to enhance food and nutritional security. This synthesis of technological innovations and insights in seed-based technology offers crop genetic enhancers further opportunities to increase crop productivity in dryland environments.
Collapse
Affiliation(s)
| | | | - Muhammad Farooq
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
- Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al Khoud, Oman
- University of Agriculture, Faisalabad, Pakistan
| | - Philip K. Thornton
- CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - Rodomiro Ortiz
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden
| |
Collapse
|
78
|
Li H, Yuan J, Wu M, Han Z, Li L, Jiang H, Jia Y, Han X, Liu M, Sun D, Chen C, Song W, Wang C. Transcriptome and DNA methylome reveal insights into yield heterosis in the curds of broccoli (Brassica oleracea L var. italic). BMC PLANT BIOLOGY 2018; 18:168. [PMID: 30103674 PMCID: PMC6090608 DOI: 10.1186/s12870-018-1384-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 08/01/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Curds are the main edible organs, which exhibit remarkable yield heterosis in F1 hybrid broccoli. However, the molecular basis underlying heterosis in broccoli remains elusive. RESULTS In the present study, transcriptome profiles revealed that the hybridization made most genes show additive expression patterns in hybrid broccoli. The differentially expressed genes including the non-additively expressed genes detected in the hybrid broccoli and its parents were mainly involved in light, hormone and hydrogen peroxide-mediated signaling pathways, responses to stresses, and regulation of floral development, which suggested that these biological processes should play crucial roles in the yield heterosis of broccoli. Among them, light and hydrogen peroxide-mediated signaling pathways represent two novel classes of regulatory processes that could function in yield or biomass heterosis of plants. Totally, 53 candidate genes closely involved in curd yield heterosis were identified. Methylome data indicated that the DNA methylation ratio of the hybrids was higher than that of their parents. However, the DNA methylation levels of most sites also displayed additive expression patterns. These sites with differential methylation levels were predominant in the intergenic regions. In most cases, the changes of DNA methylation levels in gene regions did not significantly affect their expression levels. CONCLUSIONS The differentially expressed genes, the regulatory processes and the possible roles of DNA methylation modification in the formation of curd yield heterotic trait were discovered. These findings provided comprehensive insights into the curd yield heterosis in broccoli, and were significant for breeding high-yield broccoli varieties.
Collapse
Affiliation(s)
- Hui Li
- College of Horticulture and Landscape, Tianjin Agricultural University, Tianjin, China
| | - Jiye Yuan
- College of Life Sciences, Nankai University, Tianjin, China
| | - Mei Wu
- College of Life Sciences, Nankai University, Tianjin, China
| | - Zhanpin Han
- College of Horticulture and Landscape, Tianjin Agricultural University, Tianjin, China
| | - Lihong Li
- College of Life Sciences, Nankai University, Tianjin, China
| | - Hanmin Jiang
- Tianjin Kernel Vegetable Research Institute, Tianjin, China
| | - Yinglan Jia
- College of Life Sciences, Nankai University, Tianjin, China
| | - Xue Han
- College of Life Sciences, Nankai University, Tianjin, China
| | - Min Liu
- College of Life Sciences, Shandong Normal University, Jinan, Shandong China
| | - Deling Sun
- Tianjin Kernel Vegetable Research Institute, Tianjin, China
| | - Chengbin Chen
- College of Life Sciences, Nankai University, Tianjin, China
| | - Wenqin Song
- College of Life Sciences, Nankai University, Tianjin, China
| | - Chunguo Wang
- College of Life Sciences, Nankai University, Tianjin, China
| |
Collapse
|
79
|
Wang C, Wang C, Xu W, Zou J, Qiu Y, Kong J, Yang Y, Zhang B, Zhu S. Epigenetic Changes in the Regulation of Nicotiana tabacum Response to Cucumber Mosaic Virus Infection and Symptom Recovery through Single-Base Resolution Methylomes. Viruses 2018; 10:E402. [PMID: 30060626 PMCID: PMC6115852 DOI: 10.3390/v10080402] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/20/2018] [Accepted: 07/27/2018] [Indexed: 12/13/2022] Open
Abstract
Plants have evolved multiple mechanisms to respond to viral infection. These responses have been studied in detail at the level of host immune response and antiviral RNA silencing (RNAi). However, the possibility of epigenetic reprogramming has not been thoroughly investigated. Here, we identified the role of DNA methylation during viral infection and performed reduced representation bisulfite sequencing (RRBS) on tissues of Cucumber mosaic virus (CMV)-infected Nicotiana tabacum at various developmental stages. Differential methylated regions are enriched with CHH sequence contexts, 80% of which are located on the gene body to regulate gene expression in a temporal style. The methylated genes depressed by methyltransferase inhibition largely overlapped with methylated genes in response to viral invasion. Activation in the argonaute protein and depression in methyl donor synthase revealed the important role of dynamic methylation changes in modulating viral clearance and resistance signaling. Methylation-expression relationships were found to be required for the immune response and cellular components are necessary for the proper defense response to infection and symptom recovery.
Collapse
Affiliation(s)
- Chenguang Wang
- College of Plant Protection, China Agricultural University, Beijing 100083, China.
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100083, China.
| | - Chaonan Wang
- College of Plant Protection, China Agricultural University, Beijing 100083, China.
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100083, China.
| | - Wenjie Xu
- College of Plant Protection, China Agricultural University, Beijing 100083, China.
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100083, China.
| | - Jingze Zou
- College of Plant Protection, China Agricultural University, Beijing 100083, China.
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100083, China.
- College of Biological Sciences, China Agricultural University, Beijing 100083, China.
| | - Yanhong Qiu
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100083, China.
| | - Jun Kong
- College of Plant Protection, China Agricultural University, Beijing 100083, China.
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100083, China.
| | - Yunshu Yang
- Beijing Academy of Food Sciences, Beijing 100162, China.
| | - Boyang Zhang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Shuifang Zhu
- College of Plant Protection, China Agricultural University, Beijing 100083, China.
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100083, China.
| |
Collapse
|
80
|
Seifert F, Thiemann A, Schrag TA, Rybka D, Melchinger AE, Frisch M, Scholten S. Small RNA-based prediction of hybrid performance in maize. BMC Genomics 2018; 19:371. [PMID: 29783940 PMCID: PMC5963143 DOI: 10.1186/s12864-018-4708-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 04/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Small RNA (sRNA) sequences are known to have a broad impact on gene regulation by various mechanisms. Their performance for the prediction of hybrid traits has not yet been analyzed. Our objective was to analyze the relation of parental sRNA expression with the performance of their hybrids, to develop a sRNA-based prediction approach, and to compare it to more common SNP and mRNA transcript based predictions using a factorial mating scheme of a maize hybrid breeding program. RESULTS Correlation of genomic differences and messenger RNA (mRNA) or sRNA expression differences between parental lines with hybrid performance of their hybrids revealed that sRNAs showed an inverse relationship in contrast to the other two data types. We associated differences for SNPs, mRNA and sRNA expression between parental inbred lines with the performance of their hybrid combinations and developed two prediction approaches using distance measures based on associated markers. Cross-validations revealed parental differences in sRNA expression to be strong predictors for hybrid performance for grain yield in maize, comparable to genomic and mRNA data. The integration of both positively and negatively associated markers in the prediction approaches enhanced the prediction accurary. The associated sRNAs belong predominantly to the canonical size classes of 22- and 24-nt that show specific genomic mapping characteristics. CONCLUSION Expression profiles of sRNA are a promising alternative to SNPs or mRNA expression profiles for hybrid prediction, especially for plant species without reference genome or transcriptome information. The characteristics of the sRNAs we identified suggest that association studies based on breeding populations facilitate the identification of sRNAs involved in hybrid performance.
Collapse
Affiliation(s)
- Felix Seifert
- Developmental Biology, Biocenter Klein Flottbek, University of Hamburg, 22609 Hamburg, Germany
| | - Alexander Thiemann
- Developmental Biology, Biocenter Klein Flottbek, University of Hamburg, 22609 Hamburg, Germany
| | - Tobias A. Schrag
- Institute for Plant Breeding, Seed Science and Population Genetics, Quantitative Genetics and Genomics of Crops, University of Hohenheim, Fruwirthstrasse 21, 70599 Stuttgart, Germany
| | - Dominika Rybka
- Developmental Biology, Biocenter Klein Flottbek, University of Hamburg, 22609 Hamburg, Germany
| | - Albrecht E. Melchinger
- Institute for Plant Breeding, Seed Science and Population Genetics, Quantitative Genetics and Genomics of Crops, University of Hohenheim, Fruwirthstrasse 21, 70599 Stuttgart, Germany
| | - Matthias Frisch
- Institute of Agronomy and Plant Breeding II, Justus Liebig University, 35392 Giessen, Germany
| | - Stefan Scholten
- Developmental Biology, Biocenter Klein Flottbek, University of Hamburg, 22609 Hamburg, Germany
- Institute for Plant Breeding, Seed Science and Population Genetics, Quantitative Genetics and Genomics of Crops, University of Hohenheim, Fruwirthstrasse 21, 70599 Stuttgart, Germany
| |
Collapse
|
81
|
Fiévet JB, Nidelet T, Dillmann C, de Vienne D. Heterosis Is a Systemic Property Emerging From Non-linear Genotype-Phenotype Relationships: Evidence From in Vitro Genetics and Computer Simulations. Front Genet 2018; 9:159. [PMID: 29868111 PMCID: PMC5968397 DOI: 10.3389/fgene.2018.00159] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 04/17/2018] [Indexed: 11/13/2022] Open
Abstract
Heterosis, the superiority of hybrids over their parents for quantitative traits, represents a crucial issue in plant and animal breeding as well as evolutionary biology. Heterosis has given rise to countless genetic, genomic and molecular studies, but has rarely been investigated from the point of view of systems biology. We hypothesized that heterosis is an emergent property of living systems resulting from frequent concave relationships between genotypic variables and phenotypes, or between different phenotypic levels. We chose the enzyme-flux relationship as a model of the concave genotype-phenotype (GP) relationship, and showed that heterosis can be easily created in the laboratory. First, we reconstituted in vitro the upper part of glycolysis. We simulated genetic variability of enzyme activity by varying enzyme concentrations in test tubes. Mixing the content of "parental" tubes resulted in "hybrids," whose fluxes were compared to the parental fluxes. Frequent heterotic fluxes were observed, under conditions that were determined analytically and confirmed by computer simulation. Second, to test this model in a more realistic situation, we modeled the glycolysis/fermentation network in yeast by considering one input flux, glucose, and two output fluxes, glycerol and acetaldehyde. We simulated genetic variability by randomly drawing parental enzyme concentrations under various conditions, and computed the parental and hybrid fluxes using a system of differential equations. Again we found that a majority of hybrids exhibited positive heterosis for metabolic fluxes. Cases of negative heterosis were due to local convexity between certain enzyme concentrations and fluxes. In both approaches, heterosis was maximized when the parents were phenotypically close and when the distributions of parental enzyme concentrations were contrasted and constrained. These conclusions are not restricted to metabolic systems: they only depend on the concavity of the GP relationship, which is commonly observed at various levels of the phenotypic hierarchy, and could account for the pervasiveness of heterosis.
Collapse
Affiliation(s)
- Julie B Fiévet
- GQE-Le Moulon, INRA, Centre National de la Recherche Scientifique, AgroParisTech, Université Paris-Sud, Gif-sur-Yvette, France
| | - Thibault Nidelet
- Sciences Pour l'Œnologie, INRA, Université de Montpellier, Montpellier, France
| | - Christine Dillmann
- GQE-Le Moulon, INRA, Centre National de la Recherche Scientifique, AgroParisTech, Université Paris-Sud, Gif-sur-Yvette, France
| | - Dominique de Vienne
- GQE-Le Moulon, INRA, Centre National de la Recherche Scientifique, AgroParisTech, Université Paris-Sud, Gif-sur-Yvette, France
| |
Collapse
|
82
|
Diurnal down-regulation of ethylene biosynthesis mediates biomass heterosis. Proc Natl Acad Sci U S A 2018; 115:5606-5611. [PMID: 29735680 DOI: 10.1073/pnas.1722068115] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heterosis is widely applied in agriculture; however, the underlying molecular mechanisms for superior performance are not well understood. Ethylene biosynthesis and signaling genes are shown to be down-regulated in Arabidopsis interspecific hybrids. Ethylene is a plant hormone that promotes fruit ripening and maturation but inhibits hypocotyl elongation. Here we report that application of exogenous ethylene could eliminate biomass vigor in Arabidopsis thaliana F1 hybrids, suggesting a negative role of ethylene in heterosis. Ethylene biosynthesis is mediated by the rate-limiting enzyme, 1-aminocyclopropane-1-carboxylate synthase (ACS). Down-regulation of ACS genes led to the decrease of ethylene production, which was associated with the high-vigor F1 hybrids, but not with the low-vigor ones. At the mechanistic level, expression of ACS genes was down-regulated diurnally and indirectly by Circadian Clock Associated 1 (CCA1) during the day and directly by Phyotochrome-Interacting Factor 5 (PIF5) at night. Consistent with the negative role of ethylene in plant growth, biomass vigor was higher in the acs mutants than in wild-type plants, while increasing endogenous ethylene production in the hybridizing parents reduced growth vigor in the hybrids. Thus, integrating circadian rhythms and light signaling into ethylene production is another regulatory module of complex biological networks, leading to biomass heterosis in plants.
Collapse
|
83
|
Liu C, Wang M, Wang L, Guo Q, Liang G. Extensive genetic and DNA methylation variation contribute to heterosis in triploid loquat hybrids. Genome 2018; 61:437-447. [PMID: 29687741 DOI: 10.1139/gen-2017-0232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We aim to overcome the unclear origin of the loquat and elucidate the heterosis mechanism of the triploid loquat. Here we investigated the genetic and epigenetic variations between the triploid plant and its parental lines using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplified fragment length polymorphism (MSAP) analyses. We show that in addition to genetic variations, extensive DNA methylation variation occurred during the formation process of triploid loquat, with the triploid hybrid having increased DNA methylation compared to the parents. Furthermore, a correlation existed between genetic variation and DNA methylation remodeling, suggesting that genome instability may lead to DNA methylation variation or vice versa. Sequence analysis of the MSAP bands revealed that over 53% of them overlap with protein-coding genes, which may indicate a functional role of the differential DNA methylation in gene regulation and hence heterosis phenotypes. Consistent with this, the genetic and epigenetic alterations were associated closely to the heterosis phenotypes of triploid loquat, and this association varied for different traits. Our results suggested that the formation of triploid is accompanied by extensive genetic and DNA methylation variation, and these changes contribute to the heterosis phenotypes of the triploid loquats from the two cross lines.
Collapse
Affiliation(s)
- Chao Liu
- a Key Laboratory of Horticulture Science for Southern Mountainous Region, Ministry of Education/College of Horticulture and Landscape Architecture, Southwest University, Tiansheng Road 2, 400715, Chongqing, P.R. China
| | - Mingbo Wang
- b CSIRO Agriculture and Food, Clunies Ross Street, Canberra ACT 2061, Australia
| | - Lingli Wang
- c Technical Advice Station of Economic Crop, Yubei district, Chongqing, P.R. China
| | - Qigao Guo
- a Key Laboratory of Horticulture Science for Southern Mountainous Region, Ministry of Education/College of Horticulture and Landscape Architecture, Southwest University, Tiansheng Road 2, 400715, Chongqing, P.R. China
| | - Guolu Liang
- a Key Laboratory of Horticulture Science for Southern Mountainous Region, Ministry of Education/College of Horticulture and Landscape Architecture, Southwest University, Tiansheng Road 2, 400715, Chongqing, P.R. China
| |
Collapse
|
84
|
Tian M, Nie Q, Li Z, Zhang J, Liu Y, Long Y, Wang Z, Wang G, Liu R. Transcriptomic analysis reveals overdominance playing a critical role in nicotine heterosis in Nicotiana tabacum L. BMC PLANT BIOLOGY 2018; 18:48. [PMID: 29566653 PMCID: PMC5863848 DOI: 10.1186/s12870-018-1257-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 03/01/2018] [Indexed: 05/23/2023]
Abstract
BACKGROUND As a unique biological phenomenon, heterosis has been concerned with the superior performance of the heterosis than either parents. Despite several F1 hybrids, containing supernal nicotine content, had been discovered and applied to heterosis utilization in Nicotiana tabacum L., nevertheless, the potential molecular mechanism revealing nicotine heterosis has not been illustrated clearly. RESULT Phenotypically, the F1 hybrids (Vall6 × Basma) show prominent heterosis in nicotine content by 3 years of field experiments. Transcriptome analysis revealed that genes participating in nicotine anabolism (ADC, PMT, MPO, QPT, AO, QS, QPT, A622, BBLs) and nicotine transport (JAT2, MATE1 and 2, NUP1 and 2) showed an upregulated expression in the hybrid, a majority of which demonstrated an overdominant performance. RT-PCR confirmed that nicotine anabolism was induced in the hybrid. CONCLUSIONS These findings strongly suggest that nicotine synthesis and transport efficiency improved in hybrid and overdominance at gene-expression level played a critical role in heterosis of nicotine metabolism.
Collapse
Affiliation(s)
- Maozhu Tian
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China
- College of Tobacco, Guizhou University, Guiyang, 550025, China
| | - Qiong Nie
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China
- College of Tobacco, Guizhou University, Guiyang, 550025, China
| | - Zhenhua Li
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China
| | - Jie Zhang
- National Maize Improvement Center of China, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yiling Liu
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China
- College of Tobacco, Guizhou University, Guiyang, 550025, China
| | - Yao Long
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China
- College of Tobacco, Guizhou University, Guiyang, 550025, China
| | - Zhiwei Wang
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China
- College of Tobacco, Guizhou University, Guiyang, 550025, China
| | - Guoqing Wang
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China
- College of Tobacco, Guizhou University, Guiyang, 550025, China
| | - Renxiang Liu
- Key Laboratory of Tobacco Quality in Guizhou province, Guizhou University, Guiyang, 550025, China.
- College of Tobacco, Guizhou University, Guiyang, 550025, China.
| |
Collapse
|
85
|
Fujimoto R, Uezono K, Ishikura S, Osabe K, Peacock WJ, Dennis ES. Recent research on the mechanism of heterosis is important for crop and vegetable breeding systems. BREEDING SCIENCE 2018; 68:145-158. [PMID: 29875598 PMCID: PMC5982191 DOI: 10.1270/jsbbs.17155] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 01/29/2018] [Indexed: 05/18/2023]
Abstract
Heterosis or hybrid vigor is a phenomenon where hybrid progeny have superior performance compared to their parental inbred lines. This is important in the use of F1 hybrid cultivars in many crops and vegetables. However, the molecular mechanism of heterosis is not clearly understood. Gene interactions between the two genomes such as dominance, overdominance, and epistasis have been suggested to explain the increased biomass and yield. Genetic analyses of F1 hybrids in maize, rice, and canola have defined a large number of quantitative trait loci, which may contribute to heterosis. Recent molecular analyses of transcriptomes together with reference to the epigenome of the parents and hybrids have begun to uncover new facts about the generation of heterosis. These include the identification of gene expression changes in hybrids, which may be important for heterosis, the role of epigenetic processes in heterosis, and the development of stable high yielding lines.
Collapse
Affiliation(s)
- Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University,
Rokkodai, Nada-ku, Kobe, Hyogo 657-8501,
Japan
- Corresponding author (e-mail: )
| | - Kosuke Uezono
- Graduate School of Agricultural Science, Kobe University,
Rokkodai, Nada-ku, Kobe, Hyogo 657-8501,
Japan
| | - Sonoko Ishikura
- Graduate School of Agricultural Science, Kobe University,
Rokkodai, Nada-ku, Kobe, Hyogo 657-8501,
Japan
| | - Kenji Osabe
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University,
Onna-son, Okinawa 904-0495,
Japan
| | - W. James Peacock
- CSIRO Agriculture and Food,
Canberra, ACT 2601,
Australia
- University of Technology, Sydney,
PO Box 123, Broadway, NSW 2007,
Australia
| | - Elizabeth S. Dennis
- CSIRO Agriculture and Food,
Canberra, ACT 2601,
Australia
- University of Technology, Sydney,
PO Box 123, Broadway, NSW 2007,
Australia
| |
Collapse
|
86
|
Lauss K, Wardenaar R, Oka R, van Hulten MHA, Guryev V, Keurentjes JJB, Stam M, Johannes F. Parental DNA Methylation States Are Associated with Heterosis in Epigenetic Hybrids. PLANT PHYSIOLOGY 2018; 176:1627-1645. [PMID: 29196538 PMCID: PMC5813580 DOI: 10.1104/pp.17.01054] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/14/2017] [Indexed: 05/18/2023]
Abstract
Despite the importance and wide exploitation of heterosis in commercial crop breeding, the molecular mechanisms behind this phenomenon are not completely understood. Recent studies have implicated changes in DNA methylation and small RNAs in hybrid performance; however, it remains unclear whether epigenetic changes are a cause or a consequence of heterosis. Here, we analyze a large panel of over 500 Arabidopsis (Arabidopsis thaliana) epigenetic hybrid plants (epiHybrids), which we derived from near-isogenic but epigenetically divergent parents. This proof-of-principle experimental system allowed us to quantify the contribution of parental methylation differences to heterosis. We measured traits such as leaf area, growth rate, flowering time, main stem branching, rosette branching, and final plant height and observed several strong positive and negative heterotic phenotypes among the epiHybrids. Using an epigenetic quantitative trait locus mapping approach, we were able to identify specific differentially methylated regions in the parental genomes that are associated with hybrid performance. Sequencing of methylomes, transcriptomes, and genomes of selected parent-epiHybrid combinations further showed that these parental differentially methylated regions most likely mediate the remodeling of methylation and transcriptional states at specific loci in the hybrids. Taken together, our data suggest that locus-specific epigenetic divergence between the parental lines can directly or indirectly trigger heterosis in Arabidopsis hybrids independent of genetic changes. These results add to a growing body of evidence that points to epigenetic factors as one of the key determinants of hybrid performance.
Collapse
Affiliation(s)
- Kathrin Lauss
- University of Amsterdam, Swammerdam Institute for Life Sciences, 1098XH Amsterdam, The Netherlands
| | - René Wardenaar
- University of Groningen, Groningen Bioinformatics Centre, Faculty of Mathematics and Natural Sciences, 9747 AG Groningen, The Netherlands
| | - Rurika Oka
- University of Amsterdam, Swammerdam Institute for Life Sciences, 1098XH Amsterdam, The Netherlands
| | - Marieke H A van Hulten
- Wageningen University and Research, Laboratory of Genetics, 6708PB Wageningen, The Netherlands
| | - Victor Guryev
- Genome Structure Aging, European Research Institute for the Biology of Aging, University Medical Centre Groningen and University of Groningen, 9713 AV Groningen, The Netherlands
| | - Joost J B Keurentjes
- Wageningen University and Research, Laboratory of Genetics, 6708PB Wageningen, The Netherlands
| | - Maike Stam
- University of Amsterdam, Swammerdam Institute for Life Sciences, 1098XH Amsterdam, The Netherlands
| | - Frank Johannes
- Population Epigenetics and Epigenomics, Department of Plant Sciences, Technical University of Munich, 85354 Freising, Germany
- Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany
| |
Collapse
|
87
|
Seifert F, Thiemann A, Grant-Downton R, Edelmann S, Rybka D, Schrag TA, Frisch M, Dickinson HG, Melchinger AE, Scholten S. Parental Expression Variation of Small RNAs Is Negatively Correlated with Grain Yield Heterosis in a Maize Breeding Population. FRONTIERS IN PLANT SCIENCE 2018; 9:13. [PMID: 29441076 PMCID: PMC5797689 DOI: 10.3389/fpls.2018.00013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 01/04/2018] [Indexed: 05/26/2023]
Abstract
Heterosis refers to a quantitative phenomenon in which F1 hybrid trait values exceed the mean of the parental values in a positive direction. Generally, it is dependent on a high degree of heterozygosity, which is maintained in hybrid breeding by developing parental lines in separate, genetically distinct heterotic groups. The mobility of small RNAs (sRNAs) that mediate epigenetic regulation of gene expression renders them promising candidates for modulating the action of combined diverse genomes in trans-and evidence already indicates their contribution to transgressive phenotypes. By sequencing small RNA libraries of a panel of 21 maize parental inbred lines we found a low overlap of 35% between the sRNA populations from both distinct heterotic groups. Surprisingly, in contrast to genetic or gene expression variation, parental sRNA expression variation is negatively correlated with grain yield (GY) heterosis. Among 0.595 million expressed sRNAs, we identified 9,767, predominantly 22- and 24-nt long sRNAs, which showed an association of their differential expression between parental lines and GY heterosis of the respective hybrids. Of these sRNAs, 3,485 or 6,282 showed an association with high or low GY heterosis, respectively, thus the low heterosis associated group prevailing at 64%. The heterosis associated sRNAs map more frequently to genes that show differential expression between parental lines than reference sets. Together these findings suggest that trans-chromosomal actions of sRNAs in hybrids might add up to a negative contribution in heterosis formation, mediated by unfavorable gene expression regulation. We further revealed an exclusive accumulation of 22-nt sRNAs that are associated with low GY heterosis in pericentromeric genomic regions. That recombinational suppression led to this enrichment is indicated by its close correlation with low recombination rates. The existence of this enrichment, which we hypothesize resulted from the separated breeding of inbred lines within heterotic groups, may have implications for hybrid breeding strategies addressing the recombinational constraints characteristic of complex crop genomes.
Collapse
Affiliation(s)
- Felix Seifert
- Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | | | | | - Susanne Edelmann
- Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Dominika Rybka
- Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Tobias A. Schrag
- Institute for Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Stuttgart, Germany
| | - Matthias Frisch
- Institute of Agronomy and Plant Breeding II, Justus-Liebig University, Giessen, Germany
| | - Hugh G. Dickinson
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Albrecht E. Melchinger
- Institute for Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Stuttgart, Germany
| | - Stefan Scholten
- Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
- Institute for Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Stuttgart, Germany
| |
Collapse
|
88
|
Itabashi E, Osabe K, Fujimoto R, Kakizaki T. Epigenetic regulation of agronomical traits in Brassicaceae. PLANT CELL REPORTS 2018; 37:87-101. [PMID: 29058037 DOI: 10.1007/s00299-017-2223-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/05/2017] [Indexed: 05/08/2023]
Abstract
Epigenetic regulation, covalent modification of DNA and changes in histone proteins are closely linked to plant development and stress response through flexibly altering the chromatin structure to regulate gene expression. In this review, we will illustrate the importance of epigenetic influences by discussing three agriculturally important traits of Brassicaceae. (1) Vernalization, an acceleration of flowering by prolonged cold exposure regulated through epigenetic silencing of a central floral repressor, FLOWERING LOCUS C. This is associated with cold-dependent repressive histone mark accumulation, which confers competency of consequence vegetative-to-reproductive phase transition. (2) Hybrid vigor, in which an F1 hybrid shows superior performance to the parental lines. Combination of distinct epigenomes with different DNA methylation states between parental lines is important for increase in growth rate in a hybrid progeny. This is independent of siRNA-directed DNA methylation but dependent on the chromatin remodeler DDM1. (3) Self-incompatibility, a reproductive mating system to prevent self-fertilization. This is controlled by the S-locus consisting of SP11 and SRK which are responsible for self/non-self recognition. Because self-incompatibility in Brassicaceae is sporophytically controlled, there are dominance relationships between S haplotypes in the stigma and pollen. The dominance relationships in the pollen rely on de novo DNA methylation at the promoter region of a recessive allele, which is triggered by siRNA production from a flanking region of a dominant allele.
Collapse
Affiliation(s)
- Etsuko Itabashi
- Institute of Vegetable and Floriculture Science, NARO, Kusawa, Ano, Tsu, Mie, 514-2392, Japan.
| | - Kenji Osabe
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Kunigami, Okinawa, 904-0495, Japan
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Tomohiro Kakizaki
- Institute of Vegetable and Floriculture Science, NARO, Kusawa, Ano, Tsu, Mie, 514-2392, Japan
| |
Collapse
|
89
|
Shen Y, Sun S, Hua S, Shen E, Ye CY, Cai D, Timko MP, Zhu QH, Fan L. Analysis of transcriptional and epigenetic changes in hybrid vigor of allopolyploid Brassica napus uncovers key roles for small RNAs. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:874-893. [PMID: 28544196 DOI: 10.1111/tpj.13605] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 05/08/2017] [Accepted: 05/17/2017] [Indexed: 05/23/2023]
Abstract
Heterosis is a fundamental biological phenomenon characterized by the superior performance of a hybrid compared with its parents. The underlying molecular basis for heterosis, particularly for allopolyploids, remains elusive. In this study we analyzed the transcriptomes of Brassica napus parental lines and their F1 hybrids at three stages of early flower development. Phenotypically, the F1 hybrids show remarkable heterosis in silique number and grain yield. Transcriptome analysis revealed that various phytohormone (auxin and salicylic acid) response genes are significantly altered in the F1 hybrids relative to the parental lines. We also found evidence for decreased expression divergence of the homoeologous gene pairs in the allopolyploid F1 hybrids and suggest that high-parental expression-level dominance plays an important role in heterosis. Small RNA and methylation studies aimed at examining the epigenetic effect of the changes in gene expression level in the F1 hybrids showed that the majority of the small interfering RNA (siRNA) clusters had a higher expression level in the F1 hybrids than in the parents, and that there was an increase in genome-wide DNA methylation in the F1 hybrid. Transposable elements associated with siRNA clusters had a higher level of methylation and a lower expression level in the F1 hybrid, implying that the non-additively expressed siRNA clusters resulted in lower activity of the transposable elements through DNA methylation in the hybrid. Our data provide insights into the role that changes in gene expression pattern and epigenetic mechanisms contribute to heterosis during early flower development in allopolyploid B. napus.
Collapse
Affiliation(s)
- Yifei Shen
- Institute of Crop Science and Institute of Bioinformatics, Zhejiang University, Hangzhou, 310058, China
| | - Shuo Sun
- Institute of Crop Science and Institute of Bioinformatics, Zhejiang University, Hangzhou, 310058, China
| | - Shuijin Hua
- Institute of Crop and Utilization of Nuclear Technology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Enhui Shen
- Institute of Crop Science and Institute of Bioinformatics, Zhejiang University, Hangzhou, 310058, China
| | - Chu-Yu Ye
- Institute of Crop Science and Institute of Bioinformatics, Zhejiang University, Hangzhou, 310058, China
| | - Daguang Cai
- Institute of Phytopathology, Christian Albrechts University of Kiel, Hermann Rodewald Str. 9, D-24118, Kiel, Germany
| | - Michael P Timko
- Department of Biology, University of Virginia, Charlottesville, VA, 22903, USA
| | - Qian-Hao Zhu
- CSIRO Agriculture and Food, Black Mountain Laboratories, Canberra, ACT, 2601, Australia
| | - Longjiang Fan
- Institute of Crop Science and Institute of Bioinformatics, Zhejiang University, Hangzhou, 310058, China
| |
Collapse
|
90
|
Dwivedi SL, Scheben A, Edwards D, Spillane C, Ortiz R. Assessing and Exploiting Functional Diversity in Germplasm Pools to Enhance Abiotic Stress Adaptation and Yield in Cereals and Food Legumes. FRONTIERS IN PLANT SCIENCE 2017; 8:1461. [PMID: 28900432 PMCID: PMC5581882 DOI: 10.3389/fpls.2017.01461] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/07/2017] [Indexed: 05/03/2023]
Abstract
There is a need to accelerate crop improvement by introducing alleles conferring host plant resistance, abiotic stress adaptation, and high yield potential. Elite cultivars, landraces and wild relatives harbor useful genetic variation that needs to be more easily utilized in plant breeding. We review genome-wide approaches for assessing and identifying alleles associated with desirable agronomic traits in diverse germplasm pools of cereals and legumes. Major quantitative trait loci and single nucleotide polymorphisms (SNPs) associated with desirable agronomic traits have been deployed to enhance crop productivity and resilience. These include alleles associated with variation conferring enhanced photoperiod and flowering traits. Genetic variants in the florigen pathway can provide both environmental flexibility and improved yields. SNPs associated with length of growing season and tolerance to abiotic stresses (precipitation, high temperature) are valuable resources for accelerating breeding for drought-prone environments. Both genomic selection and genome editing can also harness allelic diversity and increase productivity by improving multiple traits, including phenology, plant architecture, yield potential and adaptation to abiotic stresses. Discovering rare alleles and useful haplotypes also provides opportunities to enhance abiotic stress adaptation, while epigenetic variation has potential to enhance abiotic stress adaptation and productivity in crops. By reviewing current knowledge on specific traits and their genetic basis, we highlight recent developments in the understanding of crop functional diversity and identify potential candidate genes for future use. The storage and integration of genetic, genomic and phenotypic information will play an important role in ensuring broad and rapid application of novel genetic discoveries by the plant breeding community. Exploiting alleles for yield-related traits would allow improvement of selection efficiency and overall genetic gain of multigenic traits. An integrated approach involving multiple stakeholders specializing in management and utilization of genetic resources, crop breeding, molecular biology and genomics, agronomy, stress tolerance, and reproductive/seed biology will help to address the global challenge of ensuring food security in the face of growing resource demands and climate change induced stresses.
Collapse
Affiliation(s)
| | - Armin Scheben
- School of Biological Sciences, Institute of Agriculture, University of Western Australia, PerthWA, Australia
| | - David Edwards
- School of Biological Sciences, Institute of Agriculture, University of Western Australia, PerthWA, Australia
| | - Charles Spillane
- Plant and AgriBiosciences Research Centre, Ryan Institute, National University of Ireland GalwayGalway, Ireland
| | - Rodomiro Ortiz
- Department of Plant Breeding, Swedish University of Agricultural SciencesAlnarp, Sweden
| |
Collapse
|
91
|
Hofmeister BT, Lee K, Rohr NA, Hall DW, Schmitz RJ. Stable inheritance of DNA methylation allows creation of epigenotype maps and the study of epiallele inheritance patterns in the absence of genetic variation. Genome Biol 2017; 18:155. [PMID: 28814343 PMCID: PMC5559844 DOI: 10.1186/s13059-017-1288-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 07/27/2017] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Differences in DNA methylation can arise as epialleles, which are loci that differ in chromatin state and are inherited over generations. Epialleles offer an additional source of variation that can affect phenotypic diversity beyond changes to nucleotide sequence. Previous research has looked at the rate at which spontaneous epialleles arise but it is currently unknown how they are maintained across generations. RESULTS We used two Arabidopsis thaliana mutation accumulation (MA) lines and determined that over 99.998% of the methylated regions in the genome are stably inherited across each generation indicating that spontaneous epialleles are rare. We also developed a novel procedure that determines genotypes for offspring of genetically identical parents using only DNA methylation data. The resulting epigenotype maps are highly accurate and strongly agree with expected allele frequency and crossover number. Using epigenotype maps, we explore the inheritance of methylation states in regions of differential methylation between the parents of genetic crosses. Over half of the regions show methylation levels consistent with cis inheritance, whereas the other half show evidence of trans-chromosomal methylation and demethylation as well as other possibilities. CONCLUSIONS DNA methylation is stably inherited by offspring and spontaneous epialleles are rare. The epigenotyping procedure that we describe provides an important first step to epigenetic quantitative trait loci mapping in genetically identical individuals.
Collapse
Affiliation(s)
| | - Kevin Lee
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Nicholas A Rohr
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - David W Hall
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA.
| |
Collapse
|
92
|
Abstract
Heterosis is most frequently manifested by the substantially increased vigorous growth of hybrids compared with their parents. Investigating genomic variations in natural populations is essential to understand the initial molecular mechanisms underlying heterosis in plants. Here, we characterized the genomic architecture associated with biomass heterosis in 200 Arabidopsis hybrids. The genome-wide heterozygosity of hybrids makes a limited contribution to biomass heterosis, and no locus shows an obvious overdominance effect in hybrids. However, the accumulation of significant genetic loci identified in genome-wide association studies (GWAS) in hybrids strongly correlates with better-parent heterosis (BPH). Candidate genes for biomass BPH fall into diverse biological functions, including cellular, metabolic, and developmental processes and stimulus-responsive pathways. Important heterosis candidates include WUSCHEL, ARGOS, and some genes that encode key factors involved in cell cycle regulation. Interestingly, transcriptomic analyses in representative Arabidopsis hybrid combinations reveal that heterosis candidate genes are functionally enriched in stimulus-responsive pathways, including responses to biotic and abiotic stimuli and immune responses. In addition, stimulus-responsive genes are repressed to low-parent levels in hybrids with high BPH, whereas middle-parent expression patterns are exhibited in hybrids with no BPH. Our study reveals a genomic architecture for understanding the molecular mechanisms of biomass heterosis in Arabidopsis, in which the accumulation of the superior alleles of genes involved in metabolic and cellular processes improve the development and growth of hybrids, whereas the overall repressed expression of stimulus-responsive genes prioritizes growth over responding to environmental stimuli in hybrids under normal conditions.
Collapse
|
93
|
Abstract
Epigenetic profiling in diploid, allopolyploid, and domesticated cotton shows that despite most DNA methylation being conserved and stably inherited, alterations likely due to hybridization and domestication affect gene expression.
Collapse
Affiliation(s)
- Scott A Jackson
- Center for Applied Genetic Technologies, University of Georgia, Riverbend Drive, Athens, GA, 30602, USA.
| |
Collapse
|
94
|
Song Q, Zhang T, Stelly DM, Chen ZJ. Epigenomic and functional analyses reveal roles of epialleles in the loss of photoperiod sensitivity during domestication of allotetraploid cottons. Genome Biol 2017; 18:99. [PMID: 28558752 PMCID: PMC5450403 DOI: 10.1186/s13059-017-1229-8] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 05/03/2017] [Indexed: 02/08/2023] Open
Abstract
Background Polyploidy is a pervasive evolutionary feature of all flowering plants and some animals, leading to genetic and epigenetic changes that affect gene expression and morphology. DNA methylation changes can produce meiotically stable epialleles, which are transmissible through selection and breeding. However, the relationship between DNA methylation and polyploid plant domestication remains elusive. Results We report comprehensive epigenomic and functional analyses, including ~12 million differentially methylated cytosines in domesticated allotetraploid cottons and their tetraploid and diploid relatives. Methylated genes evolve faster than unmethylated genes; DNA methylation changes between homoeologous loci are associated with homoeolog-expression bias in the allotetraploids. Significantly, methylation changes induced in the interspecific hybrids are largely maintained in the allotetraploids. Among 519 differentially methylated genes identified between wild and cultivated cottons, some contribute to domestication traits, including flowering time and seed dormancy. CONSTANS (CO) and CO-LIKE (COL) genes regulate photoperiodicity in Arabidopsis. COL2 is an epiallele in allotetraploid cottons. COL2A is hypermethylated and silenced, while COL2D is repressed in wild cottons but highly expressed due to methylation loss in all domesticated cottons tested. Inhibiting DNA methylation activates COL2 expression, and repressing COL2 in cultivated cotton delays flowering. Conclusions We uncover epigenomic signatures of domestication traits during cotton evolution. Demethylation of COL2 increases its expression, inducing photoperiodic flowering, which could have contributed to the suitability of cotton for cultivation worldwide. These resources should facilitate epigenetic engineering, breeding, and improvement of polyploid crops. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1229-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Qingxin Song
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Tianzhen Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - David M Stelly
- Department of Soil and Crop Sciences, Texas A&M University, College Station, TX, 78743, USA
| | - Z Jeffrey Chen
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, TX, 78712, USA. .,State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China.
| |
Collapse
|
95
|
Geyer KK, Niazi UH, Duval D, Cosseau C, Tomlinson C, Chalmers IW, Swain MT, Cutress DJ, Bickham-Wright U, Munshi SE, Grunau C, Yoshino TP, Hoffmann KF. The Biomphalaria glabrata DNA methylation machinery displays spatial tissue expression, is differentially active in distinct snail populations and is modulated by interactions with Schistosoma mansoni. PLoS Negl Trop Dis 2017; 11:e0005246. [PMID: 28510608 PMCID: PMC5433704 DOI: 10.1371/journal.pntd.0005246] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 12/10/2016] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The debilitating human disease schistosomiasis is caused by infection with schistosome parasites that maintain a complex lifecycle alternating between definitive (human) and intermediate (snail) hosts. While much is known about how the definitive host responds to schistosome infection, there is comparably less information available describing the snail's response to infection. METHODOLOGY/PRINCIPLE FINDINGS Here, using information recently revealed by sequencing of the Biomphalaria glabrata intermediate host genome, we provide evidence that the predicted core snail DNA methylation machinery components are associated with both intra-species reproduction processes and inter-species interactions. Firstly, methyl-CpG binding domain protein (Bgmbd2/3) and DNA methyltransferase 1 (Bgdnmt1) genes are transcriptionally enriched in gonadal compared to somatic tissues with 5-azacytidine (5-AzaC) treatment significantly inhibiting oviposition. Secondly, elevated levels of 5-methyl cytosine (5mC), DNA methyltransferase activity and 5mC binding in pigmented hybrid- compared to inbred (NMRI)- B. glabrata populations indicate a role for the snail's DNA methylation machinery in maintaining hybrid vigour or heterosis. Thirdly, locus-specific detection of 5mC by bisulfite (BS)-PCR revealed 5mC within an exonic region of a housekeeping protein-coding gene (Bg14-3-3), supporting previous in silico predictions and whole genome BS-Seq analysis of this species' genome. Finally, we provide preliminary evidence for parasite-mediated host epigenetic reprogramming in the schistosome/snail system, as demonstrated by the increase in Bgdnmt1 and Bgmbd2/3 transcript abundance following Bge (B. glabrata embryonic cell line) exposure to parasite larval transformation products (LTP). CONCLUSIONS/SIGNIFICANCE The presence of a functional DNA methylation machinery in B. glabrata as well as the modulation of these gene products in response to schistosome products, suggests a vital role for DNA methylation during snail development/oviposition and parasite interactions. Further deciphering the role of this epigenetic process during Biomphalaria/Schistosoma co-evolutionary biology may reveal key factors associated with disease transmission and, moreover, enable the discovery of novel lifecycle intervention strategies.
Collapse
Affiliation(s)
- Kathrin K. Geyer
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingodm
| | - Umar H. Niazi
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingodm
| | - David Duval
- Université Perpignan Via Domitia, CNRS, IFREMER, Perpignan, France
| | - Céline Cosseau
- Université Perpignan Via Domitia, CNRS, IFREMER, Perpignan, France
| | - Chad Tomlinson
- Genome Sequencing Center, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Iain W. Chalmers
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingodm
| | - Martin T. Swain
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingodm
| | - David J. Cutress
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingodm
| | - Utibe Bickham-Wright
- Department of Pathobiological Sciences, School of Veterinary Medicine University of Wisconsin, Madison, United States of America
| | - Sabrina E. Munshi
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingodm
| | - Christoph Grunau
- Université Perpignan Via Domitia, CNRS, IFREMER, Perpignan, France
| | - Timothy P. Yoshino
- Department of Pathobiological Sciences, School of Veterinary Medicine University of Wisconsin, Madison, United States of America
| | - Karl F. Hoffmann
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingodm
| |
Collapse
|
96
|
Ng DWK, Chen HHY, Chen ZJ. Heterologous protein-DNA interactions lead to biased allelic expression of circadian clock genes in interspecific hybrids. Sci Rep 2017; 7:45087. [PMID: 28345627 PMCID: PMC5366859 DOI: 10.1038/srep45087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/20/2017] [Indexed: 02/02/2023] Open
Abstract
Genomic interactions in allopolyploids create expression variation of homoeologous alleles through protein-protein and protein-DNA interactions. However, the molecular basis for this is largely unknown. Here we investigated the protein-protein and protein-DNA interactions among homoeologous transcription factors in the circadian-clock feedback loop, consisting of CCA1 HIKING EXPEDITION (CHE), CIRCADIAN CLOCK ASSOCIATED1 (CCA1), and TIMING OF CAB EXPRESSION1 (TOC1), plus the interaction with a chromatin factor, HISTONE DEACETYLASE1 (HD1). In the allotetraploids formed between A. thaliana (At) and Arabidopsis arenosa (Aa), AtCCA1 is expressed at lower levels than AaCCA1, which could alter clock output traits. The reduced AtCCA1 expressions in the allotetraploids are consistent with the biochemical data that AaCHE showed preferential binding to the AtCCA1 promoter, in which AaCHE interacts with a higher affinity to AtHD1 than AtCHE. AaCHE also showed a higher affinity to TOC1 than AtCHE, consistent with the effect of TOC1 on repressing CCA1. Thus, stronger AaCHE-TOC1 and AaCHE-AtHD1 interactions reduce AtCC1 allelic expression. Our current data suggest a biochemical basis for protein interactions in trans with a preference to the cis-acting elements in heterologous combinations to reduce AtCCA1 expression, while altered CCA1 expression has been shown to affect metabolic and biomass heterosis in interspecific hybrids or allotetraploids.
Collapse
Affiliation(s)
- Danny W-K Ng
- Department of Molecular Biosciences and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas 78712, USA.,Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.,The Partner State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Helen H Y Chen
- Department of Molecular Biosciences and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Z Jeffrey Chen
- Department of Molecular Biosciences and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas 78712, USA
| |
Collapse
|
97
|
Hao M, Li A, Shi T, Luo J, Zhang L, Zhang X, Ning S, Yuan Z, Zeng D, Kong X, Li X, Zheng H, Lan X, Zhang H, Zheng Y, Mao L, Liu D. The abundance of homoeologue transcripts is disrupted by hybridization and is partially restored by genome doubling in synthetic hexaploid wheat. BMC Genomics 2017; 18:149. [PMID: 28187716 PMCID: PMC5303294 DOI: 10.1186/s12864-017-3558-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 02/07/2017] [Indexed: 11/10/2022] Open
Abstract
Background The formation of an allopolyploid is a two step process, comprising an initial wide hybridization event, which is later followed by a whole genome doubling. Both processes can affect the transcription of homoeologues. Here, RNA-Seq was used to obtain the genome-wide leaf transcriptome of two independent Triticum turgidum × Aegilops tauschii allotriploids (F1), along with their spontaneous allohexaploids (S1) and their parental lines. The resulting sequence data were then used to characterize variation in homoeologue transcript abundance. Results The hybridization event strongly down-regulated D-subgenome homoeologues, but this effect was in many cases reversed by whole genome doubling. The suppression of D-subgenome homoeologue transcription resulted in a marked frequency of parental transcription level dominance, especially with respect to genes encoding proteins involved in photosynthesis. Singletons (genes where no homoeologues were present) were frequently transcribed at both the allotriploid and allohexaploid plants. Conclusions The implication is that whole genome doubling helps to overcome the phenotypic weakness of the allotriploid, restoring a more favourable gene dosage in genes experiencing transcription level dominance in hexaploid wheat. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3558-0) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ming Hao
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Aili Li
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Tongwei Shi
- Biomarker Technologies Corporation, Beijing, 101300, China
| | - Jiangtao Luo
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Lianquan Zhang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Xuechuan Zhang
- Biomarker Technologies Corporation, Beijing, 101300, China
| | - Shunzong Ning
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Zhongwei Yuan
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Deying Zeng
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Xingchen Kong
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Xiaolong Li
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Hongkun Zheng
- Biomarker Technologies Corporation, Beijing, 101300, China
| | - Xiujin Lan
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Huaigang Zhang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810001, China
| | - Youliang Zheng
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Long Mao
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
| | - Dengcai Liu
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China. .,Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810001, China.
| |
Collapse
|
98
|
Zhu A, Greaves IK, Dennis ES, Peacock WJ. Genome-wide analyses of four major histone modifications in Arabidopsis hybrids at the germinating seed stage. BMC Genomics 2017; 18:137. [PMID: 28173754 PMCID: PMC5297046 DOI: 10.1186/s12864-017-3542-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 02/02/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hybrid vigour (heterosis) has been used for decades in cropping agriculture, especially in the production of maize and rice, because hybrid varieties exceed their parents in plant biomass and seed yield. The molecular basis of hybrid vigour is not fully understood. Previous studies have suggested that epigenetic systems could play a role in heterosis. RESULTS In this project, we investigated genome-wide patterns of four histone modifications in Arabidopsis hybrids in germinating seeds. We found that although hybrids have similar histone modification patterns to the parents in most regions of the genome, they have altered patterns at specific loci. A small subset of genes show changes in histone modifications in the hybrids that correlate with changes in gene expression. Our results also show that genome-wide patterns of histone modifications in geminating seeds parallel those at later developmental stages of seedlings. CONCLUSION Ler/C24 hybrids showed similar genome-wide patterns of histone modifications as the parents at an early germination stage. However, a small subset of genes, such as FLC, showed correlated changes in histone modification and in gene expression in the hybrids. The altered patterns of histone modifications for those genes in hybrids could be related to some heterotic traits in Arabidopsis, such as flowering time, and could play a role in hybrid vigour establishment.
Collapse
Affiliation(s)
- Anyu Zhu
- Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia.,Faculty of Science, University of Technology, Sydney, New South Wales, 2007, Australia
| | - Ian K Greaves
- Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia
| | - Elizabeth S Dennis
- Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia.,Faculty of Science, University of Technology, Sydney, New South Wales, 2007, Australia
| | - W James Peacock
- Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia. .,Faculty of Science, University of Technology, Sydney, New South Wales, 2007, Australia.
| |
Collapse
|
99
|
An Arabidopsis Natural Epiallele Maintained by a Feed-Forward Silencing Loop between Histone and DNA. PLoS Genet 2017; 13:e1006551. [PMID: 28060933 PMCID: PMC5257005 DOI: 10.1371/journal.pgen.1006551] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 01/23/2017] [Accepted: 12/24/2016] [Indexed: 12/26/2022] Open
Abstract
The extent of epigenetic variation is currently well documented, but the number of natural epialleles described so far remains very limited. Determining the relevance of epigenetic changes for natural variation is an important question of research that we investigate by isolating natural epialleles segregating in Arabidopsis recombinant populations. We previously described a genetic incompatibility among Arabidopsis strains based on the silencing of a gene involved in fitness. Here, we isolated a new epiallele resulting from the silencing of a transfer-RNA editing gene in an Arabidopsis accession from the Netherlands (Nok-1). Crosses with the reference accession Col-0 show a complete incompatibility between this epiallele and another locus localized on a different chromosome. We demonstrate that conversion of an unmethylated version of this allele occurs in hybrids, associated with modifications of small RNA populations. These epialleles can also spontaneously revert within the population. Furthermore, we bring evidence that neither METHYLTRANSFERASE 1, maintaining methylation at CGs, nor components of RNA-directed DNA methylation, are key factors for the transmission of the epiallele over generations. This depends only on the self-reinforcing loop between CHROMOMETHYLASE 3 and KRYPTONITE, involving DNA methylated in the CHG context and histone H3 lysine 9 methylation. Our findings reveal a predominant role of this loop in maintaining a natural epiallele. Epialleles are gene variants based on epigenetic marks stably transmitted between generations. Most of the known epialleles existing in the wild were described in plant populations but very few are associated with phenotypes or agronomical traits. In this study, we isolated a new natural epiallele resulting from the silencing of a RNA editing gene essential for plants. We demonstrated that an incompatibility between two Arabidopsis strains depending on this epiallele, is based on DNA methylation of cytosines, an epigenetic mark influencing gene function. In F1 hybrids, obtained by crossing the incompatible parental lines, unmethylated versions of the allele can be converted to methylated ones. The epiallele can also spontaneously revert in very rare cases, within the population. The methylation status of this epiallele can therefore potentially change within the population and is maintained in a metastable state. Indeed, two enzymes promoting histone or DNA methylation, respectively, and acting in loop, are involved in maintaining the epiallele in natural populations, over generations.
Collapse
|
100
|
Goulet BE, Roda F, Hopkins R. Hybridization in Plants: Old Ideas, New Techniques. PLANT PHYSIOLOGY 2017; 173:65-78. [PMID: 27895205 PMCID: PMC5210733 DOI: 10.1104/pp.16.01340] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/24/2016] [Indexed: 05/18/2023]
Abstract
Hybridization has played an important role in the evolution of many lineages. With the growing availability of genomic tools and advancements in genomic analyses, it is becoming increasingly clear that gene flow between divergent taxa can generate new phenotypic diversity, allow for adaptation to novel environments, and contribute to speciation. Hybridization can have immediate phenotypic consequences through the expression of hybrid vigor. On longer evolutionary time scales, hybridization can lead to local adaption through the introgression of novel alleles and transgressive segregation and, in some cases, result in the formation of new hybrid species. Studying both the abundance and the evolutionary consequences of hybridization has deep historical roots in plant biology. Many of the hypotheses concerning how and why hybridization contributes to biological diversity currently being investigated were first proposed tens and even hundreds of years ago. In this Update, we discuss how new advancements in genomic and genetic tools are revolutionizing our ability to document the occurrence of and investigate the outcomes of hybridization in plants.
Collapse
Affiliation(s)
- Benjamin E Goulet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (B.E.G., F.R., R.H.); and
- Arnold Arboretum of Harvard University, Boston, Massachusetts 02131 (R.H.)
| | - Federico Roda
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (B.E.G., F.R., R.H.); and
- Arnold Arboretum of Harvard University, Boston, Massachusetts 02131 (R.H.)
| | - Robin Hopkins
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (B.E.G., F.R., R.H.); and
- Arnold Arboretum of Harvard University, Boston, Massachusetts 02131 (R.H.)
| |
Collapse
|