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Salim S, Hussain S, Banu A, Gowda SBM, Ahammad F, Alwa A, Pasha M, Mohammad F. The ortholog of human ssDNA-binding protein SSBP3 influences neurodevelopment and autism-like behaviors in Drosophila melanogaster. PLoS Biol 2023; 21:e3002210. [PMID: 37486945 PMCID: PMC10399856 DOI: 10.1371/journal.pbio.3002210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 08/03/2023] [Accepted: 06/21/2023] [Indexed: 07/26/2023] Open
Abstract
1p32.3 microdeletion/duplication is implicated in many neurodevelopmental disorders-like phenotypes such as developmental delay, intellectual disability, autism, macro/microcephaly, and dysmorphic features. The 1p32.3 chromosomal region harbors several genes critical for development; however, their validation and characterization remain inadequate. One such gene is the single-stranded DNA-binding protein 3 (SSBP3) and its Drosophila melanogaster ortholog is called sequence-specific single-stranded DNA-binding protein (Ssdp). Here, we investigated consequences of Ssdp manipulations on neurodevelopment, gene expression, physiological function, and autism-associated behaviors using Drosophila models. We found that SSBP3 and Ssdp are expressed in excitatory neurons in the brain. Ssdp overexpression caused morphological alterations in Drosophila wing, mechanosensory bristles, and head. Ssdp manipulations also affected the neuropil brain volume and glial cell number in larvae and adult flies. Moreover, Ssdp overexpression led to differential changes in synaptic density in specific brain regions. We observed decreased levels of armadillo in the heads of Ssdp overexpressing flies, as well as a decrease in armadillo and wingless expression in the larval wing discs, implicating the involvement of the canonical Wnt signaling pathway in Ssdp functionality. RNA sequencing revealed perturbation of oxidative stress-related pathways in heads of Ssdp overexpressing flies. Furthermore, Ssdp overexpressing brains showed enhanced reactive oxygen species (ROS), altered neuronal mitochondrial morphology, and up-regulated fission and fusion genes. Flies with elevated levels of Ssdp exhibited heightened anxiety-like behavior, altered decisiveness, defective sensory perception and habituation, abnormal social interaction, and feeding defects, which were phenocopied in the pan-neuronal Ssdp knockdown flies, suggesting that Ssdp is dosage sensitive. Partial rescue of behavioral defects was observed upon normalization of Ssdp levels. Notably, Ssdp knockdown exclusively in adult flies did not produce behavioral and functional defects. Finally, we show that optogenetic manipulation of Ssdp-expressing neurons altered autism-associated behaviors. Collectively, our findings provide evidence that Ssdp, a dosage-sensitive gene in the 1p32.3 chromosomal region, is associated with various anatomical, physiological, and behavioral defects, which may be relevant to neurodevelopmental disorders like autism. Our study proposes SSBP3 as a critical gene in the 1p32.3 microdeletion/duplication genomic region and sheds light on the functional role of Ssdp in neurodevelopmental processes in Drosophila.
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Affiliation(s)
- Safa Salim
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Sadam Hussain
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Ayesha Banu
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Swetha B. M. Gowda
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Foysal Ahammad
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Amira Alwa
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Mujaheed Pasha
- HBKU Core Labs, Hamad Bin Khalifa University (HBKU): Doha, Qatar
| | - Farhan Mohammad
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, Qatar
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2
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Wan J, Wang Q, Zhao J, Zhang X, Guo Z, Hu D, Meng S, Lin Y, Qiu X, Mu L, Ding D, Tang J. Gene expression variation explains maize seed germination heterosis. BMC PLANT BIOLOGY 2022; 22:301. [PMID: 35718761 PMCID: PMC9208091 DOI: 10.1186/s12870-022-03690-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Heterosis has been extensively utilized in plant breeding, however, the underlying molecular mechanism remains largely elusive. Maize (Zea mays), which exhibits strong heterosis, is an ideal material for studying heterosis. RESULTS In this study, there is faster imbibition and development in reciprocal crossing Zhengdan958 hybrids than in their parent lines during seed germination. To investigate the mechanism of heterosis of maize germination, comparative transcriptomic analyses were conducted. The gene expression patterns showed that 1324 (47.27%) and 1592 (66.44%) of the differential expression genes between hybrids and either parental line display parental dominance up or higher levels in the reciprocal cross of Zhengdan958, respectively. Notably, these genes were mainly enriched in metabolic pathways, including carbon metabolism, glycolysis/gluconeogenesis, protein processing in endoplasmic reticulum, etc. CONCLUSION: Our results provide evidence for the higher expression level genes in hybrid involved in metabolic pathways acting as main contributors to maize seed germinating heterosis. These findings provide new insights into the gene expression variation of maize embryos and improve the understanding of maize seed germination heterosis.
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Affiliation(s)
- Jiong Wan
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Qiyue Wang
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Jiawen Zhao
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Xuehai Zhang
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Zhanyong Guo
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Desheng Hu
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Shujun Meng
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yuan Lin
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Xiaoqian Qiu
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Liqin Mu
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
| | - Dong Ding
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Jihua Tang
- National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China.
- The Shennong Laboratory, Zhengzhou, 450002, China.
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3
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Nanni AV, Morse AM, Newman JRB, Choquette NE, Wedow JM, Liu Z, Leakey ADB, Conesa A, Ainsworth EA, McIntyre LM. Variation in leaf transcriptome responses to elevated ozone corresponds with physiological sensitivity to ozone across maize inbred lines. Genetics 2022; 221:6586798. [PMID: 35579358 DOI: 10.1093/genetics/iyac080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/27/2022] [Indexed: 11/13/2022] Open
Abstract
We examine the impact of sustained elevated ozone concentration on the leaf transcriptome of 5 diverse maize inbred genotypes, which vary in physiological sensitivity to ozone (B73, Mo17, Hp301, C123, NC338), using long reads to assemble transcripts and short reads to quantify expression of these transcripts. More than 99% of the long reads, 99% of the assembled transcripts, and 97% of the short reads map to both B73 and Mo17 reference genomes. Approximately 95% of the genes with assembled transcripts belong to known B73-Mo17 syntenic loci and 94% of genes with assembled transcripts are present in all temperate lines in the NAM pan-genome. While there is limited evidence for alternative splicing in response to ozone stress, there is a difference in the magnitude of differential expression among the 5 genotypes. The transcriptional response to sustained ozone stress in the ozone resistant B73 genotype (151 genes) was modest, while more than 3,300 genes were significantly differentially expressed in the more sensitive NC338 genotype. There is the potential for tandem duplication in 30% of genes with assembled transcripts, but there is no obvious association between potential tandem duplication and differential expression. Genes with a common response across the 5 genotypes (83 genes) were associated with photosynthesis, in particular photosystem I. The functional annotation of genes not differentially expressed in B73 but responsive in the other 4 genotypes (789) identifies reactive oxygen species. This suggests that B73 has a different response to long term ozone exposure than the other 4 genotypes. The relative magnitude of the genotypic response to ozone, and the enrichment analyses are consistent regardless of whether aligning short reads to: long read assembled transcripts; the B73 reference; the Mo17 reference. We find that prolonged ozone exposure directly impacts the photosynthetic machinery of the leaf.
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Affiliation(s)
- Adalena V Nanni
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32611, USA.,Genetics Institute, University of Florida, Gainesville, Florida 32611, USA
| | - Alison M Morse
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32611, USA.,Genetics Institute, University of Florida, Gainesville, Florida 32611, USA
| | - Jeremy R B Newman
- Department of Pathology, University of Florida, Gainesville, Florida 32611, USA.,Genetics Institute, University of Florida, Gainesville, Florida 32611, USA
| | - Nicole E Choquette
- Carl R. Woese Institute for Genomic Biology, Department of Plant Biology, and Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Jessica M Wedow
- Carl R. Woese Institute for Genomic Biology, Department of Plant Biology, and Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Zihao Liu
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32611, USA.,Genetics Institute, University of Florida, Gainesville, Florida 32611, USA
| | - Andrew D B Leakey
- Carl R. Woese Institute for Genomic Biology, Department of Plant Biology, and Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Ana Conesa
- Department of Cell and Microbial Sciences, University of Florida, Gainesville, Florida 32611, USA.,Institute for Integrative Systems Biology, Spanish National Research Council, 46980 Paterna, Spain
| | - Elizabeth A Ainsworth
- Carl R. Woese Institute for Genomic Biology, Department of Plant Biology, and Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.,USDA ARS Global Change and Photosynthesis Research Unit, Urbana, IL 61801, USA
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32611, USA.,Genetics Institute, University of Florida, Gainesville, Florida 32611, USA
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4
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Ullastres A, Merenciano M, González J. Regulatory regions in natural transposable element insertions drive interindividual differences in response to immune challenges in Drosophila. Genome Biol 2021; 22:265. [PMID: 34521452 PMCID: PMC8439047 DOI: 10.1186/s13059-021-02471-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 08/19/2021] [Indexed: 02/08/2023] Open
Abstract
Background Variation in gene expression underlies interindividual variability in relevant traits including immune response. However, the genetic variation responsible for these gene expression changes remains largely unknown. Among the non-coding variants that could be relevant, transposable element insertions are promising candidates as they have been shown to be a rich and diverse source of cis-regulatory elements. Results In this work, we use a population genetics approach to identify transposable element insertions likely to increase the tolerance of Drosophila melanogaster to bacterial infection by affecting the expression of immune-related genes. We identify 12 insertions associated with allele-specific expression changes in immune-related genes. We experimentally validate three of these insertions including one likely to be acting as a silencer, one as an enhancer, and one with a dual role as enhancer and promoter. The direction in the change of gene expression associated with the presence of several of these insertions is consistent with an increased survival to infection. Indeed, for one of the insertions, we show that this is the case by analyzing both natural populations and CRISPR/Cas9 mutants in which the insertion is deleted from its native genomic context. Conclusions We show that transposable elements contribute to gene expression variation in response to infection in D. melanogaster and that this variation is likely to affect their survival capacity. Because the role of transposable elements as regulatory elements is not restricted to Drosophila, transposable elements are likely to play a role in immune response in other organisms as well. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-021-02471-3.
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Affiliation(s)
- Anna Ullastres
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Spain
| | - Miriam Merenciano
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Spain
| | - Josefa González
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Spain.
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5
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Spontaneous mutations in maize pollen are frequent in some lines and arise mainly from retrotranspositions and deletions. Proc Natl Acad Sci U S A 2019; 116:10734-10743. [PMID: 30992374 DOI: 10.1073/pnas.1903809116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
While studying spontaneous mutations at the maize bronze (bz) locus, we made the unexpected discovery that specific low-copy number retrotransposons are mobile in the pollen of some maize lines, but not of others. We conducted large-scale genetic experiments to isolate new bz mutations from several Bz stocks and recovered spontaneous stable mutations only in the pollen parent in reciprocal crosses. Most of the new stable bz mutations resulted from either insertions of low-copy number long terminal repeat (LTR) retrotransposons or deletions, the same two classes of mutations that predominated in a collection of spontaneous wx mutations [Wessler S (1997) The Mutants of Maize, pp 385-386]. Similar mutations were recovered at the closely linked sh locus. These events occurred with a frequency of 2-4 × 10-5 in two lines derived from W22 and in 4Co63, but not at all in B73 or Mo17, two inbreds widely represented in Corn Belt hybrids. Surprisingly, the mutagenic LTR retrotransposons differed in the active lines, suggesting differences in the autonomous element make-up of the lines studied. Some active retrotransposons, like Hopscotch, Magellan, and Bs2, a Bs1 variant, were described previously; others, like Foto and Focou in 4Co63, were not. By high-throughput sequencing of retrotransposon junctions, we established that retrotranposition of Hopscotch, Magellan, and Bs2 occurs genome-wide in the pollen of active lines, but not in the female germline or in somatic tissues. We discuss here the implications of these results, which shed light on the source, frequency, and nature of spontaneous mutations in maize.
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6
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Zhou P, Hirsch CN, Briggs SP, Springer NM. Dynamic Patterns of Gene Expression Additivity and Regulatory Variation throughout Maize Development. MOLECULAR PLANT 2019; 12:410-425. [PMID: 30593858 DOI: 10.1016/j.molp.2018.12.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/14/2018] [Accepted: 12/18/2018] [Indexed: 05/26/2023]
Abstract
Gene expression variation is a key component underlying phenotypic variation and heterosis. Transcriptome profiling was performed on 23 different tissues or developmental stages of two maize inbreds, B73 and Mo17, as well as their F1 hybrid. The obtained large-scale datasets provided opportunities to monitor the developmental dynamics of differential expression, additivity for gene expression, and regulatory variation. The transcriptome can be divided into ∼30 000 genes that are expressed in at least one tissue of one inbred and an additional ∼10 000 ″silent" genes that are not expressed in any tissue of any genotype, 90% of which are non-syntenic relative to other grasses. Many (∼74%) of the expressed genes exhibit differential expression in at least one tissue. However, the majority of genes with differential expression do not exhibit consistent differential expression in different tissues. These genes often exhibit tissue-specific differential expression with equivalent expression in other tissues, and in many cases they switch the directionality of differential expression in different tissues. This suggests widespread variation for tissue-specific regulation of gene expression between the two maize inbreds B73 and Mo17. Nearly 5000 genes are expressed in only one parent in at least one tissue (single parent expression) and 97% of these genes are expressed at mid-parent levels or higher in the hybrid, providing extensive opportunities for hybrid complementation in heterosis. In general, additive expression patterns are much more common than non-additive patterns, and this trend is more pronounced for genes with strong differential expression or single parent expression. There is relatively little evidence for non-additive expression patterns that are maintained in multiple tissues. The analysis of allele-specific expression allowed classification of cis- and trans-regulatory variation. Genes with cis-regulatory variation often exhibit additive expression and tend to have more consistent regulatory variation throughout development. In contrast, genes with trans-regulatory variation are enriched for non-additive patterns and often show tissue-specific differential expression. Taken together, this study provides a deeper understanding of regulatory variation and the degree of additive gene expression throughout maize development. The dynamic nature of differential expression, additivity, and regulatory variation imply abundant variability for tissue-specific regulatory mechanisms and suggest that connections between transcriptome and phenome will require expression data from multiple tissues.
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Affiliation(s)
- Peng Zhou
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, MN 55108, USA
| | - Candice N Hirsch
- Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, MN 55108, USA
| | - Steven P Briggs
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nathan M Springer
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, MN 55108, USA.
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7
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Pan Q, Li L, Yang X, Tong H, Xu S, Li Z, Li W, Muehlbauer GJ, Li J, Yan J. Genome-wide recombination dynamics are associated with phenotypic variation in maize. THE NEW PHYTOLOGIST 2016; 210:1083-94. [PMID: 26720856 DOI: 10.1111/nph.13810] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 11/11/2015] [Indexed: 05/04/2023]
Abstract
Meiotic recombination is a major driver of genetic diversity, species evolution, and agricultural improvement. Thus, an understanding of the genetic recombination landscape across the maize (Zea mays) genome will provide insight and tools for further study of maize evolution and improvement. Here, we used c. 50 000 single nucleotide polymorphisms to precisely map recombination events in 12 artificial maize segregating populations. We observed substantial variation in the recombination frequency and distribution along the ten maize chromosomes among the 12 populations and identified 143 recombination hot regions. Recombination breakpoints were partitioned into intragenic and intergenic events. Interestingly, an increase in the number of genes containing recombination events was accompanied by a decrease in the number of recombination events per gene. This kept the overall number of intragenic recombination events nearly invariable in a given population, suggesting that the recombination variation observed among populations was largely attributed to intergenic recombination. However, significant associations between intragenic recombination events and variation in gene expression and agronomic traits were observed, suggesting potential roles for intragenic recombination in plant phenotypic diversity. Our results provide a comprehensive view of the maize recombination landscape, and show an association between recombination, gene expression and phenotypic variation, which may enhance crop genetic improvement.
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Affiliation(s)
- Qingchun Pan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lin Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
- Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Xiaohong Yang
- National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Hao Tong
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shutu Xu
- National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Zhigang Li
- National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Weiya Li
- National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Gary J Muehlbauer
- Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, MN, 55108, USA
- Department of Plant Biology, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Jiansheng Li
- National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Jianbing Yan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
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8
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Llaurens V, Joron M, Billiard S. Molecular mechanisms of dominance evolution in Müllerian mimicry. Evolution 2015; 69:3097-108. [DOI: 10.1111/evo.12810] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 10/02/2015] [Accepted: 10/22/2015] [Indexed: 11/29/2022]
Affiliation(s)
- V. Llaurens
- Institut de Systématique Evolution et Biodiversité, UMR7205, CNRS, EPHE, UPMC; Museum National d'Histoire Naturelle; Bâtiment d'entomologie, CP50, 45 rue Buffon 75005 Paris France
| | - M. Joron
- Institut de Systématique Evolution et Biodiversité, UMR7205, CNRS, EPHE, UPMC; Museum National d'Histoire Naturelle; Bâtiment d'entomologie, CP50, 45 rue Buffon 75005 Paris France
- Centre d'Ecologie Fonctionnelle et Evolutive; UMR 5175, CNRS-Universite de Montpellier-Universite Paul Valery Montpellier - EPHE; 1919 Route de Mende 34293 Montpellier Cedex 05 France
| | - S. Billiard
- Unité Evo-Eco-Paléo; UMR CNRS 8198, Université des Sciences et Technologies de Lille 1; Bâtiment SN2 59655 Villeneuve d'Ascq Cedex France
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Zheng L, McMullen MD, Bauer E, Schön CC, Gierl A, Frey M. Prolonged expression of the BX1 signature enzyme is associated with a recombination hotspot in the benzoxazinoid gene cluster in Zea mays. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:3917-30. [PMID: 25969552 PMCID: PMC4473990 DOI: 10.1093/jxb/erv192] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Benzoxazinoids represent preformed protective and allelopathic compounds. The main benzoxazinoid in maize (Zea mays L.) is 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA confers resistance to herbivores and microbes. Protective concentrations are found predominantly in young plantlets. We made use of the genetic diversity present in the maize nested association mapping (NAM) panel to identify lines with significant benzoxazinoid concentrations at later developmental stages. At 24 d after imbibition (dai), only three lines, including Mo17, showed effective DIMBOA concentrations of 1.5mM or more; B73, by contrast, had low a DIMBOA content. Mapping studies based on Mo17 and B73 were performed to reveal mechanisms that influence the DIMBOA level in 24 dai plants. A major quantitative trait locus mapped to the Bx gene cluster located on the short arm of chromosome 4, which encodes the DIMBOA biosynthetic genes. Mo17 was distinguished from all other NAM lines by high transcriptional expression of the Bx1 gene at later developmental stages. Bx1 encodes the signature enzyme of the pathway. In Mo17×B73 hybrids at 24 dai, only the Mo17 Bx1 allele transcript was detected. A 3.9kb cis-element, termed DICE (distal cis-element), that is located in the Bx gene cluster approximately 140 kb upstream of Bx1, was required for high Bx1 transcript levels during later developmental stages in Mo17. The DICE region was a hotspot of meiotic recombination. Genetic analysis revealed that high 24 dai DIMBOA concentrations were not strictly dependent on high Bx1 transcript levels. However, constitutive expression of Bx1 in transgenics increased DIMBOA levels at 24 dai, corroborating a correlation between DIMBOA content and Bx1 transcription.
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MESH Headings
- Alleles
- Base Pairing/genetics
- Benzoxazines/metabolism
- Biosynthetic Pathways/genetics
- Chromosome Mapping
- Chromosomes, Plant/genetics
- Crosses, Genetic
- Gene Expression Regulation, Plant
- Genes, Plant
- Genotype
- Inbreeding
- Multigene Family
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plants, Genetically Modified
- Promoter Regions, Genetic/genetics
- Quantitative Trait Loci
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombination, Genetic
- Seedlings/metabolism
- Transcription, Genetic
- Zea mays/genetics
- Zea mays/growth & development
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Affiliation(s)
- Linlin Zheng
- Lehrstuhl für Genetik, Wissenschaftszentrum Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | | | - Eva Bauer
- Lehrstuhl für Pflanzenzüchtung, Wissenschaftszentrum Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - Chris-Carolin Schön
- Lehrstuhl für Pflanzenzüchtung, Wissenschaftszentrum Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - Alfons Gierl
- Lehrstuhl für Genetik, Wissenschaftszentrum Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - Monika Frey
- Lehrstuhl für Genetik, Wissenschaftszentrum Weihenstephan, Technische Universität München, 85354 Freising, Germany
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