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Zeng Y, Somers J, Bell HS, Dawe RK, Fowler JE, Nelms B, Gent JI. Potent pollen gene regulation by DNA glycosylases in maize. bioRxiv 2024:2024.02.13.580204. [PMID: 38405940 PMCID: PMC10888782 DOI: 10.1101/2024.02.13.580204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Although DNA methylation primarily represses transposable elements (TEs) in plants, it also represses select endosperm and pollen genes. These genes, or their cis-regulatory elements, are methylated in plant body tissues but are demethylated by DNA glycosylases (DNGs) in endosperm and pollen, enabling their transcription. Activity of either one of two DNGs, MDR1 or DNG102, is essential for pollen viability in maize. Using single-pollen mRNA sequencing on pollen segregating mutations in both genes, we identified 58 candidate DNG target genes, whose expression is strongly decreased in double mutant pollen (124-fold decrease on average). These genes account for 11.1% of the wild-type pollen polyadenylated transcriptome, but they are silent or barely detectable in the plant body. They are unusual in their tendency to lack introns but even more so in their having TE-like methylation in their coding DNA sequence. Moreover, they are strongly enriched for predicted functions in cell wall modification. While some may support development of the pollen grain cell wall, expansins and pectinases in this set of genes suggest a function in cell wall loosening to support the rapid tip growth characteristic of pollen tubes as they carry the sperm cells through maternal apoplast and extracellular matrix of the pistil. These results suggest a critical role for DNA methylation and demethylation in regulating maize genes with potential for extremely high expression in pollen but constitutive silencing elsewhere.
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Affiliation(s)
- Yibing Zeng
- University of Georgia, Department of Genetics, Athens, GA 30602
| | - Julian Somers
- University of Georgia, Department of Genetics, Athens, GA 30602
| | - Harrison S Bell
- Oregon State University, Department of Botany and Plant Pathology, Corvallis, OR 97331
| | - R Kelly Dawe
- University of Georgia, Department of Genetics, Athens, GA 30602
- University of Georgia, Department of Plant Biology, Athens, GA 30602
| | - John E Fowler
- Oregon State University, Department of Botany and Plant Pathology, Corvallis, OR 97331
| | - Brad Nelms
- University of Georgia, Department of Plant Biology, Athens, GA 30602
| | - Jonathan I Gent
- University of Georgia, Department of Plant Biology, Athens, GA 30602
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Liu Q, Ma X, Li X, Zhang X, Zhou S, Xiong L, Zhao Y, Zhou DX. Paternal DNA methylation is remodeled to maternal levels in rice zygote. Nat Commun 2023; 14:6571. [PMID: 37852973 PMCID: PMC10584822 DOI: 10.1038/s41467-023-42394-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023] Open
Abstract
Epigenetic reprogramming occurs during reproduction to reset the genome for early development. In flowering plants, mechanistic details of parental methylation remodeling in zygote remain elusive. Here we analyze allele-specific DNA methylation in rice hybrid zygotes and during early embryo development and show that paternal DNA methylation is predominantly remodeled to match maternal allelic levels upon fertilization, which persists after the first zygotic division. The DNA methylation remodeling pattern supports the predominantly maternal-biased gene expression during zygotic genome activation (ZGA) in rice. However, parental allelic-specific methylations are reestablished at the globular embryo stage and associate with allelic-specific histone modification patterns in hybrids. These results reveal that paternal DNA methylation is remodeled to match the maternal pattern during zygotic genome reprogramming and suggest existence of a chromatin memory allowing parental allelic-specific methylation to be maintained in the hybrid.
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Affiliation(s)
- Qian Liu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuan Ma
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xue Li
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xinran Zhang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shaoli Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lizhong Xiong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
- Institute of Plant Science Paris-Saclay (IPS2), CNRS, INRAE, University Paris-Saclay, 91405, Orsay, France.
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Zhou H, Deng XW, He H. Gene expression variations and allele-specific expression of two rice and their hybrid in caryopses at single-nucleus resolution. Front Plant Sci 2023; 14:1171474. [PMID: 37287712 PMCID: PMC10242081 DOI: 10.3389/fpls.2023.1171474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/26/2023] [Indexed: 06/09/2023]
Abstract
Seeds are an indispensable part of the flowering plant life cycle and a critical determinant of agricultural production. Distinct differences in the anatomy and morphology of seeds separate monocots and dicots. Although some progress has been made with respect to understanding seed development in Arabidopsis, the transcriptomic features of monocotyledon seeds at the cellular level are much less understood. Since most important cereal crops, such as rice, maize, and wheat, are monocots, it is essential to study transcriptional differentiation and heterogeneity during seed development at a finer scale. Here, we present single-nucleus RNA sequencing (snRNA-seq) results of over three thousand nuclei from caryopses of the rice cultivars Nipponbare and 9311 and their intersubspecies F1 hybrid. A transcriptomics atlas that covers most of the cell types present during the early developmental stage of rice caryopses was successfully constructed. Additionally, novel specific marker genes were identified for each nuclear cluster in the rice caryopsis. Moreover, with a focus on rice endosperm, the differentiation trajectory of endosperm subclusters was reconstructed to reveal the developmental process. Allele-specific expression (ASE) profiling in endosperm revealed 345 genes with ASE (ASEGs). Further pairwise comparisons of the differentially expressed genes (DEGs) in each endosperm cluster among the three rice samples demonstrated transcriptional divergence. Our research reveals differentiation in rice caryopsis from the single-nucleus perspective and provides valuable resources to facilitate clarification of the molecular mechanism underlying caryopsis development in rice and other monocots.
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Affiliation(s)
- Han Zhou
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing, China
- Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong, China
| | - Xing Wang Deng
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing, China
- Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong, China
| | - Hang He
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing, China
- Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong, China
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Szala K, Dmochowska-Boguta M, Bocian J, Orczyk W, Nadolska-Orczyk A. Transgenerational Paternal Inheritance of TaCKX GFMs Expression Patterns Indicate a Way to Select Wheat Lines with Better Parameters for Yield-Related Traits. Int J Mol Sci 2023; 24:ijms24098196. [PMID: 37175902 PMCID: PMC10179260 DOI: 10.3390/ijms24098196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/18/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
Members of the TaCKX gene family (GFMs) encode the cytokinin oxygenase/dehydrogenase enzyme (CKX), which irreversibly degrades cytokinins in the organs of wheat plants; therefore, these genes perform a key role in the regulation of yield-related traits. The purpose of the investigation was to determine how expression patterns of these genes, together with the transcription factor-encoding gene TaNAC2-5A, and yield-related traits are inherited to apply this knowledge to speed up breeding processes. The traits were tested in 7 days after pollination (DAP) spikes and seedling roots of maternal and paternal parents and their F2 progeny. The expression levels of most of them and the yield were inherited in F2 from the paternal parent. Some pairs or groups of genes cooperated, and some showed opposite functions. Models of up- or down-regulation of TaCKX GFMs and TaNAC2-5A in low-yielding maternal plants crossed with higher-yielding paternal plants and their high-yielding F2 progeny reproduced gene expression and yield of the paternal parent. The correlation coefficients between TaCKX GFMs, TaNAC2-5A, and yield-related traits in high-yielding F2 progeny indicated which of these genes were specifically correlated with individual yield-related traits. The most common was expressed in 7 DAP spikes TaCKX2.1, which positively correlated with grain number, grain yield, spike number, and spike length, and seedling root mass. The expression levels of TaCKX1 or TaNAC2-5A in the seedling roots were negatively correlated with these traits. In contrast, the thousand grain weight (TGW) was negatively regulated by TaCKX2.2.2, TaCKX2.1, and TaCKX10 in 7 DAP spikes but positively correlated with TaCKX10 and TaNAC2-5A in seedling roots. Transmission of TaCKX GFMs and TaNAC2-5A expression patterns and yield-related traits from parents to the F2 generation indicate their paternal imprinting. These newly shown data of nonmendelian epigenetic inheritance shed new light on crossing strategies to obtain a high-yielding F2 generation.
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Affiliation(s)
- Karolina Szala
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzikow, 05-870 Blonie, Poland
| | - Marta Dmochowska-Boguta
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzikow, 05-870 Blonie, Poland
| | - Joanna Bocian
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzikow, 05-870 Blonie, Poland
| | - Waclaw Orczyk
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzikow, 05-870 Blonie, Poland
| | - Anna Nadolska-Orczyk
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzikow, 05-870 Blonie, Poland
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Gent JI, Higgins KM, Swentowsky KW, Fu FF, Zeng Y, Kim DW, Dawe RK, Springer NM, Anderson SN. The maize gene maternal derepression of r1 encodes a DNA glycosylase that demethylates DNA and reduces siRNA expression in the endosperm. Plant Cell 2022; 34:3685-3701. [PMID: 35775949 PMCID: PMC9516051 DOI: 10.1093/plcell/koac199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 06/27/2022] [Indexed: 06/01/2023]
Abstract
Demethylation of transposons can activate the expression of nearby genes and cause imprinted gene expression in the endosperm; this demethylation is hypothesized to lead to expression of transposon small interfering RNAs (siRNAs) that reinforce silencing in the next generation through transfer either into egg or embryo. Here we describe maize (Zea mays) maternal derepression of r1 (mdr1), which encodes a DNA glycosylase with homology to Arabidopsis thaliana DEMETER and which is partially responsible for demethylation of thousands of regions in endosperm. Instead of promoting siRNA expression in endosperm, MDR1 activity inhibits it. Methylation of most repetitive DNA elements in endosperm is not significantly affected by MDR1, with an exception of Helitrons. While maternally-expressed imprinted genes preferentially overlap with MDR1 demethylated regions, the majority of genes that overlap demethylated regions are not imprinted. Double mutant megagametophytes lacking both MDR1 and its close homolog DNG102 result in early seed failure, and double mutant microgametophytes fail pre-fertilization. These data establish DNA demethylation by glycosylases as essential in maize endosperm and pollen and suggest that neither transposon repression nor genomic imprinting is its main function in endosperm.
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Affiliation(s)
| | - Kaitlin M Higgins
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Kyle W Swentowsky
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Fang-Fang Fu
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Yibing Zeng
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Dong won Kim
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Nathan M Springer
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, Minnesota 55108, USA
| | - Sarah N Anderson
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
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