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Rajabhoj MP, Sankar S, Bondada R, Shanmukhan AP, Prasad K, Maruthachalam R. Gametophytic epigenetic regulators, MEDEA and DEMETER, synergistically suppress ectopic shoot formation in Arabidopsis. PLANT CELL REPORTS 2024; 43:68. [PMID: 38341844 DOI: 10.1007/s00299-024-03159-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/11/2024] [Indexed: 02/13/2024]
Abstract
KEY MESSAGE The gametophytic epigenetic regulators, MEA and DME, extend their synergistic role to the sporophytic development by regulating the meristematic activity via restricting the gene expression in the shoot apex. The gametophyte-to-sporophyte transition facilitates the alternation of generations in a plant life cycle. The epigenetic regulators DEMETER (DME) and MEDEA (MEA) synergistically control central cell proliferation and differentiation, ensuring proper gametophyte-to-sporophyte transition in Arabidopsis. Mutant alleles of DME and MEA are female gametophyte lethal, eluding the recovery of recessive homozygotes to examine their role in the sporophyte. Here, we exploited the paternal transmission of these mutant alleles coupled with CENH3-haploid inducer to generate mea-1;dme-2 sporophytes. Strikingly, the simultaneous loss of function of MEA and DME leads to the emergence of ectopic shoot meristems at the apical pole of the plant body axis. DME and MEA are expressed in the developing shoot apex and regulate the expression of various shoot-promoting factors. Chromatin immunoprecipitation (ChIP), DNA methylation, and gene expression analysis revealed several shoot regulators as potential targets of MEA and DME. RNA interference-mediated transcriptional downregulation of shoot-promoting factors STM, CUC2, and PLT5 rescued the twin-plant phenotype to WT in 9-23% of mea-1-/-;dme-2-/- plants. Our findings reveal a previously unrecognized synergistic role of MEA and DME in restricting the meristematic activity at the shoot apex during sporophytic development.
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Affiliation(s)
- Mohit P Rajabhoj
- School of Biology, IISER Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India
| | - Sudev Sankar
- School of Biology, IISER Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - Ramesh Bondada
- School of Biology, IISER Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India
| | | | - Kalika Prasad
- Department of Biology, IISER Pune, Pune, Maharashtra, 411008, India.
| | - Ravi Maruthachalam
- School of Biology, IISER Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India.
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Bondada R, Kulaar DS, Siddiqi I, Maruthachalam R. Cantil - a new organ or a morphological oddity? THE NEW PHYTOLOGIST 2021; 232:1904-1908. [PMID: 34537960 DOI: 10.1111/nph.17744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Cantil is reported as a new-found organ specific to the model plant Arabidopsis thaliana that is prominent only in short-day-grown wild-type accessions or long-day-grown genetic mutants with delayed vegetative to reproductive transition. Here, we show that cantils (previously known as nubbins) arise as one of the many phenotypic consequences of aneuploidy resulting from chromosome dosage imbalances in Arabidopsis polyaneuploids despite normal reproductive transition in long-day photoperiods. Without a demonstrated function or adaptive significance, we view cantils as a morphological oddity rather than a separate organ, and as a manifestation of physiological perturbations triggered by genetic and environmental factors. We also note a striking phenotypic resemblance between 'cantil' and 'gynophore', a floral morphological structure that is naturally present in the allopolyploid Arabidopsis suecica.
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Affiliation(s)
- Ramesh Bondada
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram (IISER TVM), Maruthamala PO, Vithura, Thiruvananthapuram, Kerala, 695551, India
| | - Dilsher Singh Kulaar
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram (IISER TVM), Maruthamala PO, Vithura, Thiruvananthapuram, Kerala, 695551, India
| | - Imran Siddiqi
- CSIR-Centre for Cellular and Molecular Biology (CCMB), Habsiguda, Uppal Road, Hyderabad, Telangana, 500007, India
| | - Ravi Maruthachalam
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram (IISER TVM), Maruthamala PO, Vithura, Thiruvananthapuram, Kerala, 695551, India
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Marimuthu MPA, Maruthachalam R, Bondada R, Kuppu S, Tan EH, Britt A, Chan SWL, Comai L. Epigenetically mismatched parental centromeres trigger genome elimination in hybrids. SCIENCE ADVANCES 2021; 7:eabk1151. [PMID: 34797718 PMCID: PMC8604413 DOI: 10.1126/sciadv.abk1151] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Wide crosses result in postzygotic elimination of one parental chromosome set, but the mechanisms that result in such differential fate are poorly understood. Here, we show that alterations of centromeric histone H3 (CENH3) lead to its selective removal from centromeres of mature Arabidopsis eggs and early zygotes, while wild-type CENH3 persists. In the hybrid zygotes and embryos, CENH3 and essential centromere proteins load preferentially on the CENH3-rich centromeres of the wild-type parent, while CENH3-depleted centromeres fail to reconstitute new CENH3-chromatin and the kinetochore and are frequently lost. Genome elimination is opposed by E3 ubiquitin ligase VIM1. We propose a model based on cooperative binding of CENH3 to chromatin to explain the differential CENH3 loading rates. Thus, parental CENH3 polymorphisms result in epigenetically distinct centromeres that instantiate a strong mating barrier and produce haploids.
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Affiliation(s)
- Mohan P. A. Marimuthu
- UC Davis Genome Center, UC Davis, Davis, CA, USA
- Department of Plant Biology, UC Davis, Davis, CA, USA
| | - Ravi Maruthachalam
- School of Biology, Indian Institute of Science Education and Research (IISER), Thiruvananthapuram, Vithura, Kerala 695551, India
| | - Ramesh Bondada
- School of Biology, Indian Institute of Science Education and Research (IISER), Thiruvananthapuram, Vithura, Kerala 695551, India
| | | | | | - Anne Britt
- Department of Plant Biology, UC Davis, Davis, CA, USA
| | | | - Luca Comai
- UC Davis Genome Center, UC Davis, Davis, CA, USA
- Department of Plant Biology, UC Davis, Davis, CA, USA
- Corresponding author.
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Thondehaalmath T, Kulaar DS, Bondada R, Maruthachalam R. Understanding and exploiting uniparental genome elimination in plants: insights from Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4646-4662. [PMID: 33851980 DOI: 10.1093/jxb/erab161] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 04/10/2021] [Indexed: 06/12/2023]
Abstract
Uniparental genome elimination (UGE) refers to the preferential exclusion of one set of the parental chromosome complement during embryogenesis following successful fertilization, giving rise to uniparental haploid progeny. This artificially induced phenomenon was documented as one of the consequences of distant (wide) hybridization in plants. Ten decades since its discovery, attempts to unravel the molecular mechanism behind this process remained elusive due to a lack of genetic tools and genomic resources in the species exhibiting UGE. Hence, its successful adoption in agronomic crops for in planta (in vivo) haploid production remains implausible. Recently, Arabidopsis thaliana has emerged as a model system to unravel the molecular basis of UGE. It is now possible to simulate the genetic consequences of distant crosses in an A. thaliana intraspecific cross by a simple modification of centromeres, via the manipulation of the centromere-specific histone H3 variant gene, CENH3. Thus, the experimental advantages conferred by A. thaliana have been used to elucidate and exploit the benefits of UGE in crop breeding. In this review, we discuss developments and prospects of CENH3 gene-mediated UGE and other in planta haploid induction strategies to illustrate its potential in expediting plant breeding and genetics in A. thaliana and other model plants.
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Affiliation(s)
- Tejas Thondehaalmath
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
| | - Dilsher Singh Kulaar
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
| | - Ramesh Bondada
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
| | - Ravi Maruthachalam
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
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Seguí-Simarro JM, Moreno JB, Fernández MG, Mir R. Species with Haploid or Doubled Haploid Protocols. Methods Mol Biol 2021; 2287:41-103. [PMID: 34270025 DOI: 10.1007/978-1-0716-1315-3_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In this chapter, we present a list of species (and few interspecific hybrids) where haploids and/or doubled haploids have been published, including the method by which they were obtained and the corresponding references. This list is an update of the compilation work of Maluszynski et al. published in 2003, including new species for which protocols were not available at that time, and also novel methodologies developed during these years. The list includes 383 different backgrounds. In this book, we present full protocols to produce DHs in 43 of the species included in this list. In addition, this book includes a chapter for one species not included in the list. This makes a total of 384 species where haploids and/or DHs have been reported up to date.
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Affiliation(s)
- Jose M Seguí-Simarro
- Cell Biology Group - COMAV Institute, Universitat Politècnica de València, Valencia, Spain.
| | | | | | - Ricardo Mir
- Cell Biology Group - COMAV Institute, Universitat Politècnica de València, Valencia, Spain
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Bondada R, Somasundaram S, Marimuthu MP, Badarudeen MA, Puthiyaveedu VK, Maruthachalam R. Natural epialleles of Arabidopsis SUPERMAN display superwoman phenotypes. Commun Biol 2020; 3:772. [PMID: 33319840 PMCID: PMC7738503 DOI: 10.1038/s42003-020-01525-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 11/25/2020] [Indexed: 01/07/2023] Open
Abstract
Epimutations are heritable changes in gene function due to loss or gain of DNA cytosine methylation or chromatin modifications without changes in the DNA sequence. Only a few natural epimutations displaying discernible phenotypes are documented in plants. Here, we report natural epimutations in the cadastral gene, SUPERMAN(SUP), showing striking phenotypes despite normal transcription, discovered in a natural tetraploid, and subsequently in eleven diploid Arabidopsis genetic accessions. This natural lois lane(lol) epialleles behave as recessive mendelian alleles displaying a spectrum of silent to strong superwoman phenotypes affecting only the carpel whorl, in contrast to semi-dominant superman or supersex features manifested by induced epialleles which affect both stamen and carpel whorls. Despite its unknown origin, natural lol epialleles are subjected to the same epigenetic regulation as induced clk epialleles. The existence of superwoman epialleles in diverse wild populations is interpreted in the light of the evolution of unisexuality in plants. Ramesh Bondada et al. report natural epimutations in the Arabidopsis SUPERMAN gene from tetraploid and diploid accessions. The existence of these epialleles in diverse wild populations have the potential to shed light on the evolution of unisexuality in plants.
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Affiliation(s)
- Ramesh Bondada
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | - Saravanakumar Somasundaram
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | | | - Mohammed Afsal Badarudeen
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | - Vaishak Kanjirakol Puthiyaveedu
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | - Ravi Maruthachalam
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India.
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Abstract
Recombinant inbred lines (RILs) are an essential tool for quantitative trait locus (QTL) mapping in Arabidopsis thaliana. Conventionally, the development of these lines is a time-consuming and tedious process requiring six to eight generations of selfing. Here, we describe an alternative approach: the rapid generation of RILs in A. thaliana via the creation of doubled haploids. In this method, F1 plants are crossed to an engineered haploid inducer to produce haploid plants. The chromosomes of these haploids then spontaneously double, generating immortalized homozygous F2 lines called doubled haploid RILs (DH RILs). Finally, DH RILs are genotyped using low-coverage whole-genome sequencing and are ready to be used for QTL mapping.
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