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Ladinig U, Hörandl E, Klatt S, Wagner J. Reproductive Performance of the Alpine Plant Species Ranunculus kuepferi in a Climatic Elevation Gradient: Apomictic Tetraploids Do Not Show a General Fitness Advantage over Sexual Diploids. Life (Basel) 2024; 14:1202. [PMID: 39337984 PMCID: PMC11433044 DOI: 10.3390/life14091202] [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: 07/30/2024] [Revised: 09/15/2024] [Accepted: 09/18/2024] [Indexed: 09/30/2024] Open
Abstract
Previous studies on the mountain plant Ranunculus kuepferi concluded that apomictic self-compatible tetraploids have experienced a niche shift toward a colder climate during the Holocene, which suggests a fitness advantage over the sexual, self-sterile diploid parents under cold and stressful high-mountain conditions. However, there is still a lack of information on whether reproductive development would be advantageous for tetraploids. Here, we report on microsporogenesis, megagametogenesis, the dynamics of flower and seed development, and the consequences for reproductive success in a common garden experiment along a 1000 m climatic elevation gradient and in natural populations. Flower buds were initiated in the year preceding anthesis and passed winter in a pre-meiotic stage. Flower morphology differed in the known cytotype-specific way in that tetraploid flowers produced about twice as many carpels and fewer petals, stamens, and pollen grains than diploid flowers. Tetraploids developed precociously aposporous embryo sacs and showed a high rate of developmental disturbances. Sexual seed formation prevailed in diploids and pseudogamous apomixis in tetraploids. Along the elevation gradient, stigma pollen load, pollen performance, and seed output decreased. Combinations of reproductive traits, namely, bypass of meiosis irregularities and uniparental reproduction, might have promoted the vast expansion of apomictic R. kuepferi lines across the European Alps.
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Affiliation(s)
- Ursula Ladinig
- Department of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, A-6020 Innsbruck, Austria
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, D-37073 Goettingen, Germany
| | - Simone Klatt
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, D-37073 Goettingen, Germany
- Central Administration, University of Goettingen, Humboldtallee 15, D-37073 Goettingen, Germany
| | - Johanna Wagner
- Department of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, A-6020 Innsbruck, Austria
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Li X, Zhang L, Wei X, Datta T, Wei F, Xie Z. Polyploidization: A Biological Force That Enhances Stress Resistance. Int J Mol Sci 2024; 25:1957. [PMID: 38396636 PMCID: PMC10888447 DOI: 10.3390/ijms25041957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 02/01/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
Organisms with three or more complete sets of chromosomes are designated as polyploids. Polyploidy serves as a crucial pathway in biological evolution and enriches species diversity, which is demonstrated to have significant advantages in coping with both biotic stressors (such as diseases and pests) and abiotic stressors (like extreme temperatures, drought, and salinity), particularly in the context of ongoing global climate deterioration, increased agrochemical use, and industrialization. Polyploid cultivars have been developed to achieve higher yields and improved product quality. Numerous studies have shown that polyploids exhibit substantial enhancements in cell size and structure, physiological and biochemical traits, gene expression, and epigenetic modifications compared to their diploid counterparts. However, some research also suggested that increased stress tolerance might not always be associated with polyploidy. Therefore, a more comprehensive and detailed investigation is essential to complete the underlying stress tolerance mechanisms of polyploids. Thus, this review summarizes the mechanism of polyploid formation, the polyploid biochemical tolerance mechanism of abiotic and biotic stressors, and molecular regulatory networks that confer polyploidy stress tolerance, which can shed light on the theoretical foundation for future research.
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Affiliation(s)
- Xiaoying Li
- Henan International Joint Laboratory of Crop Gene Resources and Improvements, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
- Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T & R Base of Zhengzhou University, Zhengzhou 450002, China
| | - Luyue Zhang
- Henan International Joint Laboratory of Crop Gene Resources and Improvements, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Xiaochun Wei
- Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T & R Base of Zhengzhou University, Zhengzhou 450002, China
| | - Tanusree Datta
- Henan International Joint Laboratory of Crop Gene Resources and Improvements, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Fang Wei
- Henan International Joint Laboratory of Crop Gene Resources and Improvements, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
| | - Zhengqing Xie
- Henan International Joint Laboratory of Crop Gene Resources and Improvements, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China
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Niccolò T, Anderson AW, Emidio A. Apomixis: oh, what a tangled web we have! PLANTA 2023; 257:92. [PMID: 37000270 PMCID: PMC10066125 DOI: 10.1007/s00425-023-04124-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Apomixis is a complex evolutionary trait with many possible origins. Here we discuss various clues and causes, ultimately proposing a model harmonizing the three working hypotheses on the topic. Asexual reproduction through seeds, i.e., apomixis, is the holy grail of plant biology. Its implementation in modern breeding could be a game-changer for agriculture. It has the potential to generate clonal crops and maintain valuable complex genotypes and their associated heterotic traits without inbreeding depression. The genetic basis and origins of apomixis are still unclear. There are three central hypothesis for the development of apomixis that could be: i) a deviation from the sexual developmental program caused by an asynchronous development, ii) environmentally triggered through epigenetic regulations (a polyphenism of sex), iii) relying on one or more genes/alleles. Because of the ever-increasing complexity of the topic, the path toward a detailed understanding of the mechanisms underlying apomixis remains unclear. Here, we discuss the most recent advances in the evolution perspective of this multifaceted trait. We incorporated our understanding of the effect of endogenous effectors, such as small RNAs, epigenetic regulation, hormonal pathways, protein turnover, and cell wall modification in response to an upside stress. This can be either endogenous (hybridization or polyploidization) or exogenous environmental stress, mainly due to oxidative stress and the corresponding ROS (Reacting Oxygen Species) effectors. Finally, we graphically represented this tangled web.
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Affiliation(s)
- Terzaroli Niccolò
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy.
| | - Aaron W Anderson
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Fulbright Scholar From Department of Plant Sciences, University of California, Davis, USA
| | - Albertini Emidio
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Consorzio Interuniversitario per le Biotecnologie (CIB), Trieste, Italy
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Hörandl E. Geographical Parthenogenesis in Alpine and Arctic Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:844. [PMID: 36840192 PMCID: PMC9959270 DOI: 10.3390/plants12040844] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
The term "Geographical parthenogenesis" describes the phenomenon that asexual organisms usually occupy larger and more northern distribution areas than their sexual relatives, and tend to colonize previously glaciated areas. Several case studies on alpine and arctic plants confirm the geographical pattern, but the causal factors behind the phenomenon are still unclear. Research of the last decade in several plant families has shed light on the question and evaluated some of the classical evolutionary theories. Results confirmed, in general, that the advantages of uniparental reproduction enable apomictic plants to re-colonize faster in larger and more northern distribution areas. Associated factors like polyploidy seem to contribute mainly to the spatial separation of sexual and asexual cytotypes. Ecological studies suggest a better tolerance of apomicts to colder climates and temperate extremes, whereby epigenetic flexibility and phenotypic plasticity play an important role in occupying ecological niches under harsh conditions. Genotypic diversity appears to be of lesser importance for the distributional success of asexual plants. Classical evolutionary theories like a reduced pressure of biotic interactions in colder climates and hence an advantage to asexuals (Red Queen hypothesis) did not gain support from studies on plants. However, it is also still enigmatic why sexual outcrossing remains the predominant mode of reproduction also in alpine floras. Constraints for the origin of apomixis might play a role. Interestingly, some studies suggest an association of sexuality with abiotic stresses. Light stress in high elevations might explain why most alpine plants retain sexual reproduction despite other environmental factors that would favor apomixis. Directions for future research will be given.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, 37073 Göttingen, Germany
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Rajpal VR, Rathore P, Mehta S, Wadhwa N, Yadav P, Berry E, Goel S, Bhat V, Raina SN. Epigenetic variation: A major player in facilitating plant fitness under changing environmental conditions. Front Cell Dev Biol 2022; 10:1020958. [PMID: 36340045 PMCID: PMC9628676 DOI: 10.3389/fcell.2022.1020958] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Recent research in plant epigenetics has increased our understanding of how epigenetic variability can contribute to adaptive phenotypic plasticity in natural populations. Studies show that environmental changes induce epigenetic switches either independently or in complementation with the genetic variation. Although most of the induced epigenetic variability gets reset between generations and is short-lived, some variation becomes transgenerational and results in heritable phenotypic traits. The short-term epigenetic responses provide the first tier of transient plasticity required for local adaptations while transgenerational epigenetic changes contribute to stress memory and help the plants respond better to recurring or long-term stresses. These transgenerational epigenetic variations translate into an additional tier of diversity which results in stable epialleles. In recent years, studies have been conducted on epigenetic variation in natural populations related to various biological processes, ecological factors, communities, and habitats. With the advent of advanced NGS-based technologies, epigenetic studies targeting plants in diverse environments have increased manifold to enhance our understanding of epigenetic responses to environmental stimuli in facilitating plant fitness. Taking all points together in a frame, the present review is a compilation of present-day knowledge and understanding of the role of epigenetics and its fitness benefits in diverse ecological systems in natural populations.
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Affiliation(s)
- Vijay Rani Rajpal
- Department of Botany, Hansraj College, University of Delhi, Delhi, India
- *Correspondence: Vijay Rani Rajpal, , ; Shailendra Goel, ; Vishnu Bhat, ; Soom Nath Raina,
| | | | - Sahil Mehta
- School of Agricultural Sciences, K.R. Mangalam University, Gurugram, Haryana, India
| | - Nikita Wadhwa
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India
| | | | - Eapsa Berry
- Maharishi Kanad Bhawan, Delhi School of Climate Change and Sustainability, University of Delhi, Delhi, India
| | - Shailendra Goel
- Department of Botany, University of Delhi, Delhi, India
- *Correspondence: Vijay Rani Rajpal, , ; Shailendra Goel, ; Vishnu Bhat, ; Soom Nath Raina,
| | - Vishnu Bhat
- Department of Botany, University of Delhi, Delhi, India
- *Correspondence: Vijay Rani Rajpal, , ; Shailendra Goel, ; Vishnu Bhat, ; Soom Nath Raina,
| | - Soom Nath Raina
- Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
- *Correspondence: Vijay Rani Rajpal, , ; Shailendra Goel, ; Vishnu Bhat, ; Soom Nath Raina,
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Syngelaki E, Paetzold C, Hörandl E. Gene Expression Profiles Suggest a Better Cold Acclimation of Polyploids in the Alpine Species Ranunculus kuepferi (Ranunculaceae). Genes (Basel) 2021; 12:1818. [PMID: 34828424 PMCID: PMC8625111 DOI: 10.3390/genes12111818] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 12/17/2022] Open
Abstract
Alpine habitats are shaped by harsh abiotic conditions and cold climates. Temperature stress can affect phenotypic plasticity, reproduction, and epigenetic profiles, which may affect acclimation and adaptation. Distribution patterns suggest that polyploidy seems to be advantageous under cold conditions. Nevertheless, whether temperature stress can induce gene expression changes in different cytotypes, and how the response is initialized through gene set pathways and epigenetic control remain vague for non-model plants. The perennial alpine plant Ranunculus kuepferi was used to investigate the effect of cold stress on gene expression profiles. Diploid and autotetraploid individuals were exposed to cold and warm conditions in climate growth chambers and analyzed via transcriptome sequencing and qRT-PCR. Overall, cold stress changed gene expression profiles of both cytotypes and induced cold acclimation. Diploids changed more gene set pathways than tetraploids, and suppressed pathways involved in ion/cation homeostasis. Tetraploids mostly activated gene set pathways related to cell wall and plasma membrane. An epigenetic background for gene regulation in response to temperature conditions is indicated. Results suggest that perennial alpine plants can respond to temperature extremes via altered gene expression. Tetraploids are better acclimated to cold conditions, enabling them to colonize colder climatic areas in the Alps.
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Affiliation(s)
- Eleni Syngelaki
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
| | - Claudia Paetzold
- Department of Botany and Molecular Evolution, Senckenberg Research Institute, 60325 Frankfurt am Main, Germany;
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
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Ulum FB, Hadacek F, Hörandl E. Polyploidy Improves Photosynthesis Regulation within the Ranunculus auricomus Complex (Ranunculaceae). BIOLOGY 2021; 10:biology10080811. [PMID: 34440043 PMCID: PMC8389576 DOI: 10.3390/biology10080811] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/12/2021] [Accepted: 08/19/2021] [Indexed: 01/10/2023]
Abstract
Simple Summary Genome duplication or multiplication, polyploidy, has contributed substantially to the evolutionary success of plants. Polyploidy is often connected to a higher resilience to environmental stress. We have chosen the goldilocks, the Ranunculus auricomus complex, to study effects of light stress. In this species complex, diploid (2x), tetraploid (4x), and hexaploid (6x) cytotypes occur in Central Europe in both shaded and sun-exposed habitats. In this study, we exposed them to different photoperiods in climate growth chambers to explore how the efficiency of photosynthesis varied between the various ploidies (2x, 4x, and 6x). We used fluorescence experiments exploring the proportion of light that is captured for photosynthesis and the resulting energy fluxes. In addition, quenching coefficients can be calculated that inform about the capability of a plant to deal with excess light. We found that the polyploids can quench excess light better, which concurs with their adaptation to open habitats and their predominantly asexual mode of reproduction that is probably favored by low stress levels in the reproductive tissues. Abstract Polyploidy has substantially contributed to successful plant evolution, and is often connected to a higher resilience to environmental stress. We test the hypothesis that polyploids tolerate light stress better than diploids. The Ranunculus auricomus complex comprises diploid (2x), tetraploid (4x), and hexaploid (6x) cytotypes, the former of which occur in shaded habitats and the latter more in open, sun-exposed habitats in Central Europe. In this study, we experimentally explored the effects of ploidy and photoperiod extension on the efficiency of photosystem II in the three cytotypes in climate growth chambers. Quantum yields and various coefficients that can be calculated from light curve, Kautsky curve, and fluorescent transient OJIP experiments provided support for the hypothesis that, in comparison to diploids, the improved regulation of excess light by more efficient photochemical and non-chemical quenching in polyploids might have facilitated the adaptation to unshaded habitats. We suggest how lower stress levels in reproductive tissues of polyploids might have favored asexual reproduction.
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Affiliation(s)
- Fuad Bahrul Ulum
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, 37073 Göttingen, Germany;
- Georg-August University School of Science (GAUSS), University of Göttingen, 37073 Göttingen, Germany
- Biology Department, Faculty of Mathematics and Sciences, Jember University, Jember 68121, Indonesia
| | - Franz Hadacek
- Department of Plant Biochemistry, Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, 37077 Göttingen, Germany;
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Göttingen, 37073 Göttingen, Germany;
- Correspondence: ; Tel.: +49-551-39-7843
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Syngelaki E, Daubert M, Klatt S, Hörandl E. Phenotypic Responses, Reproduction Mode and Epigenetic Patterns under Temperature Treatments in the Alpine Plant Species Ranunculus kuepferi (Ranunculaceae). BIOLOGY 2020; 9:E315. [PMID: 33003474 PMCID: PMC7600421 DOI: 10.3390/biology9100315] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/18/2020] [Accepted: 09/26/2020] [Indexed: 12/04/2022]
Abstract
Plant life in alpine habitats is shaped by harsh abiotic conditions and cold climates. Phenotypic variation of morphological characters and reproduction can be influenced by temperature stress. Nevertheless, little is known about the performance of different cytotypes under cold stress and how epigenetic patterns could relate to phenotypic variation. Ranunculus kuepferi, a perennial alpine plant, served as a model system for testing the effect of cold stress on phenotypic plasticity, reproduction mode, and epigenetic variation. Diploid and autotetraploid individuals were placed in climate growth cabinets under warm and cold conditions. Morphological traits (height, leaves and flowers) and the proportion of well-developed seeds were measured as fitness indicators, while flow cytometric seed screening (FCSS) was utilized to determine the reproduction mode. Subsequently, comparisons with patterns of methylation-sensitive amplified fragment-length polymorphisms (AFLPs) were conducted. Diploids grew better under warm conditions, while tetraploids performed better in cold treatments. Epigenetic patterns were correlated with the expressed morphological traits. Cold stress reduced the reproduction fitness but did not induce apomixis in diploids. Overall, our study underlines the potential of phenotypic plasticity for acclimation under environmental conditions and confirms the different niche preferences of cytotypes in natural populations. Results help to understand the pattern of geographical parthenogenesis in the species.
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Affiliation(s)
- Eleni Syngelaki
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
| | - Mareike Daubert
- Institute of Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany;
| | - Simone Klatt
- Section Safety and Environmental Protection, Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
| | - Elvira Hörandl
- Albrecht-von-Haller-Institute for Plant Sciences, Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Georg-August-Universität Göttingen, 37073 Göttingen, Germany;
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Chasing the Apomictic Factors in the Ranunculus auricomus Complex: Exploring Gene Expression Patterns in Microdissected Sexual and Apomictic Ovules. Genes (Basel) 2020; 11:genes11070728. [PMID: 32630035 PMCID: PMC7397075 DOI: 10.3390/genes11070728] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/10/2020] [Accepted: 06/27/2020] [Indexed: 12/24/2022] Open
Abstract
Apomixis, the asexual reproduction via seeds, is associated to polyploidy and hybridization. To identify possible signatures of apomixis, and possible candidate genes underlying the shift from sex to apomixis, microarray-based gene expression patterns of live microdissected ovules at four different developmental stages were compared between apomictic and sexual individuals of the Ranunculus auricomus complex. Following predictions from previous work on mechanisms underlying apomixis penetrance and expressivity in the genus, gene expression patterns were classified into three categories based on their relative expression in apomicts compared to their sexual parental ancestors. We found evidence of misregulation and differential gene expression between apomicts and sexuals, with the highest number of differences detected during meiosis progression and emergence of aposporous initial (AI) cells, a key developmental stage in the ovule of apomicts where a decision between divergent reproductive pathways takes place. While most of the differentially expressed genes (DEGs) could not be annotated, gene expression was classified into transgressive, parent of origin and ploidy effects. Genes related to gametogenesis and meiosis demonstrated patterns reflective of transgressive and genome dosage effects, which support the hypothesis of a dominant factor controlling apomixis in Ranunculus and modulated by secondary modifiers. Three genes with probable functions in sporogenesis and gametogenesis development are identified and characterized for future studies.
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