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Binmöller L, Volkert C, Kiefer C, Zühl L, Slawinska MW, Loreth A, Nauerth BH, Ibberson D, Martinez R, Mandakova TM, Zipper R, Schmidt A. Differential expression and evolutionary diversification of RNA helicases in Boechera sexual and apomictic reproduction. J Exp Bot 2024; 75:2451-2469. [PMID: 38263359 DOI: 10.1093/jxb/erae026] [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] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 01/22/2024] [Indexed: 01/25/2024]
Abstract
In higher plants, sexual reproduction is characterized by meiosis of the first cells of the germlines, and double fertilization of the egg and central cell after gametogenesis. In contrast, in apomicts of the genus Boechera, meiosis is omitted or altered and only the central cell requires fertilization, while the embryo forms parthenogenetically from the egg cell. To deepen the understanding of the transcriptional basis underlying these differences, we applied RNA-seq to compare expression in reproductive tissues of different Boechera accessions. This confirmed previous evidence of an enrichment of RNA helicases in plant germlines. Furthermore, few RNA helicases were differentially expressed in female reproductive ovule tissues harboring mature gametophytes from apomictic and sexual accessions. For some of these genes, we further found evidence for a complex recent evolutionary history. This included a homolog of Arabidopsis thaliana FASCIATED STEM4 (FAS4). In contrast to AtFAS4, which is a single-copy gene, FAS4 is represented by three homologs in Boechera, suggesting a potential for subfunctionalization to modulate reproductive development. To gain first insights into functional roles of FAS4, we studied Arabidopsis lines carrying mutant alleles. This identified the crucial importance of AtFAS4 for reproduction, as we observed developmental defects and arrest during male and female gametogenesis.
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Affiliation(s)
- Laura Binmöller
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Christopher Volkert
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Christiane Kiefer
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Luise Zühl
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Magdalena W Slawinska
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Anna Loreth
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Berit H Nauerth
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany
| | - Rafael Martinez
- Centre for Organismal Studies Heidelberg, Department of Developmental Biology, Heidelberg University, Im Neuenheimer Feld 230, D-69120, Heidelberg, Germany
| | - Terezie M Mandakova
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Reinhard Zipper
- Institute of Biology, Plant Evolutionary Biology, University of Hohenheim, Garbenstrasse 30, D-70599 Stuttgart, Germany
| | - Anja Schmidt
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
- Institute of Biology, Plant Evolutionary Biology, University of Hohenheim, Garbenstrasse 30, D-70599 Stuttgart, Germany
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Kiefer M, Nauerth BH, Volkert C, Ibberson D, Loreth A, Schmidt A. Gene Function Rather than Reproductive Mode Drives the Evolution of RNA Helicases in Sexual and Apomictic Boechera. Genome Biol Evol 2020; 12:656-673. [PMID: 32302391 PMCID: PMC7250504 DOI: 10.1093/gbe/evaa078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2020] [Indexed: 12/20/2022] Open
Abstract
In higher plants, sexual and asexual reproductions through seeds (apomixis) have evolved as alternative strategies. Evolutionary advantages leading to coexistence of both reproductive modes are currently not well understood. It is expected that accumulation of deleterious mutations leads to a rapid elimination of apomictic lineages from populations. In this line, apomixis originated repeatedly, likely from deregulation of the sexual pathway, leading to alterations in the development of reproductive lineages (germlines) in apomicts as compared with sexual plants. This potentially involves mutations in genes controlling reproduction. Increasing evidence suggests that RNA helicases are crucial regulators of germline development. To gain insights into the evolution of 58 members of this diverse gene family in sexual and apomictic plants, we applied target enrichment combined with next-generation sequencing to identify allelic variants from 24 accessions of the genus Boechera, comprising sexual, facultative, and obligate apomicts. Interestingly, allelic variants from apomicts did not show consistently increased mutation frequency. Either sequences were highly conserved in any accession, or allelic variants preferentially harbored mutations in evolutionary less conserved C- and N-terminal domains, or presented high mutation load independent of the reproductive mode. Only for a few genes allelic variants harboring deleterious mutations were only identified in apomicts. To test if high sequence conservation correlates with roles in fundamental cellular or developmental processes, we analyzed Arabidopsis thaliana mutant lines in VASA-LIKE (VASL), and identified pleiotropic defects during ovule and reproductive development. This indicates that also in apomicts mechanisms of selection are in place based on gene function.
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Affiliation(s)
- Markus Kiefer
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Berit H Nauerth
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Christopher Volkert
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Heidelberg, Germany
| | - Anna Loreth
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Anja Schmidt
- Department of Biodiversity and Plant Systematics, Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
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