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Abstract BackgroundMeiosis is a specialized cell division that underpins sexual reproduction in most eukaryotes. During meiosis, interhomolog meiotic recombination facilitates accurate chromosome segregation and generates genetic diversity by shuffling parental alleles in the gametes. The frequency of meiotic recombination inArabidopsishas a U-shaped curve in response to environmental temperature, and is dependent on the Type I, crossover (CO) interference-sensitive pathway. The mechanisms that modulate recombination frequency in response to temperature are not yet known. ResultsIn this study, we compare the transcriptomes of thermally-stressed meiotic-stage anthers frommsh4andmus81mutants that mediate the Type I and Type II meiotic recombination pathways, respectively. We show that heat stress reduces the number of expressed genes regardless of genotype. In addition,msh4mutants have a distinct gene expression pattern compared tomus81and wild type controls. Interestingly,ASY1,which encodes a HORMA domain protein that is a component of meiotic chromosome axes, is up-regulated in wild type andmus81but not inmsh4. In addition,SDSthe meiosis-specific cyclin-like gene,DMC1the meiosis-specific recombinase,SYN1/REC8the meiosis-specific cohesion complex component, andSWI1which functions in meiotic sister chromatid cohesion are up-regulated in all three genotypes. We also characterize 51 novel, previously unannotated transcripts, and show that their promoter regions are associated with A-rich meiotic recombination hotspot motifs. ConclusionsOur transcriptomic analysis ofmsh4andmus81mutants enhances our understanding of how the Type I and Type II meiotic CO pathway respond to environmental temperature stress and might provide a strategy to manipulate recombination levels in plants.
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Defining the developmental program leading to meiosis in maize
In multicellular organisms, the entry into meiosis is a complex process characterized by increasing meiotic specialization. Using single-cell RNA sequencing, we reconstructed the developmental program into maize male meiosis. A smooth continuum of expression stages before meiosis was followed by a two-step transcriptome reorganization in leptotene, during which 26.7% of transcripts changed in abundance by twofold or more. Analysis of cell-cycle gene expression indicated that nearly all pregerminal cells proliferate, eliminating a stem-cell model to generate meiotic cells. Mutants defective in somatic differentiation or meiotic commitment expressed transcripts normally present in early meiosis after a delay; thus, the germinal transcriptional program is cell autonomous and can proceed despite meiotic failure.
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- Award ID(s):
- 1754097
- PAR ID:
- 10093320
- Date Published:
- Journal Name:
- Science
- Volume:
- 364
- Issue:
- 6435
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- 52 to 56
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/science.aav6428
