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Seetharam AS, Yu Y, Bélanger S, Clark LG, Meyers BC, Kellogg EA, Hufford MB. The Streptochaeta Genome and the Evolution of the Grasses. FRONTIERS IN PLANT SCIENCE 2021; 12:710383. [PMID: 34671369 PMCID: PMC8521107 DOI: 10.3389/fpls.2021.710383] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 09/08/2021] [Indexed: 05/15/2023]
Abstract
In this work, we sequenced and annotated the genome of Streptochaeta angustifolia, one of two genera in the grass subfamily Anomochlooideae, a lineage sister to all other grasses. The final assembly size is over 99% of the estimated genome size. We find good collinearity with the rice genome and have captured most of the gene space. Streptochaeta is similar to other grasses in the structure of its fruit (a caryopsis or grain) but has peculiar flowers and inflorescences that are distinct from those in the outgroups and in other grasses. To provide tools for investigations of floral structure, we analyzed two large families of transcription factors, AP2-like and R2R3 MYBs, that are known to control floral and spikelet development in rice and maize among other grasses. Many of these are also regulated by small RNAs. Structure of the gene trees showed that the well documented whole genome duplication at the origin of the grasses (ρ) occurred before the divergence of the Anomochlooideae lineage from the lineage leading to the rest of the grasses (the spikelet clade) and thus that the common ancestor of all grasses probably had two copies of the developmental genes. However, Streptochaeta (and by inference other members of Anomochlooideae) has lost one copy of many genes. The peculiar floral morphology of Streptochaeta may thus have derived from an ancestral plant that was morphologically similar to the spikelet-bearing grasses. We further identify 114 loci producing microRNAs and 89 loci generating phased, secondary siRNAs, classes of small RNAs known to be influential in transcriptional and post-transcriptional regulation of several plant functions.
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Affiliation(s)
- Arun S. Seetharam
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
| | - Yunqing Yu
- Donald Danforth Plant Science Center, St. Louis, MO, United States
| | | | - Lynn G. Clark
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
| | - Blake C. Meyers
- Donald Danforth Plant Science Center, St. Louis, MO, United States
- Division of Plant Sciences, University of Missouri, Columbia, MO, United States
| | | | - Matthew B. Hufford
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
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Barakate A, Orr J, Schreiber M, Colas I, Lewandowska D, McCallum N, Macaulay M, Morris J, Arrieta M, Hedley PE, Ramsay L, Waugh R. Barley Anther and Meiocyte Transcriptome Dynamics in Meiotic Prophase I. FRONTIERS IN PLANT SCIENCE 2021; 11:619404. [PMID: 33510760 PMCID: PMC7835676 DOI: 10.3389/fpls.2020.619404] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/15/2020] [Indexed: 05/07/2023]
Abstract
In flowering plants, successful germinal cell development and meiotic recombination depend upon a combination of environmental and genetic factors. To gain insights into this specialized reproductive development program we used short- and long-read RNA-sequencing (RNA-seq) to study the temporal dynamics of transcript abundance in immuno-cytologically staged barley (Hordeum vulgare) anthers and meiocytes. We show that the most significant transcriptional changes in anthers occur at the transition from pre-meiosis to leptotene-zygotene, which is followed by increasingly stable transcript abundance throughout prophase I into metaphase I-tetrad. Our analysis reveals that the pre-meiotic anthers are enriched in long non-coding RNAs (lncRNAs) and that entry to meiosis is characterized by their robust and significant down regulation. Intriguingly, only 24% of a collection of putative meiotic gene orthologs showed differential transcript abundance in at least one stage or tissue comparison. Argonautes, E3 ubiquitin ligases, and lys48 specific de-ubiquitinating enzymes were enriched in prophase I meiocyte samples. These developmental, time-resolved transcriptomes demonstrate remarkable stability in transcript abundance in meiocytes throughout prophase I after the initial and substantial reprogramming at meiosis entry and the complexity of the regulatory networks involved in early meiotic processes.
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Affiliation(s)
- Abdellah Barakate
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Jamie Orr
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Miriam Schreiber
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Isabelle Colas
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | | | - Nicola McCallum
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Malcolm Macaulay
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Jenny Morris
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Mikel Arrieta
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Pete E. Hedley
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Luke Ramsay
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Robbie Waugh
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
- School of Agriculture and Wine, University of Adelaide, Adelaide, SA, Australia
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