Barley Anther and Meiocyte Transcriptome Dynamics in Meiotic Prophase I

• Main Authors: Abdellah Barakate, Jamie Orr, Miriam Schreiber, Isabelle Colas, Dominika Lewandowska, Nicola McCallum, Malcolm Macaulay, Jenny Morris, Mikel Arrieta, Pete E. Hedley, Luke Ramsay, Robbie Waugh
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2021-01-01
• Series: Frontiers in Plant Science
• Subjects: barley; anther; meiocyte; transcriptome; meiosis; argonaute
• Online Access: https://www.frontiersin.org/articles/10.3389/fpls.2020.619404/full

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.