Potato cyst nematodes (PCN; Globodera rostochiensis and G. pallida) are quarantine pests (EPPO 2013) and have recently been reported from Kenya (Mburu et al. 2018) and Rwanda (Niragire et al. 2019)...

Pasteuria spp. are endospore forming bacteria which act as natural antagonists to many of the most economically significant plant parasitic nematodes (PPNs). Highly species-specific nematode suppression may be observed in soils containing a sufficiently high density of Pasteuria spp. spores. This suppression is enacted by the bacteria via inhibition of root invasion and sterilization of the nematode host. Molecular methods for the detection of Pasteuria spp. from environmental DNA (eDNA) have been described; however, these methods are limited in both scale and in depth. We report the use of small subunit rRNA gene metabarcoding to profile Pasteuria spp. and nematode communities in parallel. We have investigated Pasteuria spp. population structure in Scottish soils using eDNA from two sources: soil extracted DNA from the second National Soil Inventory of Scotland (NSIS2); and nematode extracted DNA collected from farms in the East Scotland Farm Network (ESFN). We compared the Pasteuria spp. community culture to both nematode community structure and the physiochemical properties of soils. Our results indicate that Pasteuria spp. populations in Scottish soils are broadly dominated by two sequence variants. The first of these aligns with high identity to Pasteuria hartismeri, a species first described parasitizing Meloidogyne ardenensis, a nematode parasite of woody and perennial plants in northern Europe. The second aligns with a Pasteuria-like sequence which was first recovered from a farm near Edinburgh which was found to contain bacterial feeding nematodes and Pratylenchus spp. encumbered by Pasteuria spp. endospores. Further, soil carbon, moisture, bulk density, and pH showed a strong correlation with the Pasteuria spp. community composition. These results indicate that metabarcoding is appropriate for the sensitive, specific, and semi-quantitative profiling of Pasteuria species from eDNA.

Meiosis is a specialized cell division which is essential to sexual reproduction. The success of this highly ordered process involves the timely activation, interaction, movement, and removal of many proteins. Ubiquitination is an extraordinarily diverse post-translational modification with a regulatory role in almost all cellular processes. During meiosis, ubiquitin localizes to chromatin and the expression of genes related to ubiquitination appears to be enhanced. This may be due to extensive protein turnover mediated by proteasomal degradation. However, degradation is not the only substrate fate conferred by ubiquitination which may also mediate, for example, the activation of key transcription factors. In plant meiosis, the specific roles of several components of the ubiquitination cascade—particularly SCF complex proteins, the APC/C, and HEI10—have been partially characterized indicating diverse roles in chromosome segregation, recombination, and synapsis. Nonetheless, these components remain comparatively poorly understood to their counterparts in other processes and in other eukaryotes. In this review, we present an overview of our understanding of the role of ubiquitination in plant meiosis, highlighting recent advances, remaining challenges, and high throughput methods which may be used to overcome them.

In flowering plants, successful germinal cell development and meiotic recombination depend upon a combination of environmental and genetic factors. To gain insights into this specialised reproductive development programme 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 occur at the transition from pre-meiosis to leptotene–zygotene, which is followed by largely stable transcript abundance throughout prophase I. Our analysis reveals that the developing anthers and meiocytes 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 orthologues showed differential transcript abundance in at least one stage or tissue comparison. Changes in the abundance of numerous transcription factors, representatives of the small RNA processing machinery, and post-translational modification pathways highlight the complexity of the regulatory networks involved. These developmental, time-resolved, and dynamic transcriptomes increase our understanding of anther and meiocyte development and will help guide future research. One sentence summary: Analysis of RNA-seq data from meiotically staged barley anthers and meiocytes highlights the role of lncRNAs within a complex network of transcriptional and post-transcriptional regulation accompanied by a hiatus in differential gene expression during prophase I. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors ( www.plantcell.org ) is: Robbie Waugh ( robbie.waugh@hutton.ac.uk )