SODplex, a Series of Hierarchical Multiplexed Real-Time PCR Assays for the Detection and Lineage Identification of Phytophthora ramorum, the Causal Agent of Sudden Oak Death and Sudden Larch Death

Since its emergence in the 1990s, the invasive pathogen Phytophthora ramorum has spread in Europe and the west coast of North America, causing sudden oak death in the United States and sudden larch death in the United Kingdom, resulting in the mortality or destruction of millions of trees. Due to its invasive nature, its damage potential, its wide host range, and its ability to disseminate via the plant trade, P. ramorum has been placed on quarantine lists worldwide. Rapid and reliable detection of the pathogen and identification of its lineages are crucial to limit spread and inform mitigation and eradication efforts. SODplex, a suite of new multiplex real-time PCR tools, was developed to streamline the detection and identification of P. ramorum. It offers four multiplexed assays covering different use cases. SODplex-base combines primers and probes for the sensitive and accurate detection of Phytophthora spp. and P. ramorum. SODplex-ITS and SODplex-mito offer a single-step identification of P. ramorum and the EU1, NA1, and NA2 lineages present in the United States and Canada. SODplex-lin targets each of the four P. ramorum lineages present in Europe and North America in a single reaction. The assays have high levels of accuracy and are robust to the use of different instruments, different operators, and different temperatures. The redundancy within the assays reduces the likelihood of false negatives and false positives. The SODplex assays presented here improve the toolbox available for the detection of P. ramorum and its lineages. [Graphic: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license

Data from: Genetic and genomic evidence of niche partitioning and adaptive radiation in mountain pine beetle fungal symbionts

Bark beetles form multipartite symbiotic associations with blue stain fungi (Ophiostomatales, Ascomycota). These fungal symbionts play an important role during the beetle's life cycle by providing nutritional supplementation, overcoming tree defences and modifying host tissues to favour brood development. The maintenance of stable multipartite symbioses with seemingly less competitive symbionts in similar habitats is of fundamental interest to ecology and evolution. We tested the hypothesis that the coexistence of three fungal species associated with the mountain pine beetle is the result of niche partitioning and adaptive radiation using SNP genotyping coupled with genotype–environment association analysis and phenotypic characterization of growth rate under different temperatures. We found that genetic variation and population structure within each species is best explained by distinct spatial and environmental variables. We observed both common (temperature seasonality and the host species) and distinct (drought, cold stress, precipitation) environmental and spatial factors that shaped the genomes of these fungi resulting in contrasting outcomes. Phenotypic intraspecific variations in Grosmannia clavigera and Leptographium longiclavatum, together with high heritability, suggest potential for adaptive selection in these species. By contrast, Ophiostoma montium displayed narrower intraspecific variation but greater tolerance to extreme high temperatures. Our study highlights unique phenotypic and genotypic characteristics in these symbionts that are consistent with our hypothesis. By maintaining this multipartite relationship, the bark beetles have a greater likelihood of obtaining the benefits afforded by the fungi and reduce the risk of being left aposymbiotic. Complementarity among species could facilitate colonization of new habitats and survival under adverse conditions

275 years of forestry meets genomics in Pinus sylvestris

Abstract Pinus sylvestris has a long history of basic and applied research that is relevant for both forestry and evolutionary studies. Its patterns of adaptive variation and role in forest economic and ecological systems have been studied extensively for nearly 275 years, detailed demography for a 100 years and mating system more than 50 years. However, its reference genome sequence is not yet available and genomic studies have been lagging compared to, for example, Pinus taeda and Picea abies, two other economically important conifers. Despite the lack of reference genome, many modern genomic methods are applicable for a more detailed look at its biological characteristics. For example, RNA‐seq has revealed a complex transcriptional landscape and targeted DNA sequencing displays an excess of rare variants and geographically homogenously distributed molecular genetic diversity. Current DNA and RNA resources can be used as a reference for gene expression studies, SNP discovery, and further targeted sequencing. In the future, specific consequences of the large genome size, such as functional effects of regulatory open chromatin regions and transposable elements, should be investigated more carefully. For forest breeding and long‐term management purposes, genomic data can help in assessing the genetic basis of inbreeding depression and the application of genomic tools for genomic prediction and relatedness estimates. Given the challenges of breeding (long generation time, no easy vegetative propagation) and the economic importance, application of genomic tools has a potential to have a considerable impact. Here, we explore how genomic characteristics of P. sylvestris, such as rare alleles and the low extent of linkage disequilibrium, impact the applicability and power of the tools