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| (A) Douglas-fir native range in the Pacific Northwest (Little, 1971). The darker green shaded area is the Marine West Coast Forest EPA Level I Ecoregion, which is the study area used to train and test our lineage distribution modelings (LDMs). The lighter green shaded area is the rest of the Douglas-fir native range, the Area of Interest onto which we extrapolate our LDM predictions. (B) 62 presence and 9 absence points of lineage 1 of Nothophaeocryptopus gaeumannii across 71 sampled locations. (C) 42 presence and 29 absence points of lineage 2 of N. gaeumannii across 71 sampled locations.
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A growing body of evidence suggests that climate change is altering the epidemiology of many forest diseases. Nothophaeocryptopus gaeumannii (Rhode) Petrak, an ascomycete native to the Pacific Northwest and the causal agent of the Swiss needle cast (SNC) disease of Douglas-fir [ Pseudotsuga menziesii (Mirbel) Franco], is no exception. In the past f...
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... study area chosen for the training and testing of our LDMs is the Marine West Coast Forests EPA Level I ecoregion, which covers the area of monitoring and provides a relatively ecologically homogeneous area for pseudo-absence selection ( Figure 1A). The area of interest onto which we extrapolated our predictions is the entire Douglas-fir native range, which encompasses both the coastal (P. ...
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... to establish an equivalency in presence detection between these two sources of points, a lineage was considered absent in Bennett and Stone's (2019) collection of isolates wherever the proportion of the lineage was below 5%. The compilation of points from these two sources produced a dataset of 62 presence points and 9 absence points of lineage 1 (Figure 1B), and 42 presence points and 29 absence points of lineage 2 ( Figure 1C). In order to reduce the spatial clustering of the data, the points were rarefied to a 5 km resolution using the SDMtoolbox 2.0 python package ( Brown et al., 2017). ...
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... to establish an equivalency in presence detection between these two sources of points, a lineage was considered absent in Bennett and Stone's (2019) collection of isolates wherever the proportion of the lineage was below 5%. The compilation of points from these two sources produced a dataset of 62 presence points and 9 absence points of lineage 1 (Figure 1B), and 42 presence points and 29 absence points of lineage 2 ( Figure 1C). In order to reduce the spatial clustering of the data, the points were rarefied to a 5 km resolution using the SDMtoolbox 2.0 python package ( Brown et al., 2017). ...
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... logistic regression model fit of our global model was excellent, with a Hosmer Lemeshow test p-value of 0.99 and no concerning patterns in the residuals once a log-transformation was applied to PAS01 (Supplementary Figure S1). ...
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... Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/ffgc.2021. 756678/full#supplementary-material Supplementary Figure S1 | Assumptions of logistic regression tested on our global model. (A) Parametric bootstrap of the deviance simulated on 5000 binomial models. ...
Citations
... Recently, two major sympatric genetic lineages of N. gaeumannii were identified in the coastal Pacific Northwest. A distribution modelling approach suggested that the environmental tolerance range of lineage 1 exceeds that of lineage 2 and that lineage 1 should expand inland while distribution of lineage 2 should remain limited to its current range (Herpin-Saunier et al., 2022). ...
Understanding the genetic basis of how plants defend against pathogens is important to monitor and maintain resilient tree populations. Swiss needle cast (SNC) and Rhabdocline needle cast (RNC) epidemics are responsible for major damage of forest ecosystems in North America.
Here we investigate the genetic architecture of tolerance and resistance to needle cast diseases in Douglas‐fir (Pseudotsuga menziesii) caused by two fungal pathogens: SNC caused by Nothophaeocryptopus gaeumannii, and RNC caused by Rhabdocline pseudotsugae.
We performed case–control genome‐wide association analyses and found disease resistance and tolerance in Douglas‐fir to be polygenic and under strong selection. We show that stomatal regulation as well as ethylene and jasmonic acid pathways are important for resisting SNC infection, and secondary metabolite pathways play a role in tolerating SNC once the plant is infected. We identify a major transcriptional regulator of plant defense, ERF1, as the top candidate for RNC resistance.
Our findings shed light on the highly polygenic architectures underlying fungal disease resistance and tolerance and have important implications for forestry and conservation as the climate changes.
... Moreover, the study of pathogen-environment interactions through GEA allows the identification of genetic lineages or genes associated with environmental variation. This, in turn, facilitates the prediction of pathogen and pest distributions, as well as outbreak severity under various climate scenarios (Herpin-Saunier et al. 2022). ...
... Careful selection of less-susceptible oaks can thus help maintain a more robust urban and rural forest against invasion. There is clearly an urgent need to study pest resistance as the climatic suitability of multiple native pests and pathogens has increased and they now can be found in novel habitats and with expanded distributions (Marshall and Roe 2021;Sambaraju and Goodsman 2021;Herpin-Saunier et al. 2022). ...
To preserve biodiversity and maintain ecosystem services provided by trees in the course of climate change, it is essential to consider challenging tree species, which are less studied primarily due to a lack of investment compared to commercial species. Species of the genus Quercus present an interesting case because of their economic and ecological importance, and their syngameon biology. As a model for exploring ecological diversification, and with recent advances in forest genomics, knowledge, data, and genomic resources for oak have accumulated and are summarized in this review to foster oaks as potential candidate species for future reforestation programs in Canadian natural, peri-urban, and urban ecosystems. We summarize the state of current genomic research in oak and the accompanying opportunities genomics can provide to achieve the potential of oak silviculture in Canada. Further, we highlight the socio-economic benefits of planting oaks and genomic tools for the development of a traceability system along the value chain. Finally, we discuss some of the remaining challenges to successfully integrate oaks into different forest management programs. In light of their increased drought resistance, oak species exhibit a strong potential as viable choices for future forests, resilient agricultural landscapes, and urban areas. By leveraging the progress made in oak genomics and the new applications that have been developed for commercial species, we can foster the successful management of oak genetic resources for the production of suitable seedlings, thereby aiding Canada in its ambitious pursuit of planting two billion trees to combat climate change.
... mensiezii var. mensiezii); they have different levels of suitability to climates, increasing concerns that N. gaeumannii could rapidly adapt to environmental changes (6,7). A third lineage, lineage 1i, was recently identified on the Rocky Mountain variety of Douglas-fir (P. ...
Here, we present the nearly complete genome sequences of the three main genetic lineages of Nothophaeocryptopus gaeumannii , an endophytic ascomycete fungus responsible for Swiss needle cast, a foliar disease that is emerging as a significant threat to the Douglas-fir tree in its natural distribution range.
Invasions of exotic forest insects and pathogens can devastate evolutionarily naïve habitats and could cause irreversible changes to urban and natural ecosystems. Given the ever-increasing volume of trade in wood and plant stock worldwide, establishment of non-native pests under climate change is one of the most important forest health concerns currently. The European spruce bark beetle, Ips typographus, is a damaging, phloem-feeding insect of Norway spruce, Picea abies, in Eurasia. Endoconidiophora polonica is the most virulent ophiostomatoid fungal associate of I. typographus. Spruce species native to North America are susceptible to this insect-pathogen complex. We studied the suitability of ‘current’ (1970–2000) and future climates (2021–2100) in Canada and the United States for these two species via ensemble species distribution models. We also determined overlapping regions favorable to both I. typographus and E. polonica. Our results indicate that, currently, climate is particularly suitable for I. typographus and E. polonica in western Canada and throughout the United States. Northward shifts in climatic suitability are projected to occur in Canada for both species under climate change. By the end of the 21st century, a coast-to-coast corridor of climatic suitability for I. typographus and E. polonica will occur in Canada under high-temperature regimes.
