An official website of the United States government
Neodothiora populina Crous, G.C. Adams & Winton was determined to be a new pathogen of trembling aspen (Populus tremuloides) growing in Alaska, based on completion of Koch’s Postulates in replicated forest and growth chamber inoculation trials. The pathogen is responsible for severe damage and widespread rapid mortality of sapling to mature aspen (≥ 80 years) in the boreal forests of interior Alaska, due to large diffuse annual (1–2 years) cankers. Isolation of the pathogen was challenging, and identification based on cultural characters was difficult. Fruiting bodies were not found on wild diseased trees, but erumpent pycnidia were found in bark overlying cankers on several stems inoculated with pure cultures.
more »
« less
Draft Genome data including functional annotation of an emerging fungal pathogen Neodothiora populina causing a canker disease of trembling aspen in Interior Alaska
Neodothiora populina is a black yeast-like fungus in the family of Dothioraceae. It causes an aggressive canker disease of trembling aspen that results in widespread mortality of aspen across the boreal forest of Interior Alaska. Here we report a high-quality draft genome including functional annotation of this emerging fungal pathogen based on Nanopore Technology longread sequences. Our initial genome assembly totaled 23,960,169 bp and contained 18 contigs and we identified 7,343 genes. This resource announcement provides new genomic data useful long-term to improve our understanding of forest health in Alaska.
more »
« less
- Award ID(s):
- 2224776
- PAR ID:
- 10570345
- Publisher / Repository:
- American Phytopathological Society
- Date Published:
- Journal Name:
- PhytoFrontiers™
- ISSN:
- 2690-5442
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Koch, Frank H. (Ed.)Over the past several decades, growth declines and mortality of trembling aspen throughout western Canada and the United States have been linked to drought, often interacting with outbreaks of insects and fungal pathogens, resulting in a “sudden aspen decline” throughout much of aspen’s range. In 2015, we noticed an aggressive fungal canker causing widespread mortality of aspen throughout interior Alaska and initiated a study to quantify potential drivers for the incidence, virulence, and distribution of the disease. Stand-level infection rates among 88 study sites distributed across 6 Alaska ecoregions ranged from <1 to 69%, with the proportion of trees with canker that were dead averaging 70% across all sites. The disease is most prevalent north of the Alaska Range within the Tanana Kuskokwim ecoregion. Modeling canker probability as a function of ecoregion, stand structure, landscape position, and climate revealed that smaller-diameter trees in older stands with greater aspen basal area have the highest canker incidence and mortality, while younger trees in younger stands appear virtually immune to the disease. Sites with higher summer vapor pressure deficits had significantly higher levels of canker infection and mortality. We believe the combined effects of this novel fungal canker pathogen, drought, and the persistent aspen leaf miner outbreak are triggering feedbacks between carbon starvation and hydraulic failure that are ultimately driving widespread mortality. Warmer early-season temperatures and prolonged late summer drought are leading to larger and more severe wildfires throughout interior Alaska that are favoring a shift from black spruce to forests dominated by Alaska paper birch and aspen. Widespread aspen mortality fostered by this rapidly spreading pathogen has significant implications for successional dynamics, ecosystem function, and feedbacks to disturbance regimes, particularly on sites too dry for Alaska paper birch.more » « less
-
Abstract Ploidy level in plants may influence ecological functioning, demography and response to climate change. However, measuring ploidy level typically requires intensive cell or molecular methods.We map ploidy level variation in quaking aspen, a dominant North American tree species that can be diploid or triploid and that grows in spatially extensive clones. We identify the predictors and spatial scale of ploidy level variation using a combination of genetic and ground‐based and airborne remote sensing methods.We show that ground‐based leaf spectra and airborne canopy spectra can both classify aspen by ploidy level with a precision‐recall harmonic mean of 0.75–0.95 and Cohen's kappa ofc.0.6–0.9. Ground‐based bark spectra cannot classify ploidy level better than chance. We also found that diploids are more common on higher elevation and steeper sites in a network of forest plots in Colorado, and that ploidy level distribution varies at subkilometer spatial scales.Synthesis. Our proof‐of‐concept study shows that remote sensing of ploidy level could become feasible in this tree species. Mapping ploidy level across landscapes could provide insights into the genetic basis of species' responses to climate change.more » « less
-
The future of boreal forests in Alaska, United States, will likely consist of more deciduous-dominant stands because larger and more severe fires facilitate the establishment of deciduous species such as trembling aspen (Populus tremuloides Michx.) and Alaska birch (Betula neoalaskana Sarg.). Whether stands transition to a deciduous-dominant system or mixed-wood forest or return to being dominated by black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) depends on the capacity of regenerating black spruce to grow and produce seed before the next fire. We hypothesized that winter herbivory by snowshoe hares (Lepus americanus Erxleben, 1777) can suppress black spruce under deciduous canopies. We addressed this question by measuring changes in spruce height and herbivory across 54 plots in Interior Alaska that burned 8–88 years ago and related these data to plot-level data collected by the Bonanza Creek Long-Term Ecological Research program. Spruce were more likely browsed at deciduous-dominant sites with dense canopies, and this browsing likely reduced their height growth. Although we found more subtle effects of browsing on height at the individual level, browsing was an important variable in a confirmatory path analysis at the plot level. These observations affirm our broader hypothesis of the selectivity of hare browsing, in that snowshoe hares prefer to browse spruce that are taller and faster growing, effectively “leveling” regenerating seedlings and saplings so that browsed and unbrowsed individuals within a site are the same height.more » « less
-
Research Highlights: Interior Alaska boreal forest is still largely intact and forest harvest management, if applied appropriately across the forest landscape, can potentially mitigate the effects of climate warming, such as increasing wildfire and decreasing mature tree growth. Background and Objectives: This study examines historical relationships between forest growth and harvest in central boreal Alaska over the last 40 years in order to contribute to the development of sustainable forest harvesting practices. Materials and Methods: We compiled data from forest inventory and forest harvest and reforestation databases and analyzed harvesting intensity relative to growth. Results: Forest harvest management has relied heavily on natural regeneration due to a small profit margin. We found that volume harvested in the last 40 years was lower than volume growth; however, harvest activity was concentrated on the small road-accessible area and in the mature white spruce type. As a result, harvest activities need to be distributed geographically and by species in a way that prevents reduction of forest productivity or loss of ecosystem services. An expansion of the road network, or a shift in harvesting and utilization from white spruce to broadleaf would allow a significant increase in sustainable wood yield. Conclusions: There are two potential areas that could provide increased harvest, which contain a large amount of white spruce, birch, and aspen. Under rapid climate change, sustainable forest harvest management must consider the effects of fires, such as needs of salvage logging and a potential reduction of harvestable timber volumes due to damages. Forest harvest management could emulate natural fire disturbance and help reduce fuel amounts to prevent intensive and large-scale fires in the future in areas where fires are most aggressively suppressed.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1094/PHYTOFR-09-24-0101-A
