Dataset Information

Widespread mortality of trembling aspen (Populus tremuloides) throughout interior Alaskan boreal forests resulting from a novel canker disease.

ABSTRACT: 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.

SUBMITTER: Ruess RW

PROVIDER: S-EPMC8032200 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Plants have evolved heavy metal tolerance mechanisms to adapt and cope with nickel (Ni) toxicity. Decrypting whole gene expression of Trembling Aspen (Pinus tremuloides) under nickel stress could elucidate the nickel resistance/tolerance mechanisms. The main objectives of the present research were to 1) characterize the P. tremuloides transcriptome, and 2) compare gene expression dynamics between nickel-resistant and nickel-susceptible P. tremuloides genotypes with Whole Transcriptome (WT) sequencing. Illumina Sequencing generated 27-45 million 2X150 paired-end reads of raw data per sample. The alignment performed with StringTie Software added two groups of transcripts to the draft genome annotation. One group contained 32,677 new isoforms that match to 17,254 genes. The second group contained 17,349 novel transcripts that represent 16,157 novel genes. Overall, 52,987 genes were identified from which 36,770 genes were selected as differently expressed. With the high stringency (two-fold change, FDR value ≤ 0.05 and logFC value ≥1 (upregulated) or ≤ -1 (downregulated), after GSEA analysis and filtering for gene set size, 575 gene sets were upregulated and 146 were downregulated in nickel resistant phenotypes compared to susceptible genotypes. For biological process, genes associated with translation were significantly upregulated while signal transduction and cellular protein process genes were downregulated in resistant compared to susceptible genotypes. For molecular function, there was a significant downregulation of genes associated with DNA binding in resistant compared to susceptible lines. Significant upregulation was observed in genes located in ribosome while downregulation of genes in chloroplast and mitochondrion were preponderant in resistant genotypes compared to susceptible. Hence, from a whole transcriptome level, an upregulation in ribosomal and translation activities was identified as the main response to Ni toxicity in the resistant plants. More importantly, this study revealed that a metal transport protein (Potrs038704g29436 -ATOX1-related copper transport) was among the top upregulated genes in resistant genotypes when compared to susceptible plants. Other identified upregulated genes associated with abiotic stress include genes coding for Dirigent Protein 10, GATA transcription factor, Zinc finger protein, Auxin response factor, Bidirectional sugar transporter, and thiamine thiazole synthase.

Project description:Quaking aspen (Populus tremuloides Michx.), a widespread and keystone tree species in North America, experienced heat and drought stress in the years 2002 and 2003 in the southwestern United States. This led to widespread aspen mortality that has altered the composition of forests, and is expected to occur again if climate change continues. Understanding interactions between aspen and its environments is essential to understanding future mortality risk in forests. Polyploidy, which is common in aspen, can modify plant structure and function and therefore plant-environment interactions, but the influence of polyploidy on aspen physiology is still not well understood. Furthermore, the ploidy types of aspen have different biogeographies, with triploids being most frequent at lower latitudes in generally warmer and drier climates, while the northerly populations are virtually 100% diploid. This suggests that ploidy-environment interactions differ, and could mean that the ploidy types have different vulnerabilities to environmental stress. In this study, to understand aspen ploidy-environment interactions, we measured 38 different traits important to carbon uptake, water loss and water-use efficiency in diploid and triploid aspen in Colorado. We found that triploid aspen had lower stand density, and greater leaf area, leaf mass, leaf mass per area, percent nitrogen content, chlorophyll content and stomatal size. These differences corresponded to greater potential net carbon assimilation (A, measured using A/Ci curves, and chlorophyll fluorescence) and stomatal conductance (gs) in triploids than diploids. While triploid aspen had higher intrinsic water-use efficiency (iWUE, calculated from measurements of δ13C in leaf tissue), they also had greater potential water loss from higher measured gs and lower stomatal sensitivity to increasing vapor pressure deficit. Therefore, despite greater iWUE, triploids may have lower resilience to climate-induced stress. We conclude that ploidy type strongly influences physiological traits and function, and mediates drought stress responses in quaking aspen.

Dataset Information

Widespread mortality of trembling aspen (Populus tremuloides) throughout interior Alaskan boreal forests resulting from a novel canker disease.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets