The distribution of beech leaf disease and the causal agents of beech bark disease (Cryptoccocus fagisuga, Neonectria faginata, N. ditissima) in forests surrounding Lake Erie and future implications

Reed, Sharon E.; Volk, Daniel; Martin, Danielle K.H.; Hausman, Constance E.; Macy, Tom; Tomon, Tim; Cousins, Stella

doi:10.1016/j.foreco.2021.119753

Cited by 12 publications

(4 citation statements)

References 39 publications

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“…An indirect example of the physiological changes associated with BLD is the noteworthy reduction of root ectomycorrhizal fungal colonization associated with severe diseased BLD trees [ 21 ]. As the disease progresses in the following years, there is a significant reduction in bud/leaf survival leading to a substantial decrease in the tree canopy, and eventually tree mortality [ 1 , 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Cellular insights of beech leaf disease reveal abnormal ectopic cell division of symptomatic interveinal leaf areas

Vieira,

Kantor,

Jansen

et al. 2023

PLoS ONE

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The beech leaf disease nematode, Litylenchus crenatae subsp. mccannii, is recognized as a newly emergent nematode species that causes beech leaf disease (BLD) in beech trees (Fagus spp.) in North America. Changes of leaf morphology before emergence from the bud induced by BLD can provoke dramatic effects on the leaf architecture and consequently to tree performance and development. The initial symptoms of BLD appear as dark green, interveinal banding patterns of the leaf. Despite the fast progression of this disease, the cellular mechanisms leading to the formation of such aberrant leaf phenotype remains totally unknown. To understand the cellular basis of BLD, we employed several types of microscopy to provide an exhaustive characterization of nematode-infected buds and leaves. Histological sections revealed a dramatic cell change composition of these nematode-infected tissues. Diseased bud scale cells were typically hypertrophied and showed a high variability of size. Moreover, while altered cell division had no influence on leaf organogenesis, induction of cell proliferation on young leaf primordia led to a dramatic change in cell layer architecture. Hyperplasia and hypertrophy of the different leaf cell layers, coupled with an abnormal proliferation of chloroplasts especially in the mesophyll cell layers, resulted in the typical interveinal leaf banding. These discrepancies in leaf cell structure were depicted by an abnormal rate of cellular division of the leaf interveinal areas infected by the nematode, promoting significant increase of cell size and leaf thickness. The formation of symptomatic BLD leaves is therefore orchestrated by distinct cellular processes, to enhance the value of these feeding sites and to improve their nutrition status for the nematode. Our findings thus uncover relevant cellular events and provide a structural framework to understand this important disease.

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Section: Introductionmentioning

confidence: 99%

Cellular insights of beech leaf disease reveal abnormal ectopic cell division of symptomatic interveinal leaf areas

Vieira,

Kantor,

Jansen

et al. 2023

PLoS ONE

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“…In contrast, when ash is treated as a subcanopy species, five status metrics are rated critical. As beech bark disease complex and the emerging beech leaf disease complex continue to spread through this region (Morin et al, 2007; Reed et al, 2022), we may similarly see exacerbated regeneration debt in parks such as PRWI, Rock Creek Park (ROCR), and SAGA, where American beech is the dominant regeneration component. Moreover, beech thickets formed in response to beech bark disease can suppress regeneration of other native canopy species (Giencke et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Overabundant deer and invasive plants drive widespread regeneration debt in eastern United States national parks

Miller

Perles

Schmit

et al. 2023

Ecological Applications

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Advanced regeneration, in the form of tree seedlings and saplings, is critical for ensuring the long-term viability and resilience of forest ecosystems in the eastern United States. Lack of regeneration and/or compositional mismatch between regeneration and canopy layers, called regeneration debt, can lead to shifts in forest composition, structure, and, in extreme cases, forest loss. In this study, we examined status and trends in regeneration across 39 national parks from Virginia to Maine, spanning 12 years to apply the regeneration debt concept. We further refined the concept by adding new metrics and classifying results into easily interpreted categories adapted from the literature: imminent failure, probable failure, insecure, and secure. We then used model selection to determine the potential drivers most influencing patterns of regeneration debt. Status and trends indicated widespread regeneration debt in eastern national parks, with 27 of 39 parks classified as imminent or probable failure.Deer browse impact was consistently the strongest predictor of regeneration abundance. The most pervasive component of regeneration debt observed across parks was a sapling bottleneck, characterized by critically low sapling density of native canopy species and significant declines in native canopy sapling basal area or density for most parks. Regeneration mismatches also threaten forest resilience in many parks, where native canopy seedlings and saplings were outnumbered by native subcanopy species, particularly species that are less palatable deer browse. The devastating impact of emerald ash borer eliminating ash as a native canopy tree also drove regeneration mismatches in many parks that contain abundant ash regeneration, demonstrating the vulnerability of forests that lack diverse understories to invasive pests and pathogens. These findings underscore the critical importance of an integrated forest management approach that promotes an abundant and diverse regeneration layer. In most cases, this can only be achieved through long-term (i.e., multidecadal) management of white-tailed deer and

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“…F. grandifolia is a native, dominant canopy species in many forests in the U.S. and Canada. F. grandifolia is characteristic of midwestern forests in the Great Lakes region, currently making up >80% of overstory basal area in Beech-Maple-Birch dominated forests, according to the USDA Forest Service Forest Inventory Assessment [5]. The emergence of BLD presents a major threat to the survival and persistence of beech trees across North America [4].…”

Section: Introductionmentioning

confidence: 99%

Beech Leaf Disease Severity Affects Ectomycorrhizal Colonization and Fungal Taxa Composition

Bashian-Victoroff

Brown

Loyd³

et al. 2023

JoF

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Beech leaf disease (BLD) is an emerging forest infestation affecting beech trees (Fagus spp.) in the midwestern and northeastern United States and southeastern Canada. BLD is attributed to the newly recognized nematode Litylenchus crenatae subsp. mccannii. First described in Lake County, Ohio, BLD leads to the disfigurement of leaves, canopy loss, and eventual tree mortality. Canopy loss limits photosynthetic capacity, likely impacting tree allocation to belowground carbon storage. Ectomycorrhizal fungi are root symbionts, which rely on the photosynthesis of autotrophs for nutrition and growth. Because BLD limits tree photosynthetic capacity, ECM fungi may receive less carbohydrates when associating with severely affected trees compared with trees without BLD symptoms. We sampled root fragments from cultivated F. grandifolia sourced from two provenances (Michigan and Maine) at two timepoints (fall 2020 and spring 2021) to test whether BLD symptom severity alters colonization by ectomycorrhizal fungi and fungal community composition. The studied trees are part of a long-term beech bark disease resistance plantation at the Holden Arboretum. We sampled from replicates across three levels of BLD symptom severity and compared fungal colonization via visual scoring of ectomycorrhizal root tip abundance. Effects of BLD on fungal communities were determined through high-throughput sequencing. We found that ectomycorrhizal root tip abundance was significantly reduced on the roots of individuals of the poor canopy condition resulting from BLD, but only in the fall 2020 collection. We found significantly more ectomycorrhizal root tips from root fragments collected in fall 2020 than in spring 2021, suggesting a seasonal effect. Community composition of ectomycorrhizal fungi was not impacted by tree condition but did vary between provenances. We found significant species level responses of ectomycorrhizal fungi between levels of both provenance and tree condition. Of the taxa analyzed, two zOTUs had significantly lower abundance in high-symptomatology trees compared with low-symptomatology trees. These results provide the first indication of a belowground effect of BLD on ectomycorrhizal fungi and contribute further evidence to the role of these root symbionts in studies of tree disease and forest pathology.

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The distribution of beech leaf disease and the causal agents of beech bark disease (Cryptoccocus fagisuga, Neonectria faginata, N. ditissima) in forests surrounding Lake Erie and future implications

Cited by 12 publications

References 39 publications

Cellular insights of beech leaf disease reveal abnormal ectopic cell division of symptomatic interveinal leaf areas

Cellular insights of beech leaf disease reveal abnormal ectopic cell division of symptomatic interveinal leaf areas

Overabundant deer and invasive plants drive widespread regeneration debt in eastern United States national parks

Beech Leaf Disease Severity Affects Ectomycorrhizal Colonization and Fungal Taxa Composition

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