Biology subjects

Cottrell, J. E.

Publications and source records attributed to Cottrell, J. E..

7 recordsLinked to original sources

bioRxiv2026

A decade of disease survey data in a progeny-provenance trial: Dothistroma needle blight in Scots pine

Longitudinal data on disease susceptibility in forest trees are rare but essential for understanding host-pathogen dynamics and genetic variation in susceptibility traits. We present a long-term multisite common garden dataset quantifying susceptibility of Scots pine (Pinus sylvestris) to Dothistroma needle blight. The dataset comprises annual disease assessments collected from the same trees across 11 years, spanning 168 families and 21 Scottish provenances. This design enables partitioning of genetic and environmental sources of variation, evaluation of temporal stability in host response, and estimation of variance components and narrow-sense heritability of susceptibility. The data support analyses of phenotypic plasticity, provenance-level responses, and interactions between disease susceptibility and other adaptive traits. This resource will facilitate predictive modelling of host susceptibility under current and future environmental conditions.

ecology↗

bioRxiv2026

PKMζ-KIBRA interactions, molecular turnover, and memory

How can the molecules that strengthen synaptic connections maintain memory in the face of molecular turnover? Our previous work showed that persistent interaction between the postsynaptic scaffolding protein, KIBRA, and the autonomously active PKC isoform, PKM{zeta}, is crucial for maintaining synaptic long-term potentiation (LTP) and memory for at least a month. This duration is longer than the lifespans of individual KIBRA and PKM{zeta} molecules. Biophysical modeling of the interaction suggests oligomers of KIBRA-PKM{zeta} dimers, but not individual dimers or monomers, can overcome molecular turnover by continually incorporating newly synthesized KIBRA and PKM{zeta}, replacing those that have degraded. Here we used AlphaFold 3 to predict the structures of KIBRA-PKM{zeta} heterodimers and heterohexamers and to examine the sites of action of two structurally distinct inhibitors of KIBRA-PKM{zeta} interaction that disrupt established late-LTP and long-term memory. The structures predict that the peptide K-ZAP blocks formation of heterodimers, whereas the small molecule {zeta}-stat prevents PKM{zeta} of one heterodimer from binding a second KIBRA and PKM{zeta}, essential for forming larger oligomeric structures. We show that {zeta}-stat, like K-ZAP, disrupts 1-month-old spatial memory. Thus, continual formation of KIBRA-PKM{zeta} oligomers can be a core molecular mechanism driving the persistence of long-term memory in the face of molecular turnover.

neuroscience↗

bioRxiv2025

PKMζ-PKC{iota}/{lambda} double-knockout reveals the atypical PKCs are crucial for hippocampal late-LTP and spatial long-term memory

PKM{zeta}, a persistently active atypical PKC (aPKC) isoform, is thought to maintain late-phase long-term potentiation (late-LTP) and long-term memory. However, PKM{zeta}-knockout mice still exhibit hippocampal LTP and spatial memory while lacking neocortical LTP, questioning whether this kinase is fundamental to enduring synaptic potentiation and memory. Tsokas et al. (2016) showed the other aPKC, PKC{iota}/{lambda}, likely compensates for PKM{zeta} during maintenance in the hippocampus of PKM{zeta}-null mice. In wild-type mice, PKC{iota}/{lambda} drives early-LTP and short-term memory, while PKM{zeta} compensates for PKC{iota}/{lambda} knockout by supporting both early- and late-phase processes. Here we show PKC{iota}/{lambda} persistently increases during maintenance in two mouse models: PKM{zeta}-conditional knockout (cKO) mice, and double-knockout mice carrying both conditional deletion of PKC{iota}/{lambda} and constitutive loss of PKM{zeta}. In the double-knockout mice, PKC{iota}/{lambda} was measured while the kinase was still present, prior to its inducible ablation, to characterize its compensatory upregulation in late-LTP before removal. To test whether this compensation was functional, we ablated PKC{iota}/{lambda} in the hippocampus of the double-knockout mice. The double-knockout eliminated late-LTP, whereas individual knockout of either aPKC alone showed normal-appearing LTP. Double-knockout also abolished spatial long-term memory without affecting short-term memory. Thus, when PKM{zeta} is absent, PKC{iota}/{lambda} persists to maintain hippocampal late-LTP and long-term memory.

neuroscience↗

bioRxiv2024

Significant and persistent carryover effects in Scots pine

After tracking Scots pine plants from germination to 15 years old, through contrasting early life environments, we observed significant and persistent carryover effects. Groups of plants from common genetic backgrounds were raised in distinct nursery environments, and growth and phenology traits were measured repeatedly once trees had established in their field sites. Growth and phenology differences were evident for 10 and 6 years post-transplantation to the field, respectively. There was a clear interaction between site of origin and carryover effect, indicating that local adaptation also played a role. Given the increasing rate of tree planting initiatives being undertaken around the world in the name of the climate and biodiversity crises, and the strong dependence on those initiatives of nursery-grown plants, our finding of strong carryover effects of the early life environment has significant implications.

ecology↗

bioRxiv2024

Tree nursery environments and their effect on early trait variation

Despite the major role of nurseries in raising young plants and trees prior to transplantation, not enough is known about how the nursery climate impacts the growth and development of plants from germination through to maturity. It is important for forestry practitioners to understand the effect that different nursery environments may have on early stage growth as these may exceed differences due to genetic variation and can confound the use of early stage traits for selection. Here, a replicated progeny-provenance experiment of the economically and ecologically important species Scots pine (Pinus sylvestris L.) was established in three environmentally distinct nurseries in Scotland and traits including survival, growth, form and phenology were measured. Temperature variation and photoperiod were the only uncontrolled environmental variables during this period, and their effect on measured traits was found to be significant among nurseries from the first growing season onwards. Trait interactions were not consistent between nurseries, indicating that the effectiveness of using proxy traits to select for desirable characteristics may depend on the environment in which the trees are grown. This study is the first in a series that will examine trait variation in Scots pine from seedlings to mature trees and highlights the importance of carefully considering and accounting for the nursery environment when growing trees for subsequent transplantation.

ecology↗

bioRxiv2022

Phenotypic trait variation in a long-term, multisite common garden of Scots pine in Scotland

Multisite common garden experiments, exposing common pools of genetic diversity to a range of environments, allow quantification of plastic and genetic components of trait variation. For tree species, such studies must be long term as they typically only express mature traits after many years. As well as evaluating standing genetic diversity, these experiments provide an ongoing test of genetic variation against changing environmental conditions and form a vital resource for understanding how species respond to abiotic and biotic variation. Finally, quantitative assessments of phenotypic variation are essential to pair with rapidly accumulating genomic data to advance understanding of the genetic basis of trait variation, and its interaction with climatic change. We describe a multisite, population-progeny, common garden experiment of the economically and ecologically important tree species, Scots pine, collected from across its native range in Scotland and grown in three contrasting environments. Phenotypic traits, including height, stem diameter and budburst were measured over 14 growing seasons from nursery to field site. The datasets presented have a wide range of applications.

ecology↗

bioRxiv2020

PKMζ traces hippocampal LTP maintenance and spatial long-term memory

PKM{zeta} is an autonomously active PKC isoform crucial for the maintenance of synaptic long-term potentiation (LTP) and long-term memory. Unlike other protein kinases that are transiently stimulated by second messengers, PKM{zeta} is persistently activated through sustained increases in kinase protein expression. Therefore, visualizing increases in PKM{zeta} expression during long-term memory storage might reveal the sites of its persistent action and thus the location of memory-associated LTP maintenance in the brain. Using quantitative immunohistochemistry validated by the lack of staining in PKM{zeta}-null mice, we examined the amount and distribution of PKM{zeta} in subregions of the hippocampal formation of wild-type mice during LTP maintenance and spatial long-term memory storage. During LTP maintenance in hippocampal slices, PKM{zeta} increases in the pyramidal cell body and stimulated dendritic layers of CA1 for at least 2 h. During spatial memory storage, PKM{zeta} increases in CA1 pyramidal cells for at least 1 month, paralleling the persistence of the memory. The subset of CA1 pyramidal cells that are tagged by immediate early gene Arc-driven transcription of fluorescent proteins, whose expression increases during initial memory formation, also expresses the persistent increase of PKM{zeta} during memory storage. In the memory-tagged cells, the increased PKM{zeta} expression persists in dendritic compartments within stratum radiatum for 1 month, indicating the long-term storage of information in the CA3-to-CA1 pathway during remote spatial memory. We conclude that persistent increases in PKM{zeta} trace the molecular mechanism of LTP maintenance and thus the sites of information storage within brain circuitry during long-term memory.

neuroscience↗