Temperature Cues Research Articles

Birds use individually consistent temperature cues to time their migration departure.

A fundamental issue in migration biology is how birds decide when to start their journey, given that arriving too early or too late in a variable environment reduces individual fitness. Internal circannual regulation and predictable cues such as photoperiod prepare birds for migration, while variable external cues such as temperature and wind are thought to fine-tune departure times; however, this has not been demonstrated at the key point at which an individual animal decides to start migrating. In theory, environmental cues correlated between departure and arrival sites allow informed departure decisions. For 48 satellite-tracked Asian houbara Chlamydotis macqueenii, a medium-distance migrant with climatic connectivity between wintering and breeding areas, each tracked across multiple years, spring departure was under individually consistent temperature conditions, with greater individual repeatability than for photoperiod or wind. Individuals occupied a range of wintering sites latitudinally spanning 1,200 km but departed at lower temperatures from more northerly latitudes. These individual departure decisions produced earlier mean population-level departure and arrival dates in warmer springs. Phenological adjustments were fully compensatory, because individuals arrived on the breeding grounds under similar temperature conditions each year. Individuals' autumn departure decisions were also repeatable for temperature but less distinct than for spring, likely because of relaxed time constraints on leaving breeding grounds and the use of wind as a supplementary departure cue. We show that individual-level departure decisions informed by local temperatures can preadapt a population to adjust its population-level phenology in response to annual variability in spring temperatures without requiring genetic change in reaction thresholds.

Thermal Tactile Perception

Using thermal tactile sensing mechanism based on semi-infinite body model, and combining with the advantages of maximum proportional controller, fuzzy and PID controller, a thermal tactile perception and reproduction experiment device (TTPRED) was designed based on the composite control strategy of threshold switching. The finger difference threshold measurement experiment of thermal tactile was carried out and the finger thermal tactile difference threshold was measured. The relationship between thermal tactile sensation and emotion based on temperature cues has been explored. The experiment results show that, the temperature control range of TTPRED is from -10℃ to 130℃, the temperature resolution and precision are 0.01℃ and ±0.1℃ respectively, the maximum heating or cooling rate is greater than 12℃, and the TTPRED can realize the temperature output of the specific waveform quickly and accurately. The experiment results of psychophysical experiment will provide the experimental foundations and technical support for the further study of thermal tactile perception and reproduction.

Multi-Sensory Color Expression with Sound and Temperature in Visual Arts Appreciation for People with Visual Impairment

For years the HCI community’s research has been focused on the hearing and sight senses. However, in recent times, there has been an increased interest in using other types of senses, such as smell or touch. Moreover, this has been accompanied with growing research related to sensory substitution techniques and multi-sensory systems. Similarly, contemporary art has also been influenced by this trend and the number of artists interested in creating novel multi-sensory works of art has increased substantially. As a result, the opportunities for visually impaired people to experience artworks in different ways are also expanding. In spite of all this, the research focusing on multimodal systems for experiencing visual arts is not large and user tests comparing different modalities and senses, particularly in the field of art, are insufficient. This paper attempts to design a multi-sensory mapping to convey color to visually impaired people employing musical sounds and temperature cues. Through user tests and surveys with a total of 18 participants, we show that this multi-sensory system is properly designed to allow the user to distinguish and experience a total of 24 colors. The tests consist of several semantic correlational adjective-based surveys for comparing the different modalities to find out the best way to express colors through musical sounds and temperature cues based on previously well-established sound-color and temperature-color coding algorithms. In addition, the resulting final algorithm is also tested with 12 more users.

Natural temperature fluctuations promote COOLAIR regulation of FLC.

Plants monitor many aspects of their fluctuating environments to help align their development with seasons. Molecular understanding of how noisy temperature cues are registered has emerged from dissection of vernalization in Arabidopsis, which involves a multiphase cold-dependent silencing of the floral repressor locus FLOWERING LOCUS C (FLC). Cold-induced transcriptional silencing precedes a low probability PRC2 epigenetic switching mechanism. The epigenetic switch requires the absence of warm temperatures as well as long-term cold exposure. However, the natural temperature inputs into the earlier transcriptional silencing phase are less well understood. Here, through investigation of Arabidopsis accessions in natural and climatically distinct field sites, we show that the first seasonal frost strongly induces expression of COOLAIR, the antisense transcripts at FLC Chamber experiments delivering a constant mean temperature with different fluctuations showed the freezing induction of COOLAIR correlates with stronger repression of FLC mRNA. Identification of a mutant that ectopically activates COOLAIR revealed how COOLAIR up-regulation can directly reduce FLC expression. Consistent with this, transgenes designed to knockout COOLAIR perturbed the early phase of FLC silencing. However, all transgenes designed to remove COOLAIR resulted in increased production of novel convergent FLC antisense transcripts. Our study reveals how natural temperature fluctuations promote COOLAIR regulation of FLC, with the first autumn frost acting as a key indicator of autumn/winter arrival.

Plant thermotropism: an underexplored thermal engagement and avoidance strategy.

Various strategies evolved in plants to adjust the position of organs relative to the prevailing temperature condition, which allows optimal plant growth and performance. Such responses are classically separated into nastic and tropic responses. During plant thermotropic responses, organs move towards (engage) or away (avoid) from a directional temperature cue. Despite thermotropism being a classic botanical concept, the underlying ecological function and molecular and biophysical mechanisms remain poorly understood to this day. This contrasts to the relatively well-studied thermonastic movements (hyponasty) of e.g., rosette leaves. In this review, we provide an update on the current knowledge on plant thermotropisms and propose directions for future research and application.

Repeated ex situ Spawning in Two Highly Disease Susceptible Corals in the Family Meandrinidae

Members of the family Meandrinidae are highly susceptible to stony coral tissue loss disease, resulting in population reductions up to 88% in both Dendrogyra cylindrus and Meandrina meandrites along the Florida Reef Tract. Reductions in abundance on this scale leave these species susceptible to limitations in sexual reproduction and natural recovery without intervention. In response to the ongoing outbreak of the disease across the Caribbean, a variety of genetic rescue projects have been implemented to bring disease susceptible species into ex situ culture and preserve living genetic diversity. In this study, corals being held in a long-term ex situ genetic bank were maintained using artificial lighting and temperature cues programmed to mimic natural cycles in Key Largo, FL, United States. Synchronized broadcast spawning events in both species were documented in aquaria over two annual spawning cycles in 2019 and 2020. Timing of gamete release relative to the perceived date and sunset was highly synchronized with wild observations. Up to 21 unique D. cylindrus genotypes collected from reef locations spanning over 230 km contributed gametes to the larval pool. The majority of these parental colonies are no longer alive in the wild. Repeatable and predictable ex situ spawning events such as these will become an essential tool for managed breeding and assisted fertilization in species suffering from severe population declines. These annual events have the potential to produce thousands of genetically diverse offspring for restoration efforts and offer future hope for the long-term survival of these threatened species.

Phytochrome B and PHYTOCHROME INTERACTING FACTOR8 modulate seasonal growth in trees.

The seasonally synchronized annual growth cycle that is regulated mainly by photoperiod and temperature cues is a crucial adaptive strategy for perennial plants in boreal and temperate ecosystems. Phytochrome B (phyB), as a light and thermal sensor, has been extensively studied in Arabidopsis. However, the specific mechanisms for how the phytochrome photoreceptors control the phenology in tree species remain poorly understood. We characterized the functions of PHYB genes and their downstream PHYTOCHROME INTERACTING FACTOR (PIF) targets in the regulation of shade avoidance and seasonal growth in hybrid aspen trees. We show that while phyB1 and phyB2, as phyB in other plants, act as suppressors of shoot elongation during vegetative growth, they act as promoters of tree seasonal growth. Furthermore, while the Populus homologs of both PIF4 and PIF8 are involved in the shade avoidance syndrome (SAS), only PIF8 plays a major role as a suppressor of seasonal growth. Our data suggest that the PHYB-PIF8 regulon controls seasonal growth through the regulation of FT and CENL1 expression while a genome-wide transcriptome analysis suggests how, in Populus trees, phyB coordinately regulates SAS responses and seasonal growth cessation.

Photoperiod Alters Visceral Adiposity and Molecular Circadian Rhythms in White‐footed Mice at Thermoneutrality

The length of daylight (photoperiod) and environmental temperature fluctuate seasonally and act as cues for physiology. How photoperiod per se impacts adipose physiology is essential to consider as misalignment of circadian rhythms is suggested to promote obesity. Photoperiod alters fat deposition when temperature simultaneously acts as a cue. However, whether photoperiod regulates adipose physiology independent of temperature is unknown, as ambient temperatures below thermoneutrality are typically used. We compared the effects of 4 weeks of long (LD - 16hrs light:8hrs dark) and short (SD – 8hrs light:16hrs dark) photoperiod exposure at thermoneutrality (27°C) to isolate photoperiod from temperature cues in photosensitive F1 generation, male white-footed mice (Peromyscus leucopus). Short photoperiod selectively lowered visceral white adipose tissue (WAT) (vWAT) mass (p<0.05 vs LD), with no effect on subcutaneous WAT or interscapular brown adipose tissue mass or bodyweight. Calorie consumption and 24-hour feeding behaviour were not affected by photoperiod, although short photoperiod mice ate almost exclusively in the dark (SD ate 8.5% of daily intake in 8hr light phase vs. LD ate 26% of intake in 16hr light phase (p<0.0001)). In vWAT, short photoperiod increased Adrβ3, Lpl and Nr1d1 mRNA expression (p<0.05 vs LD), with no change in Ucp1, Pgc1a or Hsl. Circadian Per1 and Per2 gene expression aligned with the onset of dark and thus were misaligned between photoperiods (p<0.05), while Bmal1 and Clock were also misaligned. Thus, photoperiod alone is a strong enough cue to alter visceral fat accumulation and alter clock gene misalignment, without temperature-induced thermogenesis. These findings have important implications for understanding obesity in humans in whom day light is artificially extended while environmental temperatures are kept consistent.

New evidence for the importance of soil nitrogen on the survival and adaptation of silver birch to climate warming

AbstractStrong seasonality in the subarctic causes unfavorable conditions for plant growth driving strong latitudinal clines in growth onset and cessation related to temperature and photoperiodic cues. Results from controlled experiments indeed show such clines, but results from field experiments seem to indicate that such clines may depend on site characteristics, suggesting that environmental variation, other than temperature and photoperiod, is relevant under climate change. Here, we increase our understanding of the effects of climate change on survival, height growth, and the phenological cycle by investigating their inter‐ and intrapopulation variation using three common gardens and six silver birch (Betula pendula) populations (each represented by up to five cloned genotypes) spanning the Finnish subarctic. We found clinal south–north variation among populations in survival and growth and in spring and autumn phenology to be largely absent. Sapling survival decreased with a transfer of over five degrees of latitude southward, but growth and phenology showed little evidence for adaptation to the local climate. Instead, ample genetic variation and plastic responses were found for all traits studied. Higher soil N availability increased sapling survival and growth, and phenology seemed to be adapted to soil N and day length rather than to temperature. Our results suggest that the climatic conditions predicted for the end of this century may, at least for poor soils, reduce the survival of northern silver birch trees in their early growth. However, those saplings that survive seem to have sufficient phenotypic plasticity to acclimatize to the changing climate. Along with climate, soil fertility plays a significant role and clearly warrants inclusion in the future tests of the effects of climate warming on tree growth and survival.

Climate warming causes mast seeding to break down by reducing sensitivity to weather cues.

Climate change is altering patterns of seed production worldwide with consequences for population recruitment and migration potential. For the many species that regenerate through synchronized, quasiperiodic reproductive events termed masting, these changes include decreases in the synchrony and interannual variation in seed production. This breakdown in the occurrence of masting features harms reproduction by decreasing the efficiency of pollination and increasing seed predation. Changes in masting are often paralleled by warming temperatures, but the underlying proximate mechanisms are unknown. We used a unique 39-year study of 139 European beech (Fagus sylvatica) trees that experienced masting breakdown to track the seed developmental cycle and pinpoint phases where weather effects on seed production have changed over time. A cold followed by warm summer led to large coordinated flowering efforts among plants. However, trees failed to respond to the weather signal as summers warmed and the frequency of reproductive cues changed fivefold. Less synchronous flowering resulted in less efficient pollination that further decreased the synchrony of seed maturation. As global temperatures are expected to increase this century, perennial plants that fine-tune their reproductive schedules based on temperature cues may suffer regeneration failures.

Feeling Every Bit of Winter - Distributed Temperature Sensitivity in Vernalization.

Temperature intrinsically influences all aspects of biochemical and biophysical processes. Organisms have therefore evolved strategies to buffer themselves against thermal perturbations. Many organisms also use temperature signals as cues to align behavior and development with certain seasons. These developmentally important thermosensory mechanisms have generally been studied in constant temperature conditions. However, environmental temperature is an inherently noisy signal, and it has been unclear how organisms reliably extract specific temperature cues from fluctuating temperature profiles. In this context, we discuss plant thermosensory responses, focusing on temperature sensing throughout vernalization in Arabidopsis. We highlight many different timescales of sensing, which has led to the proposal of a distributed thermosensing paradigm. Within this paradigm, we suggest a classification system for thermosensors. Finally, we focus on the longest timescale, which is most important for sensing winter, and examine the different mechanisms in which memory of cold exposure can be achieved.

Lunar phase as a cue for migrations to two species of explosive breeding amphibians—implications for conservation

In species with explosive breeding strategies, large numbers of individuals may congregate at a defined location for a very short period of time. Effective synchronisation in arrival at breeding sites is crucial to ensure mating success. Amphibians with explosive breeding strategies often congregate at ponds for only a few days or weeks a year. Previous research has shown that frogs and toads may use a variety of exogenous cues to initiate breeding migrations which include temperature, rainfall and lunar cues. Although the effects of temperature and rainfall on amphibians are widely studied and understood, the impacts of lunar phase are poorly known and vary by species and location. In this study, we examined the effects of lunar phase on the numbers of common toads (Bufo bufo) and common frogs (Rana temporaria) migrating to breeding ponds at 43 sites across the UK over 4 years. Our findings show that peak migration of both common toads and common frogs coincides with the waxing phase of the moon, peaking around the full moon. Temperature and rainfall also had an effect on peak migrations with the highest numbers of common toads and common frogs occurring on warm and damp evenings close to a full moon. Our results have implications for amphibian conservation initiatives such as ‘Toads on Roads’ as they will help inform conservationists on the most effective timing to help toads and frogs across roads.

Recognition of CCA1 alternative protein isoforms during temperature acclimation.

CCA1α and CCA1β protein variants respond to environmental light and temperature cues, and higher temperature promotes CCA1β protein production and causes its retention detectable in the cytoplasm. CIRCADIAN CLOCK ASSOCIATED1 (CCA1), as the core transcription factor of circadian clock, is involved in the regulation of endogenous circadian rhythm in Arabidopsis. Previous studies have shown that CCA1 consists of two abundant splice variants, fully spliced CCA1α and intron-retaining CCA1β. CCA1β is believed to form a nonfunctional heterodimer with CCA1α and its closed-related homolog LHY. Many studies have established that CCA1β is a transcription product, while how CCA1β protein is produced and how two CCA1 isoforms respond to environmental cues have not been elucidated. In this study, we identified CCA1α and CCA1β protein variants under different photoperiods with warm or cold temperature cycles, respectively. Our results showed that CCA1 protein production is regulated by prolonged light exposure and warm temperature. The protein levels of CCA1α and CCA1β peak in the morning, but the detection of CCA1β is dependent on immunoprecipitation enrichment at 22°C. Higher temperature of 37°C promotes CCA1β protein production and causes its retention to be detectable in the cytoplasm. Overall, our results indicate that two splice variants of the CCA1 protein respond to environmental light and temperature signals and may, therefore, maintain the circadian rhythms and give individuals the ability to adapt to environment.

Impacts of predator-induced behavioural plasticity on the temperature dependence of predator-prey activity and population dynamics.

Predation is a key ecological interaction affecting populations and communities. Climate warming can modify this interaction both directly by the kinetic effects of temperature on biological rates and indirectly through integrated behavioural and physiological responses of the predators and prey. Temperature dependence of predation rates can further be altered by predator-induced plasticity of prey locomotor activity, but empirical data about this effect are lacking. We propose a general framework to understand the influence of predator-induced developmental plasticity on behavioural thermal reaction norms in prey and their consequences for predator-prey dynamics. Using a mesocosm experiment with dragonfly larvae (predator) and newt larvae (prey), we tested if the predator-induced plasticity alters the elevation or the slope of the thermal reaction norms for locomotor activity metrics in prey. We also estimated the joint predator-prey thermal response in mean locomotor speed, which determines prey encounter rate, and modelled the effect of both phenomena on predator-prey population dynamics. Thermal reaction norms for locomotor activity in prey were affected by predation risk cues but with minor influence on the joint predator-prey behavioural response. We found that predation risk cues significantly decreased the intercept of thermal reaction norm for total activity rate (i.e. all body movements) but not the other locomotor activity metrics in the prey, and that prey locomotor activity rate and locomotor speed increased with prey density. Temperature had opposite effects on the mean relative speed of predator and prey as individual speed increased with temperature in predators but decreased in prey. This led to a negligible effect of body temperature on predicted prey encounter rates and predator-prey dynamics. The behavioural component of predator-prey interaction varied much more between individuals than with temperature and the presence of predation risk cues in our system. We conclude that within-population variation in locomotor activity can buffer the influence of body temperature and predation risk cues on predator-prey interactions, and further research should focus on the magnitude and sources of behavioural variation in interacting species to predict the impact of climate change on predator-prey interactions and food web dynamics.

Changes in the Magnitude of the Individual and Combined Effects of Contaminants, Warming, and Predators on Tropical Cladocerans across 11 Generations.

A massive challenge in ecotoxicology is assessing how the interaction of contaminants, climate change, and biotic stressors shapes the structure and functions of natural populations. Furthermore, it is not known whether contemporary evolutionary responses to multiple stressors across multigenerations may alter the interaction of these stressors. To address these issues, we exposed Moina dubia to lead (Pb, 50 μg/L) under two temperatures (25 and 28 °C) with/without predator cues from climbing perch (Anabas testudineus) for 11 generations (F1-F11). We assessed changes in M. dubia fitness, including development time, adult size, lifespan, fecundity, and neonate production. We found strong negative effects of Pb, elevated temperature, and predator cues on the fitness of M. dubia. Strikingly, Pb-induced reduction in the performance of M. dubia was stronger at 25 °C and in the absence of predator cues. The individual and interactive effects of Pb, temperature, and predator cues on M. dubia were stronger across F1-F9 and generally leveled off in F10-F11. Our results highlight the high vulnerability of M. dubia to multiple stressors, thus weakening top-down control on algal blooms in eutrophic lakes. Our study underscores the importance of integrating evolutionary responses in realistic ecotoxicological risk assessments of contaminants interacting with climatic and biotic stressors.

Effects of ozone stress on flowering phenology, plant-pollinator interactions and plant reproductive success.

Tropospheric ozone is a highly oxidative pollutant with the potential to alter plant metabolism. The direct effects of ozone on plant phenotype may alter interactions with other organisms, such as pollinators, and, consequently, affect plant reproductive success. In a set of greenhouse experiments, we tested whether exposure of plants to a high level of ozone affected their phenological development, their attractiveness to four different pollinators (mason bees, honeybees, hoverflies and bumblebees) and, ultimately, their reproductive success. Exposure of plants to ozone accelerated flowering, particularly on plants that were growing in autumn, when light and temperature cues, that commonly promote flowering, were weaker. Simultaneously, there was a tendency for ozone-exposed plants to disinvest in vegetative growth. Plant exposure to ozone did not substantially affect pollinator preference, but bumblebees had a tendency to visit more flowers on ozone-exposed plants, an effect that was driven by the fact that these plants tended to have more open flowers, meaning a stronger attraction signal. Honeybees spent more time per flower on ozone-exposed plants than on control plants. Acceleration of flower production and the behavioural responses of pollinators to ozone-exposed plants resulted in retained reproductive fitness of plants pollinated by bumblebees, honeybees and mason bees, despite the negative effects of ozone on plant growth. Plants that were pollinated by hoverflies had a reduction in reproductive fitness in response to ozone. In a natural setting, acceleration of flowering by ozone might foster desynchronization between plant and pollinator activities. This can have a strong impact on plants with short flowering periods and on plants that, unlike wild mustard, lack compensatory mechanisms to cope with the absence of pollinator activity in the beginning of flowering.

Molecular pathways regulating elongation of aerial plant organs: a focus on light, the circadian clock, and temperature.

Organs such as hypocotyls and petioles rapidly elongate in response to shade and temperature cues, contributing to adaptive responses that improve plant fitness. Growth plasticity in these organs is achieved through a complex network of molecular signals. Besides conveying information from the environment, this signaling network also transduces internal signals, such as those associated with the circadian clock. A number of studies performed in Arabidopsis hypocotyls, and to a lesser degree in petioles, have been informative for understanding the signaling networks that regulate elongation of aerial plant organs. In particular, substantial progress has been made towards understanding the molecular mechanisms that regulate responses to light, the circadian clock, and temperature. Signals derived from these three stimuli converge on the BAP module, a set of three different types of transcription factors that interdependently promote gene transcription and growth. Additional key positive regulators of growth that are also affected by environmental cues include the CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) and SUPPRESSOR OF PHYA-105 (SPA) E3 ubiquitin ligase proteins. In this review we summarize the key signaling pathways that regulate the growth of hypocotyls and petioles, focusing specifically on molecular mechanisms important for transducing signals derived from light, the circadian clock, and temperature. While it is clear that similarities abound between the signaling networks at play in these two organs, there are also important differences between the mechanisms regulating growth in hypocotyls and petioles.

Relationship between spawning and egg and larval stages of a unique estuarine-resident species and environmental variables and prey

This study has elucidated the environmental factors associated with spawning and the ecology of early life cycle stages of the sparid Acanthopagrus butcheri, which is atypically long-lived and large for a species confined to its natal estuary. The prevalence of A. butcheri eggs in monthly plankton samples from the Blackwood River Estuary, south-western Australia, in 2014/15, allied with long-term gonadal data, imply that spawning in this estuary commences in mid-spring (October) as water temperatures increase to ~17 °C and peak at ~22 °C in early summer (December). Eggs were initially found only in deeper, downstream areas, where a salt wedge had started to penetrate following precipitous seasonal decline in freshwater discharge. Spawning occurred progressively further upstream during November/December as the salt wedge continued its intrusion of the upper estuary. The concentrations of eggs and yolk-sac and preflexion larvae, which were related positively to salinity and temperature and less so to oxygen concentration, were located predominantly below the halocline, implying that successful spawning typically requires salinities ≥15. Concentrations of eggs and yolk-sac and preflexion larvae peaked in December and of flexion larvae in January. As the concentrations of copepod nauplii exceeded by orders of magnitude those of larval A. butcheri, with which they co-occur and constitute their main prey, it is unlikely that restricted food resources accounted for the poor recruitment of the 2014/15 year class. In this context, the presence of many yolk-sac larvae and preflexion larvae in the low oxygen concentrations, which have become increasingly prevalent in microtidal estuaries of south-western Australia due to climate change, is likely to have led to considerable mortality. In most populations throughout its range in southern Australia, A. butcheri spawns in a restricted period between the austral mid-spring and mid-summer, with the synchrony achieved through differences in the temperatures that cue spawning at different latitudes, i.e. higher temperature cues at lower and thus warmer latitudes. Spawning occurs earlier, however, in atypical estuaries in which salinities and temperatures are high in late winter/spring. Despite experiencing episodic recruitment, A. butcheri sustains substantial populations through maturing early relative to its maximum age, and therefore producing numerous offspring in those few years when spawning conditions are optimal. Episodic recruitment could thus be related to subtle inter-annual differences in environmental conditions during the short spawning periods, with oxygen levels greater than usual a potential key factor. The adaptability of A. butcheri makes this sparid useful in assessing the degree, direction and scale of climate change effects.

Regulation of COP1 Function by Brassinosteroid Signaling.

Small increases in temperature result in enhanced elongation of the hypocotyl and petioles and hyponastic growth, in an adaptive response directed to the cooling of the leaves and to protect the shoot meristem from the warm soil. This response, collectively termed as thermomorphogenesis, relies on the faster reversion of phyB Pfr at warmer temperatures, which leads to enhanced activity of the basic-helix-loop-helix PHYTOCHROME INTERACTING FACTOR 4 (PIF4). PIF4 acts as a molecular hub integrating light and temperature cues with endogenous hormonal signaling, and drives thermoresponsive growth by directly activating auxin synthesis and signaling genes. Growth promotion by PIF4 depends on brassinosteroid (BR) signaling, as indicated by the impaired thermoresponse of BR-defective mutants and the partial restoration of pifq thermoresponsive defects by brassinolide (BL) application. Also, phyB limits thermomorphogenic elongation through negative regulation of the E3 ubiquitin ligase COP1 that triggers nuclear degradation of multiple photomorphogenesis-promoting factors acting antagonistically to PIF4. COP1 is indeed observed to accumulate in the nucleus in darkness, or in response to warm temperatures, with constitutive photomorphogenic cop1 mutants failing to respond to temperature. Here we explored the role of BR signaling on COP1 function, by growing cop1 seedlings on BL or the inhibitor brassinazole (BRZ), under different light and temperature regimes. We show that weak cop1 alleles exhibit a hyposensitive response to BL. Furthermore, while cop1-6 mutants display as described a wild-type response to temperature in continuous darkness, this response is abolished by BRZ. Application of this inhibitor likewise suppressed temperature-induced COP1 nuclear accumulation in N. benthamiana leaves. Overall these results demonstrate that cop1-6 is not a temperature-conditional allele, but this mutation allows for a partially active protein which unveils a pivotal role of active BR signaling in the control of COP1 activity.

Deciphering mollusc shell production: the roles of genetic mechanisms through to ecology, aquaculture and biomimetics.

Most molluscs possess shells, constructed from a vast array of microstructures and architectures. The fully formed shell is composed of calcite or aragonite. These CaCO3 crystals form complex biocomposites with proteins, which although typically less than 5% of total shell mass, play significant roles in determining shell microstructure. Despite much research effort, large knowledge gaps remain in how molluscs construct and maintain their shells, and how they produce such a great diversity of forms. Here we synthesize results on how shell shape, microstructure, composition and organic content vary among, and within, species in response to numerous biotic and abiotic factors. At the local level, temperature, food supply and predation cues significantly affect shell morphology, whilst salinity has a much stronger influence across latitudes. Moreover, we emphasize how advances in genomic technologies [e.g. restriction site-associated DNA sequencing (RAD-Seq) and epigenetics] allow detailed examinations of whether morphological changes result from phenotypic plasticity or genetic adaptation, or a combination of these. RAD-Seq has already identified single nucleotide polymorphisms associated with temperature and aquaculture practices, whilst epigenetic processes have been shown significantly to modify shell construction to local conditions in, for example, Antarctica and New Zealand. We also synthesize results on the costs of shell construction and explore how these affect energetic trade-offs in animal metabolism. The cellular costs are still debated, with CaCO3 precipitation estimates ranging from 1-2 J/mg to 17-55 J/mg depending on experimental and environmental conditions. However, organic components are more expensive (~29 J/mg) and recent data indicate transmembrane calcium ion transporters can involve considerable costs. This review emphasizes the role that molecular analyses have played in demonstrating multiple evolutionary origins of biomineralization genes. Although these are characterized by lineage-specific proteins and unique combinations of co-opted genes, a small set of protein domains have been identified as a conserved biomineralization tool box. We further highlight the use of sequence data sets in providing candidate genes for in situ localization and protein function studies. The former has elucidated gene expression modularity in mantle tissue, improving understanding of the diversity of shell morphology synthesis. RNA interference (RNAi) and clustered regularly interspersed short palindromic repeats - CRISPR-associated protein 9 (CRISPR-Cas9) experiments have provided proof of concept for use in the functional investigation of mollusc gene sequences, showing for example that Pif (aragonite-binding) protein plays a significant role in structured nacre crystal growth and that the Lsdia1 gene sets shell chirality in Lymnaea stagnalis. Much research has focused on the impacts of ocean acidification on molluscs. Initial studies were predominantly pessimistic for future molluscan biodiversity. However, more sophisticated experiments incorporating selective breeding and multiple generations are identifying subtle effects and that variability within mollusc genomes has potential for adaption to future conditions. Furthermore, we highlight recent historical studies based on museum collections that demonstrate a greater resilience of molluscs to climate change compared with experimental data. The future of mollusc research lies not solely with ecological investigations into biodiversity, and this review synthesizes knowledge across disciplines to understand biomineralization. It spans research ranging from evolution and development, through predictions of biodiversity prospects and future-proofing of aquaculture to identifying new biomimetic opportunities and societal benefits from recycling shell products.