scholarly journals Light environment drives evolution of color vision genes in butterflies and moths

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yash Sondhi ◽  
Emily A. Ellis ◽  
Seth M. Bybee ◽  
Jamie C. Theobald ◽  
Akito Y. Kawahara
Keyword(s):  
Amino Acids ◽  
Color Vision ◽  
Light Availability ◽  
High Light ◽  
Light Environment ◽  
Evolution Rate ◽  
Animal Evolution ◽  
Light Sensing ◽  
Rates Of Evolution ◽  
Gains And Losses

AbstractOpsins, combined with a chromophore, are the primary light-sensing molecules in animals and are crucial for color vision. Throughout animal evolution, duplications and losses of opsin proteins are common, but it is unclear what is driving these gains and losses. Light availability is implicated, and dim environments are often associated with low opsin diversity and loss. Correlations between high opsin diversity and bright environments, however, are tenuous. To test if increased light availability is associated with opsin diversification, we examined diel niche and identified opsins using transcriptomes and genomes of 175 butterflies and moths (Lepidoptera). We found 14 independent opsin duplications associated with bright environments. Estimating their rates of evolution revealed that opsins from diurnal taxa evolve faster—at least 13 amino acids were identified with higher dN/dS rates, with a subset close enough to the chromophore to tune the opsin. These results demonstrate that high light availability increases opsin diversity and evolution rate in Lepidoptera.

scholarly journals Light environment drives evolution of color vision genes in butterflies and moths

2020 ◽  
Author(s):  
Yash Sondhi ◽  
Emily A. Ellis ◽  
Jamie C. Theobald ◽  
Akito Y. Kawahara
Keyword(s):  
Amino Acids ◽  
Gene Diversity ◽  
Light Availability ◽  
Structural Models ◽  
Color Discrimination ◽  
High Light ◽  
Light Environment ◽  
Diel Activity ◽  
Ancestral State ◽  
Light Sensing

AbstractOpsins are the primary light-sensing molecules in animals. Opsins have peak sensitivities to specific wavelengths which allows for color discrimination. The opsin protein family has undergone duplications and losses, dynamically expanding and contracting the number of opsins, throughout invertebrate evolution, but it is unclear what drives this diversity. Light availability, however, appears to play a significant role. Dim environments are associated with low opsin diversity in deep-sea fishes and cave-dwelling animals. Correlations between high opsin diversity and bright environments, however, are tenuous. Insects are a good system to test whether opsin expansion is associated with greater light availability because they are enormously diverse and consequently display large variation in diel activity. To test this, we used 200 insect transcriptomes and examined the patterns of opsin diversity associated with diel-niche. We focused on the butterflies and moths (Lepidoptera) because this group has significant variation in diel-niche, substantial opsin recovery (n=100), and particularly well-curated transcriptomes. We identified opsin duplications using ancestral state reconstruction and examined rates of opsin evolution, and compared them across diel-niches. We find Lepidoptera species active in high light environments have independently expanded their opsins at least 10 times. Opsins from diurnal taxa also evolve faster; 13 amino acids were identified across different opsins that were under diversifying selection. Structural models reveal that four of these amino acids overlap with opsin color-tuning regions. By parsing nocturnal and diurnal switches, we show that light environment can influence gene diversity, selection, and protein structure of opsins in Lepidoptera.

scholarly journals Sprouts of shoot-clipped oak (Quercus alba and Q. robur) germinants show morphological and photosynthetic acclimation to contrasting light environments

New Forests ◽  
2019 ◽  
Vol 51 (5) ◽  
pp. 817-834 ◽  
Author(s):  
Linda K. Petersson ◽  
Magnus Löf ◽  
Anna M. Jensen ◽  
Daryl R. Chastain ◽  
Emile S. Gardiner
Keyword(s):  
Critical Role ◽  
Light Availability ◽  
Net Photosynthesis ◽  
High Light ◽  
Light Environment ◽  
Leaf Mass Per Area ◽  
Quercus Alba ◽  
Ecological Requirements ◽  
The North ◽  
Sprouting Capacity

AbstractSprouting by woody plants can increase species resilience to disturbance and foster regeneration during periods with little recruitment from seed. Though sprouting often plays a critical role in oak forest regeneration, there is little information available on sprouting capacity and sprout physiology at the seedling stage, particularly for new germinants. This study compared sprouting capacity and sprout photosynthesis of shoot-clipped germinants of two temperate oaks established in contrasting light environments. We studied the North American Quercus alba and the European Q. robur, both are in the section Quercus and appear to share similar biological and ecological requirements. Sprouting capacity for both species was enhanced under high light availability (29% more sprouts per plant), a response not previously noted for oak germinants. Seedling sprouts acclimated to high light with a 34% decrease in leaf area ratio, a 56% increase in leaf mass per area, and a 49% increase in the light-saturated maximum photosynthetic rate. Though both species appeared similarly adapted to shoot loss, a greater sprouting capacity (29% more sprouts per plant) and plant-level net photosynthesis (73% higher) was observed for Q. robur, regardless of light environment. As naturally regenerated oak seedlings in forest understories often experience disturbance or stress resulting in shoot loss or die-back, our results highlight the importance of the light environment during early plant development. Our comparison of temperate oaks from different continents should facilitate exchange of successful stand regeneration practices within the range of temperate oak forests.

Cone visual pigments of aquatic mammals

2005 ◽  
Vol 22 (6) ◽  
pp. 873-879 ◽  
Author(s):  
LUCY A. NEWMAN ◽  
PHYLLIS R. ROBINSON
Keyword(s):  
Color Vision ◽  
Mammalian Cells ◽  
Marine Mammals ◽  
Light Availability ◽  
Splice Site Mutation ◽  
Harbor Seal ◽  
Site Mutation ◽  
Cetacean Species ◽  
Cone Opsin ◽  
Aquatic Mammals

It has long been hypothesized that the visual systems of animals are evolutionarily adapted to their visual environment. The entrance many millions of years ago of mammals into the sea gave these new aquatic mammals completely novel visual surroundings with respect to light availability and predominant wavelengths. This study examines the cone opsins of marine mammals, hypothesizing, based on previous studies [Fasick et al. (1998) and Levenson & Dizon (2003)], that the deep-dwelling marine mammals would not have color vision because the pressure to maintain color vision in the dark monochromatic ocean environment has been relaxed. Short-wavelength-sensitive (SWS) and long-wavelength-sensitive (LWS) cone opsin genes from two orders (Cetacea and Sirenia) and an additional suborder (Pinnipedia) of aquatic mammals were amplified from genomic DNA (for SWS) and cDNA (for LWS) by PCR, cloned, and sequenced. All animals studied from the order Cetacea have SWS pseudogenes, whereas a representative from the order Sirenia has an intact SWS gene, for which the corresponding mRNA was found in the retina. One of the pinnipeds studied (harp seal) has an SWS pseudogene, while another species (harbor seal) appeared to have an intact SWS gene. However, no SWS cone opsin mRNA was found in the harbor seal retina, suggesting a promoter or splice site mutation preventing transcription of the gene. The LWS opsins from the different species were expressed in mammalian cells and reconstituted with the 11-cis-retinal chromophore in order to determine maximal absorption wavelengths (λmax) for each. The deeper dwelling Cetacean species had blue shifted λmax values compared to shallower-dwelling aquatic species. Taken together, these findings support the hypothesis that in the monochromatic oceanic habitat, the pressure to maintain color vision has been relaxed and mutations are retained in the SWS genes, resulting in pseudogenes. Additionally, LWS opsins are retained in the retina and, in deeper-dwelling animals, are blue shifted in λmax.

scholarly journals Phenology as a strategy for carbon optimality: a global model

2014 ◽  
Vol 11 (3) ◽  
pp. 763-778 ◽  
Author(s):  
S. Caldararu ◽  
D. W. Purves ◽  
P. I. Palmer
Keyword(s):  
Leaf Growth ◽  
Mechanistic Model ◽  
Leaf Age ◽  
Light Availability ◽  
Carbon Assimilation ◽  
Carbon Gain ◽  
Area Index ◽  
Growing Season Length ◽  
Tropical Areas ◽  
Gains And Losses

Abstract. Phenology is essential to our understanding of biogeochemical cycles and the climate system. We develop a global mechanistic model of leaf phenology based on the hypothesis that phenology is a strategy for optimal carbon gain at the canopy level so that trees adjust leaf gains and losses in response to environmental factors such as light, temperature and soil moisture, to achieve maximum carbon assimilation. We fit this model to five years of satellite observations of leaf area index (LAI) using a Bayesian fitting algorithm. We show that our model is able to reproduce phenological patterns for all vegetation types and use it to explore variations in growing season length and the climate factors that limit leaf growth for different biomes. Phenology in wet tropical areas is limited by leaf age physiological constraints while at higher latitude leaf seasonality is limited by low temperature and light availability. Leaf growth in grassland regions is limited by water availability but often in combination with other factors. This model will advance the current understanding of phenology for ecosystem carbon models and our ability to predict future phenological behaviour.

scholarly journals Dichromatic color vision at high light levels: Red/green discrimination using the blue-sensitive mechanism

1998 ◽  
Vol 38 (7) ◽  
pp. 973-983 ◽  
Author(s):  
Matthew J. Mcmahon ◽  
Donald I.A. Macleod
Keyword(s):  
Color Vision ◽  
High Light ◽  
Light Levels

Assimilate Movement in Lolium and Sorghum Leaves. II. Irradiance Effects on the Products of Photosynthesis

1976 ◽  
Vol 3 (3) ◽  
pp. 389 ◽  
Author(s):  
IF Wardlaw ◽  
C Marshall
Keyword(s):  
Amino Acids ◽  
Species Differences ◽  
High Irradiance ◽  
High Light ◽  
Light Conditions ◽  
Primary Metabolites ◽  
Lolium Temulentum ◽  
C4 Species ◽  
Sorghum Sudanense ◽  
Storage Starch

The rate of export and longitudinal movement of 14C-labelled assimilates in the phloem was found to be greater in Sorghum sudanense than in Lolium temulentum. Sucrose was the predominant metabolite translocated from the leaf in both species in both low and high light conditions. The effect of irradiance on the rate of formation and nature of the products of photosynthesis was examined using 14CO2 pulse-chase techniques and the differences in the primary metabolites closely followed those expected for a C3 and a C4 species. Reduction in irradiance reduced the rate of incorporation of 14C into sucrose, especially in Sorghum, and led to the accumulation of amino acids in both species. Although species differences in export of 14C-labelled assimilate were not apparently related to the rate of 14C incorporation into sucrose, this could account for the delay in export of 14C-labelled assimilates associated with reduced irradiance. There was a rapid initial labelling of starch and the proportion of *14C incorporated as starch was enhanced at high irradiance, particularly in Sorghum. Overall, the results support the view that there is a greater partitioning of assimilate into storage (starch) at high irradiance relative to assimilate moving into the phloem and that irradiance (in the range 20-96 W m-2) did not directly influence vein loading.

scholarly journals High light alongside elevated PCO2 alleviates thermal depression of photosynthesis in a hard coral (Pocillopora acuta)

2020 ◽  
Vol 223 (20) ◽  
pp. jeb223198
Author(s):  
Robert A. B. Mason ◽  
Christopher B. Wall ◽  
Ross Cunning ◽  
Sophie Dove ◽  
Ruth D. Gates
Keyword(s):  
Elevated Temperature ◽  
Ocean Acidification ◽  
Environmental Changes ◽  
Dark Respiration ◽  
Interactive Effect ◽  
Light Availability ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Photochemical Quenching ◽  
Strong Light

ABSTRACTThe absorbtion of human-emitted CO2 by the oceans (elevated PCO2) is projected to alter the physiological performance of coral reef organisms by perturbing seawater chemistry (i.e. ocean acidification). Simultaneously, greenhouse gas emissions are driving ocean warming and changes in irradiance (through turbidity and cloud cover), which have the potential to influence the effects of ocean acidification on coral reefs. Here, we explored whether physiological impacts of elevated PCO2 on a coral–algal symbiosis (Pocillopora acuta–Symbiodiniaceae) are mediated by light and/or temperature levels. In a 39 day experiment, elevated PCO2 (962 versus 431 µatm PCO2) had an interactive effect with midday light availability (400 versus 800 µmol photons m−2 s−1) and temperature (25 versus 29°C) on areal gross and net photosynthesis, for which a decline at 29°C was ameliorated under simultaneous high-PCO2 and high-light conditions. Light-enhanced dark respiration increased under elevated PCO2 and/or elevated temperature. Symbiont to host cell ratio and chlorophyll a per symbiont increased at elevated temperature, whilst symbiont areal density decreased. The ability of moderately strong light in the presence of elevated PCO2 to alleviate the temperature-induced decrease in photosynthesis suggests that higher substrate availability facilitates a greater ability for photochemical quenching, partially offsetting the impacts of high temperature on the photosynthetic apparatus. Future environmental changes that result in moderate increases in light levels could therefore assist the P. acuta holobiont to cope with the ‘one–two punch’ of rising temperatures in the presence of an acidifying ocean.

Acclimation to a Change in Light Regime in Seedlings of Six Australian Rainforest Tree Species

1991 ◽  
Vol 39 (6) ◽  
pp. 591 ◽  
Author(s):  
OO Osunkoya ◽  
JE Ash
Keyword(s):  
Light Availability ◽  
Area Ratio ◽  
Light Regime ◽  
Light Environment ◽  
Specific Leaf Weight ◽  
Relative Growth ◽  
Light Regimes ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Acclimation Potential

Acclimation potential of seedlings of six non-pioneer, North Queensland rainforest tree species (Diploglottis diphyllostegia, Flindersia brayleyana, Dysoxylum schgneri, Prunus turnerana, Neisosperma poweri and Castanospora alphandii) were evaluated in three different light regimes. The seedlings were grown from seeds and raised in 37, 10 and 2.5% photosynthetically active radiation (PAR) of full sunlight in a shade house. Plants were harvested at 1, 4, and 15 months after germination. At 4 months, for each species, one-third of the seedlings in each light environment were transferred to each of the two other light environments. The remaining one-third stayed in the same light environment and formed the control. The control seedlings of all species showed a marked response to increasing PAR: relative growth rate (RGR) and total biomass were low in the 2.5% PAR level, increased in the 10% PAR level and were maximal in the 37% PAR level, except for Neisosperma. The seedlings in the 25% PAR level showed a typical shade plant morphology with a high leaf area ratio, low root-shoot ratio and low specific leaf weight. For seedlings of Dysoxylum and Prunus, a change in light regime from 37% PAR to 2.5% PAR resulted in negative relative growth rates. Eleven months after transfer, many growth characteristics still showed significant initial × final light environment interactions, an indication of incomplete adjustment. Acclimation to increasing light availability was faster than acclimation to decreasing light availability. On the basis of biomass allocation patterns (root-shoot ratio, leaf area ratio and specific leaf weight), the six species could not be differentiated under the three light regimes and their dynamics. However, using RGR as a relative measure of carbon economy, it was possible to differentiate the species in their acclimation ability to decreased but not to increased irradiance. It was concluded that, for non-pioneer species, acclimation potential may be more related to physiological than to morphological plasticity.

Are resources allocated differently to symbiosis and reproduction in Geranium sylvaticum under different light conditions?

2004 ◽  
Vol 82 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Jarkko Korhonen ◽  
Minna-Maarit Kytöviita ◽  
Pirkko Siikamäki
Keyword(s):  
Resource Allocation ◽  
Forest Canopy ◽  
Light Availability ◽  
Growing Season ◽  
High Light ◽  
Mycorrhizal Colonization ◽  
Fungal Colonization ◽  
Low Light ◽  
Light Levels ◽  
Dark Septate Fungi

Light levels under the forest canopy are low and generally limit plant photosynthetic gains. We hypothesized that in low-light habitats, plant photosynthate acquisition is too low to allow the same magnitude of resource allocation to symbiosis and reproduction as in high-light habitats. We tested this hypothesis in a field study where Geranium sylvaticum L. plants were collected on three occasions during the growing season from shade and light habitats. In addition, we investigated the relationship between mycorrhizal colonization level and soil nutrient levels in shade and high-light habitats over a growing season. We found that light availability affects resource allocation in G. sylvaticum. Plants were intensively colonized with both arbuscular mycorrhizal and dark septate fungi, and the colonization intensities of these two different groups of fungi correlated positively with each other. In comparison with high-light meadows, mycorrhizal colonization levels were as high or higher in low-light forest habitats, but plants produced fewer flowers. This indicates that allocation to symbiosis was of higher priority than allocation to reproduction in low light. Seed size was not affected by light levels and did not correlate with fungal colonization levels. We found no relationship between fungal colonization levels and soil characteristics.Key words: arbuscular mycorrhiza, dark septate fungi, Geranium sylvaticum, reproduction, shade.

Salt-induced accumulation of glycine betaine is inhibited by high light in durum wheat

2011 ◽  
Vol 38 (2) ◽  
pp. 139 ◽  
Author(s):  
Petronia Carillo ◽  
Danila Parisi ◽  
Pasqualina Woodrow ◽  
Giovanni Pontecorvo ◽  
Giuseppina Massaro ◽  
...  
Keyword(s):  
Amino Acids ◽  
Durum Wheat ◽  
Glycine Betaine ◽  
High Light ◽  
Light Conditions ◽  
Salt Treatment ◽  
Wheat Seedlings ◽  
Triticum Durum Desf ◽  
Tyrosine Content

In this study, we determined the effects of both salinity and high light on the metabolism of durum wheat (Triticum durum Desf. cv. Ofanto) seedlings, with a special emphasis on the potential role of glycine betaine in their protection. Unexpectedly, it appears that high light treatment inhibits the synthesis of glycine betaine, even in the presence of salt stress. Additional solutes such as sugars and especially amino acids could partially compensate for the decrease in its synthesis upon exposure to high light levels. In particular, tyrosine content was strongly increased by high light, this effect being enhanced by salt treatment. Interestingly, a large range of well-known detoxifying molecules were also not induced by salt treatment in high light conditions. Taken together, our results question the role of glycine betaine in salinity tolerance under light conditions close to those encountered by durum wheat seedlings in their natural environment and suggest the importance of other mechanisms, such as the accumulation of minor amino acids.

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