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1.
Cryptochromes are blue-light absorbing photoreceptors found in many organisms where they have been involved in numerous growth,
developmental, and circadian responses. In Arabidopsis thaliana, two cryptochromes, CRY1 and CRY2, mediate several blue-light-dependent responses including hypocotyl growth inhibition.
Our study shows that an increase in the intensity of the ambient magnetic field from 33–44 to 500 μT enhanced growth inhibition
in A. thaliana under blue light, when cryptochromes are the mediating photoreceptor, but not under red light when the mediating receptors
are phytochromes, or in total darkness. Hypocotyl growth of Arabidopsis mutants lacking cryptochromes was unaffected by the increase in magnetic intensity. Additional cryptochrome-dependent responses,
such as blue-light-dependent anthocyanin accumulation and blue-light-dependent degradation of CRY2 protein, were also enhanced
at the higher magnetic intensity. These findings show that higher plants are sensitive to the magnetic field in responses
that are linked to cryptochrome-dependent signaling pathways. Because cryptochromes form radical pairs after photoexcitation,
our results can best be explained by the radical-pair model. Recent evidence indicates that the magnetic compass of birds
involves a radical pair mechanism, and cryptochrome is a likely candidate for the avian magnetoreception molecule. Our findings
thus suggest intriguing parallels in magnetoreception of animals and plants that appear to be based on common physical properties
of photoexcited cryptochromes. 相似文献
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Elena V. Artyukova Marina M. Kozyrenko Peter G. Gorovoy Yury N. Zhuravlev 《Genetica》2009,137(2):201-212
Microbiota decussata Kom. (Cupressaceae) is a subalpine species endemic to the Sikhote Alin Mountains with populations scattered throughout the
range. We used sequence data for four noncoding regions of chloroplast DNA to characterize the genetic diversity in populations
sampled from different parts of M. decussata natural range. No variation was observed in the trnT–trnF region, whereas the trnH–psbA, trnS–trnfM, and trnS–trnG regions showed polymorphisms. At the species level, we found a low nucleotide diversity (π = 0.0009) and high haplotype diversity
(h = 0.981) as well as high differentiation (ΦST = 0.420). N
ST and G
ST values suggested the existence of a phylogeographic structure in M. decussata. The observed patterns of diversity could be explained in part by ecological features of the species and its long-term persistence
throughout the range with population expansion, successive fragmentation and isolation. 相似文献
4.
Many blue-light mediated physiological responses have been studied in the fern Adiantum capillus-veneris. We have isolated genomic clones encoding sequences similar to those encoding blue-light photoreceptors (cryptochromes) in
higher plants using the Arabidopsis CRY1 cDNA as a probe, and these positive clones fall into five independent groups. Using RACE procedures, we obtained full-length
cDNA sequences for three of these five groups. The deduced amino acid sequences include the photolyase-homologous domain in
the N-terminal half, and they also contain a C-terminal extension of about 200 amino acids in length. These structural features
indicate that the genes indeed encode Adiantum cryptochromes and represent a small gene family having at least three members.
Received: 16 February 1998 / Accepted: 26 April 1998 相似文献
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To select appropriate plant materials for a phylogeography of deciduous broad-leaved forests in Japan, we surveyed intraspecific chloroplast DNA variation in 34 species found in these forests. A relatively large number of intraspecific cpDNA variations were detected in ten species: Carpinus japonica (nucleotide diversity π=0.00083), C. laxiflora (π=0.00221), Magnolia obovata (π=0.00134), Lindera triloba (π=0.00255), L. obtusiloba (π=0.00289), Pourthiaea villosa var. leavis (π=0.00263), Acer japonicum (π=0.00170), A. micranthum (π=0.00237), Euonymus oxyphyllus (π=0.00322) and Styrax obassia (π=0.00100). 相似文献
8.
Plants possess photoreceptors to perceive light which controls most aspects of their lives. Three photoreceptor families are
well characterized: cryptochromes (crys), phototropins (phots), and phytochromes (phys). Two putative families have been identified
more recently: Zeitlupes (ZTLs) and UV-B photoreceptors (ULI). Using Arabidopsis thaliana and Oryza sativa photoreceptor sequences as references, we have searched for photoreceptor encoding genes in the major phyla of plant kingdom.
For each photoreceptor family, using a phylogenetic tree based on the alignment of conserved amino acid sequences, we have
tried to trace back the evolution and the emergence of the diverse photoreceptor ancestral sequences.
The green alga Chlamydomonas contains one cry and one phot sequence, probably close to the corresponding ancestral sequences, and no phy-related sequence.
The putative UV-B photoreceptors seem to be restricted to the Brassicacae. Except for mosses and ferns, which contain divergent
photoreceptor numbers, the composition of the diverse photoreceptor families is conserved between species. A high conservation
of the residues within domains is observed in each photoreceptor family. The complete phylogenic analysis of the photoreceptor
families in plants has confirmed the existence of crucial evolutionary nodes between the major phyla. For each photoreceptor
class, a major duplication occurred before the separation between Mono- and Eudicotyledons. This allowed postulating on the
putative ancestral function of the photoreceptors.
[Reviewing Editor: Dr. Rudiger Cerff] 相似文献
9.
Insect photoperiodism: seeing the light 总被引:2,自引:0,他引:2
DAVID S. SAUNDERS 《Physiological Entomology》2012,37(3):207-218
This review examines the spectral sensitivities of photoperiodic responses in insects and mites in relation to circadian‐based models for the photoperiodic clock. It concludes that there are probably a number of different photoreceptors at both the organ and molecular levels. These latter probably fall into two classes: (i) a blue‐light sensitive photoreceptor and (ii) a range of opsins (i.e. opsin proteins conjugated with a vitamin A based pigment) absorbing light at a range of wavelengths. In flesh flies (Sarcophaga spp. and possibly other higher Diptera), which are considered to exemplify the ‘external coincidence’ model, entrainment of the photoperiodic oscillator probably involves a blue‐light photoreceptor of Drosophila‐type CRYPTOCHROME (CRY1) absorbing maximally at approximately 470 nm, whereas opsins absorbing at longer wavelengths may be involved in the photo‐inductive process (diapause/nondiapause regulation) that occurs when dawn light coincides with the photo‐inducible phase. In the parasitic wasp Nasonia vitripennis, on the other hand, a species that lacks CRY1 but expresses the nonphotosensitive ‘mammalian‐type’ CRY2, and is considered to exemplify ‘internal coincidence’, entrainment of the dawn and dusk oscillators may involve opsin‐based photoreceptors absorbing light at longer wavelengths as far as the red end of the spectrum. In the Lepidoptera, which express both CRY1 and CRY2, properties of both external and internal coincidence may be evident. The presence or absence of cry1 in the genome may thus emerge as a key to the photoperiodic mechanism on its light input pathway. 相似文献
10.
Yoshiaki Tsuda Haruo Sawada Takafumi Ohsawa Katsuhiro Nakao Hiroki Nishikawa Yuji Ide 《Tree Genetics & Genomes》2010,6(3):377-387
We evaluated the genetic structure of 16 Betula maximowicziana populations in the Chichibu mountain range, central Japan, located within a 25-km radius; all but two populations were at
altitudes of 1,100–1,400 m. The results indicate the effects of geographic topology on the landscape genetic structure of
the populations and should facilitate the development of local-scale strategies to conserve and manage them. Analyses involving
11 nuclear simple sequence repeat loci showed that most populations had similar intrapopulation genetic diversity parameters.
Population differentiation (F
ST = 0.021, G′ST = 0.033) parameters for the populations examined were low but were relatively high compared to those obtained in a previous
study covering populations in a much larger area with a radius of approximately 1,000 km (F
ST = 0.062, G′ST = 0.102). Three populations (Iriyama, Kanayamasawa, and Nishizawa) were differentiated from the other populations by Monmonier’s
and spatial analysis of molecular variance algorithms or by STRUCTURE analysis. Since a high mountain ridge (nearly 2,000 m)
separates the Kanayamasawa and Nishizawa populations from the other 14 populations and the Kanayamasawa and Nishizawa populations
are themselves separated by another mountain ridge, the genetic structure appears to be partly due to mountain ridges acting
as genetic barriers and restricting gene flow. However, the Iriyama population is genetically different but not separated
by any clear geographic barrier. These results show that the landscape genetic structure is complex in the mountain range
and we need to pay attention, within landscape genetic studies and conservation programs, to geographic barriers and local
population differentiation. 相似文献
11.
Understanding the population structure and evolutionary history of the eastern Pacific seahorse Hippocampus ingens is critical for the effective management of this threatened species. Life history characteristics of H. ingens (site fidelity and brooding of young) may limit gene flow and lead to population differentiation. A recent study analyzing
conserved fragments of the mitochondrial cyt b and control region found no population structure. We re-assess this conclusion with a phylogeographic analysis of relationships
among 115 individuals of H. ingens over a broader geographic range (San Diego Bay in California, Gulf of California, Central America, Ecuador, and Peru) based
on a more variable 428 base pair fragment of the control region. This expanded analysis affirms low overall nucleotide diversity
relative to other seahorses (θπ = 0.004), and shows evidence of a recent bottleneck and population expansion since the middle Pleistocene. AMOVA analysis
shows moderate overall population structure (ΦST = 0.10, P val = 0.00), and pairwise ΦST estimates indicate structure between the Gulf of California and all Pacific coast localities. Knowledge of population structure
in H. ingens may improve conservation efforts by identifying evolutionarily important management units, and could determine source regions
in the continuing trade of seahorses for traditional Chinese medicine. The level of genetic divergence observed between the
Gulf of California and all other localities sampled may distinguish the Gulf as a separate management unit. Additional phylogeographic
research with more quickly evolving genetic markers and targeted sampling at the mouth of the Gulf of California is warranted
to inform strategies for conservation of this threatened seahorse. 相似文献
12.
Time measurement and light detection are inextricably linked. Cryptochromes, the blue-light photoreceptors shared between plants and animals, are critical for circadian rhythms in flies and mice [1-3]. WC-1, a putative blue-light photoreceptor, is also essential for the maintenance of circadian rhythms in Neurospora [4]. In contrast, we report here that in Arabidopsis thaliana the double mutant lacking the cryptochromes cry1 and cry2, and even a quadruple mutant lacking the red/ far-red photoreceptor phytochromes phyA and phyB as well as cry1 and cry2, retain robust circadian rhythmicity. Interestingly, the quadruple mutant was nearly blind for developmental responses but perceived a light cue for entraining the circadian clock. These results indicate that cryptochromes and phytochromes are not essential components of the central oscillator in Arabidopsis and suggest that plants could possess specific photosensory mechanisms for temporal orientation, in addition to cryptochromes and phytochromes, which are used for both spatial and temporal adaptation. 相似文献
13.
Human activities such as fragmentation and selective logging of forests can threaten population viability by modification
of ecological and genetic processes. Using six microsatellite markers, we examined the effects of forest fragmentation and
local disturbance on the genetic diversity and structure of adult trees (N = 110) and seedlings (N = 110) of Prunus africana in Kakamega Forest, western Kenya. Taking samples of adults and seedlings allowed for study of changes in genetic diversity
and structure between generations. Thereby, adults reflect the pattern before and seedlings after intensive human impact.
Overall, we found 105 different alleles in the six loci examined, 97 in adults and 88 in seedlings. Allelic richness and heterozygosity
were significantly lower in seedlings than in adults. Inbreeding increased from adult tree to seedling populations. Genetic
differentiation of adult trees was low (overall F
ST = 0.032), reflecting large population sizes and extensive gene flow in the past. Genetic differentiation of seedlings was
slightly higher (overall F
ST = 0.044) with all of the 28 pairwise F
ST-values being significantly different from zero. These results suggest that human disturbance in Kakamega Forest has significantly
reduced allelic richness and heterozygosity, increased inbreeding and slightly reduced gene flow in P. africana in the past 80–100 years. 相似文献
14.
The blue-light receptor cryptochrome 1 shows functional dependence on phytochrome A or phytochrome B in Arabidopsis thaliana 总被引:10,自引:7,他引:3
Margaret Ahmad Anthony R. Cashmore 《The Plant journal : for cell and molecular biology》1997,11(3):421-427
Blue-light responses in higher plants are mediated by specific photoreceptors, which are thought to be flavoproteins; one such flavin-type blue-light receptor, CRY1 (for cryptochrome), which mediates inhibition of hypocotyl elongation and anthocyanin biosynthesis, has recently been characterized. Prompted by classical photobiological studies suggesting possible co-action of the red/far-red absorbing photoreceptor phytochrome with blue-light photoreceptors in certain plant species, the role of phytochrome in CRY1 action in Arabidopsis was investigated. The activity of the CRY1 photoreceptor can be substantially altered by manipulating the levels of active phytochrome (Pfr) with red or far-red light pulses subsequent to blue-light treatments. Furthermore, analysis of severely phytochrome-deficient mutants showed that CRY1-mediated blue-light responses were considerably reduced, even though Western blots confirmed that levels of CRY1 photoreceptor are unaffected in these phytochrome-deficient mutant backgrounds. It was concluded that CRY1-mediated inhibition of hypocotyl elongation and anthocyanin production requires active phytochrome for full expression, and that this requirement can be supplied by low levels of either phyA or phyB. 相似文献
15.
The cryptochromes are a family of blue light photoreceptors that play important roles in the control of plant development.
We have characterised the cryptochrome gene family in the model legume garden pea (Pisum sativum L.). Pea contains three expressed cryptochrome genes; a single CRY1 orthologue, and two distinct CRY2 genes that we have termed CRY2a and CRY2b. Genomic southern blots indicate that there are unlikely to be more CRY genes in pea. Each of the three genes encodes a full-length CRY protein that contains all the major domains characteristic
of other higher plant cryptochromes. Database searches have identified Medicago truncatula expressed sequence tags (ESTs) corresponding to all three genes, whereas only a single CRY2 is represented in EST collections from the more distantly related legumes soybean and Lotus japonicus. The proteins encoded by the pea and Medicago CRY2b genes are distinguished from other CRY2 proteins by their shorter C-terminus. Expression analyses have identified marked
differences in the regulation of the three genes, with CRY2b expression in particular distinguished by high-amplitude diurnal cycling and rapid repression in seedlings transferred from
darkness to blue light. 相似文献
16.
Dai-Chang Kuo Chia-Chia Lin Kuo-Chieh Ho Yu-Pin Cheng Shih-Ying Hwang Tsan-Piao Lin 《Conservation Genetics》2010,11(3):803-812
Cinnamomum kanehirae Hayata (Lauraceae), the most valuable subtropical and temperate broadleaf timber tree in Taiwan, is rapidly disappearing
from the wild. Taking advantage of a scion garden established by the Taiwan Forestry Research Institute, we examined patterns
of chloroplast DNA (cpDNA) variations in 19 populations including 94 individuals. By sequencing two cpDNA fragments using
universal primers (the trnL-trnF and petG-trnP intergenic spacers), we found eight polymorphic sites, six haplotypes, and extremely low nucleotide diversity (π = 0.00016) from 792 bp aligned sequences. The ancestral haplotype is widely distributed. Among the populations studied, three
separated populations, at Yungfeng, Fuli, and Tahu have high nucleotide diversity. No phylogeographical structures of haplotypes
were revealed because the tests of N
ST−G
ST for populations did not differ from zero in any situations; a ‘star-like’ genealogy is characteristic when all haplotypes
rapidly coalesce and is a general outcome of population expansion. The neutrality test also suggested demographic expansion.
The genetic divergence and diversity analyses suggested that two potential refugia existed during the last glaciation with
a major one located in southeastern Taiwan and a minor one located in Tahu in north-central Taiwan in the Hsuehshan Range,
west of the Central Mountain Range. 相似文献
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Jean‐Baptiste Lamy Christophe Plomion Antoine Kremer Sylvain Delzon 《Molecular ecology》2012,21(23):5646-5655
A key aim of evolutionary biology – inferring the action of natural selection on wild species – can be achieved by comparing neutral genetic differentiation between populations (FST) with quantitative genetic variation (QST). Each of the three possible outcomes of comparisons of QST and FST (QST > FST, QST = FST, QST < FST) is associated with an inference (diversifying selection, genetic drift, uniform selection, respectively). However, published empirical and theoretical studies have focused on the QST > FST outcome. We believe that this reflects the absence of a straightforward biological interpretation of the QST < FST pattern. We here report recent evidence of this neglected evolutionary pattern, provide guidelines to its interpretation as either a canalization phenomenon or a consequence of uniform selection and discuss the significant importance this issue will have for the area of evolutionary biology. 相似文献
19.
Tomato contains homologues of Arabidopsis cryptochromes 1 and 2 总被引:4,自引:0,他引:4
Perrotta G Ninu L Flamma F Weller JL Kendrick RE Nebuloso E Giuliano G 《Plant molecular biology》2000,42(5):765-773
Cryptochromes are blue light photoreceptors found in both plants and animals. They probably evolved from photolyases, which are blue/UV-light-absorbing photoreceptors involved in DNA repair. In seed plants, two different cryptochrome (CRY) genes have been found in Arabidopsis and one in Sinapis, while three genes have been found in the fern Adiantum. We report the characterisation of tomato CRY genes CRY1 and CRY2. They map to chromosomes 4 and 9, respectively, show relatively constitutive expression and encode proteins of 679 and 635 amino acids, respectively. These proteins show higher similarity to their Arabidopsis counterparts than to each other, suggesting that duplication between CRY1 and CRY2 is an ancient event in the evolution of seed plants. The seed plant cryptochromes form a group distinct from the fern cryptochromes, implying that only one gene was present in the common ancestor between these two groups of plants. Most intron positions in CRY genes from plants and ferns are highly conserved. Tomato cry1 and cry2 proteins carry C-terminal domains 210 and 160 amino acids long, respectively. Several conserved motifs are found in these domains, some of which are common to both types of cryptochromes, while others are cryptochrome-type-specific. 相似文献
20.
The genetic diversity and population structure of the vulnerable Chinese Egret (Egretta eulophotes) were surveyed in the present study from three archipelagoes that cover the most southerly to the very northerly parts of
the Chinese distribution range of this species, using a 433-bp fragment of the mitochondrial control region (CR). Among 90
individual samples, 31 different haplotypes were defined by 30 polymorphic sites. Overall haplotype diversity, nucleotide
diversity and mean sequence divergence (p-distance) of this egret were 0.920, 0.0088 and 1.11%, respectively. NJ tree and
parsimony network for the CR haplotypes of the Chinese Egret showed little genetic structure, and analysis of molecular variance
indicated low but significant genetic differentiation (haplotype-based ΦST = 0.03267, P < 0.05 and distance-based ΦST = 0.04194, P < 0.05) among populations. The significant Fu’s F
S
tests (Fu’s F
S
= −16.946, P < 0.01) and mismatch distribution analysis (τ = 4.463, SSD = 0.0081, P = 0.12) suggested that the low genetic differentiation and little geographical structure of the genetic differentiation might
be explained by the population expansion. The Mantel test (haplotype-based F
ST, r = 0.639, P = 0.34 and distance-based F
ST, r = 0.947, P = 0.15) suggest that the significant genetic differentiation among populations was likely due to isolation by distance. 相似文献