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Yasue Nemoto, Kiyosumi Hori, Takeshi Izawa
Many short-day plants have a critical day length that fixes the schedule for flowering time, limiting the range of natural growth habitats (or growth and cultivation areas). Thus, fine-tuning of the critical day-length setting in photoperiodic flowering determines ecological niches within latitudinal clines; however, little is known about the molecular mechanisms controlling the fine-tuning of the critical day-length setting in plants. Previously, we determined that florigen genes are regulated by day length, and identified several key genes involved in setting the critical day length in rice...
December 10, 2017: Journal of Experimental Botany
Jin A Kim, Hyun-Soon Kim, Seo-Hwa Choi, Ji-Young Jang, Mi-Jeong Jeong, Soo In Lee
Carbohydrates are the primary energy source for plant development. Plants synthesize sucrose in source organs and transport them to sink organs during plant growth. This metabolism is sensitive to environmental changes in light quantity, quality, and photoperiod. In the daytime, the synthesis of sucrose and starch accumulates, and starch is degraded at nighttime. The circadian clock genes provide plants with information on the daily environmental changes and directly control many developmental processes, which are related to the path of primary metabolites throughout the life cycle...
December 11, 2017: International Journal of Molecular Sciences
Ling Lu, Yuanqi Wu, Zhengqiao Liao, Jing Xiong, Fengkai Wu, Jie Xu, Hai Lan, Qiling Tang, Shufeng Zhou, Yaxi Liu, Yanli Lu
ZEITLUPE (ZTL), LOV KELCH PROTEIN 2 (LKP2), and FLAVIN-BINDING KELCH REPEAT F-BOX 1 (FKF1)-blue-light photoreceptors-play important roles in regulating the circadian clock and photoperiodic flowering pathway in plants. In this study, phylogenetic analysis revealed that the LOV (Light, Oxygen, or Voltage) and Kelch repeat-containing F-box (LFK) gene family can be classified into two clades, ZTL/LKP2 and FKF1, with clear differentiation between monocots and dicots within each clade. The LFK family genes underwent strong purifying selection; however, signatures of positive selection to adapt to local conditions still existed in 18 specific codons...
December 11, 2017: Heredity
Xinxin Zhao, B Shaun Bushman, Xinquan Zhang, Matthew D Robbins, Steven R Larson, Joseph G Robins, Aaron Thomas
Flowering occurs in response to cues from both temperature and photoperiod elicitors in cool-season, long-day forage grasses, and genes involved in sensing the elicitors and inducing downstream flowering responses have been associated with heading date and flowering time in perennial forage grasses as well as cereal grasses. In this study we test for association between orchardgrass (Dactylis glomerata L.) heading date and polymorphisms in the CONSTANS (DgCO1), FLOWERING TIME (DgFT1), a VRN1 like MADS-box (DgMADS), and PHOTOPERIOD (DgPPD1-like) containing genes...
December 2017: Plant Science: An International Journal of Experimental Plant Biology
Tao Lin, Yong You, Zhao-Hua Zeng, Shuo Lin, Yi-Xin Chen, Hong-Jiao Cai, Jian-Wei Zhao, Hui Wei
The effect of nine constant temperatures on developmental time of Oligota flavicornis (Boisduval and Lacordaire) preying on Tetranychus cinnabarinus (Boisduval) (Acari: Tetranychidae) eggs was determined under laboratory conditions of 75 ± 5% RH and a 16:8 (L:D) h photoperiod. O. flavicornis survival rates were highest between 18 and 30°C, although O. flavicornis eggs developed successfully to adults at 12-32°C, and the developmental durations to adult at the seven temperatures (12, 15, 18, 20, 25, 30, and 32°C) were 114...
December 5, 2017: Journal of Economic Entomology
Kate L Hawley, Carolyn M Rosten, Thrond O Haugen, Guttorm Christensen, Martyn C Lucas
Polar regions are characterized by acute seasonal changes in the environment, with organisms inhabiting these regions lacking diel photoperiodic information for parts of the year. We present, to our knowledge, the first high-resolution analysis of diel and seasonal activity of free-living fishes in polar waters (74°N), subject to extreme variation in photoperiod, temperature and food availability. Using biotelemetry, we tracked two sympatric ecomorphs of lake-dwelling Arctic charr (Salvelinus alpinus n = 23) over an annual cycle...
December 2017: Biology Letters
Cumali Ozaslan, Shahid Farooq, Huseyin Onen, Selcuk Ozcan, Bekir Bukun, Hikmet Gunal
Two Solanaceae invasive plant species (Physalis angulata L. and P. philadelphica Lam. var. immaculata Waterfall) infest several arable crops and natural habitats in Southeastern Anatolia region, Turkey. However, almost no information is available regarding germination biology of both species. We performed several experiments to infer the effects of environmental factors on seed germination and seedling emergence of different populations of both species collected from various locations with different elevations and habitat characteristics...
December 5, 2017: Scientific Reports
Jorge Mariano Collantes-Alegre, Florian Mattenberger, Miquel Barberà, David Martínez-Torres
Organisms exhibit a wide range of seasonal responses as adaptions to predictable annual changes in their environment. These changes are originally caused by the effect of the Earth's cycles around the sun and its axial tilt. Examples of seasonal responses include floration, migration, reproduction and diapause. In temperate climate zones, the most robust variable to predict seasons is the length of the day (i.e. the photoperiod). The first step to trigger photoperiodic driven responses involves measuring the duration of the light-dark phases, but the molecular clockwork performing this task is poorly characterized...
December 1, 2017: Journal of Insect Physiology
Somanshu Banerjee, Chandra Mohini Chaturvedi
The hypothalamo-hypophyseal-gonadal axis mediated differential photosexual responses in quail kept under different simulated photoperiodic conditions have been studied in details. Local testicular GnRH-GnIH and their receptor system has been hypothesized to be modulated in quail showing different photo-sexual responses and thus influence the testicular activity and steroidogenesis through local (paracrine and autocrine) action. To validate this hypothesis, we studied the expression of gonadotropin releasing hormone receptor (GnRH-R), gonadotropin inhibiting hormone receptor (GnIH-R) mRNA, growth hormone receptor (GH-R), proliferating cell nuclear antigen (PCNA), 14-3-3, Connexin-43 (Cnx-43), steroidogenic factor-1 (SF-1), Steroidogenic Acute Regulatory protein (StAR), steroidogenic enzyme (3β HSD) in testis as well as androgen receptor (AR) in testis and epididymis of photosensitive (PS), scotorefractory (SR), photorefractory (PR) and scotosensitive (SS) quail...
November 30, 2017: Journal of Photochemistry and Photobiology. B, Biology
Cathy A Goldstein, Louise M O'Brien, Ingrid L Bergin, Thomas L Saunders
Female shift workers are at increased risk for negative reproductive outcomes, and animal evidence suggests that manipulation of the light-dark cycle is detrimental to early gestation in female mice. Specifically, failure of implantation may be responsible for these findings. The objective of this study was to better delineate which reproductive processes are vulnerable to detrimental effects of maternal circadian disturbance. We exposed mice undergoing embryo transfer to repetitive phase advances of the photoperiod...
November 30, 2017: Systems Biology in Reproductive Medicine
Somayeh Rahimi-Kaldeh, Ahmad Ashouri, Alireza Bandani, Kenji Tomioka
The short day lengths of late summer in moderate regions are used to induce diapause in various insects. Many studies have shown the maternal effect of photoperiod on diapause induction of Trichogramma wasps, but there is no study to show the relationship between photoperiodic regimes and clock genes in these useful biological control agents. Here, we investigated the role of photoperiods on diapause, fecundity, and clock gene expression (clk, cyc, cry2, per, and timeout) in asexual and sexual Trichogramma brassicae as a model insect to find any differences between two strains...
November 2017: Development Genes and Evolution
Lilian Franco-Belussi, Diogo Borges Provete, Classius De Oliveira
Internal organs of ectotherms have melanin-containing cells that confer different degrees of coloration to them. Previous experimental studies analyzed their developmental origin, role in immunity, and hormonal regulation. For example, melanin increases with ultraviolet radiation (UV) and temperature in frogs and fish. However, little is known about how environmental variables influence the amount of coloration on organs among amphibian species over a large spatial extent. Here, we tested how climatic variables (temperature, UV, and photoperiod) influence the coloration of internal organs of anurans...
November 2017: Ecology and Evolution
Natalia Ordonez-Herrera, Laura Trimborn, Melanie Menje, Monique Henschel, Lennart Robers, David Kaufholdt, Robert Hänsch, Jessika Adrian, Jathish Ponnu, Ute Hoecker
The ambient light environment controls many aspects of plant development throughout a plant's life cycle. Such complex control is achieved because a key repressor of light signaling, the Arabidopsis COP1/SPA E3 ubiquitin ligase, causes the degradation of multiple regulators of endogenous developmental pathways. This includes the CONSTANS (CO) transcription factor which is responsible for photoperiodic control of flowering time. There are 16 CONSTANS-like proteins whose functions are only partly understood. Here, we show that 14 COL proteins bind COP1 and SPA1 in vitro...
November 29, 2017: Plant Physiology
Y Takano, M S Ullah, T Gotoh
Previous studies on the spider mite Eotetranychus smithi Pritchard & Baker have shown that diapause in eggs is induced by low temperature alone and that females developed at ≤ 17.5 °C laid diapause eggs, regardless of the photoperiod. In this study, diapause eggs were kept at 5 °C and a photoperiod of 16L:8D for 0-120 days and then maintained at 25 °C to know the effect of chilling on diapause termination. Diapause eggs mostly hatched when they were maintained at 25 °C after chilling for 30-90 days at 5 °C, which suggests that diapause termination is favored by low temperatures...
November 28, 2017: Experimental & Applied Acarology
Valeria Zonato, Stefano Vanin, Rodolfo Costa, Eran Tauber, Charalambos P Kyriacou
The spread of adaptive genetic variants in populations is a cornerstone of evolutionary theory but with relatively few biologically well-understood examples. Previous work on the ls-tim variant of timeless, which encodes the light-sensitive circadian regulator in Drosophila melanogaster, suggests that it may have originated in southeastern Italy. Flies characterized by the new allele show photoperiod-related phenotypes likely to be adaptive in seasonal environments. ls-tim may be spreading from its point of origin in Italy by directional selection, but there are alternative explanations for its observed clinal geographical distribution, including balancing selection and demography...
November 1, 2017: Journal of Biological Rhythms
V Carcangiu, C Giannetto, S Luridiana, G Piccione
The scope of the present study was to explore the features of the daily rhythms of plasma melatonin and blood glucose in goats during different natural photoperiod imposed by the four seasons. Five Sarda breed pluriparus female goats, 2 years old, with a mean body weight 40.5 ± 2.3 kg, lead to a natural pasture, were cannulated the day before the start of the study for sample collection performed during spring and autumn equinoxes, and winter and summer solstices for a 48-h period. On blood samples, melatonin and glucose concentrations were assessed...
November 28, 2017: Chronobiology International
Christa Kistenpfennig, Mayumi Nakayama, Ruri Nihara, Kenji Tomioka, Charlotte Helfrich-Förster, Taishi Yoshii
In many animals, the circadian clock plays a role in adapting to the coming season by measuring day length. The mechanism for measuring day length and its neuronal circuits remains elusive, however. Under laboratory conditions, the fruit fly, Drosophila melanogaster, displays 2 activity peaks: one in the morning and one in the evening. These peaks appear to be regulated by 2 separate circadian oscillators (the morning and evening oscillators) that reside in different subsets of pacemaker clock neurons in the brain...
November 1, 2017: Journal of Biological Rhythms
Guangyan Feng, Linkai Huang, Ji Li, Jianping Wang, Lei Xu, Ling Pan, Xinxin Zhao, Xia Wang, Ting Huang, Xinquan Zhang
BACKGROUND: Vernalization and the transition from vegetative to reproductive growth involve multiple pathways, vital for controlling floral organ formation and flowering time. However, little transcription information is available about the mechanisms behind environmental adaption and growth regulation. Here, we used high-throughput sequencing to analyze the comprehensive transcriptome of Dactylis glomerata L. during six different growth periods. RESULTS: During vernalization, 4689 differentially expressed genes (DEGs) significantly increased in abundance, while 3841 decreased...
November 22, 2017: BMC Plant Biology
Chunqiao Zhao, Xifeng Fan, Xincun Hou, Yi Zhu, Yuesen Yue, Juying Wu
Switchgrass is a photoperiod-sensitive energy grass suitable for growing in the marginal lands of China. We explored the effects of extended photoperiods of low-irradiance light (7 μmol·m-2·s-1, no effective photosynthesis) on the growth, the biomass dry weight, the biomass allocation, and, especially, the stem digestibility and cell wall characteristics of switchgrass. Two extended photoperiods (i.e., 18 and 24 h) were applied over Alamo. Extended light exposure (18 and 24 h) resulted in delayed heading and higher dry weights of vegetative organs (by 32...
2017: PloS One
Takayuki Ohara, Akiko Satake
Plants need to avoid carbon starvation and resultant growth inhibition under fluctuating light environments to ensure optimal growth and reproduction. As diel patterns of carbon metabolism are influenced by the circadian clock, appropriate regulation of the clock is essential for plants to properly manage their carbon resources. For proper adjustment of the circadian phase, higher plants utilize environmental signals such as light or temperature and metabolic signals such as photosynthetic products; the importance of the latter as phase regulators has been recently elucidated...
2017: Frontiers in Plant Science
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