Light regulates hydrogen sulfide signalling during skoto- and photo-morphogenesis in foxtail millet

2019 ◽  
Vol 46 (10) ◽  
pp. 916 ◽  
Author(s):  
Zhiqiang Liu ◽  
Chunyu Cao ◽  
Yawen Li ◽  
Guangdong Yang ◽  
Yanxi Pei

Signal transduction mediated by photoreceptors regulates many physiological processes during plant growth and development including seed germination, flowering and photosynthesis, which are also regulated by hydrogen sulfide (H2S). However, studies of the connection between the vital environmental factors – light and the significant endogenous gasotransmitter – H2S, is lacking. Here, the seedlings of foxtail millet were used to reveal the mechanism of light regulation in H2S generation. Results showed that seedling hypocotyl elongation was promoted by H2S, but inhibited by HA under dark or white light condition. H2S contents in hypocotyl increased at first under red, blue or white light then decreased, and the duration of increase under white light was longer than under red or blue light. The activity of cysteine desulfhydrases, which catalyse H2S generation, was increased by red light but decreased by blue and white light. The expressions of cysteine desulfhydrases coding genes LCD1 and LCD2 were promoted by red or white light, but inhibited by blue light. In contrast, DES gene was promoted by white light but inhibited by red or blue light. In addition, the activities of LCDs were regulated by the phosphorylation mediated by photoreceptors PHYB and CRY1/CRY2. Finally, there are two pathways of light regulating H2S production, including a rapid process that involves the modification of phosphorylation on LCDs protein mediated by photoreceptors directly or indirectly, as well as a slower process that involves in regulating the expressions of LCDs and DES genes. This discovery has potential value for the application of H2S in agricultural production protecting the crops from unsuited light condition.

Author(s):  
Niroj Paudel ◽  
Prakash Deep Rai

<p class="abstract"><strong>Background:</strong> Germination of <em>Desmodium triflorum</em> is used for the scarification using the acid is valuable for the different light condition.</p><p class="abstract"><strong>Methods:</strong> The sample was collected as four month of interval of time and the seed is treated with acids with different time.  </p><p class="abstract"><strong>Results:</strong> seeds scarified with sulfuric acids for 10 min before sowing had better germination than those scarified for 5 and 15 min. Among them light qualities, red and white light had slightly promoted effect whereas blue light and dark condition had slightly negative effect on seed germination.</p><p><strong>Conclusions:</strong> In comparison to blue light and dark condition, red light and white light were promoted to percentage germination indicating the role of phytochrome in seed germination of <em>Desmodium triflorum</em>. </p>


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1211
Author(s):  
Barbara Frąszczak ◽  
Monika Kula-Maximenko

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.


RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4707-4715 ◽  
Author(s):  
Qiwei Zhang ◽  
Haiqin Sun ◽  
Tao Kuang ◽  
Ruiguang Xing ◽  
Xihong Hao

Materials emitting red light (∼611 nm) under excitation with blue light (440–470 nm) are highly desired for fabricating high-performance white light-emitting diodes (LEDs).


2017 ◽  
Vol 69 (1) ◽  
pp. 93-101
Author(s):  
Zexiong Chen ◽  
Juan Lou

Light is the source of energy for plants. Light wavelengths, densities and irradiation periods act as signals directing morphological and physiological characteristics during plant growth and development. To evaluate the effects of light wavelengths on tomato growth and development, Solanum lycopersicum (cv. micro-Tom) seedlings were exposed to different light-quality environments, including white light and red light supplemented with blue light (at ratios of 3:1 and 8;1, respectively). Tomatoes grown under red light supplemented with blue light displayed significantly shorter stem length, a higher number of flower buds and rate of fruit set, but an extremely late flowering compared to white-light-grown plants. To illustrate the mechanism underlying the inhibition of stem growth and floral transition mediated by red/blue light, 10 trehalose-6-phosphate synthase (TPS) genes were identified in tomato, and bioinformatics analysis was performed. qRT-PCR analysis showed that SlTPSs were expressed widely throughout plant development and SlTPS1 was expressed at extremely high levels in stems and buds. Further analysis of several flowering-associated genes and microRNAs showed that the expressions of SlTPS1, SlFT and miR172 were significantly downregulated in tomato grown under red and blue light compared with those grown under white light, whereas miR156 transcript levels were increased. A regulatory model underlying vegetative growth and floral transition regulated by light qualities is presented. Our data provide evidence that light quality strongly affects plant growth and phase transition, most likely via the TPS1-T6P signaling pathway.


1986 ◽  
Vol 41 (5-6) ◽  
pp. 591-596 ◽  
Author(s):  
Stefan Kraiss ◽  
Armin R. Gemmrich

In the gametophyte of the fern Anemia phyllitidis synthesis of linolenic acid esterified in monogalactosyldiglyceride requires light. By induction-reversion experim ents it could be demonstrated that this light-dependent step is mediated by phytochrome. There is also evidence for phytochrome control of galactolipid and hexadecatrienoic acid synthesis. In continuous blue light the synthesis of linolenic acid is inhibited and linoleic acid accumulates. It is concluded that the blue light photoreceptor affects an inhibition of linoleic acid desaturase. In continuous blue light chloroplasts contain abundant multilayered thylakoids, the grana regions are not as distinct as in white light, and membranes appear less appressed. In continuous red light the membranes are reduced in number and contain less grana-like appressions. It is concluded that both photoreceptors are necessary for a coordinate synthesis and assembly of the individual components of the chloroplast membrane.


1988 ◽  
Vol 66 (6) ◽  
pp. 1021-1027 ◽  
Author(s):  
Zdenko Rengel ◽  
Herbert A. Kordan

Anthocyanin production in roots and shoots of Zea mays L. seedlings was higher in blue than in red light and was very low in far red light. Under dichromatic irradiation, a phytochrome mediation of a blue-dependent photoreaction was evident. Pretreatments with both white and blue light allowed increased anthocyanin production under subsequent inductive conditions, as did occurs in treatments with continuous blue, red, far red, or white light. It is suggested that the effect of light pretreatments on phytochrome-controlled anthocyanin formation may differ from that controlled by the combination of cryptochrome and phytochrome.


2018 ◽  
Vol 56 (1) ◽  
pp. 41-66 ◽  
Author(s):  
Gwyn A. Beattie ◽  
Bridget M. Hatfield ◽  
Haili Dong ◽  
Regina S. McGrane

Plants collect, concentrate, and conduct light throughout their tissues, thus enhancing light availability to their resident microbes. This review explores the role of photosensing in the biology of plant-associated bacteria and fungi, including the molecular mechanisms of red-light sensing by phytochromes and blue-light sensing by LOV (light-oxygen-voltage) domain proteins in these microbes. Bacteriophytochromes function as major drivers of the bacterial transcriptome and mediate light-regulated suppression of virulence, motility, and conjugation in some phytopathogens and light-regulated induction of the photosynthetic apparatus in a stem-nodulating symbiont. Bacterial LOV proteins also influence light-mediated changes in both symbiotic and pathogenic phenotypes. Although red-light sensing by fungal phytopathogens is poorly understood, fungal LOV proteins contribute to blue-light regulation of traits, including asexual development and virulence. Collectively, these studies highlight that plant microbes have evolved to exploit light cues and that light sensing is often coupled with sensing other environmental signals.


2021 ◽  
Vol 8 ◽  
Author(s):  
Peian Zhang ◽  
Suwen Lu ◽  
Zhongjie Liu ◽  
Ting Zheng ◽  
Tianyu Dong ◽  
...  

Different light qualities have various impacts on the formation of fruit quality. The present study explored the influence of different visible light spectra (red, green, blue, and white) on the formation of quality traits and their metabolic pathways in grape berries. We found that blue light and red light had different effects on the berries. Compared with white light, blue light significantly increased the anthocyanins (malvidin-3-O-glucoside and peonidin-3-O-glucoside), volatile substances (alcohols and phenols), and soluble sugars (glucose and fructose), reduced the organic acids (citric acid and malic acid), whereas red light achieved the opposite effect. Transcriptomics and metabolomics analyses revealed that 2707, 2547, 2145, and 2583 differentially expressed genes (DEGs) and (221, 19), (254, 22), (189, 17), and (234, 80) significantly changed metabolites (SCMs) were filtered in the dark vs. blue light, green light, red light, and white light, respectively. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, most of the DEGs identified were involved in photosynthesis and biosynthesis of flavonoids and flavonols. Using weighted gene co-expression network analysis (WGCNA) of 23410 highly expressed genes, two modules significantly related to anthocyanins and soluble sugars were screened out. The anthocyanins accumulation is significantly associated with increased expression of transcription factors (VvHY5, VvMYB90, VvMYB86) and anthocyanin structural genes (VvC4H, Vv4CL, VvCHS3, VvCHI1, VvCHI2, VvDFR), while significantly negatively correlated with VvPIF4. VvISA1, VvISA2, VvAMY1, VvCWINV, VvβGLU12, and VvFK12 were all related to starch and sucrose metabolism. These findings help elucidate the characteristics of different light qualities on the formation of plant traits and can inform the use of supplemental light in the field and after harvest to improve the overall quality of fruit.


2019 ◽  
Vol 53 (2) ◽  
pp. 38-45
Author(s):  
Irem Deniz ◽  
Zeliha Demirel ◽  
Esra Imamoglu ◽  
Meltem Conk Dalay

AbstractInternal illumination systems are being considered for use as an alternative light supply technique in microalgal products. The main goal of the study was to analyze the roles of different light wavelengths in internally illuminated airlift photobioreactors (PBRs) providing the light energy in an efficient way for the biomass production, lipid yield, and fatty acid composition of Amphora capitellata. The maximum chlorophyll-a concentration per unit biomass (2.62 ± 0.16 mg L−1) was obtained under red light, which was only 14% higher than under blue light in internally illuminated airlift PBR, whereas low chlorophyll-a content was found under white light. Maximum specific growth rate of 0.317 day−1, which corresponded to a doubling time of 2.185 days, was obtained under red light for A. capitellata. It was found that lipid content increased with decreasing growth rate for A. capitellata. Palmitic acid (C16:0) and palmitoleic acid (C16:1) were the principal fatty acids accounting for between 31%‐33% and 31%‐32% of total fatty acids, respectively. It is important to underline that red and blue light spectrum ranges contribute to improved biomass growth, whereas white light has the potential to support lipid content of diatoms.


1942 ◽  
Vol 25 (4) ◽  
pp. 553-569 ◽  
Author(s):  
Simon Shlaer ◽  
Emil L. Smith ◽  
Aurin M. Chase

The relation between visual acuity and illumination was measured in red and blue light, using a broken circle or C and a grating as test objects. The red light data fall on single continuous curves representing pure cone vision. The blue light data fall on two distinct curves with a transition at about 0.03 photons. Values below this intensity represent pure rod vision. Those immediately above represent the cooperative activity of rods and cones, and yield higher visual acuities than either. Pure cone vision in this intensity region is given by central fixation (C test object). All the rest of the values above this transition region represent pure cone vision. In blue light the rod data with the C lie about 1.5 log units lower on the intensity axis (cone scale) than they do in white light, while with the grating they lie about 1.0 log unit lower than in white light. Both the pure rod and cone data with the C test object are precisely described by one form of the stationary state equation. With the grating test object and a non-limiting pupil, the pure rod and cone data are described by another form of the same equation in which the curve is half as steep. The introduction of a small pupil, which limits maximum visual acuity, makes the relation between visual acuity and illumination appear steeper. Determinations of maximum visual acuities under a variety of conditions show that for the grating the pupil has to be larger, the longer the wavelength of the light, in order for the pupil not to be the limiting factor. Similar measurements with the C show that when intensity discrimination at the retina is experimentally made the limiting factor in resolution, visual acuity is improved by conditions designed to increase image contrast. However, intensity discrimination cannot be the limiting factor for the ordinary test object resolution because the conditions designed to improve image contrast do not improve maximum visual acuity, while those which reduce image contrast do not produce proportional reductions of visual acuity.


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