scholarly journals Guard cells control hypocotyl elongation through HXK1, HY5, and PIF4

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gilor Kelly ◽  
Danja Brandsma ◽  
Aiman Egbaria ◽  
Ofer Stein ◽  
Adi Doron-Faigenboim ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Blue Light ◽  
Opposite Effect ◽  
Red Light ◽  
Guard Cells ◽  
Cell Types ◽  
Hypocotyl Elongation ◽  
Sugar Production ◽  
Effect Of Light

AbstractThe hypocotyls of germinating seedlings elongate in a search for light to enable autotrophic sugar production. Upon exposure to light, photoreceptors that are activated by blue and red light halt elongation by preventing the degradation of the hypocotyl-elongation inhibitor HY5 and by inhibiting the activity of the elongation-promoting transcription factors PIFs. The question of how sugar affects hypocotyl elongation and which cell types stimulate and stop that elongation remains unresolved. We found that overexpression of a sugar sensor, Arabidopsis hexokinase 1 (HXK1), in guard cells promotes hypocotyl elongation under white and blue light through PIF4. Furthermore, expression of PIF4 in guard cells is sufficient to promote hypocotyl elongation in the light, while expression of HY5 in guard cells is sufficient to inhibit the elongation of the hy5 mutant and the elongation stimulated by HXK1. HY5 exits the guard cells and inhibits hypocotyl elongation, but is degraded in the dark. We also show that the inhibition of hypocotyl elongation by guard cells’ HY5 involves auto-activation of HY5 expression in other tissues. It appears that guard cells are capable of coordinating hypocotyl elongation and that sugar and HXK1 have the opposite effect of light on hypocotyl elongation, converging at PIF4.

scholarly journals Interactive Effects of Light Quality and Temperature on Arabidopsis Growth and Immunity

2020 ◽  
Vol 61 (5) ◽  
pp. 933-941
Author(s):  
Xiaoying Liu ◽  
Chunmei Xue ◽  
Le Kong ◽  
Ruining Li ◽  
Zhigang Xu ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Blue Light ◽  
Light Quality ◽  
Red Light ◽  
Complex Interaction ◽  
Hypocotyl Elongation ◽  
Interactive Effects ◽  
Phytochrome B ◽  
Light Conditions ◽  
Effects Of Temperature

Abstract We report here the interactive effects of three light qualities (white, red and blue) and three growth temperatures (16�C, 22�C and 28�C) on rosette growth, hypocotyl elongation and disease resistance in Arabidopsis thaliana. While an increase in temperature promotes hypocotyl elongation irrespective of light quality, the effects of temperature on rosette growth and disease resistance are dependent on light quality. Maximum rosette growth rate under white, red and blue light are observed at 28�C, 16�C and 22�C, respectively. The highest disease resistance is observed at 16�C under all three light conditions, but the highest susceptibility is observed at 28�C for white light and 22�C for red and blue light. Interestingly, rosette growth is inhibited by phytochrome B (PHYB) under blue light at 28�C and by cryptochromes (CRYs) under red light at 16�C. In addition, disease resistance is inhibited by PHYB under blue light and promoted by CRYs under red light. Therefore, this study reveals a complex interaction between light and temperature in modulating rosette growth and disease resistance as well as the contribution of PHYB and CRY to disease resistance.

Photosensitivity of anthocyanin production in dark-grown and light-pretreated Zea mays seedlings

1988 ◽  
Vol 66 (6) ◽  
pp. 1021-1027 ◽  
Author(s):  
Zdenko Rengel ◽  
Herbert A. Kordan
Keyword(s):  
Zea Mays ◽  
Blue Light ◽  
White Light ◽  
Zea Mays L ◽  
Red Light ◽  
Anthocyanin Formation ◽  
Anthocyanin Production ◽  
Effect Of Light

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.

scholarly journals Procuste1 mutants identify two distinct genetic pathways controlling hypocotyl cell elongation, respectively in dark- and light-grown Arabidopsis seedlings

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 683-693 ◽  
Author(s):  
T. Desnos ◽  
V. Orbovic ◽  
C. Bellini ◽  
J. Kronenberger ◽  
M. Caboche ◽  
...  
Keyword(s):  
Blue Light ◽  
Cell Elongation ◽  
Red Light ◽  
Development Program ◽  
Hypocotyl Elongation ◽  
Growth Defect ◽  
Hypocotyl Growth ◽  
Genetic Pathways ◽  
Blue Light Receptor ◽  
Light Receptor

Plant morphogenesis is dependent on a tight control of cell division and expansion. Cell elongation during post-embryonic hypocotyl growth is under the control of a light-regulated developmental switch. Light is generally believed to exert its effects on hypocotyl elongation through a phytochrome-and blue-light receptor-mediated inhibitory action on a so far unknown cell elongation mechanism. We describe here a new class of allelic mutants in Arabidopsis, at the locus PROCUSTE1 (prc1-1 to −4), which have a hypocotyl elongation defect specifically associated with the dark-grown development program. Normal hypocotyl elongation is restored in plants grown in white, blue or red light. In agreement with this, the constitutive photomorphogenic mutation cop1-6, which induces a de-etiolated phenotype in the dark, is epistatic to prc1-2 for the hypocotyl phenotype. Epistasis analyses in red and blue light respectively, indicate that phytochrome B but not the blue light receptor HY4, is required for the switch from PRC1-dependent to PRC1-independent elongation. The conditional hypocotyl growth defect is associated with a deformation of the hypocotyl surface due to an uncontrolled swelling of epidermal, cortical or endodermal cells, suggesting a defect in the structure of the expanding cell wall. A similar phenotype was observed in elongating roots, which was however, independent of the light conditions. The aerial part of mature mutant plants grown in the light was indistinguishable from the wild type. prc1 mutants provide a means of distinguishing, for the first time, two genetic pathways regulating hypocotyl cell elongation respectively in dark- and light-grown seedlings, whereby light not only inhibits hypocotyl growth, but also activates a PRC1-independent cell elongation program.

scholarly journals Effect of light quality on the cultivation of chlorella pyrenoidosa

2020 ◽  
Vol 143 ◽  
pp. 02033
Author(s):  
Hancheng Guo ◽  
Zhiguo Fang
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Blue Light ◽  
Optical Density ◽  
Light Quality ◽  
Specific Growth ◽  
Red Light ◽  
Total Lipid Content ◽  
Chlorella Pyrenoidosa ◽  
Effect Of Light

Effect of light quality, including red light, blue light, white light, red and blue mixing light with 8:1, 8:2 and 8:3, on the growth characteristics and metabolite accumulation of chlorella pyrenoidosa was conducted based on light emitting diode (LED). Results showed that chlorella pyrenoidosa grew best under blue light, and the optical density, specific growth rate and biomass of chlorella pyrenoidosa was about 2.4, 0.10 d-1 and 6.4 g·L-1, respectively, while the optical density of chlorella pyrenoidosa was between 1.0 and 1.7, specific growth rate was between 0.06-0.10 d-1 and biomass was between 2.7 and 3.8 g·L-1 under other light quality after 30 days of cultivation. The optical density, specific growth rate and biomass of chlorella pyrenoidosa was approximately 2.05 times, 1.33 times and 2.06 times under blue light than red light, respectively. Moreover, Red and blue mixing light was conducive to the synthesis of chlorophyll a and carotenoids of chlorella pyrenoidosa, and blue light could promote the synthesis of chlorophyll b. Chlorophyll a and carotenoids content of chlorella pyrenoidosa was 13.5 mg·g-1and 5.8 mg·g-1 respectively under red and blue mixing light with 8:1, while it was 8.4 mg·g-1 and 3.6 mg·g-1 respectively under blue light. Red and blue mixing light was more conducive to protein and total lipid content per dry cell of chlorella pyrenoidosa. Protein and total lipid content was 489.3 mg·g-1 and 311.2 mg·g-1 under red and blue mixing light with 8:3, while it was 400.9 mg·g-1 and 231.9 mg·g-1 respectively under blue light.

scholarly journals Blue and red light effects on stomatal oscillations

2019 ◽  
Vol 46 (2) ◽  
pp. 146 ◽  
Author(s):  
Trevor Ballard ◽  
David Peak ◽  
Keith Mott
Keyword(s):  
Blue Light ◽  
Guard Cell ◽  
Red Light ◽  
Guard Cells ◽  
Surrounding Tissue ◽  
Single Pair ◽  
Fibre Optic ◽  
Fibre Optics ◽  
Cell Pair ◽  
Low Intensity

The response of stomata to red and blue light was investigated using small fibre optics (66µm diameter) to control light levels on a single pair of guard cells without affecting the surrounding tissue. Low intensity red light (50µmolm–2s–1) applied to the entire leaf caused stomata to oscillate continuously for several hours with no apparent decrease in amplitude with time. Adding low intensity blue light (50µmolm–2s–1) caused stomata to stop oscillating, but oscillations resumed when the blue light was removed. Adding the same intensity of red light to an oscillating leaf changed the amplitude of the oscillations but did not stop them. When blue light was added to a single guard cell pair (using a fibre optic) in a red-light-illuminated leaf, the stoma formed by that pair stopped oscillating, but adjacent stomata did not. Red light added to a single guard cell pair did not stop oscillations. Finally, blue light applied through a fibre optic to areas of leaf without stomata caused proximal stomata to stop oscillating, but distal stomata continued to oscillate. The data suggest that blue light affects stomata via direct effects on guard cells as well as by indirect effects on other cells in the leaf.

The effect of light on acid-soluble polysaccharide accumulation in Sclerotium rolfsii Sacc.

1976 ◽  
Vol 22 (7) ◽  
pp. 967-970 ◽  
Author(s):  
R. Michael Miller ◽  
Anthony E. Liberta
Keyword(s):  
Blue Light ◽  
White Light ◽  
Red Light ◽  
Sclerotium Rolfsii ◽  
Soluble Polysaccharide ◽  
Effect Of Light

A light-stimulated increase in β-1,3 glucan accumulation was observed for Sclerotium rolfsii Sacc. The acid-soluble polysaccharide accumulated in large quantities in 'white' light- and blue light-grown cultures. This polysaccharide also accumulated in both dark- and red light-grown cultures as well. However, the quantities were significantly lower when compared to the 'white' light- and blue light-grown cultures. A greater quantity of polysaccharide accumulated in red light-grown cultures than in dark-grown cultures.

A rapid phytochrome-mediated growth response in etiolated Sinapis alba hypocotyls

1987 ◽  
Vol 65 (10) ◽  
pp. 2017-2023 ◽  
Author(s):  
David N. Kristie ◽  
Peter A. Jolliffe
Keyword(s):  
Growth Rate ◽  
Blue Light ◽  
Red Light ◽  
Sinapis Alba ◽  
Hypocotyl Elongation ◽  
Wave Band ◽  
Growth Responses ◽  
Inhibitory Effects ◽  
Growth Measurement ◽  
Inhibition Of Growth

Photocontrol of hypocotyl elongation in etiolated Sinapis alba L. seedlings was investigated using a high-resolution growth-measurement system. Different photoresponses were characterized by the dynamics of plant response to monochromatic irradiations at wavelengths ranging from 380 to 780 nm. Brief puises of 660- or 670-nm red light caused a large, rapid inhibition of growth rate after a lag of ca. 5 min. Growth rate remained depressed for several hours following a single red light pulse. If given 120 min or less after the red light, a 740-nm far-red pulse reversed the inhibitory effects of prior red light treatment after a lag of ca. 6 min. Most seedlings did not respond to single far-red irradiations in the 720- to 780-nm wave band, although some underwent small depressions in growth 5 to 10 min after the end or irradiation. Irradiation with 450-nm blue light caused a deeper inhibition than red light after a lag of only 1 min. Recovery from inhibition by blue light was rapid, unless the irradiation was prolonged. Removal of the plumule and cotyledons did not affect the dynamics of the rapid blue and red – far-red growth responses. The rapid response to red light occurred at wavelengths from 550 to 710 nm. The rapid blue response occurred only from 380 to 500 nm. Within each of these wave bands, the depth of photoinhibition was nearly constant. However, the duration of photoinhibition by red light declined from about 3 h after a 660-nm pulse to about 45 min after a 710-nm pulse. Elongation in etiolated Sinapis hypocotyls is thus controlled by a classical phytochrome-mediated induction-response system and by the blue light photoreceptor. Photoinhibition of hypocotyl elongation by red light required a minimum of about 5% of total phytochrome to be in the far-red absorbing form.

scholarly journals Effect of blue and red radiation on cycling stomata of bean.

1973 ◽  
Vol 21 (2) ◽  
pp. 117-123
Author(s):  
P.A.M. Hopmans
Keyword(s):  
Blue Light ◽  
Red Light ◽  
Guard Cells ◽  
Radiant Flux ◽  
Stomatal Behaviour ◽  
Blue Radiation ◽  
Quantum Flux ◽  
Permeability For Water ◽  
Red Radiation ◽  
Blue And Red Radiation

Differences in the effect of blue and red radiation of low radiant flux density on sustained stomatal cycling were studied in Phaseolus vulgaris cv. Vroege Wagenaar. Stomatal behaviour in a constant environment was observed indirectly by recording the differences between leaf and air temperature. In radiation with equal radiant flux densities of 1.75 W/m2 and with equal estimated absorbed quantum flux densities of 0.73 nE/cm2 s of both colours, cycling was more rapid and peak-to-trough differences were smaller in red than in blue radiation. Blue radiation from below caused more rapid cycling with larger peak-to-trough differences than radiation from above. In red radiation the direction of radiation had a much smaller influence on period and peak-to-trough difference. To explain these qualitatively different effects of both colours on cycling stomata, the hypothesis is proposed that blue light increases the osmotic pressure in the guard cells more effectively than red light. In blue light the permeability for water transport of the guard cell membranes is lower than in red light. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Molecular Characterization and Expression Analysis of MYB Transcription Factors Involved in the Glucosinolate Pathway in Chinese Cabbage (Brassica rapa ssp. pekinensis)

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 807
Author(s):  
Shipra Kumari ◽  
Jung Su Jo ◽  
Hyo Seon Choi ◽  
Jun Gu Lee ◽  
Soo In Lee ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Blue Light ◽  
Brassica Rapa ◽  
Chinese Cabbage ◽  
Red Light ◽  
Defense Responses ◽  
Molecular Characteristics ◽  
Fluorescent Lamp ◽  
Glucosinolate Biosynthesis ◽  
Myb Genes

Chinese cabbage (Brassica rapa) is a perennial crucifer vegetable that has long been used for forage. Crucifers are rich sources of glucosinolates (GSLs), which are anti-carcinogenic in humans and involved in plant defense responses. Myeloblastosis (MYB) proteins are a large family of transcription factors (TFs) in plants and play major regulatory roles in many biological processes. We identified 14 functional R2R3-MYB genes involved in glucosinolate biosynthesis in B. rapa ssp. pekinensis. Bioinformatic analysis of their phylogeny, protein motifs, gene interaction network, and molecular characteristics showed that Chinese cabbage MYB genes are comparable to those of Arabidopsis thaliana. The expression levels of the 14 BrMYB genes under fluorescent lamp, blue, and red light were quantitated using qRT-PCR analysis. Almost all of the R2R3-BrMYBs were upregulated and expressed more under red light than under fluorescent lamp or blue light, except BrMYB34s. We also calculated the total GSLs under each light condition. The total GSL content was higher under red light than under fluorescent lamp or blue light. Furthermore, the individual glucosinolates, comprised of four aliphatic GSLs (progoitrin, sinigrin, gluconapin, and glucobrassicanapin) and one indolic GSL (glucobrassicin), were higher under red light than the other light conditions. The relationships between light quality and glucosinolate biosynthesis require further investigation.

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