scholarly journals A Study of Gibberellin Homeostasis and Cryptochrome-Mediated Blue Light Inhibition of Hypocotyl Elongation

2007 ◽  
Vol 145 (1) ◽  
pp. 106-118 ◽  
Author(s):  
Xiaoying Zhao ◽  
Xuhong Yu ◽  
Eloise Foo ◽  
Gregory M. Symons ◽  
Javier Lopez ◽  
...  
Keyword(s):  
Blue Light ◽  
Hypocotyl Elongation ◽  
Light Inhibition

scholarly journals The CNT1 Domain of Arabidopsis CRY1 Alone Is Sufficient to Mediate Blue Light Inhibition of Hypocotyl Elongation

2015 ◽  
Vol 8 (5) ◽  
pp. 822-825 ◽  
Author(s):  
Sheng-Bo He ◽  
Wen-Xiu Wang ◽  
Jing-Yi Zhang ◽  
Feng Xu ◽  
Hong-Li Lian ◽  
...  
Keyword(s):  
Blue Light ◽  
Hypocotyl Elongation ◽  
Light Inhibition

scholarly journals Cryptochrome 1 interacts with PIF4 to regulate high temperature-mediated hypocotyl elongation in response to blue light

2015 ◽  
Vol 113 (1) ◽  
pp. 224-229 ◽  
Author(s):  
Dingbang Ma ◽  
Xu Li ◽  
Yongxia Guo ◽  
Jingfang Chu ◽  
Shuang Fang ◽  
...  
Keyword(s):  
High Temperature ◽  
Blue Light ◽  
Abiotic Factors ◽  
Hypocotyl Elongation ◽  
Dependent Manner ◽  
Phytochrome B ◽  
Environmental Signals ◽  
Blue Light Receptor ◽  
Light Inhibition ◽  
Cryptochrome 1

Cryptochrome 1 (CRY1) is a blue light receptor that mediates primarily blue-light inhibition of hypocotyl elongation. Very little is known of the mechanisms by which CRY1 affects growth. Blue light and temperature are two key environmental signals that profoundly affect plant growth and development, but how these two abiotic factors integrate remains largely unknown. Here, we show that blue light represses high temperature-mediated hypocotyl elongation via CRY1. Furthermore, CRY1 interacts directly with PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) in a blue light-dependent manner to repress the transcription activity of PIF4. CRY1 represses auxin biosynthesis in response to elevated temperature through PIF4. Our results indicate that CRY1 signal by modulating PIF4 activity, and that multiple plant photoreceptors [CRY1 and PHYTOCHROME B (PHYB)] and ambient temperature can mediate morphological responses through the same signaling component—PIF4.

scholarly journals Similarity between Cytokinin and Blue Light Inhibition of Cucumber Hypocotyl Elongation

1991 ◽  
Vol 95 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Lila Cohen ◽  
Shimon Gepstein ◽  
Benjamin A. Horwitz
Keyword(s):  
Blue Light ◽  
Hypocotyl Elongation ◽  
Light Inhibition ◽  
Cucumber Hypocotyl

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.

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

1970 ◽  
Vol 48 (6) ◽  
pp. 1251-1257 ◽  
Author(s):  
N. P. Voskresenskaya ◽  
G. S. Grishina ◽  
S. N. Chmora ◽  
N. M. Poyarkova
Keyword(s):  
Nicotiana Tabacum ◽  
Blue Light ◽  
Photosynthetic Rate ◽  
Prolonged Exposure ◽  
Red Light ◽  
Compensation Point ◽  
Gas Analyzer ◽  
Co2 Compensation Point ◽  
Rate Of Photosynthesis ◽  
Light Inhibition

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

Cryptochrome 2 is involved in betacyanin decomposition induced by blue light in Suaeda salsa

2006 ◽  
Vol 33 (7) ◽  
pp. 697 ◽  
Author(s):  
Wang Chang-Quan ◽  
Liu Tao
Keyword(s):  
Western Blot ◽  
Blue Light ◽  
Hypocotyl Elongation ◽  
Suaeda Salsa ◽  
Biosynthesis Pathway ◽  
Tyrosine Hydroxylation ◽  
Key Enzyme ◽  
Cryptochrome 2 ◽  
Hydroxylation Activity

Seeds of the halophyte Suaeda salsa (L.) Pall. were cultured in 24 h dark and 14 h blue light / 10 h dark to examine the role of blue light and the blue-light-absorbing photoreceptor cryptochrome 2 (CRY2) in betacyanin accumulation, hypocotyl elongation and cotyledon opening in S. salsa seedlings. Darkness significantly promoted betacyanin accumulation and hypocotyl elongation but inhibited cotyledon opening. Blue light suppressed betacyanin accumulation and hypocotyl elongation but stimulated cotyledon opening. Betacyanin in S. salsa seedlings decomposed with time in blue light. Western blot analysis showed that CRY2 protein accumulated both in hypocotyls and cotyledons of S. salsa seedlings grown in dark, but degraded with time in blue light, which was paralleled by a decrease of tyrosine hydroxylation activity of tyrosinase, a key enzyme involved in the betalain biosynthesis pathway. These results suggest that CRY2 protein mediates betacyanin decomposition via inactivation of tyrosinase in S. salsa seedlings, and the blue-light-dependent degradation of CRY2 protein is crucial to its function.

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.

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