Are retinal and retinal-binding proteins involved in stomatal response to blue light?

2005 ◽  
Vol 32 (12) ◽  
pp. 1135 ◽  
Author(s):  
Fabio Paolicchi ◽  
Lara Lombardi ◽  
Nello Ceccarelli ◽  
Roberto Lorenzi
Keyword(s):  
Blue Light ◽  
Binding Proteins ◽  
Higher Plants ◽  
Guard Cells ◽  
Stomatal Response ◽  
Light Conditions ◽  
Experimental Conditions ◽  
Light Responses ◽  
Commelina Communis ◽  
Retinal Binding Proteins

Stomata respond to blue light and it is generally believed that the photoreceptor for this response is located inside the guard cells. Only a small number of blue light photoreceptors have been identified so far, namely cryptochromes and phototropins, and they show overlapping functions in regulating many different responses to light. The possibility that plants may possess other receptors regulating blue light responses under different light conditions cannot be excluded. In this paper we show the presence of two retinal-binding proteins in Commelina communis and we report the identification of retinal, a chromophore usually bound to the photoreceptor rhodopsin and previously identified in algae and other higher plants. We show that, under our experimental conditions, stomata open promptly when exposed to blue light and we demonstrated that this response is dependent on retinal. We hypothesise that rhodopsin-like retinal-binding proteins might be involved in stomatal response to blue light.

The occurrence of functional non-chlorophyllous guard cells in Paphiopedilum spp.

1975 ◽  
Vol 53 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Sherman D. Nelson ◽  
James M. Mayo
Keyword(s):  
Fluorescence Microscopy ◽  
Blue Light ◽  
Guard Cell ◽  
Direct Evidence ◽  
Light Response ◽  
Guard Cells ◽  
Epidermal Cells ◽  
Stomatal Response ◽  
Intact Leaves ◽  
Stomatal Functioning

Hypostomatous lady slipper orchids, Paphiopedilum spp., were found to have non-chlorophyllous epidermal cells, including guard cells. The lack of chlorophyll within the guard cells was demonstrated by fluorescence microscopy. A "normal" chlorophyllous mesophyll was present. The leaf resistances of intact leaves were about 5–10 s cm−1 in the light and were greater than 100 s cm−1 in the dark, indicating light opening and dark closure of the stomata. A CO2-dependent stomatal response (i.e., a tendency to close at elevated CO2 levels) was demonstrated, as was a CO2-independent light response (i.e., greater opening in blue light than in red). This provides direct evidence to support the idea that guard cell chlorophyll is not necessary for stomatal functioning.

scholarly journals Blue light sensing in higher plants.

2001 ◽  
Vol 276 (20) ◽  
pp. 17620
Author(s):  
John M. Christie ◽  
Winslow R. Briggs
Keyword(s):  
Blue Light ◽  
Higher Plants ◽  
Light Sensing

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.

Influence of light on growth, conidiation and the mutual regulation of fumonisin B2 and ochratoxin A biosynthesis by Aspergillus niger

2012 ◽  
Vol 5 (2) ◽  
pp. 169-176 ◽  
Author(s):  
F. Fanelli ◽  
M. Schmidt-Heydt ◽  
M. Haidukowski ◽  
R. Geisen ◽  
A. Logrieco ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Ochratoxin A ◽  
Blue Light ◽  
Short Wave ◽  
Light Conditions ◽  
Dark Incubation ◽  
Mutual Regulation ◽  
Blue Wavelength ◽  
Fumonisin B2 ◽  
Dark Production

Aspergillus niger is a fungus able to produce the carcinogenic mycotoxins ochratoxin A (OTA) and fumonisins. We analysed the influence of light of various wavelengths on growth, conidiation, fumonisin B2 (FB2) and OTA biosynthesis by A. niger ITEM 7097. Light from both sides of the spectrum, from long (627 nm) to short wavelengths (470-455 nm), had a stimulating effect on growth, with the highest stimulation under blue (455 nm, 1,700 Lux) and short-wave blue light (390 nm). Conidiation was reduced by 40% under a short blue wavelength (455 nm, 200 Lux), but strongly promoted under light at an even shorter wavelength (390 nm), with an increase of about 200 fold in comparison to the dark. Production of FB2 and OTA was mutually regulated by light. FB2 production was promoted under light conditions: red and blue light in particular increased FB2 biosynthesis by 40%. Conversely, OTA production was greatly inhibited under red and blue light in comparison to dark incubation, with a mean reduction of about 40 fold, indicating a reverse regulation of both biosynthetic pathways. Incubation under a 390 nm wavelength repressed the production of both toxins to non-detectable levels.

scholarly journals Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species.

2008 ◽  
Vol 55 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Jerzy Kruk ◽  
Renata Szymańska
Keyword(s):  
Substrate Specificity ◽  
Xanthophyll Cycle ◽  
Higher Plants ◽  
Light Stress ◽  
High Light ◽  
Light Conditions ◽  
Strong Light ◽  
Zeaxanthin Epoxidase ◽  
Typical Response ◽  
Cuscuta Species

In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.

scholarly journals Dynamic versus Concurrent Lighting with Red and Blue Light-emitting Diodes as the Sole Light Source Can Potentially Improve Campanula Stock Plant Morphology for Cutting Production

HortScience ◽  
2021 ◽  
pp. 1-8
Author(s):  
Devdutt Kamath ◽  
Yun Kong ◽  
Chevonne Dayboll ◽  
Youbin Zheng
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Plant Morphology ◽  
Side Branch ◽  
Controlled Environment ◽  
Stock Plant ◽  
Experimental Conditions ◽  
Branch Number ◽  
Light Emitting ◽  
Final Harvest

Short campanula (Campanula portenschlagiana ‘PGM Get MEE’®) stock plants present a difficulty in machine-harvesting of cuttings. Light adjustment may be an effective approach to mediate plant elongation. Two experiments were performed to 1) investigate whether short-term (five weeks) daily 24-h dynamic lighting (DL) with red and blue light-emitting diodes (LEDs) can promote elongation without inducing flowering, and 2) explore whether DL can be used to modify stock plant morphology to improve the cutting quality and rooting success in a controlled environment. Two lighting treatments were used: concurrent lighting (CL) with red (85%) and blue (15%) LEDs (RB) at 100 µmol·m−2·s−1 and DL with red (170 µmol·m−2·s−1), blue (30 µmol·m−2·s−1), and RB (100 µmol·m−2·s−1) LEDs sequentially at three different lighting stages, respectively, in both experiments. In Expt. 1, at final harvest of stock plants, the side branches were longer under DL compared with CL, but the five (= 2 + 2 + 1) weeks of 24-h daily lighting resulted in visible flower buds under both treatments. Based on the results of Expt. 1, a second experiment (Expt. 2) was conducted with the same cultivar and experimental conditions, but with a shorter photoperiod (10 h·d−1) for 11 (= 8 + 2 + 1) weeks. In Expt. 2, at final harvest, DL compared with CL caused more upright side branches, and reduced the dry biomass of side branches with one branching order and leaf chlorophyll content. However, the harvested cutting quality and rooting success were similar between both treatments. In both experiments, side branch number under DL was greater compared with CL at the end of the first lighting stage. Stock plants under DL were taller from the second lighting stage on to final harvest compared with CL, and the final heights of stock plants under DL met the target for machine-harvest in both experiments. Therefore, if the lighting strategy is further optimized, DL can potentially benefit controlled-environment production of campanula cuttings.

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