scholarly journals Carotenoid Biosynthesis and Plastid Development in Plants: The Role of Light

2021 ◽  
Vol 22 (3) ◽  
pp. 1184
Author(s):  
Rocio Quian-Ulloa ◽  
Claudia Stange

Light is an important cue that stimulates both plastid development and biosynthesis of carotenoids in plants. During photomorphogenesis or de-etiolation, photoreceptors are activated and molecular factors for carotenoid and chlorophyll biosynthesis are induced thereof. In fruits, light is absorbed by chloroplasts in the early stages of ripening, which allows a gradual synthesis of carotenoids in the peel and pulp with the onset of chromoplasts’ development. In roots, only a fraction of light reaches this tissue, which is not required for carotenoid synthesis, but it is essential for root development. When exposed to light, roots start greening due to chloroplast development. However, the colored taproot of carrot grown underground presents a high carotenoid accumulation together with chromoplast development, similar to citrus fruits during ripening. Interestingly, total carotenoid levels decrease in carrots roots when illuminated and develop chloroplasts, similar to normal roots exposed to light. The recent findings of the effect of light quality upon the induction of molecular factors involved in carotenoid synthesis in leaves, fruit, and roots are discussed, aiming to propose consensus mechanisms in order to contribute to the understanding of carotenoid synthesis regulation by light in plants.

2020 ◽  
Vol 170 (2) ◽  
pp. 187-201
Author(s):  
Giuseppe C. Modarelli ◽  
Carmen Arena ◽  
Giuseppe Pesce ◽  
Emilia Dell'Aversana ◽  
Giovanna M. Fusco ◽  
...  

1974 ◽  
Vol 1 (1) ◽  
pp. 119 ◽  
Author(s):  
DJ Simpson ◽  
CO Chichester ◽  
TH Lee

The effects of 2-(4-chlorophenylthio)ethyldiethylammonium chloride (CPTA) on chlorophyll accumulation, carotenoid biosynthesis and plastid ultrastructure were examined in expanding excised pumpkin cotyledons. CPTA in the dark caused an increased synthesis of non-photoconvertible protochlorophyll but had no effect on the ultrastructure of the starch-containing plastids. In the light, CPTA was a powerful inhibitor of chlorophyll synthesis in greening cotyledons, especially at high light intensity, and induced the accumulation of lycopene. When applied to the greened cotyledons, CPTA caused the transformation of the chloroplasts to chromoplast-like organelles containing osmiophilic globules and lycopene crystalloids. Two other structurally similar compounds,diethyl[4-{3'-(4"-methylphenyl)-3-oxoprop-2' -enyl}phenoxyethyl]ammonium chloride (SK&F 13831) and (2-chloroethyl)trimethylammonium chloride (chlormequat), also caused lycopene accumulation and inhibited chlorophyll synthesis. It is possible that CPTA can induce the formation of chromoplasts from proplastids and chloroplasts in tissue that does not normally contain such organelles.


1976 ◽  
Vol 29 (3) ◽  
pp. 281 ◽  
Author(s):  
YigaI Cohen

The interacting effects of light and temperature on spore formation of P. tabacina on tobacco leaves were investigated. The following points indicated that an enzymic build-up of an antisporulant during a wet light period and its enzymic decay over a dry dark period may explain the inhibitory effect of light upon sporulation, and its reversal by darkness. (1) Fluorescent blue light of relatively low photon flux density (3 �7 /lE m - 2 S -1) inhibited sporulation by 99 % at 20oe. (2) Light level and temperature during the sporulation period determined spore yield of the pathogen: at high temperatures (in the range 8-24�C) sporulation was inhibited at low light level, whilst no inhibition occurred at much higher light levels at low temperatures. (3) Preceding dry dark treatments given at 200e considerably diminished the inhibitory effect of light, but not if given at 100e. (4) The diffusion of an inhibitory compound from irradiated to unirradiated areas of detached leaves was demonstrated. (5) The continuing photosynthetic activity of the host in the light at 20oe, and the lack of sucrose following dark periods at lOoe, were not associated with the inhibitory effect of light. The similarity between the role of light in the present system and the role of light in activation and decay of phenylalanine ammonia-lyase is discussed.


2021 ◽  
Author(s):  
Namraj Dhami ◽  
Barry J Pogson ◽  
David T Tissue ◽  
Christopher I Cazzonelli

Abstract Background: Plastid-derived metabolites can signal control over nuclear gene expression, chloroplast biogenesis, and chlorophyll biosynthesis. Norflurazon (NFZ) inhibition of carotenoid biosynthesis in seedlings can elicit a protoporphyrin retrograde signal that controls chlorophyll and chloroplast biogenesis. Recent evidence reveals that plastid development can be regulated by carotenoid cleavage products called apocarotenoids. The key steps in carotenoid biosynthesis and catabolism that generate apocarotenoid signalling metabolites in foliar tissues remains to be elucidated. Here, we established an Arabidopsis foliar pigment-based bioassay using detached rosettes to differentiate plastid signalling processes in young expanding leaves containing dividing cells with active chloroplast biogenesis, from fully expanded leaves containing mature chloroplasts. Results: We demonstrate that environmental (extended darkness and cold exposure) as well as chemical (norflurazon; NFZ) inhibition of carotenoid biosynthesis can reduce chlorophyll levels in young, but not older leaves following a 24 h of rosette treatment. Mutants that disrupted xanthophyll accumulation, phytohormone biosynthesis (abscisic acid and strigolactone), or enzymatic carotenoid cleavage, did not alter chlorophyll levels in young or old leaves. Perturbations in acyclic cis-carotene biosynthesis revealed that disruption of CAROTENOID ISOMERASE (CRTISO), but not ZETA-CAROTENE ISOMERASE (Z-ISO) activity, reduced chlorophyll levels in young but not older leaves of plants growing under a long photoperiod. NFZ-induced inhibition of PHYTOENE DESATURASE (PDS) activity triggered phytoene accumulation more so in younger relative to older leaves from both WT and the crtiso mutant, indicating a continued substrate supply from the methylerythritol 4-phosphate (MEP) pathway for carotenogenesis. NFZ treatment of WT and crtiso mutant rosettes reveal similar, additive, and opposite effects on individual pigment accumulation.Conclusion: The Arabidopsis foliar pigment-based bioassay was used to differentiate signalling events elicited by environmental, chemical, genetic, and combinations thereof, that control chlorophyll biosynthesis. Genetic perturbations that impaired xanthophyll biosynthesis and/or carotenoid catabolism did not affect chlorophyll biosynthesis. The lack of CAROTENOID ISOMERISATION generated a signal that rate-limited chlorophyll accumulation, but not phytoene biosynthesis in young Arabidopsis leaves exposed to a long photoperiod. Findings generated using this new foliar pigment bioassay implicate that carotenoid isomerisation and NFZ elicit different signalling pathways to control chlorophyll homeostasis in young emerging leaves.


2019 ◽  
Author(s):  
Christopher I Cazzonelli ◽  
Xin Hou ◽  
Yagiz Alagoz ◽  
John Rivers ◽  
Namraj Dhami ◽  
...  

ABSTRACTCarotenoids are core plastid components, yet a regulatory function during plastid biogenesis remains enigmatic. A unique carotenoid biosynthesis mutant, carotenoid chloroplast regulation 2 (ccr2), that has no prolamellar body (PLB) and normal PROTOCHLOROPHYLLIDE OXIDOREDUCTASE (POR) levels, was used to demonstrate a regulatory function for carotenoids under varied dark-light regimes. A forward genetics approach revealed how an epistatic interaction between a (-carotene isomerase mutant (ziso-155) and ccr2 blocked the biosynthesis of specific cis-carotenes and restored PLB formation in etioplasts. We attributed this to a novel apocarotenoid signal, as chemical inhibition of carotenoid cleavage dioxygenase activity restored PLB formation in ccr2 etioplasts during skotomorphogenesis. The apocarotenoid acted in parallel to the transcriptional repressor of photomorphogenesis, DEETIOLATED1 (DET1), to post-transcriptionally regulate PROTOCHLOROPHYLLIDE OXIDOREDUCTASE (POR), PHYTOCHROME INTERACTING FACTOR3 (PIF3) and ELONGATED HYPOCOTYL5 (HY5) protein levels. The apocarotenoid signal and det1 complemented each other to restore POR levels and PLB formation, thereby controlling plastid development.One-sentence summaryCarotenoids are not just required as core components for plastid biogenesis, they can be cleaved into an apocarotenoid signal that regulates etioplast and chloroplast development during extended periods of darkness.


2021 ◽  
Vol 22 (5) ◽  
pp. 2512
Author(s):  
Xinwei Wang ◽  
Yaqi An ◽  
Ye Li ◽  
Jianwei Xiao

Chloroplasts cannot develop normally without the coordinated action of various proteins and signaling connections between the nucleus and the chloroplast genome. Many questions regarding these processes remain unanswered. Here, we report a novel P-type pentatricopeptide repeat (PPR) factor, named Albino Cotyledon Mutant1 (ACM1), which is encoded by a nuclear gene and involved in chloroplast development. Knock-down of ACM1 transgenic plants displayed albino cotyledons but normal true leaves, while knock-out of the ACM1 gene in seedlings was lethal. Fluorescent protein analysis showed that ACM1 was specifically localized within chloroplasts. PEP-dependent plastid transcript levels and splicing efficiency of several group II introns were seriously affected in cotyledons in the RNAi line. Furthermore, denaturing gel electrophoresis and Western blot experiments showed that the accumulation of chloroplast ribosomes was probably damaged. Collectively, our results indicate ACM1 is indispensable in early chloroplast development in Arabidopsis cotyledons.


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