scholarly journals A Foliar Pigment-Based Bioassay for Interrogating Chloroplast Signalling Reveals that Chlorophyll Biosynthesis Requires Carotenoid Isomerisation.

2021 ◽  
Author(s):  
Namraj Dhami ◽  
Barry J Pogson ◽  
David T Tissue ◽  
Christopher I Cazzonelli
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Nuclear Gene ◽  
Carotenoid Biosynthesis ◽  
Chloroplast Biogenesis ◽  
Plastid Development ◽  
Environmental Chemical ◽  
Chemical Genetic ◽  
Genetic Perturbations ◽  
Key Steps ◽  
Long Photoperiod

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.

Chemical Regulation of Plastid Development. I. Inhibition of Chlorophyll Biosynthesis in Detached Pumpkin Cotyledons by CPTA. A Pigment and Ultrastructual Study

1974 ◽  
Vol 1 (1) ◽  
pp. 119 ◽  
Author(s):  
DJ Simpson ◽  
CO Chichester ◽  
TH Lee
Keyword(s):  
Light Intensity ◽  
Chlorophyll Biosynthesis ◽  
Carotenoid Biosynthesis ◽  
Chlorophyll Synthesis ◽  
High Light Intensity ◽  
High Light ◽  
Trimethylammonium Chloride ◽  
Plastid Development ◽  
Plastid Ultrastructure ◽  
Chlorophyll Accumulation

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.

scholarly journals The Role of Tetrapyrrole- and GUN1-Dependent Signaling on Chloroplast Biogenesis

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 196
Author(s):  
Takayuki Shimizu ◽  
Tatsuru Masuda
Keyword(s):  
Protein Import ◽  
Nuclear Gene ◽  
Retrograde Signaling ◽  
Chloroplast Biogenesis ◽  
Plastid Development ◽  
Nuclear Gene Expression ◽  
Coordinated Expression ◽  
Plastid Protein ◽  
Working Hypotheses

Chloroplast biogenesis requires the coordinated expression of the chloroplast and nuclear genomes, which is achieved by communication between the developing chloroplasts and the nucleus. Signals emitted from the plastids, so-called retrograde signals, control nuclear gene expression depending on plastid development and functionality. Genetic analysis of this pathway identified a set of mutants defective in retrograde signaling and designated genomes uncoupled (gun) mutants. Subsequent research has pointed to a significant role of tetrapyrrole biosynthesis in retrograde signaling. Meanwhile, the molecular functions of GUN1, the proposed integrator of multiple retrograde signals, have not been identified yet. However, based on the interactions of GUN1, some working hypotheses have been proposed. Interestingly, GUN1 contributes to important biological processes, including plastid protein homeostasis, through transcription, translation, and protein import. Furthermore, the interactions of GUN1 with tetrapyrroles and their biosynthetic enzymes have been revealed. This review focuses on our current understanding of the function of tetrapyrrole retrograde signaling on chloroplast biogenesis.

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
Keyword(s):  
Light Quality ◽  
Chloroplast Development ◽  
Chlorophyll Biosynthesis ◽  
Carotenoid Biosynthesis ◽  
Plastid Development ◽  
Carotenoid Synthesis ◽  
Role Of Light ◽  
Synthesis Regulation ◽  
Effect Of Light

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.

scholarly journals A PPR Protein ACM1 Is Involved in Chloroplast Gene Expression and Early Plastid Development in Arabidopsis

2021 ◽  
Vol 22 (5) ◽  
pp. 2512
Author(s):  
Xinwei Wang ◽  
Yaqi An ◽  
Ye Li ◽  
Jianwei Xiao
Keyword(s):  
Fluorescent Protein ◽  
Chloroplast Development ◽  
Nuclear Gene ◽  
Pentatricopeptide Repeat ◽  
Plastid Development ◽  
Chloroplast Gene Expression ◽  
Knock Out ◽  
Rnai Line ◽  
Ppr Protein ◽  
P Type

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.

Somatic instability of carotenoid biosynthesis in the tomato ghost mutant and its effect on plastid development

Planta ◽  
1987 ◽  
Vol 171 (1) ◽  
pp. 11-18 ◽  
Author(s):  
P. A. Scolnik ◽  
P. Hinton ◽  
I. M. Greenblatt ◽  
G. Giuliano ◽  
M. R. Delanoy ◽  
...  
Keyword(s):  
Carotenoid Biosynthesis ◽  
Plastid Development ◽  
Somatic Instability

scholarly journals Microscopic Analyses of Fruit Cell Plastid Development in Loquat (Eriobotrya japonica) during Fruit Ripening

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 448 ◽  
Author(s):  
Pengjun Lu ◽  
Ruqian Wang ◽  
Changqing Zhu ◽  
Xiumin Fu ◽  
Shasha Wang ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
De Novo ◽  
Microscopic Analysis ◽  
Carotenoid Biosynthesis ◽  
Direct Conversion ◽  
Eriobotrya Japonica ◽  
Plastid Development ◽  
Carotenoid Accumulation ◽  
The Relationship ◽  
Late Stages

Plastids are sites for carotenoid biosynthesis and accumulation, but detailed information on fruit plastid development and its relation to carotenoid accumulation remains largely unclear. Here, using Baisha (BS; white-fleshed) and Luoyangqing (LYQ; red-fleshed) loquat (Eriobotrya japonica), a detailed microscopic analysis of plastid development during fruit ripening was carried out. In peel cells, chloroplasts turned into smaller chromoplasts in both cultivars, and the quantity of plastids in LYQ increased by one-half during fruit ripening. The average number of chromoplasts per peel cell in fully ripe fruit was similar between the two cultivars, but LYQ peel cell plastids were 20% larger and had a higher colour density, associated with the presence of larger plastoglobules. In flesh cells, chromoplasts could be observed only in LYQ during the middle and late stages of ripening, and the quantity on a per-cell basis was higher than that in peel cells, but the size of chromoplasts was smaller. It was concluded that chromoplasts are derived from the direct conversion of chloroplasts to chromoplasts in the peel, and from de novo differentiation of proplastids into chromoplasts in flesh. The relationship between plastid development and carotenoid accumulation is discussed.

scholarly journals Selenium Regulates Gene Expression for Glucosinolate and Carotenoid Biosynthesis in Arabidopsis

2011 ◽  
Vol 136 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Carl E. Sams ◽  
Dilip R. Panthee ◽  
Craig S. Charron ◽  
Dean A. Kopsell ◽  
Joshua S. Yuan
Keyword(s):  
Gene Expression ◽  
Differentially Expressed Genes ◽  
Plant Species ◽  
Chlorophyll Biosynthesis ◽  
Plant Secondary Metabolites ◽  
Carotenoid Biosynthesis ◽  
Differentially Expressed ◽  
Biosynthesis Pathway ◽  
Tissue Samples ◽  
Expression Of Genes

Glucosinolates (GSs) and carotenoids are important plant secondary metabolites present in several plant species, including arabidopsis (Arabidopsis thaliana). Although genotypic and environmental regulation of GSs and carotenoid compounds has been reported, few studies present data on their regulation at the molecular level. Therefore, the objective of this study was to explore differential expression of genes associated with GSs and carotenoids in arabidopsis in response to selenium fertilization, shown previously to impact accumulations of both classes of metabolites in Brassica species. Arabidopsis was grown under 0.0 or 10.0 μM Na2SeO4 in hydroponic culture. Shoot and root tissue samples were collected before anthesis to measure GSs and carotenoid compounds and conduct gene expression analysis. Gene expression was determined using arabidopsis oligonucleotide chips containing more than 31,000 genes. There were 1274 differentially expressed genes in response to selenium (Se), of which 516 genes were upregulated. Ontology analysis partitioned differentially expressed genes into 20 classes. Biosynthesis pathway analysis using AraCyc revealed that four GSs, one carotenoid, and one chlorophyll biosynthesis pathways were invoked by the differentially expressed genes. Involvement of the same gene in more than one biosynthesis pathway indicated that the same enzyme may be involved in multiple GS biosynthesis pathways. The decrease in carotenoid biosynthesis under Se treatment occurred through the downregulation of phytoene synthase at the beginning of the carotenoid biosynthesis pathway. These findings may be useful to modify the GS and carotenoid levels in arabidopsis and may lead to modification in agriculturally important plant species.

scholarly journals Integrating images from multiple microscopy screens reveals diverse patterns of change in the subcellular localization of proteins

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Alex X Lu ◽  
Yolanda T Chong ◽  
Ian Shen Hsu ◽  
Bob Strome ◽  
Louis-Francois Handfield ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
High Throughput ◽  
Cell Biology ◽  
Protein Localization ◽  
Imaging Data ◽  
Environmental Chemical ◽  
Genetic Perturbations ◽  
Proteomic Responses ◽  
High Throughput Imaging ◽  
Localization Behavior

The evaluation of protein localization changes on a systematic level is a powerful tool for understanding how cells respond to environmental, chemical, or genetic perturbations. To date, work in understanding these proteomic responses through high-throughput imaging has catalogued localization changes independently for each perturbation. To distinguish changes that are targeted responses to the specific perturbation or more generalized programs, we developed a scalable approach to visualize the localization behavior of proteins across multiple experiments as a quantitative pattern. By applying this approach to 24 experimental screens consisting of nearly 400,000 images, we differentiated specific responses from more generalized ones, discovered nuance in the localization behavior of stress-responsive proteins, and formed hypotheses by clustering proteins that have similar patterns. Previous approaches aim to capture all localization changes for a single screen as accurately as possible, whereas our work aims to integrate large amounts of imaging data to find unexpected new cell biology.

scholarly journals Light Harvesting-like Protein 3 Interacts with Phytoene Synthase and Is Necessary for Carotenoid and Chlorophyll Biosynthesis in Rice

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Feng Yang ◽  
Das Debatosh ◽  
Tao Song ◽  
Jian-hua Zhang
Keyword(s):  
Light Harvesting ◽  
Genetic Manipulation ◽  
Chlorophyll Biosynthesis ◽  
Flower Color ◽  
Carotenoid Biosynthesis ◽  
Phytoene Synthase ◽  
Low Fertility ◽  
Cell Wall Modification ◽  
Light Harvesting Complex ◽  
Pigment Biosynthesis

Abstract Background Carotenoid biosynthesis is essential for the generation of photosynthetic pigments, phytohormone production, and flower color development. The light harvesting like 3 (LIL3) protein, which belongs to the light-harvesting complex protein family in photosystems, interacts with geranylgeranyl reductase (GGR) and protochlorophyllide oxidoreductase (POR) both of which are known to regulate terpenoid and chlorophyll biosynthesis, respectively, in both rice and Arabidopsis. Results In our study, a CRISPR-Cas9 generated 4-bp deletion mutant oslil3 showed aberrant chloroplast development, growth defects, low fertility rates and reduced pigment contents. A comparative transcriptomic analysis of oslil3 suggested that differentially expressed genes (DEGs) involved in photosynthesis, cell wall modification, primary and secondary metabolism are differentially regulated in the mutant. Protein-protein interaction assays indicated that LIL3 interacts with phytoene synthase (PSY) and in addition the gene expression of PSY genes are regulated by LIL3. Subcellular localization of LIL3 and PSY suggested that both are thylakoid membrane anchored proteins in the chloroplast. We suggest that LIL3 directly interacts with PSY to regulate carotenoid biosynthesis. Conclusion This study reveals a new role of LIL3 in regulating pigment biosynthesis through interaction with the rate limiting enzyme PSY in carotenoid biosynthesis in rice presenting it as a putative target for genetic manipulation of pigment biosynthesis pathways in crop plants.

scholarly journals Mechanism-based design of bioactive cyclopropanated sugars

2021 ◽  
Author(s):  
◽  
Dylan Davies
Keyword(s):  
Genetic Analysis ◽  
Biological Activities ◽  
Chemical Mechanism ◽  
Chemical Proteomics ◽  
Structure Activity Relationships ◽  
Chemical Genetic ◽  
Structure Activity ◽  
Biological Target ◽  
A Cell ◽  
Key Steps

<p>Carbohydrates are important feed stocks in synthesis of natural products and so attract the interest of many organic researchers throughout the world, most notably in the last 10 years. The work described within explores the manipulation of the glucose-derived glucal. The addition of a reactive substituted cyclopropane across the alkene has been employed synthetically for many years, the subsequent ring breaking/expansion has been identified in the lab as slow and needing the support of catalysts. We ask the question, “Will cyclopropanated carbohydrates undergo the slow ring breaking/expansion in the presence of proteins, and are we able to identify which of the two types of mechanisms the reaction is going through?” The cyclopropane will act as a warhead to bind to proteins through Ferrier like rearrangements, resulting in irreversible inhibition. To identify the potential of such compounds, a combination of techniques are used to identify potential pathways, protein targets and reactivity through structure activity relationships.  The key steps involved in finding out the potential of cyclopropanated carbohydrates are to determine biological activities through bio-assays, structure activity relationships, selective binding, chemical genetics and chemical proteomics. The bio-assays together with structure activity relationships provides evidence on which chemical mechanism is occurring when the biological target is interacting with the bioactive cyclopropanated carbohydrates. The most active compound, benzose (7), was subjected to chemical genetic analysis to determine the pathways and processes that are involved with the mode of action. The chemical genetic analysis was complimented by chemical proteomics to identify the direct biological target. Analogues of benzose were synthesised by the addition of azide groups to undergo a Huisgen Cyclisation within a cell lysate to facilitate binding to an alkyne-substituted matrix.</p>

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