scholarly journals Plant Adaptation to Light Stress: Genetic Regulatory Mechanisms

2004 ◽  
Author(s):  
David A. Christopher ◽  
Avihai Danon
Keyword(s):  
Physcomitrella Patens ◽  
Higher Plants ◽  
Vascular Plant ◽  
Light Stress ◽  
Photosynthetic Apparatus ◽  
In Vitro Translation ◽  
Regulatory Mechanisms ◽  
Redox Potentials ◽  
Rnase Protection ◽  
High Molecular Weight Complex

Original Objectives: 1. Purify and biochemically characterize RB60 orthologs in higher plant chloroplasts; 2. Clone the gene(s) encoding plant RB60 orthologs and determine their structure and expression; 3. Manipulate the expression of RB60; 4. Assay the effects of altered RB60 expression on thylakoid biogenesis and photosynthetic function in plants exposed to different light conditions. In addition, we also examined the gene structure and expression of RB60 orthologs in the non-vascular plant, Physcomitrella patens and cloned the poly(A)-binding protein orthologue (43 kDa RB47-like protein). This protein is believed to a partner that interacts with RB60 to bind to the psbA5' UTR. Thus, to obtain a comprehensive view of RB60 function requires analysis of its biochemical partners such as RB43. Background & Achievements: High levels of sunlight reduce photosynthesis in plants by damaging the photo system II reaction center (PSII) subunits, such as D1 (encoded by the chloroplast tpsbAgene). When the rate of D1 synthesis is less than the rate of photo damage, photo inhibition occurs and plant growth is decreased. Plants use light-activated translation and enhanced psbAmRNA stability to maintain D1 synthesis and replace the photo damaged 01. Despite the importance to photosynthetic capacity, these mechanisms are poorly understood in plants. One intriguing model derived from the algal chloroplast system, Chlamydomonas, implicates the role of three proteins (RB60, RB47, RB38) that bind to the psbAmRNA 5' untranslated leader (5' UTR) in the light to activate translation or enhance mRNA stability. RB60 is the key enzyme, protein D1sulfide isomerase (Pill), that regulates the psbA-RN :Binding proteins (RB's) by way of light-mediated redox potentials generated by the photosystems. However, proteins with these functions have not been described from higher plants. We provided compelling evidence for the existence of RB60, RB47 and RB38 orthologs in the vascular plant, Arabidopsis. Using gel mobility shift, Rnase protection and UV-crosslinking assays, we have shown that a dithiol redox mechanism which resembles a Pill (RB60) activity regulates the interaction of 43- and 30-kDa proteins with a thermolabile stem-loop in the 5' UTR of the psbAmRNA from Arabidopsis. We discovered, in Arabidopsis, the PD1 gene family consists of II members that differ in polypeptide length from 361 to 566 amino acids, presence of signal peptides, KDEL motifs, and the number and positions of thioredoxin domains. PD1's catalyze the reversible formation an disomerization of disulfide bonds necessary for the proper folding, assembly, activity, and secretion of numerous enzymes and structural proteins. PD1's have also evolved novel cellular redox functions, as single enzymes and as subunits of protein complexes in organelles. We provide evidence that at least one Pill is localized to the chloroplast. We have used PDI-specific polyclonal and monoclonal antisera to characterize the PD1 (55 kDa) in the chloroplast that is unevenly distributed between the stroma and pellet (containing membranes, DNA, polysomes, starch), being three-fold more abundant in the pellet phase. PD1-55 levels increase with light intensity and it assembles into a high molecular weight complex of ~230 kDa as determined on native blue gels. In vitro translation of all 11 different Pill's followed by microsomal membrane processing reactions were used to differentiate among PD1's localized in the endoplasmic reticulum or other organelles. These results will provide.1e insights into redox regulatory mechanisms involved in adaptation of the photosynthetic apparatus to light stress. Elucidating the genetic mechanisms and factors regulating chloroplast photosynthetic genes is important for developing strategies to improve photosynthetic efficiency, crop productivity and adaptation to high light environments.  

Plant carotenoid cleavage oxygenases: structure–function relationships and role in development and metabolism

2019 ◽  
Vol 19 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Manoj Kumar Dhar ◽  
Sonal Mishra ◽  
Archana Bhat ◽  
Sudha Chib ◽  
Sanjana Kaul
Keyword(s):  
Higher Plants ◽  
Domain Architecture ◽  
Heme Iron ◽  
Critical Assessment ◽  
Protein Family ◽  
Regulatory Mechanisms ◽  
Non Heme Iron ◽  
Functional Aspects ◽  
Functional Understanding ◽  
Signal Production

Abstract A plant communicates within itself and with the outside world by deploying an array of agents that include several attractants by virtue of their color and smell. In this category, the contribution of ‘carotenoids and apocarotenoids’ is very significant. Apocarotenoids, the carotenoid-derived compounds, show wide representation among organisms. Their biosynthesis occurs by oxidative cleavage of carotenoids, a high-value reaction, mediated by carotenoid cleavage oxygenases or carotenoid cleavage dioxygenases (CCDs)—a family of non-heme iron enzymes. Structurally, this protein family displays wide diversity but is limited in its distribution among plants. Functionally, this protein family has been recognized to offer a role in phytohormones, volatiles and signal production. Further, their wide presence and clade-specific functional disparity demands a comprehensive account. This review focuses on the critical assessment of CCDs of higher plants, describing recent progress in their functional aspects and regulatory mechanisms, domain architecture, classification and localization. The work also highlights the relevant discussion for further exploration of this multi-prospective protein family for the betterment of its functional understanding and improvement of crops.

scholarly journals Compensation Mechanism of the Photosynthetic Apparatus in Arabidopsis thaliana ch1 Mutants

2020 ◽  
Vol 22 (1) ◽  
pp. 221
Author(s):  
Joanna Wójtowicz ◽  
Adam K. Jagielski ◽  
Agnieszka Mostowska ◽  
Katarzyna B. Gieczewska
Keyword(s):  
Light Stress ◽  
Photosynthetic Apparatus ◽  
Protein Composition ◽  
Mrna Levels ◽  
Chlorophyll B ◽  
Low Light ◽  
Plant Acclimation ◽  
Chlorophyll B Deficiency ◽  
Composition Changes

The origin of chlorophyll b deficiency is a mutation (ch1) in chlorophyllide a oxygenase (CAO), the enzyme responsible for Chl b synthesis. Regulation of Chl b synthesis is essential for understanding the mechanism of plant acclimation to various conditions. Therefore, the main aim of this study was to find the strategy in plants for compensation of low chlorophyll content by characterizing and comparing the performance and spectral properties of the photosynthetic apparatus related to the lipid and protein composition in four selected Arabidopsis ch1 mutants and two Arabidopsis ecotypes. Mutation in different loci of the CAO gene, viz., NW41, ch1.1, ch1.2 and ch1.3, manifested itself in a distinct chlorina phenotype, pigment and photosynthetic protein composition. Changes in the CAO mRNA levels and chlorophyllide a (Chlide a) content in ecotypes and ch1 mutants indicated their significant role in the adjustment mechanism of the photosynthetic apparatus to low-light conditions. Exposure of mutants with a lower chlorophyll b content to short-term (1LL) and long-term low-light stress (10LL) enabled showing a shift in the structure of the PSI and PSII complexes via spectral analysis and the thylakoid composition studies. We demonstrated that both ecotypes, Col-1 and Ler-0, reacted to high-light (HL) conditions in a way remarkably resembling the response of ch1 mutants to normal (NL) conditions. We also presented possible ways of regulating the conversion of chlorophyll a to b depending on the type of light stress conditions.

scholarly journals Flavodiiron proteins act as safety valve for electrons in Physcomitrella patens

2016 ◽  
Vol 113 (43) ◽  
pp. 12322-12327 ◽  
Author(s):  
Caterina Gerotto ◽  
Alessandro Alboresi ◽  
Andrea Meneghesso ◽  
Martina Jokel ◽  
Marjaana Suorsa ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Physcomitrella Patens ◽  
Safety Valve ◽  
Cell Metabolism ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Flowering Plants ◽  
Knock Out ◽  
Electron Sink

Photosynthetic organisms support cell metabolism by harvesting sunlight to fuel the photosynthetic electron transport. The flow of excitation energy and electrons in the photosynthetic apparatus needs to be continuously modulated to respond to dynamics of environmental conditions, and Flavodiiron (FLV) proteins are seminal components of this regulatory machinery in cyanobacteria. FLVs were lost during evolution by flowering plants, but are still present in nonvascular plants such as Physcomitrella patens. We generated P. patens mutants depleted in FLV proteins, showing their function as an electron sink downstream of photosystem I for the first seconds after a change in light intensity. flv knock-out plants showed impaired growth and photosystem I photoinhibition when exposed to fluctuating light, demonstrating FLV’s biological role as a safety valve from excess electrons on illumination changes. The lack of FLVs was partially compensated for by an increased cyclic electron transport, suggesting that in flowering plants, the FLV’s role was taken by other alternative electron routes.

Protein N-glycosylation is similar in the moss Physcomitrella patens and in higher plants

Planta ◽  
2003 ◽  
Vol 218 (2) ◽  
pp. 269-275 ◽  
Author(s):  
Remco Vi�tor ◽  
Corinne Loutelier-Bourhis ◽  
Anne-Catherine Fitchette ◽  
Pierre Margerie ◽  
Martine Gonneau ◽  
...  
Keyword(s):  
Physcomitrella Patens ◽  
Higher Plants

Functions of RMR proteins in intracellular trafficking in the moss "Physcomitrium patens" Mitten (previously "Physcomitrella patens")

2021 ◽  
Author(s):  
◽  
Carla Coppola
Keyword(s):  
Ubiquitin Ligase ◽  
Physcomitrella Patens ◽  
Fluorescent Protein ◽  
Storage Proteins ◽  
Higher Plants ◽  
E3 Ubiquitin Ligase ◽  
E3 Ligases ◽  
Ubiquitin Ligase Activity ◽  
Vacuolar Transport

In this study, I focused on a new family of receptors, called RMRs (Receptor-like Membrane RING-H2) and I tried to investigate their role in the moss Physcomitrium patens Mitten (previously Physcomitrella patens). There is some evidence that in Angiosperms, RMRs are vacuolar receptors for the neutral/storage vacuole that is a compartment where storage proteins and metabolites are accumulated during seeds development or in somatic tissues. It is distinguished from lytic vacuole which has the same functions as animal lysosomes. The five PpRMR genes have been knocked-out, yielding viable material without visible phenotype (Ayachi, 2012). A trafficking phenotype was described by Fahr (2017) who generated the construct Citrine-Cardosin (Ci-Card) composed of the fluorescent protein Citrine fused to the C-terminal vacuolar sorting determinant (ctVSD) from cardosin A (cardosin is addressed to the vacuole in higher plants —Pereira et al., 2013). The fusion protein was delivered to the central vacuole of PpWT but mistargeted in PpRMR-KO lines, indicating that the targeting of this protein to the vacuole depends on PpRMRs. The introduction of this thesis presents the plant endomembrane system, with particular attention to vacuolar transport and ubiquitylation. In the second chapter, I show the techniques used to attempt to detect PpRMRs by Western Blot: our failure may be due to a rapid degradation of these proteins, which could prevent their detection. In the third chapter, I focused on PpRMR2 involvement in ubiquitylation. We hypothesize that PpRMRs are E3 ligases because they are members of the PA-TM-RING protein family. Most of these proteins have an E3 ubiquitin ligase activity in animals (Seroogy et al., 2004; Borchers et al., 2002), for this reason, we think that plant PpRMRs could have this function as well, which could contribute to vacuolar targeting. Indeed, I could confirm that PpRMR2 has an E3 ubiquitin ligase activity. PpRMRs substrates are still unknown in moss thus we have analysed putative candidates supposing that they could be ubiquitylated by PpRMRs. We have tested this hypothesis through in vitro ubiquitylation assays, obtaining ambiguous results. In the fourth chapter, I show preliminary results about the visible phenotype of PpRMR-KO mutants: PpWT and PpRMR-KO lines displayed phenotypic differences in leafy gametophores, which were accentuated upon salt stress exposure. Lastly, I transformed the transgenic lines PpWT/Ci-Card and Pp5KO/Ci-Card with mutated versions of PpRMR2 and analysed their effect on vacuolar transport by confocal microscopy. For most of the constructions tested, the trafficking was perturbed in both lines. Only PpWT/Ci-Card expressing PpRMR2ΔSer (lacking the Serine-Rich motif) displayed a typical vacuolar pattern.

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 Molecular cloning of RBCS genes in Selaginella and the evolution of the rbcS gene family

2015 ◽  
Vol 67 (2) ◽  
pp. 373-383
Author(s):  
Bo Wang ◽  
Su Yingjuan ◽  
Ting Wang
Keyword(s):  
Gene Family ◽  
Physcomitrella Patens ◽  
Higher Plants ◽  
Genome Wide ◽  
A Genome ◽  
Rbcs Gene ◽  
Rbcs Genes ◽  
Selaginella Moellendorffii ◽  
Insight Into ◽  
Major Domain

Rubisco small subunits (RBCS) are encoded by a nuclear rbcS multigene family in higher plants and green algae. However, owing to the lack of rbcS sequences in lycophytes, the characteristics of rbcS genes in lycophytes is unclear. Recently, the complete genome sequence of the lycophyte Selaginella moellendorffii provided the first insight into the rbcS gene family in lycophytes. To understand further the characteristics of rbcS genes in other Selaginella, the full length of rbcS genes (rbcS1 and rbcS2) from two other Selaginella species were isolated. Both rbcS1 and rbcS2 genes shared more than 97% identity among three Selaginella species. RBCS proteins from Selaginella contained the Pfam RBCS domain F00101, which was a major domain of other plant RBCS proteins. To explore the evolution of the rbcS gene family across Selaginella and other plants, we identified and performed comparative analysis of the rbcS gene family among 16 model plants based on a genome-wide analysis. The results showed that (i) two rbcS genes were obtained in Selaginella, which is the second fewest number of rbcS genes among the 16 representative plants; (ii) an expansion of rbcS genes occurred in the moss Physcomitrella patens; (iii) only RBCS proteins from angiosperms contained the Pfam PF12338 domains, and (iv) a pattern of concerted evolution existed in the rbcS gene family. Our study provides new insights into the evolution of the rbcS gene family in Selaginella and other plants.

scholarly journals Chloroplasts in C3 grasses move in response to blue-light

2020 ◽  
Vol 39 (10) ◽  
pp. 1331-1343 ◽  
Author(s):  
Weronika Krzeszowiec ◽  
Maria Novokreshchenova ◽  
Halina Gabryś
Keyword(s):  
Blue Light ◽  
Higher Plants ◽  
Brachypodium Distachyon ◽  
Photosynthetic Apparatus ◽  
Light Signaling ◽  
Terrestrial Plants ◽  
Energy Capture ◽  
Chloroplast Movements ◽  
C3 Grasses ◽  
The One

Abstract Key message Brachypodium distachyonis a good model for studying chloropla st movements in the crop plants, wheat, rye and barley. The movements are activated only by blue light, similar to Arabidopsis. Abstract Chloroplast translocations are ubiquitous in photosynthetic organisms. On the one hand, they serve to optimize energy capture under limiting light, on the other hand, they minimize potential photodamage to the photosynthetic apparatus in excess light. In higher plants chloroplast movements are mediated by phototropins (phots), blue light receptors that also control other light acclimation responses. So far, Arabidopsis thaliana has been the main model for studying the mechanism of blue light signaling to chloroplast translocations in terrestrial plants. Here, we propose Brachypodium distachyon as a model in research into chloroplast movements in C3 cereals. Brachypodium chloroplasts respond to light in a similar way to those in Arabidopsis. The amino acid sequence of Brachypodium PHOT1 is 79.3% identical, and that of PHOT2 is 73.6% identical to the sequence of the corresponding phototropin in Arabidopsis. Both phototropin1 and 2 are expressed in Brachypodium, as shown using quantitative real-time PCR. Intriguingly, the light-expression pattern of BradiPHOT1 and BradiPHOT2 is the opposite of that for Arabidopsis phototropins, suggesting potential unique light signaling in C3 grasses. To investigate if Brachypodium is a good model for studying grass chloroplast movements we analyzed these movements in the leaves of three C3 crop grasses, namely wheat, rye and barley. Similarly to Brachypodium, chloroplasts only respond to blue light in all these species.

Effect of Membrane Fluidity on Photoinhibition of Isolated Thylakoids Membranes at Room and Low Temperature

2001 ◽  
Vol 56 (5-6) ◽  
pp. 369-374 ◽  
Author(s):  
Maya Velitchkova ◽  
Antoaneta Popova ◽  
Tzvetelina Markova
Keyword(s):  
Low Temperature ◽  
Membrane Fluidity ◽  
Light Stress ◽  
Photosynthetic Apparatus ◽  
Chemical Properties ◽  
Thylakoid Membranes ◽  
High Light Intensity ◽  
Photochemical Activity ◽  
High Light ◽  
Time Dependencies

The relationship between thylakoid membrane fluidity and the process of photoinhibition at room and low (4 °C) temperature was investigated. Two different membrane perturbing agents - cholesterol and benzylalcohol were applied to manipulate the fluidity of isolated pea thylakoids. The photochemical activity of photosystem I (PSI) and photosystem II (PSII), polarographically determined, were measured at high light intensity for different time of illumination at both temperatures. The exposure of cholesterol- and benzylalcohol-treated thylakoid membranes to high light intensities resulted in inhibition of both studied photochemical activities, being more pronounced for PSII compared to PSI. Time dependencies of inhibition of PSI and PSII electron transport rates for untreated and membranes with altered fluidity were determined at 20 °C and 4 °C. The effect is more pronounced for PSII activity during low-temperature photoinhibition. The data are discussed in terms of the determining role of physico-chemical properties of thylakoid membranes for the response of photosynthetic apparatus to light stress.

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