scholarly journals Intersection of the tocopherol and plastoquinol metabolic pathways at the plastoglobule

2009 ◽  
Vol 425 (2) ◽  
pp. 389-399 ◽  
Author(s):  
Anna Maria Zbierzak ◽  
Marion Kanwischer ◽  
Christina Wille ◽  
Pierre-Alexandre Vidi ◽  
Patrick Giavalisco ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Photosystem Ii ◽  
Metabolic Pathways ◽  
Polar Lipids ◽  
Protein Bodies ◽  
Side Chain ◽  
Considerable Proportion ◽  
Transgenic Lines ◽  
Tocopherol Cyclase

Plastoglobules, lipid–protein bodies in the stroma of plant chloroplasts, are enriched in non-polar lipids, in particular prenyl quinols. In the present study we show that, in addition to the thylakoids, plastoglobules also contain a considerable proportion of the plastidial PQ-9 (plastoquinol-9), the redox component of photosystem II, and of the cyclized product of PQ-9, PC-8 (plastochromanol-8), a tocochromanol with a structure similar to γ-tocopherol and γ-tocotrienol, but with a C-40 prenyl side chain. PC-8 formation was abolished in the Arabidopsis thaliana tocopherol cyclase mutant vte1, but accumulated in VTE1-overexpressing plants, in agreement with a role of tocopherol cyclase (VTE1) in PC-8 synthesis. VTE1 overexpression resulted in the proliferation of the number of plastoglobules which occurred in the form of clusters in the transgenic lines. Simultaneous overexpression of VTE1 and of the methyltransferase VTE4 resulted in the accumulation of a compound tentatively identified as 5-methyl-PC-8, the methylated form of PC-8. The results of the present study suggest that the existence of a plastoglobular pool of PQ-9, along with the partial conversion of PQ-9 into PC-8, might represent a mechanism for the regulation of the antioxidant content in thylakoids and of the PQ-9 pool that is available for photosynthesis.

scholarly journals Conserved Cu-MicroRNAs in Arabidopsis thaliana Function in Copper Economy under Deficiency

Plants ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 141 ◽  
Author(s):  
Muhammad Shahbaz ◽  
Marinus Pilon
Keyword(s):  
Arabidopsis Thaliana ◽  
Small Rnas ◽  
Wild Type ◽  
Microrna Target ◽  
Electron Carrier ◽  
Cu Deficiency ◽  
Regulatory Circuits ◽  
Transgenic Lines ◽  
Cu Homeostasis

Copper (Cu) is a micronutrient for plants. Three small RNAs, which are up-regulated by Cu deficiency and target transcripts for Cu proteins, are among the most conserved microRNAs in plants. It was hypothesized that these Cu-microRNAs help save Cu for the most essential Cu-proteins under deficiency. Testing this hypothesis has been a challenge due to the redundancy of the Cu microRNAs and the properties of the regulatory circuits that control Cu homeostasis. In order to investigate the role of Cu-microRNAs in Cu homeostasis during vegetative growth, we used a tandem target mimicry strategy to simultaneously inhibit the function of three conserved Cu-microRNAs in Arabidopsis thaliana. When compared to wild-type, transgenic lines that express the tandem target mimicry construct showed reduced Cu-microRNA accumulation and increased accumulation of transcripts that encode Cu proteins. As a result, these mimicry lines showed impaired photosynthesis and growth compared to wild type on low Cu, which could be ascribed to a defect in accumulation of plastocyanin, a Cu-containing photosynthetic electron carrier, which is itself not a Cu-microRNA target. These data provide experimental support for a Cu economy model where the Cu-microRNAs together function to allow maturation of essential Cu proteins under impending deficiency.

The role of ΔpH-dependent dissipation of excitation energy in protecting photosystem II against light-induced damage in Arabidopsis thaliana

2002 ◽  
Vol 40 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Thomas Graßes ◽  
Paolo Pesaresi ◽  
Fabio Schiavon ◽  
Claudio Varotto ◽  
Francesco Salamini ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Photosystem Ii ◽  
Excitation Energy

scholarly journals Ectopic Expression of Fiber Related Gbwri1 Complements Seed Phenotype in Arabidopsis thaliana

2021 ◽  
Vol 25 (01) ◽  
pp. 123-130
Author(s):  
Mahnoor Imran
Keyword(s):  
Arabidopsis Thaliana ◽  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
Ectopic Expression ◽  
Acid Biosynthesis ◽  
Functional Homology ◽  
Normal Seedling ◽  
Transgenic Lines ◽  
Protein Isoform

WRINKLED1 belongs to AP2/EREB family of transcription factors whose role has been well established in seed oil biosynthesis. The objective of the study was to trace the role of fiber related Gbwri1 in seed development and fatty acid biosynthesis. In this study, we isolated a transcript from elite fiber producing cotton (Gossypium barbadense), which is over-expressed in G. barbadense fibers as compared to G. hirsutum and G. arboreum. The putative protein encoded by this transcript exhibited homology in specific domains and protein structure with WRINKLED1 of Arabidopsis thaliana and was thus designated as Gbwri1. In this study, we investigated the functional homology of fiber elongation related Gbwri1 with fatty acid biosynthesis regulator Atwri1. Ectopic expression of Gbwri1 in wri1-3 mutant of A. thaliana was analyzed. In the transgenic lines of A. thaliana, Gbwri1 resumed the seed weight, seed area, and surface morphology to the wild type. Gbwri1 transformation rescued the wrinkled phenotype of wri1-3 mutants by resuming the expression of fatty acid biosynthesis genes biotin carboxyl carrier protein isoform 2 (bccp2) and keto-ACP synthase 1 (kas1). Moreover, the seedling development of transgenic lines on non-sucrose medium demonstrated that the Gbwri1 was able to regulate the supply of sucrose for normal seedling establishment. Our results showed that the transformation of Gbwri1 in A. thaliana wri1-3 mutant was able to complement wri1-3 impaired phenotype. Thus, Gbwri1 is involved in cotton fiber development and fatty acid biosynthesis in seeds. © 2021 Friends Science Publishers

scholarly journals Overexpression of ANAC046 Promotes Suberin Biosynthesis in Roots of Arabidopsis thaliana

2019 ◽  
Vol 20 (24) ◽  
pp. 6117 ◽  
Author(s):  
Kashif Mahmood ◽  
Viktoria Valeska Zeisler-Diehl ◽  
Lukas Schreiber ◽  
Yong-Mei Bi ◽  
Steven J. Rothstein ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pcr Analysis ◽  
Transcription Activator ◽  
Cuticular Waxes ◽  
Plant Parts ◽  
Wide Range ◽  
Transgenic Lines ◽  
Blue Stain ◽  
Root Endodermis

NAC (NAM (no apical meristem), ATAF1/2, and CUC2 (cup-shaped cotyledon)) proteins are one of the largest families of plant-specific transcription factors, and this family is present in a wide range of land plants. Here, we have investigated the role of ANAC046 in the regulation of suberin biosynthesis and deposition in Arabidopsis. Subcellular localization and transcriptional activity assays showed that ANAC046 localizes in the nucleus, where it functions as a transcription activator. Analysis of the PANAC046:GUS lines revealed that ANAC046 is mainly expressed in the root endodermis and periderm, and is also induced in leaves by wounding. The transgenic lines overexpressing ANAC046 exhibited defective surfaces on the aerial plant parts compared to the wild-type (WT) as characterized by increased permeability for Toluidine blue stain and greater chlorophyll leaching. Quantitative RT-PCR analysis showed that the expression of suberin biosynthesis genes was significantly higher in the roots and leaves of overexpression lines compared to the WT. The biochemical analysis of leaf cuticular waxes showed that the overexpression lines accumulated 30% more waxes than the WT. Concurrently, overexpression lines also deposited almost twice the amount of suberin content in their roots compared with the WT. Taken together, these results showed that ANAC046 is an important transcription factor that promotes suberin biosynthesis in Arabidopsis thaliana roots.

Over-Expression of a NAD-Malic Enzyme Gene from Rice in Arabidopsis thaliana Confers Tolerances to Several Abiotic Stresses

2011 ◽  
Vol 393-395 ◽  
pp. 863-866 ◽  
Author(s):  
Hao Zhou ◽  
Shen Kui Liu ◽  
Chuan Ping Yang
Keyword(s):  
Arabidopsis Thaliana ◽  
Abiotic Stresses ◽  
Malic Enzyme ◽  
Expression Vector ◽  
Enzyme Gene ◽  
Over Expression ◽  
Plant Expression Vector ◽  
Malic Enzyme Gene ◽  
Transgenic Lines

In order to investigate the role of a rice NAD-malic enzyme gene (OsNAD-ME1) under different abiotic stresses, OsNAD-ME1 was constructed into plant expression vector and transformed into Agrobacterium for infecting Arabidopsis thaliana. There were higher transcriptional levels of OsNAD-ME1 in homozygous transgenic lines compared with WT plants as well as higher NAD-ME activity. WT and transgenic Arabidopsis were treated with NaCl, NaHCO3, mannitol and H2O2. And then their root lengths, crown widths and fresh weights were measured and compared. The results showed that over-expression of OsNAD-ME1 in transgenic Arabidopsis increased the resistance to abiotic stresses, which indicated that OsNAD-ME1 was related to stress tolerance.

scholarly journals Natural variation in phosphorylation of photosystem II proteins in Arabidopsis thaliana : is it caused by genetic variation in the STN kinases?

2014 ◽  
Vol 369 (1640) ◽  
pp. 20130499 ◽  
Author(s):  
Pádraic J. Flood ◽  
Lan Yin ◽  
Andrei Herdean ◽  
Jeremy Harbinson ◽  
Mark G. M. Aarts ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Genetic Variation ◽  
Photosystem Ii ◽  
Protein Phosphorylation ◽  
Natural Variation ◽  
D1 Protein ◽  
Light Harvesting Complex ◽  
Light Regimes ◽  
Light Harvesting Complex Ii

Reversible phosphorylation of photosystem II (PSII) proteins is an important regulatory mechanism that can protect plants from changes in ambient light intensity and quality. We hypothesized that there is natural variation in this process in Arabidopsis ( Arabidopsis thaliana ), and that this results from genetic variation in the STN7 and STN8 kinase genes. To test this, Arabidopsis accessions of diverse geographical origins were exposed to two light regimes, and the levels of phospho-D1 and phospho-light harvesting complex II (LHCII) proteins were quantified by western blotting with anti-phosphothreonine antibodies. Accessions were classified as having high, moderate or low phosphorylation relative to Col-0. This variation could not be explained by the abundance of the substrates in thylakoid membranes. In genotypes with atrazine-resistant forms of the D1 protein, low D1 and LHCII protein phosphorylation was observed, which may be due to low PSII efficiency, resulting in reduced activation of the STN kinases. In the remaining genotypes, phospho-D1 levels correlated with STN8 protein abundance in high-light conditions. In growth light, D1 and LHCII phosphorylation correlated with longitude and in the case of LHCII phosphorylation also with temperature variability. This suggests a possible role of natural variation in PSII protein phosphorylation in the adaptation of Arabidopsis to diverse environments.

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