scholarly journals Expression of SULTR2;2 in the Arabidopsis bundle sheath is mediated by a highly conserved positive regulator

2018 ◽  
Author(s):  
Sandra Kirschner ◽  
Helen Woodfield ◽  
Katharina Prusko ◽  
Maria Koczor ◽  
Udo Gowik ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Bundle Sheath ◽  
Deletion Analysis ◽  
Sulphur Metabolism ◽  
Mesophyll Cells ◽  
Positive Regulator ◽  
Short Region ◽  
Flaveria Bidentis

AbstractThe bundle sheath provides a conduit linking veins and mesophyll cells. In C3Arabidopsis thaliana it also plays important roles in oxidative stress and sulphur metabolism. However, the mechanisms responsible for the patterns of gene expression that underpin these metabolic specialisations are poorly understood. Here we used the A. thaliana SULTR2;2 gene as a model to better understand mechanisms that restrict expression to the bundle sheath. Deletion analysis indicated that the SULTR2;2 promoter contains a short region necessary for expression in the bundle sheath. This sequence acts as a positive regulator and is tolerant to multiple consecutive deletions indicating considerable redundancy in the cis-elements involved. It is highly conserved in SULTR2;2 genes of the Brassicaceae and is functional in the distantly related C4 species Flaveria bidentis that belongs to the Asteraceae. We conclude that expression of SULTR2;2 in the bundle sheath is underpinned by a highly redundant sequence that likely represents an ancient and conserved mechanism found in families as diverse as the Asteraceae and Brassicaceae.

scholarly journals A bipartite transcription factor module controlling expression in the bundle sheath of Arabidopsis thaliana

2018 ◽  
Author(s):  
Patrick J. Dickinson ◽  
Jana Kneřová ◽  
Marek Szecówka ◽  
Sean S. Stevenson ◽  
Steven J. Burgess ◽  
...  
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Photosynthetic Efficiency ◽  
Cell Types ◽  
Bundle Sheath ◽  
Spatial Patterning ◽  
Factor Module ◽  
Bundle Sheath Cells ◽  
Necessary And Sufficient

AbstractC4 photosynthesis evolved repeatedly from the ancestral C3 state, improving photosynthetic efficiency by ∼50%. In most C4 lineages photosynthesis is compartmented between mesophyll and bundle sheath cells but how gene expression is restricted to these cell types is poorly understood. Using the C3 model Arabidopsis thaliana we identified cis-elements and transcription factors driving expression in bundle sheath strands. Upstream of the bundle sheath preferentially expressed MYB76 gene we identified a region necessary and sufficient for expression containing two cis-elements associated with the MYC and MYB families of transcription factors. MYB76 expression is reduced in mutant alleles for each. Moreover, down-regulated genes shared by both mutants are preferentially expressed in the bundle sheath. Our findings are broadly relevant for understanding the spatial patterning of gene expression, provide specific insights into mechanisms associated with evolution of C4 photosynthesis and identify a short tuneable sequence for manipulating gene expression in the bundle sheath.

scholarly journals Singlet oxygen leads to structural changes to chloroplasts during degradation in the Arabidopsis thaliana plastid ferrochelatase two mutant

2021 ◽  
Author(s):  
Karen E Fisher ◽  
Praveen Krishnamoorthy ◽  
Matthew S Joens ◽  
Joanne Chory ◽  
James A. J. Fitzpatrick ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Arabidopsis Thaliana ◽  
Singlet Oxygen ◽  
Structural Changes ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Clear Correlation ◽  
Central Vacuole ◽  
Mesophyll Cells ◽  
Electron Microscopy Analysis

During photosynthesis, chloroplasts can produce large amounts of reactive oxygen species (ROS), particularly under stressful conditions. Along with other nutrients, chloroplasts also contain 80% of a leaf's nitrogen supply. For these reasons, chloroplasts are prime targets for cellular degradation to protect cells from photo-oxidative damage and to redistribute nutrients to sink tissues. Multiple chloroplast degradation pathways have been described and are induced by photo-oxidative stress and nutrient starvation. However, the mechanisms by which damaged or senescing chloroplasts are identified, transported to the central vacuole, and ultimately degraded are not well characterized. Here, we investigated the subcellular structures involved with degrading chloroplasts induced by the ROS singlet oxygen (1O2) in the Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant. Using a three-dimensional serial-block face electron microscopy analysis, we show up to 35% of degrading chloroplasts in fc2 mutants protrude into the central vacuole. While the location of a chloroplast within a cell had no effect on the likelihood of its degradation, chloroplasts in spongy mesophyll cells were degraded at a higher rate than those in palisade mesophyll cells. To determine if degrading chloroplasts have unique structural characteristics allowing them to be distinguished from healthy chloroplasts, we analyzed fc2 seedlings grown under different levels of photo-oxidative stress. A clear correlation was observed between chloroplast swelling, 1O2-signaling, and the state of degradation. Finally, plastoglobule enzymes involved in chloroplast disassembly were shown to be upregulated while plastoglobules increased their association with the thylakoid grana, implicating an interaction between 1O2-induced chloroplast degradation and senescence pathways.

scholarly journals Evaluation of Arabidopsis thaliana as a Model Host for Xylella fastidiosa

2012 ◽  
Vol 25 (6) ◽  
pp. 747-754 ◽  
Author(s):  
Elizabeth E. Rogers
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Generation Time ◽  
Xylella Fastidiosa ◽  
Plant Diseases ◽  
Chain Reaction ◽  
Pathogenesis Related ◽  
Polymerase Chain ◽  
Plant Susceptibility

The bacterium Xylella fastidiosa causes a number of plant diseases of significant economic impact. To date, progress determining mechanisms of host-plant susceptibility, tolerance, or resistance has been slow, due in large part to the long generation time and limited available genetic resources for grape, almond, and other known hosts of X. fastidiosa. To overcome many of these limitations, Arabidopsis thaliana has been evaluated as a host for X. fastidiosa. A pin-prick inoculation method has been developed to infect Arabidopsis with X. fastidiosa. Following infection, X. fastidiosa multiplies and can be detected by microscopy, polymerase chain reaction, and isolation. The ecotypes Van-0, LL-0, and Tsu-1 all allow more growth of strain X. fastidiosa Temecula than the reference ecotype Col-0. Affymetrix ATH1 microarray analysis of inoculated vs. noninoculated Tsu-1 reveals gene expression changes that differ greatly from changes seen after infection with apoplast-colonizing bacteria such as Psuedomonas syringae pvs. tomato or syringae. Many genes responsive to oxidative stress are differentially regulated, while classic pathogenesis-related genes are not induced by X. fastidiosa infection.

scholarly journals Gene Expression and Accumulation of Rubisco in Bundle Sheath and Mesophyll Cells during Leaf Development and Senescence in Rice, a C3 Plant

2008 ◽  
Vol 11 (3) ◽  
pp. 336-343 ◽  
Author(s):  
Koichi Tsutsumi ◽  
Michio Kawasaki ◽  
Mitsutaka Taniguchi ◽  
Hiroshi Miyake
Keyword(s):  
Gene Expression ◽  
Leaf Development ◽  
Bundle Sheath ◽  
Mesophyll Cells ◽  
C3 Plant
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