Overexpressing the HD-Zip class II transcription factor EcHB1 from Eucalyptus camaldulensis increased the leaf photosynthesis and drought tolerance of Eucalyptus

Abstract Alteration in the leaf mesophyll anatomy by genetic modification is potentially a promising tool for improving the physiological functions of trees by improving leaf photosynthesis. Homeodomain leucine zipper (HD-Zip) transcription factors are candidates for anatomical alterations of leaves through modification of cell multiplication, differentiation, and expansion. Full-length cDNA encoding a Eucalyptus camaldulensis HD-Zip class II transcription factor (EcHB1) was over-expressed in vivo in the hybrid Eucalyptus GUT5 generated from Eucalyptus grandis and Eucalyptus urophylla. Overexpression of EcHB1 induced significant modification in the mesophyll anatomy of Eucalyptus with enhancements in the number of cells and chloroplasts on a leaf-area basis. The leaf-area-based photosynthesis of Eucalyptus was improved in the EcHB1-overexpression lines, which was due to both enhanced CO2 diffusion into chloroplasts and increased photosynthetic biochemical functions through increased number of chloroplasts per unit leaf area. Additionally, overexpression of EcHB1 suppressed defoliation and thus improved the growth of Eucalyptus trees under drought stress, which was a result of reduced water loss from trees due to the reduction in leaf area with no changes in stomatal morphology. These results gave us new insights into the role of the HD-Zip II gene.

Download Full-text

Faculty Opinions recommendation of Overexpressing the HD-Zip class II transcription factor EcHB1 from Eucalyptus camaldulensis increased the leaf photosynthesis and drought tolerance of Eucalyptus.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.736700676.793578725 ◽

2020 ◽

Author(s):

Jaume Flexas ◽

Alicia Perera-Castro

Keyword(s):

Transcription Factor ◽

Drought Tolerance ◽

Eucalyptus Camaldulensis ◽

Class Ii ◽

Leaf Photosynthesis

Download Full-text

CHOP Enhancement of Gene Transcription by Interactions with Jun/Fos AP-1 Complex Proteins

Molecular and Cellular Biology ◽

10.1128/mcb.19.11.7589 ◽

1999 ◽

Vol 19 (11) ◽

pp. 7589-7599 ◽

Cited By ~ 95

Author(s):

Mariano Ubeda ◽

Mario Vallejo ◽

Joel F. Habener

Keyword(s):

Transcription Factor ◽

Gene Transcription ◽

Stress Responses ◽

Leucine Zipper ◽

Target Genes ◽

Cellular Stress ◽

Dominant Negative ◽

Dimerization Domain ◽

Mobility Shift

ABSTRACT The transcription factor CHOP (C/EBP homologous protein 10) is a bZIP protein induced by a variety of stimuli that evoke cellular stress responses and has been shown to arrest cell growth and to promote programmed cell death. CHOP cannot form homodimers but forms stable heterodimers with the C/EBP family of activating transcription factors. Although initially characterized as a dominant negative inhibitor of C/EBPs in the activation of gene transcription, CHOP-C/EBP can activate certain target genes. Here we show that CHOP interacts with members of the immediate-early response, growth-promoting AP-1 transcription factor family, JunD, c-Jun, and c-Fos, to activate promoter elements in the somatostatin, JunD, and collagenase genes. The leucine zipper dimerization domain is required for interactions with AP-1 proteins and transactivation of transcription. Analyses by electrophoretic mobility shift assays and by an in vivo mammalian two-hybrid system for protein-protein interactions indicate that CHOP interacts with AP-1 proteins inside cells and suggest that it is recruited to the AP-1 complex by a tethering mechanism rather than by direct binding of DNA. Thus, CHOP not only is a negative or a positive regulator of C/EBP target genes but also, when tethered to AP-1 factors, can activate AP-1 target genes. These findings establish the existence of a new mechanism by which CHOP regulates gene expression when cells are exposed to cellular stress.

Download Full-text

Application of HB17, an Arabidopsis class II homeodomain-leucine zipper transcription factor, to regulate chloroplast number and photosynthetic capacity

Journal of Experimental Botany ◽

10.1093/jxb/ert261 ◽

2013 ◽

Vol 64 (14) ◽

pp. 4479-4490 ◽

Cited By ~ 13

Author(s):

Graham J. Hymus ◽

Suqin Cai ◽

Elizabeth A. Kohl ◽

Hans E. Holtan ◽

Colleen M. Marion ◽

...

Keyword(s):

Transcription Factor ◽

Leucine Zipper ◽

Photosynthetic Capacity ◽

Class Ii ◽

Chloroplast Number

Download Full-text

Phosphorylation of MafA Is Essential for Its Transcriptional and Biological Properties

Molecular and Cellular Biology ◽

10.1128/mcb.21.14.4441-4452.2001 ◽

2001 ◽

Vol 21 (14) ◽

pp. 4441-4452 ◽

Cited By ~ 65

Author(s):

Sofia Benkhelifa ◽

Sylvain Provot ◽

Eugène Nabais ◽

Alain Eychène ◽

Georges Calothy ◽

...

Keyword(s):

Transcription Factor ◽

Transcriptional Activity ◽

Leucine Zipper ◽

Biological Properties ◽

Erk Pathway ◽

Mitogen Activated Protein Kinases ◽

Mitogen Activated Protein ◽

Basic Region

ABSTRACT We previously described the identification of quail MafA, a novel transcription factor of the Maf bZIP (basic region leucine zipper) family, expressed in the differentiating neuroretina (NR). In the present study, we provide the first evidence that MafA is phosphorylated and that its biological properties strongly rely upon phosphorylation of serines 14 and 65, two residues located in the transcriptional activating domain within a consensus for phosphorylation by mitogen-activated protein kinases and which are conserved among Maf proteins. These residues are phosphorylated by ERK2 but not by p38, JNK, and ERK5 in vitro. However, the contribution of the MEK/ERK pathway to MafA phosphorylation in vivo appears to be moderate, implicating another kinase. The integrity of serine 14 and serine 65 residues is required for transcriptional activity, since their mutation into alanine severely impairs MafA capacity to activate transcription. Furthermore, we show that the MafA S14A/S65A mutant displays reduced capacity to induce expression of QR1, an NR-specific target of Maf proteins. Likewise, the integrity of serines 14 and 65 is essential for the MafA ability to stimulate expression of crystallin genes in NR cells and to induce NR-to-lens transdifferentiation. Thus, the MafA capacity to induce differentiation programs is dependent on its phosphorylation.

Download Full-text

Growth Analysis of the Effect of Phosphorus Nutrition on Seedings of Eucalyptus grandis

Functional Plant Biology ◽

10.1071/pp9920055 ◽

1992 ◽

Vol 19 (1) ◽

pp. 55 ◽

Cited By ~ 24

Author(s):

MUF Kirschbaum ◽

DW Bellingham ◽

RN Cromer

Keyword(s):

Leaf Area ◽

Specific Leaf Area ◽

Carbon Fixation ◽

Eucalyptus Grandis ◽

Dry Weight ◽

Plant Size ◽

Phosphorus Concentration ◽

Fixation Rate ◽

Unit Leaf ◽

Addition Rate

Download Full-text

Reexamining the empirical relation between plant growth and leaf photosynthesis

Functional Plant Biology ◽

10.1071/fp05310 ◽

2006 ◽

Vol 33 (5) ◽

pp. 421 ◽

Cited By ~ 63

Author(s):

Eric L. Kruger ◽

John C. Volin

Keyword(s):

Gas Exchange ◽

Plant Growth ◽

Leaf Area ◽

Leaf Gas Exchange ◽

Empirical Relation ◽

Leaf Photosynthesis ◽

Unit Leaf Area ◽

Leaf Mass ◽

Unit Leaf ◽

Growth Variation

Technological advances during the past several decades have greatly enhanced our ability to measure leaf photosynthesis virtually anywhere and under any condition. Associated with the resulting proliferation of gas-exchange data is a lingering uncertainty regarding the importance of such measurements when it comes to explaining intrinsic causes of plant growth variation. Accordingly, in this paper we rely on a compilation of data to address the following questions: from both statistical and mechanistic standpoints, how closely does plant growth correlate with measures of leaf photosynthesis? Moreover, in this context, does the importance of leaf photosynthesis as an explanatory variable differ among growth light environments? Across a wide array of species and environments, relative growth rate (RGR) was positively correlated with daily integrals of photosynthesis expressed per unit leaf area (Aarea), leaf mass (Amass), and plant mass (Aplant). The amount of RGR variation explained by these relationships increased from 36% for the former to 93% for the latter. Notably, there was close agreement between observed RGR and that estimated from Aplant after adjustment for theoretical costs of tissue construction. Overall, based on an analysis of growth response coefficients (GRCs), gross assimilation rate (GAR), a photosynthesis-based estimate of biomass gain per unit leaf area, explained about as much growth variation as did leaf mass ratio (LMR) and specific leaf area (SLA). Further analysis of GRCs indicated that the importance of GAR in explaining growth variation increased with increasing light intensity. Clearly, when considered in combination with other key determinants, appropriate measures of leaf gas exchange effectively capture the fundamental role of leaf photosynthesis in plant growth variation.

Download Full-text

Nuclear Import of c-Jun Is Mediated by Multiple Transport Receptors

Journal of Biological Chemistry ◽

10.1074/jbc.m703301200 ◽

2007 ◽

Vol 282 (38) ◽

pp. 27685-27692 ◽

Cited By ~ 51

Author(s):

Inga Waldmann ◽

Sarah Wälde ◽

Ralph H. Kehlenbach

Keyword(s):

Transcription Factor ◽

Nuclear Import ◽

Leucine Zipper ◽

Dependent Manner ◽

Reporter Protein ◽

Permeabilized Cells ◽

Import Receptors ◽

Factor C

c-Jun and c-Fos are major components of the transcriptional complex AP-1. Here, we investigate the nuclear import pathway(s) of the transcription factor c-Jun. c-Jun bound specifically to the nuclear import receptors importin β, transportin, importin 5, importin 7, importin 9, and importin 13. In digitonin-permeabilized cells, importin β, transportin, importin 7, and importin 9 promoted efficient import of c-Jun into the nucleus. Importin α, by contrast, inhibited nuclear import of c-Jun in vitro. A single basic region preceding the leucine zipper of c-Jun functions as a nuclear localization signal (NLS) and was required for interaction with all tested import receptors. In vivo, nuclear import of a c-Jun reporter protein lacking the leucine zipper strictly depended on this NLS. In a leucine zipper-dependent manner, c-Jun with mutations in its NLS was still imported into the nucleus in a complex with endogenous leucine zipper proteins or, for example, with cotransfected c-Fos. Together, these results explain the highly efficient nuclear import of the transcription factor c-Jun.

Download Full-text

START domain mediates Arabidopsis GLABRA2 transcription factor dimerization and turnover independently of homeodomain DNA binding

10.1101/2021.11.23.469727 ◽

2021 ◽

Author(s):

Thiya Mukherjee ◽

Bibek Subedi ◽

Aashima Khosla ◽

Adara L Warner ◽

Ruben Lerma-Reyes ◽

...

Keyword(s):

Transcription Factor ◽

Dna Binding ◽

Leucine Zipper ◽

Root Hairs ◽

Epidermal Differentiation ◽

Missense Mutations ◽

Lipid Transfer ◽

Mutant Proteins ◽

Start Domain

Class IV homeodomain leucine-zipper transcription factors (HD-Zip IV TFs) are key regulators of epidermal differentiation that are characterized by a DNA-binding homeodomain (HD) in conjunction with lipid sensor domain termed START (Steroidogenic Acute Regulatory (StAR)-related lipid Transfer). Previous work demonstrated that the START domain of GLABRA2 (GL2), a HD-Zip IV member from Arabidopsis, is required for transcription factor activity. Here, we address the functions and possible interactions of START and the HD in DNA binding, dimerization, and protein turnover. Deletion analysis of the HD and missense mutations of a conserved lysine (K146) result in phenotypic defects in leaf trichomes, root hairs and seed mucilage, similar to those observed for START mutants, despite nuclear localization of the mutant proteins. Gel shift and ChIP-seq experiments demonstrate that while HD mutations impair binding to target DNA, the START domain is dispensable for DNA binding. Vice versa, yeast two-hybrid assays reveal impaired GL2 dimerization for START domain mutants, but not HD mutants. Using in vivo cycloheximide chase experiments, we provide evidence for the role of START, but not HD, in maintaining protein stability. This work advances our fundamental understanding of HD-Zip TFs as multidomain regulators of epidermal development in plants.

Download Full-text

Photosynthetic Responses to Phosphorus Nutrition in Eucalyptus grandis Seedlings

Functional Plant Biology ◽

10.1071/pp9900527 ◽

1990 ◽

Vol 17 (5) ◽

pp. 527 ◽

Cited By ~ 39

Author(s):

MUF Kirschbaum ◽

D Tompkins

Keyword(s):

Nitrogen Content ◽

Leaf Area ◽

Eucalyptus Grandis ◽

Phosphorus Nutrition ◽

Assimilation Rate ◽

Unit Leaf Area ◽

Unit Leaf ◽

Leaf Weight ◽

Partial Pressures ◽

Phosphorus Status

Eucalyptus grandis seedlings were grown in growth units in which plant roots were suspended in air while continuously being sprayed with nutrient solution (aeroponic system). Phosphorus was added to nutrient solutions in exponentially increasing amounts which determined plant growth rates. Plants were grown at five relative phosphorus addition rates, and photosynthetic performance of leaves was compared across treatments. Carbon assimilation rates ranged from 11.7 μmol m-2 s-1 for plants with lowest phosphorus status to 23.1 μmol m-2 s-1 for plants with highest phosphorus status. Intercellular partial pressures of CO2 concomitantly decreased from 260 pbar for plants with lowest to 220 μbar for plants with highest phosphorus status. Leaves in all treatments showed a decrease in assimilation rate at intercellular partial pressures of CO2 above c. 600 μbar. There was no consistent correlation between the extent of that decrease and the phosphorus status of leaves. Assimilation rates were correlated with leaf phosphorus content. This relationship was apparent on either a unit leaf area or unit leaf weight basis. Assimilation rates and leaf nitrogen content per unit leaf weight were also correlated. In contrast, there was no correlation between leaf assimilation rate per unit leaf area and nitrogen content per unit leaf area, as nitrogen content per unit area was similar for all phosphorus treatments. The differences between correlations on a weight and area basis were due to differences in specific leaf area in different treatments, with plants with lower phosphorus status having less leaf area per unit leaf weight. The photosynthetic measurements showed that CO2 assimilation rate, together with relative leaf growth rate, was one of the processes most sensitive to phosphorus nutrition.

Download Full-text