Modulation of plant growth by HD-Zip class I and II transcription factors in response to environmental stimuli

• Published in: The New phytologist 2011-06, Vol.190 (4), p.823-837
• Main Authors: Harris, John C., Hrmova, Maria, Lopato, Sergiy, Langridge, Peter
• Format: Article
• Language: English
• Subjects: abiotic stress; Adaptation; Adaptation, Physiological; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Binding; Biocompatibility; Body organs; Cell differentiation; dimerization; DNA; Environment; Environmental changes; Environmental conditions; Environmental effects; Environmental factors; Gene expression regulation; Gene Expression Regulation, Plant; Genes; Genes, Plant; HD‐Zip; Helix-Turn-Helix Motifs; Homeobox; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Leucine; leucine zipper; Leucine zipper proteins; Leucine Zippers; Light; Multiplication; Nutrient concentrations; Nutrient status; Organs; Phenotypes; Phylogeny; phytohormone; plant development; Plant growth; Plant growth regulators; Plant Growth Regulators - metabolism; Plant growth substances; Plant hormones; Plant Proteins - metabolism; Plant roots; Plants; Proteins; Rice; Stimuli; Submergence; Tansley review; temperature; toxicity; Transcription; transcription (genetics); transcription factor; Transcription factors; Transcription Factors - metabolism
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2011.03733.x

CONTENTS: Summary 823 I. Introduction 824 II. The role of HD-Zip transcription factors in plant growth adaptation to environmental changes and the phytohormone network 825 III. Dissecting the common cis element, dimerization and cell specificity of HD-Zip I and HD-Zip II transcription factors 830 IV. Conclusions 834 Acknowledgements 834 References 834 SUMMARY: Plant development is adapted to changing environmental conditions for optimizing growth. This developmental adaptation is influenced by signals from the environment, which act as stimuli and may include submergence and fluctuations in water status, light conditions, nutrient status, temperature and the concentrations of toxic compounds. The homeodomain-leucine zipper (HD-Zip) I and HD-Zip II transcription factor networks regulate these plant growth adaptation responses through integration of developmental and environmental cues. Evidence is emerging that these transcription factors are integrated with phytohormone-regulated developmental networks, enabling environmental stimuli to influence the genetically preprogrammed developmental progression. Dependent on the prevailing conditions, adaptation of mature and nascent organs is controlled by HD-Zip I and HD-Zip II transcription factors through suppression or promotion of cell multiplication, differentiation and expansion to regulate targeted growth. In vitro assays have shown that, within family I or family II, homo- and/or heterodimerization between leucine zipper domains is a prerequisite for DNA binding. Further, both families bind similar 9-bp pseudopalindromic cis elements, CAATNATTG, under in vitro conditions. However, the mechanisms that regulate the transcriptional activity of HD-Zip I and HD-Zip II transcription factors in vivo are largely unknown. The in planta implications of these protein-protein associations and the similarities in cis element binding are not clear.