title: Nicotiana attenuata NaHD20 plays a role in leaf ABA accumulation during water stress, benzylacetone emission from flowers, and the timing of bolting and flower transitions.
abstract: Homeodomain-leucine zipper type I (HD-Zip I) proteins are plant-specific transcription factors associated with the regulation of growth and development in response to changes in the environment. Nicotiana attenuata NaHD20 was identified as an HD-Zip I-coding gene whose expression was induced by multiple stress-associated stimuli including drought and wounding. To study the role of NaHD20 in the integration of stress responses with changes in growth and development, its expression was silenced by virus-induced gene silencing (VIGS), and control and silenced plants were metabolically and developmentally characterized. Phytohormone profiling showed that NaHD20 plays a positive role in abscisic acid (ABA) accumulation in leaves during water stress and in the expression of some dehydration-responsive genes including ABA biosynthetic genes. Moreover, consistent with the high levels of NaHD20 expression in corollas, the emission of benzylacetone from flowers was reduced in NaHD20-silenced plants. Additionally, bolting time and the opening of the inflorescence buds was decelerated in these plants in a specific developmental stage without affecting the total number of flowers produced. Water stress potentiated these effects; however, after plants recovered from this condition, the opening of the inflorescence buds was accelerated in NaHD20-silenced plants. In summary, NaHD20 plays multiple roles in N. attenuata and among these are the coordination of responses to dehydration and its integration with changes in flower transitions.
authors: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany.
authors: Delfina A
authors: DA
authors: Ré
authors: Carlos A
authors: CA
authors: Dezar
authors: Raquel L
authors: RL
authors: Chan
authors: Ian T
authors: IT
authors: Baldwin
authors: Gustavo
authors: G
authors: Bonaventure
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological; D014026:Nicotiana / Q000235:genetics / Q000502:physiology*; D014867:Water / Q000378:metabolism*
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D010940:Plant Proteins; D014867:Water; D000040:Abscisic Acid