Integration of light and abscisic acid signaling during seed germination and early seedling development

Hao Chen, Jingyu Zhang, Michael M. Neff, Suk Whan Hong, Huiyong Zhang, Xing Wang Deng, Liming Xiong*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

233 Citations (Scopus)


Seed germination is regulated by endogenous hormonal cues and external environmental stimuli such as water, low temperature, and light. After germination, the young seedling must rapidly establish its root system and the photoautotrophic capability appropriate to its surrounding environment. Light and the phytohormone abscisic acid (ABA) both regulate seed germination and seedling development, although how light and ABA signals are integrated at the molecular level is not understood. Here, we found that the previously described light-signaling component HY5 also mediates ABA response in seed germination, early seedling growth, and root development in Arabidopsis. HY5 binds to the promoter of the transcription factor ABI5 gene with high affinity and is required for the expression of ABI5 and ABI5-targeted late embryogenesis-abundant genes in seeds. Chromatin immunoprecipitation also indicated that the binding of HY5 to the ABI5 promoter is significantly enhanced by ABA. Overexpression of ABI5 restores ABA sensitivity in hy5 and results in enhanced light responses and shorter hypocotyls in the wild type. Our studies identified an unexpected mode of light and ABA signal integration that may help young seedlings better adapt to environmental stresses.

Original languageEnglish
Pages (from-to)4495-4500
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number11
Publication statusPublished - 18 Mar 2008

Scopus Subject Areas

  • General

User-Defined Keywords

  • Light response
  • Signal transduction


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