Starting from seed germination, various growth and developmental processes in plants are regulated by signals cued by environmental light and endogenous plant hormones; however, how plants coordinate these light and hormone signals at the molecular level is not well understood. A research team led by Dr. Shu-Hsing Wu from the Institute of Plant and Microbial Biology has recently discovered that a protein named bZIP16 plays a key role in the integration of light and hormone signaling pathways in the model plant, Arabidopsis. This research was published in the journal Plant Cell on Oct 26, 2012.

　　Seed germination can be stimulated by proper light illumination. Plant hormones are also key regulators of seed germination; for example, gibberellic acid (GA) can stimulate seed germination whereas abscisic acid inhibits this process. Dr. Wu's research team has found that a transcription factor termed bZIP16 is a key incorporating light and hormone signaling in early seedling development.

　　bZIP16 was identified by its unique association with a specific DNA sequence. Upon the perception of light, bZIP16 represses the action of abscisic acid but promotes the functions of gibberellic acid, thus stimulating seed germination and stem elongation. According to Dr. Wu, the environmental light serves as an "on/off" switch regulating plant growth and development. The discovery of bZIP16 has increased our knowledge about the sophisticated regulatory pathways through which plants integrate light and hormone pathways. This finding also provides a new molecular tool through which crop species can be engineered to optimal responsiveness to light and hormones.

　　The first author of this article Ms. Wen-Ping Hsieh is a PhD student in a collaborative graduate program between Academia Sinica and the Institute of Plant Biology, National Taiwan University.

　　The complete article entitled "Arabidopsis bZIP16 Transcription Factor Integrates Light and Hormone Signaling Pathways to Regulate Early Seedling Development" can be found at the Plant Cell journal website at: http://www.plantcell.org/content/early/2012/10/25/tpc.112.105478.full.pdf+html　

The complete list of authors is: Wen-Ping Hsieh, Hsu-Liang Hsieh, Shu-Hsing Wu.