Functional study of GA-stimulated transcript 4 (AtGASA4) involved in Infrared light signaling in Arabidopsis
Date Issued
2011
Date
2011
Author(s)
Wu, Mu-Huan
Abstract
The effects of visible light on photomorphogenesis have been extensively studied and its triggered signal transductions have been well recognized in plants. Unlike these light sources, infrared (IR) light is invisible and has been widely used in national defense industry and medical treatments. In previous study, gibberellic acid[GA]-and IR-induced gene1 (VrGIR1) was isolated by differential display from mungbean (Vigina radiate) seedlings irradiated with 3~5 μm IR light. As its homolog in Arabidopsis, GASA4 (gibberellic acid-stimulated transcripts in Arabidopsis) was differentially ex-pressed under various light conditions. However, the function of GASA4 under IR re-mains unclear. Thus, my thesis mainly investigates possible functions of GASA4 in IR signaling pathway. Here, we utilize molecular and genetic approaches to elucidate hy-pocotyl lengths of Arabidopsis seedlings under IR treatment, and to understand whether gasa4 is involved in IR signaling. The gasa4 mutant showed a longer hypocotyl than wild type under IR treatment, whereas over-expression lines of GASA4 exhibited a shorter hypocotyl than wild type. Furthermore, we introduced the GASA4 promot-er-driven GFP-GASA4 fusion construct into wild type and gasa4. Those transgenetic seedlings showed a shorter hypocotyl than their genetic-background control under IR treatment. Gene expression data indicated that light responsive genes such as CHS and RbcS1a, were upregulated in gasa4 mutant under IR treatment. In addition, higher an-thocyanin accumulation was observed in gasa4. Taken together, these results indicated that AtGASA4 may be a positive regulator in IR signaling. Moreover, Microarray Analy-sis revealed that PSAK (or PSIK, photosystem I subunit K) and NPQ4 (nonphotochem-ical quenching 4) are induced by IR treatment. Thus, our data imply that IR may change the structure of photosystem to modulate the photosystem efficiency, and then affect plant growth and development.
Subjects
photomorphogenesis
IR
light signaling
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-100-R97b42025-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):605d396154077d34be9a03727739bc4e