Investigation of FIN219 expression and its regulatory relationship with COI1 in Arabidopsis
Date Issued
2009
Date
2009
Author(s)
Wu, Pei-Yun
Abstract
Light is one of the major environmental signals that influence plant growth and development. Plants can detect almost all facets of light such as direction, duration, quantity and quality with three major classes of photoreceptors: phytochromes, cryptochromes and phototropins. Jasmonic acid (JA) has been recognized as a phytohormone, which is involved in both developments and defense pathways in Arabidopsis. How the integration of light and JA affects Arabidopsis development remains to be elucidated.IN219 is a component of phyA-mediated far-red light signaling pathway. It is highly similar to a family of proteins defined by the soybean early auxin-inducible gene GH3. FIN219 expression is rapidly induced by auxin. According to the result of microarray data, FIN219 affects the expression of several transcription factors which are localized in the nucleus, suggesting that FIN219 may directly or indirectly regulate these nuclear proteins. So we produced Arabidopsis transgenic plants containing a FIN219 promoter driven GUS-FIN219 fusion construct to understand the function of FIN219. In the fin219-null mutant background, GUS staining can be detected in the hydathode of cotyledons, and the guard cells around hydathodes. GUS staining are also found in the base of trichomes, hypocotyls and roots. In contrast, in the phyA mutant background, GUS-FIN219 was not expressed in the hypocotyls. AR1 has been shown to be the same locus as FIN219 and functions as an enzyme to conjugate isoleucine to JA. So FIN219 is also involved in JA signaling pathway. Microarray data reveal that the COI1 expression is decreased dramatically in fin219 under FR condition. Here we found that coi1-16 is insensitive to far-red light. RT-PCR results indicate that COI1 expression is down-regulated in fin219-null matant and FIN219 expression also down-regulated in coi1-16 under far-red light, which implies that they positively regulate with each other. Further regulatory relationship will be discussed in the thesis.
Subjects
Arabidopsis
light signaling transduction
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