Functional Studies of FIN219 and FIP1 Interaction on Far-Red Light and Jasmonic Acid Signaling in Arabidopsis thaliana
Date Issued
2012
Date
2012
Author(s)
Lin, Yang-Tsung
Abstract
Previous studies showed that FIN219 is not only a positive regulator in far-red (FR) light signaling but a jasmonic acid (JA) conjugating enzyme. The conjugation of JA with isoleucine (Ile) by FIN219 leads to the bio-active JA-Ile that triggers the downstream JA signaling. FIN219-interacting protein 1 (FIP1) was found to interact with FIN219 under in vitro and in vivo conditions. Further investigation found that this interaction can enhance the enzyme activity of FIN219. Besides, FIP1 is a tau class member of the glutathione S-transferase (GSTU) superfamily in Arabidopsis. Previous research indicated that GSTU members are able to bind with oxylipins and some of them, including FIP1, could be induced by JA rapidly. Given that JA belongs to oxylins, the interaction of FIP1 and FIN219 may positively regulate JA signaling in Arabidopsis. In this study, we used transgenic plants that had changes of FIN219 and FIP1 expression levels; reporter gene fusion proteins were also harbored to verify the physical functions of FIP1 and FIN219. Here, we found that FIP1 was induced by JA rapidly as well as by low concentrations of JA persistently. Furthermore, the knocked-down of FIP1 under these conditions led to a negative effect on JA signaling. Surprisingly, the overexpression of FIP1 leads to various JA sensitivity effects by JA and its derivatives. The JA deficiencies caused by the fip1as/fin219-2 double mutant implies the coordinative functions of these two genes in JA signaling. Finally, the tissue-specific data showed that FIP1 and FIN219 were highly associated with the JA-related function areas. To sum up, these results provide an insight into the GSTU-modulated JA signal pathway.
Subjects
Far-red insensitive 219
FIN219-interacting protein 1
Jasmonic acid
far-red light
Glutathione S-transferase tau class
Type
thesis
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