Download 九十三學年度植物科學研究所論文壁報展

Title︰Investigation of Functional Relationships between FIN219
and FHY1 Genes.
M.S. Student ︰Tuan – Ya Chang(R92B42010)
Advisor︰Dr. Hsu-Liang Hsieh
Abstract :
Phytochromes are plant photoreceptors that regulate plant growth and
development in response to the light environment. In Arabidopsis,
phytochrome A (phyA) is the primary photoreceptor responsible for perceiving
and mediating various responses to far-red light. Previous studies have
identified multiple phyA signaling components, such as FIN219 (far-red
insensitive 219) and FHY1 (far-red elongated hypocoty 1).
FHY1 encodes a product (FHY1) that specifically transduces signals
downstream of the far-red (FR) light-responsive phytochrome A (PHYA)
photoreceptor. FIN219 is an auxin-inducible gene and also involved in
phytochrome A signaling pathways. Complementation test between fin219 and
fhy1 show nonallelic noncomplementation, which indicates possible genetic
interactions between these two mutations. Nonallelic noncomplementation is
considered a hallmark for genes whose products act closely within the same
pathway and most likely interact directly. Hence, we suggest that FHY1 may
interact with FIN219 when response to far-red light.
The results of yeast two-hybrid show that the C-terminus of FIN219 may
interact with FHY1. When FIN219 overexpression construct was introduced
into fhy1 mutant, the transgenic plant seedlings show shorter hypocotyls under
far-red light condition, partially rescuing fhy1 phenotype. When FHY1 was
overexpressed in fin219 mutant background, FHY1 can also partially rescue
fin219 phenotype. In addition, it was found that FHY1 transcript levels
increased in the fin219 mutant; in fhy1 mutant, FIN219 transcript levels
increased as well..
Taken together, these data indicate that FHY1 and FIN219 coordinate with
each other and response to far-red light to regulate photomorphogenesis.