Functional Studies of a putative Suppressor of Arabidopsis FIN219
Date Issued
2007
Date
2007
Author(s)
KUO, CHUNG-JUNG
DOI
en-US
Abstract
A putative suppressor line 0802 of fin219 was identified from studies of FIN219 promoter activities that investigated expression patterns of fin219 transgenic seedlings harboring the construct P219：：FIN219-GUS. The T2 line of 0802 exhibited a rescued hypocotyl phenotype under far-red light, had a very short (dwarf) phenotype under white light. In addition, under hygromycin selection, 1/4 hypersensitive segregation ratio is resistant and homozygous, leading to the possibility that the phenotype of 0802 was due to a T-DNA inserted in an unknown gene to suppress the long hypocotyl phenotype of fin219. To confirm this hypothesis, we focus on the cloning of the putative suppressor gene and address the relationship between FIN219 (Far-red Insensitive 219) and its putative suppressor by a functional study approach. This putative suppressor line 0802 showed a fin219-rescued phenotype under far red light, and it also exhibited a hypersensitive phenotype under white light、red light、blue light and darkness. The flanking sequence of T-DNA was amplified by an inverse-PCR approach and sequenced. It was found that the T-DNA was inserted in the 3rd intron (1784 nt) of Arabidopsis CPD (Constitutive Photomorphogenesis and Dwarfism) gene. CPD (CYP90A1) was reported as Arabidopsis brassinosteroid biosynthetic gene and belonged to cytochrome P450 super gene family. This result was confirmed by RT-PCR and genomic southern. Besides, CPD anti-sense lines could partially suppress the long hypocotyl of fin219, fin219 -null and phyA under continuous far-red light (cFR), which indicates that CPD is the suppressor of FIN219. Furthermore, FIN219 promoter activities could be reduced by Brassinosteroid (BR), 24-epi-BL. The expression analysis show that the expression of light regulated genes such as CHS (Chalcone synthase) and RBCS (Ribulose Bisphosphate Carboxylase/oxygenase Small subunit) could be altered in 0802. Taken together, CPD might play a vital role to crosstalk between BR and light signaling.
Subjects
抑制者
遠紅光
光型態發生
FIN219
BR
CPD
suppressor
light signal
Type
other