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Gibberellin response mutants identified by luciferase imaging
Author(s) -
Meier Carsten,
Bouquin Thomas,
Nielsen Mads Eggert,
Raventos Dora,
Mattsson Ole,
Rocher Anne,
Schomburg Fritz,
Amasino Richard M.,
Mundy John
Publication year - 2001
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2001.00980.x
Subject(s) - complementation , mutant , arabidopsis , biology , gibberellin , genetics , luciferase , ectopic expression , gene , transfection
Summary The gibberellin (GA) 20‐oxidase encoded by Arabidopsis GA5 catalyzes the synthesis of active GAs. GA5 is a regulatory step in GA biosynthesis as GA5 mRNA levels are negatively regulated by its bioactive GA products. A fusion between the GA5 promoter and the firefly luciferase reporter ( GA5 ‐ LUC ) was shown to be similarly regulated, indicating GA feedback of GA5 occurs at the transcriptional level. The fidelity of the GA5 ‐ LUC reporter permitted a fusion genetic screen to identify mutants altered in transgene expression. This bioimaging screen identified two types of recessive mutants with increased LUC activity and apparent GA‐related growth phenotypes, a dwarf ( lue1 ) and two late flowering mutants ( fpa1‐3 and fpa1‐4 ). Mutant progeny exhibited altered levels of LUC and of endogenous GA5 and other GA‐regulated mRNAs. SSLP‐based mapping localized lue1 to chromosome I near the ga2 locus, although complementation analyzes showed that lue1 is not allelic to ga2 . Mapping and complementation analyzes showed that the late flowering mutants are allelic to fpa1 . This provides genetic evidence for crosstalk between the autonomous and gibberellin‐dependent flowering pathways.