Modification of distinct aspects of photomorphogenesis via targeted expression of mammalian biliverdin reductase in transgenic Arabidopsis plants.
The phenotypic consequences of targeted expression of mammalian biliverdin IXalpha reductase (BVR), an enzyme that metabolically inactivates the linear tetrapyrrole precursors of the phytochrome chromophore, are addressed in this investigation. Through comparative phenotypic analyses of multiple plastid-targeted and cytosolic BVR transgenic Arabidopsis plant lines, we show that the subcellular localization of BVR affects distinct subsets of light-mediated and light-independent processes in plant growth and development. Regardless of its cellular localization, BVR suppresses the phytochrome-modulated responses of hypocotyl growth inhibition, sucrose-stimulated anthocyanin accumulation, and inhibition of floral initiation. By contrast, reduced protochlorophyll levels in dark-grown seedlings and fluence-rate-dependent reduction of chlorophyll occur only in transgenic plants in which BVR is targeted to plastids. Together with companion analyses of the phytochrome chromophore-deficient hy1 mutant, our results suggest a regulatory role for linear tetrapyrroles within the plastid compartment distinct from their assembly with apophytochromes in the cytosol.
Montgomery
B L
BL
Section of Molecular and Cellular Biology, One Shields Avenue, University of California, Davis, California 95616, USA.
Yeh
K C
KC
Crepeau
M W
MW
Lagarias
J C
JC
D016960:Agrobacterium tumefaciens; D000818:Animals; D000872:Anthocyanins / Q000378:metabolism; D017360:Arabidopsis / Q000502:physiology*; D002734:Chlorophyll / Q000031:analogs & derivatives / Q000378:metabolism; D005822:Genetic Vectors; D018546:Hypocotyl; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008027:Light; D008322:Mammals; D009024:Morphogenesis; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D030821:Plants, Genetically Modified; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism
D000872:Anthocyanins; D011994:Recombinant Proteins; D002734:Chlorophyll; C016083:protochlorophyll; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C019789:biliverdin reductase