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The phytochrome-deficient pcd1 mutant of pea is unable to convert heme to biliverdin IXa


Weller, JL and Terry, MJ and Rameau, C and Reid, JB and Kendrick, RE, The phytochrome-deficient pcd1 mutant of pea is unable to convert heme to biliverdin IXa, The Plant Cell, 8, (1) pp. 55-67. ISSN 1040-4651 (1996) [Refereed Article]

DOI: doi:10.2307/3870068


We isolated a new pea mutant that was selected on the basis of pale color and elongated internodes in a screen under white light. The mutant was designated pcd1 for phytochrome chromophore deficient. Light-grown pcd1 plants have yellow-green foliage with a reduced chlorophyll (Chl) content and an abnormally high Chl a/Chl b ratio. Etiolated pcd1 seedlings are developmentally insensitive to far-red light, show a reduced response to red light, and have no spectrophotometrically detectable phytochrome. The phytochrome A apoprotein is present at the wild-type level in etiolated pcd1 seedlings but is not depleted by red light treatment. Crude phytochrome preparations from etiolated pcd1 tissue also lack spectral activity but can be assembled with phycocyanobilin, an analog of the endogenous phytochrome chromophore phytochromobilin, to yield a difference spectrum characteristic of an apophytochrome-phycocyanobilin adduct. These results indicate that the pcd1-conferred phenotype results from a deficiency in phytochrome chromophore synthesis. Furthermore, etioplast preparations from pcd1 seedlings can metabolize biliverdin (BV) IXα but not heme to phytochromobilin, indicating that pcd1 plants are severely impaired in their ability to convert heme to BV IXα. This provides clear evidence that the conversion of heme to BV IXα is an enzymatic process in higher plants and that it is required for synthesis of the phytochrome chromophore and hence for normal photomorphogenesis.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Weller, JL (Associate Professor Jim Weller)
UTAS Author:Reid, JB (Professor Jim Reid)
ID Code:7134
Year Published:1996
Web of Science® Times Cited:62
Deposited By:Plant Science
Deposited On:1996-08-01
Last Modified:2010-11-08

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