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Pea mutants with reduced sensitivity to far-red light define an important role for phytochrome A in day-length detection


Weller, JL and Murfet, IC and Reid, JB, Pea mutants with reduced sensitivity to far-red light define an important role for phytochrome A in day-length detection, Plant Physiology, 114, (4) pp. 1225-1336. ISSN 0032-0889 (1997) [Refereed Article]

DOI: doi:10.1104/pp.114.4.1225


In garden pea (Pisum sativum L.), a Ions-day plant, long photoperiods promote flowering by reducing the synthesis or transport of a graft-transmissible inhibitor of flowering. Previous physiological studies have indicated that this promotive effect is predominantly achieved through a response that requires long exposures to light and for which far-red (FR) light is the most effective. These characteristics implicate the action of phytochrome A (phyA). To investigate this matter further, we screened ethylmethane sulfonate-mutagenized pea seedlings for FR-unresponsive, potentially phyA-deficient mutants. Two allelic, recessive mutants were isolated and were designated fun1 for FR unresponsive. The fun1-1 mutant is specifically deficient in the PHYA apoprotein and has a seedling phenotype indistinguishable from wild type when grown under white light. However, fun1-1 plants grown to maturity under long photoperiods show a highly pleiotropic phenotype, with short internodes, thickened stems, delayed flowering and senescence, longer peduncles, and higher seed yield. This phenotype results in large part from an inability of fun1-1 to detect day extensions. These results establish a crucial role for phyA in the control of flowering in pea, and show that phyA mediates responses to both red and FR light. Furthermore, grafting and epistasis studies with fun1 and dne, a mutant deficient in the floral inhibitor, show that the roles of phyA in seedling de-etiolation and in day-length detection are genetically separable and that the phyA-mediated promotion of flowering results from a reduction in the synthesis or transport of the floral inhibitor.

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:Murfet, IC (Professor Ian Murfet)
UTAS Author:Reid, JB (Professor Jim Reid)
ID Code:10466
Year Published:1997
Web of Science® Times Cited:109
Deposited By:Plant Science
Deposited On:1997-08-01
Last Modified:2010-10-11

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