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• Gibberellin (GA) deficiency resulting from the na mutation in pea (Pisum sativum) causes a reduction in nodulation. Nodules that do form are aberrant, having poorly developed meristems and a lack of enlarged cells. Studies using additional GA-biosynthesis double mutants indicate that this results from severe GA deficiency of the roots rather than simply dwarf shoot stature. • Double mutants isolated from crosses between na and three supernodulating pea mutants exhibit a supernodulation phenotype, but the nodule structures are aberrant. This suggests that severely reduced GA concentrations are not entirely inhibitory to nodule initiation, but that higher GA concentrations are required for proper nodule development. • na mutants evolve more than double the amount of ethylene produced by wildtype plants, indicating that low GA concentrations can promote ethylene production. The excess ethylene may contribute to the reduced nodulation of na plants, as application of an ethylene biosynthesis inhibitor increased na nodule numbers. However, these nodules were still aberrant in structure. • Constitutive GA signalling mutants also form significantly fewer nodules than wild-type plants. This suggests that there is an optimum degree of GA signalling required for nodule formation and that the GA signal, and not the concentration of bioactive GA per se, is important for nodulation.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Plant biology
Research Field:	Plant physiology
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Horticultural crops
Objective Field:	Horticultural crops not elsewhere classified
UTAS Author:	Foo, E (Associate Professor Eloise Foo)
UTAS Author:	Ross, JJ (Associate Professor John Ross)
UTAS Author:	Reid, JB (Professor Jim Reid)
ID Code:	71967
Year Published:	2011
Web of Science® Times Cited:	56
Deposited By:	Plant Science
Deposited On:	2011-08-17
Last Modified:	2017-11-02
Downloads:	0