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Nodulation Phenotypes of Gibberellin and Brassinosteroid Mutants of Pea


Ferguson, BJ and Ross, JJ and Reid, JB, Nodulation Phenotypes of Gibberellin and Brassinosteroid Mutants of Pea, Plant Physiology, 138, (4) pp. 2396-2405. ISSN 0032-0889 (2005) [Refereed Article]

DOI: doi:10.1104/pp.105.062414


The initiation and development of legume nodules induced by compatible Rhizobium species requires a complex signal exchange involving both plant and bacterial compounds. Phytohormones have been implicated in this process, although in many cases direct evidence is lacking. Here, we characterize the root and nodulation phenotypes of various mutant lines of pea (Pisum sativum) that display alterations in their phytohormone levels and/or perception. Mutants possessing root systems deficient in gibberellins (GAs) or brassinosteroids (BRs) exhibited a reduction in nodule organogenesis. The question of whether these reductions represent direct or indirect effects of the hormone deficiency is addressed. For example, the application of GA to the roots of a GA-deficient mutant completely restored its number of nodules to that of the wild type. Grafting studies revealed that a wild-type shoot or root also restored the nodule number of a GA-deficient mutant These findings suggest that GAs are required for nodulation. In contrast, the shoot controlled the number of nodules that formed in graft combinations of a BR-deficient mutant and its wild type. The root levels of auxin and GA were similar among these latter graft combinations. These results suggest that BRs influence a shoot mechanism that controls nodulation and that the root levels of auxin and GA are not part of this process. Interestingly, a strong correlation between nodule and lateral root numbers was observed in all lines assessed, consistent with a possible overlap in the early developmental pathways of the two organs. © 2005 American Society of Plant Biologists.

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:Ferguson, BJ (Dr Brett Ferguson)
UTAS Author:Ross, JJ (Associate Professor John Ross)
UTAS Author:Reid, JB (Professor Jim Reid)
ID Code:35833
Year Published:2005
Web of Science® Times Cited:121
Deposited By:Plant Science
Deposited On:2005-08-01
Last Modified:2007-11-06

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