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Auxin acts independently of DELLA proteins in regulating gibberellin levels


Reid, JB and Davidson, SE and Ross, JJ, Auxin acts independently of DELLA proteins in regulating gibberellin levels, Plant Signaling & Behavior, 6, (3) pp. 406-408. ISSN 1559-2316 (2011) [Refereed Article]

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Landes Bioscience

DOI: doi:10.4161/psb.6.3.14352


Shoot elongation is a vital process for plant development and productivity, in both ecological and economic contexts. Auxin and bioactive gibberellins (GAs), such as GA1, play critical roles in the control of elongation,1-3 along with environmental and endogenous factors, including other hormones such as the brassinosteroids.4,5 The effect of auxins, such as indole-3-acetic acid (IAA), is at least in part mediated by its effect on GA metabolism,6 since auxin upregulates biosynthesis genes such as GA 3-oxidase and GA 20-oxidase and downregulates GA catabolism genes such as GA 2-oxidases, leading to elevated levels of bioactive GA1.7 In our recent paper,1 we have provided evidence that this action of IAA is largely independent of DELLA proteins, the negative regulators of GA action,8,9 since the auxin effects are still present in the DELLA-deficient la cry-s genotype of pea. This was a crucial issue to resolve, since like auxin, the DELLAs also promote GA1 synthesis and inhibit its deactivation. DELLAs are deactivated by GA, and thereby mediate a feedback system by which bioactive GA regulates its own level.10 However, our recent results,1 in themselves, do not show the generality of the auxin-GA relationship across species and phylogenetic groups or across different tissue types and responses. Further, they do not touch on the ecological benefits of the auxin-GA interaction. These issues are discussed below as well as the need for the development of suitable experimental systems to allow this process to be examined.

Item Details

Item Type:Refereed Article
Keywords:auxin, gibberellins, DELLA proteins, interactions, elongation
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:Reid, JB (Professor Jim Reid)
UTAS Author:Davidson, SE (Dr Sandra Davidson)
UTAS Author:Ross, JJ (Associate Professor John Ross)
ID Code:71971
Year Published:2011
Deposited By:Plant Science
Deposited On:2011-08-17
Last Modified:2012-04-16

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