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United States Department of Agriculture

Agricultural Research Service

Title: Analysis of the Competence to Respond to Knotted1 Activity in Arabidopsis Leaves Using a Sterioid Induction System

Authors
item Hay, Angela - ARS-UCB PLNT GENE EXP CTR
item David, Jackson - COLD SPRING HARBOR LAB NY
item Ori, Naomi - ARS-UCB PLNT GENE EXP CTR
item Hake, Sarah

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 20, 2003
Publication Date: April 1, 2003
Citation: HAY, A., DAVID, J., ORI, N., HAKE, S.C. 2003. Analysis of the Competence to Respond to KNOTTED1 Activity in Arabidopsis Leaves Using a Sterioid Induction System. Plant Physiology 131:1671-1680.

Interpretive Summary: Expression of KNOX (KNOTTED1-like homeobox) genes in the shoot apical meristem of Arabidopsis is required for maintenance of a functional meristem, whereas exclusion of KNOX gene expression from leaf primordia is required for the elaboration of normal leaf morphology. We have constructed a steroid-inducible system to regulate both the amount and timing of KN1 (KNOTTED1) misexpression in Arabidopsis leaves. We demonstrate that lobed leaf morphology is produced in a dose-dependent manner, indicating that the amount of KN1 quantitatively affects the severity of lobing. We also demonstrate that a broad range of leafage can be affect by KN1 protein.

Technical Abstract: Expression of KNOX (KNOTTED1-like homeobox) genes in the shoot apical meristem of Arabidopsis is required for maintenance of a functional meristem, whereas exclusion of KNOX gene expression from leaf primordia is required for the elaboration of normal leaf morphology. We have constructed a steroid-inducible system to regulate both the amount and timing of KN1 (KNOTTED1) misexpression in Arabidopsis leaves. We demonstrate that lobed leaf morphology is produced in a dose-dependent manner, indicating that the amount of KN1 quantitatively affects the severity of lobing. The KN1-glucocorticoid receptor fusion protein is not detected in leaves in the absence of steroid induction, suggesting that it is only stable when associated with steroid in an active state. By using a second inducible fusion protein to mark exposure of leaf primordia to the steroid, we determined the stage of leaf development that produces lobed leaves in response to KN1. Primordia as old as plastochron 7 and as young as plastochron 2 were competent to respond to KN1.

Last Modified: 7/25/2014
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