Journal Article

PICKLE Acts throughout the Plant to Repress Expression of Embryonic Traits and May Play a Role in Gibberellin-Dependent Responses

Mordhorst, Andreas P., Stanley Dean Rider, Jennifer Robey, Hui-Chun Li, Sung, Z. Renee, Cheng, Jin-Chen, Jim T. Henderson, Romero-Severson, Jeanne, de Vries, Sacco C., Ogas, Joe

2004

Overview

A seed marks the transition between two developmental states; a plant is an embryo during seed formation, whereas it is a seedling after emergence from the seed. Two factors have been identified in Arabidopsis that play a role in establishment of repression of the embryonic state: PKL (PICKLE), which codes for a putative CHD3 chromatin remodeling factor, and gibberellin (GA), a plant growth regulator. Previous observations have also suggested that PKL mediates some aspects of GA responsiveness in the adult plant. To investigate possible mechanisms by which PKL and GA might act to repress the embryonic state, we further characterized the ability of PKL and GA to repress embryonic traits and reexamined the role of PKL in mediating GA-dependent responses. We found that PKL acts throughout the seedling to repress expression of embryonic traits. Although the ability of pkl seedlings to express embryonic traits is strongly induced by inhibiting GA biosynthesis, it is only marginally responsive to abscisic acid and SPY (SPINDLY), factors that have previously been demonstrated to inhibit GA-dependent responses during germination. We also observed that pkl plants exhibit the phenotypic hallmarks of a mutation in a positive regulator of a GA response pathway including reduced GA responsiveness and increased synthesis of bioactive GAs. These observations indicate that PKL may mediate a subset of GA-dependent responses during shoot development.

• Publisher: American Society of Plant Biologists,The American Society for Plant Biologists
• Subject: abscisic acid / Arabidopsis / Arabidopsis - drug effects / Arabidopsis - embryology / Arabidopsis - genetics / Arabidopsis Proteins / Arabidopsis Proteins - genetics / Arabidopsis thaliana / Base Sequence / biosynthesis / callus culture / Development and Hormone Action / DNA Helicases / DNA, Plant / DNA, Plant - genetics / drug effects / embryology / gene expression regulation / Gene Expression Regulation, Developmental / Gene Expression Regulation, Plant / Genes, Plant / genetics / Germination / Gibberellins / Gibberellins - biosynthesis / Gibberellins - pharmacology / Hypocotyls / messenger RNA / mutation / nucleotide sequences / Penetrance / pharmacology / Phenotype / Phenotypes / Pickles / plant proteins / plant response / Plant roots / Plants / Plants, Genetically Modified / Repression / Repressor Proteins / Repressor Proteins - genetics / roots / seed germination / Seedlings / signal transduction / somatic embryogenesis / somatic embryos