Overexpression of a chromatin architecture-controlling AT-hook protein extends leaf longevity and increases the post-harvest storage life of plants.
Leaf senescence is the final stage of leaf development and is finely regulated via a complex genetic regulatory network incorporating both developmental and environmental factors. In an effort to identify negative regulators of leaf senescence, we screened activation-tagged Arabidopsis lines for mutants that exhibit a delayed leaf senescence phenotype. One of the mutants (ore7-1D) showed a highly significant delay of leaf senescence in the heterozygous state, leading to at least a twofold increase in leaf longevity. The activated gene (ORE7/ESC) encoded a protein with an AT-hook DNA-binding motif; such proteins are known to co-regulate transcription of genes through modification of chromatin architecture. We showed that ORE7/ESC, in addition to binding to a plant AT-rich DNA fragment, could also modify the chromatin architecture, as illustrated by an altered distribution of a histone-GFP fusion protein in the nucleus of the mutant. Globally altered gene expression, shown by microarray analysis, also indicated that activation of ORE7/ESC results in a younger condition in the mutant leaves. We propose that ectopically expressed ORE7/ESC is negatively regulating leaf senescence and suggest that the resulting chromatin alteration may have a role in controlling leaf longevity. Interestingly, activation of ORE7/ESC also led to a highly extended post-harvest storage life.
Lim
Pyung Ok
PO
Department of Science Education, Cheju National University, Jeju, Korea.
Kim
Yumi
Y
Breeze
Emily
E
Koo
Ja Choon
JC
Woo
Hye Ryun
HR
Ryu
Jong Sang
JS
Park
Don Ha
DH
Beynon
Jim
J
Tabrett
Alex
A
Buchanan-Wollaston
Vicky
V
Nam
Hong Gil
HG
D024761:AT-Hook Motifs / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D018515:Plant Leaves / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D029681:Arabidopsis Proteins; D002843:Chromatin; D006657:Histones; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins