Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 28, 2009
Publication Date: April 9, 2010
Citation: Horvath, D.P., Sung, S., Kim, D., Chao, W., Anderson, J. 2010. Characterization, Expression and Function of DORMANCY ASSOCIATED MADS-BOX Genes from Leafy Spurge. Plant Molecular Biology. 73:169-179. DOI:10.1007/s11103-009-9596-5.
Interpretive Summary: DORMANCY ASSOCIATED MADS-BOX (DAM) genes are required for dormancy induction in peach, and they are turned on by environmental conditions that cause dormancy in many perennial species. We have cloned several DAM genes from the perennial invasive weed leafy spurge and characterized the sequence of these genes in the genome, and the sequences of the RNA from these genes that encode the DAM proteins. We correlated the expression of the DAM genes with dormancy induction and release in leafy spurge. We also compare the sequences that turn these genes on and off in both poplar and leafy spurge and identified several short sequences that likely bind to the proteins that are part of the signaling cascade linking specific environmental conditions to dormancy induction. We have also put these genes into a small annual model plant called arabidopsis and show that expression of DAM genes delays flowering, and turns off a specific gene called FLOWERING LOCUS T that not only regulates flowering in arabidopsis, but also regulates dormancy in poplar. We also show that DAM genes are at least in part controlled by proteins that add or remove methyl groups from histones (a process called chromatin modification).
DORMANCY ASSOCIATED MADS-BOX (DAM) genes are related to AGAMOUS-LIKE 24 and SHORT VEGETATIVE PHASE genes of arabidopsis and are differentially regulated coordinately with endodormancy induction and release in buds of several perennial plant species. DAM genes were first shown to directly impact endodormancy in peach where a deletion of a series of DAM resulted in loss of endodormancy induction. We have cloned and characterized several MADS box genes from the model perennial weed leafy spurge. Leafy spurge DAM genes are preferentially expressed in shoot tips and buds in response to cold temperatures and day length in a manner that is relative to the level of endodormancy induced by various environmental conditions. Over-expression of one DAM gene in arabidopsis delays flowering. Additionally, we show that at least one DAM gene is differentially regulated by chromatin remodeling. Comparisons of the DAM gene promoters between poplar and leafy spurge have identified several conserved sequences that may be important for their expression patterns in response to dormancy-inducing stimuli.