Additional research in the Tague lab has been directed to applying the knowledge and tools developed for Arabidopsis to related crucifers. One interest in this regard was to investigate members of the Brassicaceae with developmental or morphological features not found in Arabidopsis thaliana. Our primary focus was an analysis of the signal transduction pathway for flowering in biennials, which flower after induction by cold. Understanding the induction of flowering by cold has important implications for agriculture and horticulture.
As a model, we chose the obligate biennial crucifer Barbarea verna. Like other obligate biennials, B. verna requires an extended cold treatment to flower. We showed that B. verna is unresponsive to vernalization treatment until it has grown vegetatively for five or more weeks. The vernalization treatment itself must be at least five weeks long to be effective. In addition to the cold treatment, we determined that B. verna requires long-days for flowering, producing an abortive inflorescence under short days. The long-day requirement for flowering can be replaced by gibberellic acid treatment.
Drawing an analogy to work done in Arabidopsis and other species, we asked whether the cold treatment leads to changes in DNA methylation. Treatments with a DNA demethylating agent did not lead to early flowering; other demethylating agents were also tested, and the degree of DNA methylation in cold- and chemical-treated plants was measured directly.
Additionally, we generated an Agrobacterium-based transformation protocol for B. verna, using a root regeneration protocol. Our goal was to transform B. verna with constructs known to induce early flowering in Arabidopsis thaliana to analyze the effects of overexpression of these genes in a biennial plant. We hope to use these experiments to “map” the cold requirement in the signal transduction pathway for flowering in the biennial B. verna.
Research opportunities for graduate and undergraduate students in this project included a wide array of molecular and physiological approaches to flower induction. For example, construction of genomic and cDNA libraries to aid in the isolation of genes involved in the flower signal transduction pathway. We looked at the interplay between age, temperature, light and hormones to understand the induction of flowering in this and other biennials.
Abstracts
Ferguson, BJ, RW Todd, ME Whittles and BW Tague (2001) Factors affecting flowering in the biennial crucifer Barbarea verna. Abstracts of Plant Biology 2001, American Society of Plant Biologists, July 2001, Providence RI.
Tague, BW, KO Kidd, BJ Ferguson, RW Todd, ME Whittles and Erin Davis (2002) Factors affecting flowering in the biennial crucifer Barbarea verna. The 10th International Association for Plant Tissue Culture and Biotechnology (IAPTC&B) Congress: Plant Biotechnology 2002, June 2002, Orlando FL.
Barbarea verna, Arabidopsis relatives and flowering links
NC State Horticulture Leaflet on Barbarea verna
http://www.ces.ncsu.edu/depts/hort/hil/hil-16-a.html
Purdue Horticulture Leaflet
http://www.hort.purdue.edu/newcrop/Crops/CressUpland.html
Barbarea seeds
http://www.ag.ohio-state.edu/~seedbio/seed_id/brassicaceae/barbarea_verna.html
Botany. com
http://www.botany.com/barbarea.html
Wild Relatives of Arabidopsis
http://vanilla.ice.mpg.de/departments/Gen/wild.htm
The Flowering WebRing
http://www.salk.edu/LABS/pbio-w/flower_web.html
Eat your experiments: Recipes using Barbarea verna (Upland Cress)
http://www.globalgourmet.com/food/special/1999/foiegras/apple.html
http://www.FarmersMarketOnline.com/foiegras.htm
http://www.discoversandiego.com/features/discover/restaurants/grantgrill/
http://starchefs.com/chefs/HSone_LDoumani/html/recipe_01.shtml
Turn into a cabbage!
http://www.geocities.com/Heartland/Plains/2144/index.html
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