Additional research in the Tague lab is directed to applying the knowledge and tools developed for Arabidopsis to related crucifers. One interest in this regard is to investigate members of the Brassicaceae with developmental or morphological features not found in Arabidopsis thaliana. Our primary focus is 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 have chosen the obligate biennial crucifer Barbarea verna. Like other obligate biennials, B. verna requires an extended cold treatment to flower. We have shown 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 have 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 are asking 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 are currently being tested, and the degree of DNA methylation in cold- and chemical-treated plants is being measured directly.

Additionally, we are generating an Agrobacterium-based transformation protocol for B. verna, using a root regeneration protocol. Our goal is 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 include a wide array of molecular and physiological approaches to flower induction. In the near future, for example, we will begin construction of genomic and cDNA libraries to aid in the isolation of genes involved in the flower signal transduction pathway. We will continue to look at the interplay between age, temperature, light and hormones to understand the induction of flowering in this and other biennials.

Recent 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

Turn into a cabbage!
http://www.geocities.com/Heartland/Plains/2144/index.html