Poster: Photomorphogenesis

Abs # 497: Cloning of an activation-tagged suppressor of the Arabidopsis phyB mutation

Presenter:	Wrage, Elizabeth L, elstoll@yahoo.com
Authors	Wrage, Elizabeth L (A)   Zhang, Jing-Yu  (A)   Neff, Michael M (A)
Affiliations:	(A): Washington University in St. Louis

Plants respond to environmental changes differently than most organisms because they simply cannot move. As a result, multiple photoreceptors have evolved to fine-tune plant development in response to changing light conditions. Among these receptors, mutations in phytochrome B, phyB, (such as phyB-4) are the most pleitropic. By identifying mutations that suppress the long hypocotyl phenotype of phyB-4 seedlings, genes involved in the signal transduction pathway downstream of phytochrome B may be identified. Through the use of activation tagging, sob5-D phyB-4, suppressor of phyB-4, was identified as a putative mutant of phyB-4. Its phenotypic characteristics include epinastic leaves as a seedling, and a short plant with bumpy siliques and green, curly leaves as an adult. A Southern Blot was used to determine which restriction enzymes should be used in cloning the flanking genome via plasmid rescue. The rescued plasmid was sequenced and a BLAST search identified an open reading frame (ORF) located on the Bac Clone T22D6 on chromosome 5. RT-PCR is currently being employed to verify that the identified ORF is exhibiting the overexpression and to provide some clue to the function of sob5-D phyB-4. Preliminary data indicates that there is light regulation of transcript accumulation, suggesting involvement of sob5-D phyB-4 in photomorphogenesis. Recapitulation of the overexpressed gene in wild-type will further confirm that this gene causes the mutant phenotypes.