Abstract Detail

Genetics Section

West, Nick [1], Golenberg , Edward M [2].

Gene Regulation Involved in Sexual Development of Dioecious Spinach Spinacia oleracea.

Although derived from hermaphroditic ancestors Spinacia oleracea, the common cultivated spinach, is unisexual. Previous work has shown that ectopic application of the plant hormone gibberellic acid (GA) will cause a female spinach plant to begin producing staminate or hermaphroditic flowers. This suggests that GA response is able to influence the expression of B class genes which are critical in stamen development. Similar work done in cucumber and maze has shown that ectopic application of specific hormones can influence sexual development. However, no mechanism explaining the connection between hormone response pathways and floral initiation pathways have been presented in any species thus far. We hypothesize that the GA response element SpGAI is able to repress SpLFY (a floral identity transcription factor) activation of B class gene expression, thereby preventing the the development of stamen in female individuals. We propose this repression is released by the GA–induced SpUFO-meditated proteolysis of SpGAI, allowing male organ development in male individuals.
Our current work is focused on analyzing potential interactions between proteins known to be in the GA hormone pathway and the floral organ identity pathways. Presently we are using yeast-2-hybrid (Y2H) and bimolecular fluorescence complimentation (BiFC) assays to investigate these interactions. At this time we have observed that SpLFY interacts with SpGAI in both the Y2H and BiFC assays. The F-box protein SpUFO is known to be involved in targeting proteins for ubiquitin-mediated proteolysis. We observed SpUFO interacting with SpGAI in the BiFC assay but not the Y2H assay. Likewise, SpLFY and SpUFO were observed to interact in the BiFC assay but not the Y2H assay. In order to shed light on these discrepencies we plan to repeat these tests using co-immunoprecipitation in the near future. Identification of the link between the GA hormone pathway and the floral initiation pathway is the first step to understanding the mechanism of regulation that governs sexual development in dioecious spinach.

1 - Wayne State University, Biological Sciences, 5047 Gullen Mall, Detroit, MI, 48201, USA
2 - Department Of Biological Sciences, Wayne State University, Department Of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA

Keywords:
dioecy
dioecious
spinach
floral development
leafy
LFY
gibberellic acid insensitive
GAI
gibberellic acid
floral regulation.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PGN002
Abstract ID:373
Candidate for Awards:None