Poster: Hormones

Abs # 603: Pollination/fertilization and seed regulation of GA 3b-hydroxylase gene expression in pea fruit

Presenter:	Ozga, Jocelyn A, jocelyn.ozga@ualberta.ca
Authors	Ozga, Jocelyn A (A)   Reinecke, Dennis M (A)
Affiliations:	(A): University of Alberta

To understand further how pollination/fertilization and seed development regulate GA biosynthesis in pea (Pisum sativum) fruit, we studied expression of the gene PsGA3ox1 that codes for the enzyme that converts GA₂₀ to biologically active GA₁ using real-time reverse transcription-polymerase chain reaction analysis. PsGA3ox1 mRNA levels were minimally detectable in prepollinated pericarps and ovules (-2 d after anthesis [DAA]), increased dramatically after pollination (0 DAA), then decreased by 1 DAA. Seed PsGA3ox1 mRNA levels increased at 4 DAA and again 8 to 12 DAA, when seed development was rapid. Pericarp PsGA3ox1 mRNA levels peaked coincidentally with rapid pod diameter expansion (6-10 DAA) to accommodate the growing seeds. These data show that PsGA3ox1 is expressed and developmentally regulated in pea pericarps and seeds and suggest that the conversion of GA₂₀ to GA₁ occurs in the pericarp and seeds to stimulate organ growth and development. Supported by NSERC grant #138166.