1. Importance of microRNA for seedling development in Arabidopsis thaliana Jennifer Coppersmith Department of Biochemistry and Biophysics Mentor: Dr. Hiro Nonogaki (Horticulture)

2. Significance of Seed Development pgrc3.agr.ca/images/seeds.gif Agriculture and Food Why Arabidopsis?

3. Arabidopsis Seed Structure Embryo Endosperm Testa

4. Overview of Experiment T DNA insert SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE13 (mSPL13) SPL13

5. microRNA 21-24nt in length Gene regulation at the mRNA level www.qiagen.com/about/PressReleases/images/9.jpg

6. RISC miRNA microRNA mRNA miRNA

7. RISC miRNA microRNA mutation mRNA Mutation Hypothesis: SPL13 needs to be down regulated by microRNA156 to maintain normal developmental program for germination or seedling establishment. AAAA SPL13 miR156 mSPL13

8. WT Cont mSPL13 rRNA SPL13 Overaccumulation of SPL13

9. Mutant Phenotype Cot 4 leaf seedling (normal) 2 leaf seedling (delayed) Cot

10. 2-leaf seedlings4-leaf seedlings Developmental Delay

11. Temporal Seedling Arrest WT mSPL13 CONTROL

12. 0 d Shoot Apical Meristem (SAM) 2 d

13. Storage Protein and Meristem Meristem Embryo Cot Hypocotyl Radical

14. WT 1 d3 d2 d4 d mSPL13 WT 3 d mSPL13 WT 2 d mSPL13 WT 4 d Meristem Development

15. mSPL13 WT 8 d Visible Difference

16. Analysis WTmSPL13 SPL13 Based on phenotype, down regulation of SPL13 via microRNA is essential for proper meristem development.

17. Determine Potential Targets of SPL13 miRNA156 SPL13 PromoterGene X X

18. Acknowledgements Hiro Nonogaki Kevin Ahern Howard Hughes Medical Institute Lab Members: Masa Asahina Tammy Chan Po-Pu Liu Jessica Kristof Piotr Pupel Jing Sun

19. SQUA SQUAMOSA ( or APETALA1) 10 bp conserved stretch 19-mer core seq - 419- 393 - 455- 429 AP1 SBP1SBP2 SPL13 ?

20. Normal Embryogenesis in mSPL13 Coppersmith JL, Hewitt JR, Nonogaki H, unpublished results