My Summer 2008 BBSI Experience By Natasha Williams Mentor: Wan-Ling Chiu For my experience this summer, I have been working alongside fellow lab mates on an ongoing project whose purpose is to:

Better Understanding of Plant-Cyanobacterial Symbiosis The Overall Goal of my Research is to Achieve: Better Understanding of Plant-Cyanobacterial Symbiosis

Gunnera and Nostoc’s Symbiosis Gunnera manicata Nostoc punctiforme

Negative effects of N2 fertilizers

Elucidating Host Genes Critical to Plant-Cyanobacterial Symbiosis Investigating the Role of Flavonoids in G. manicata and N. punctiforme symbiosis

What are roles of flavonoids in the development of plant-cyanobacteria symbiosis ???

10 mM nitrate 0.1 mM nitrate

N. Punctiforme traveling towards Gunnera seedling.

Flavonoids Polyphenolic compounds with 15 Carbon atoms, 2 benzene rings connected by a 3 carbon chain.

10 mM nitrate 0.1 mM nitrate N - starvation Myb transcription factor Flavonoid synthesis gland primodia inhibit auxin efflux Localized auxin accumulation Activation of cell division and gland development Remobilization of nutrients from leaves to the stem High flavonoids at the 10 mM nitrate 0.1 mM nitrate

Solving the Mystery Plan: - Expose flavonoid-deficit Gunnera mutant to cyanobacteria under N2-deprived conditions. Gunnera Plant Mutant Gunnera Plant Functional analysis. How does my summer experience contribute to this project? Expose to N2-deficient environment in presence of cyanobacteria

RNAi refers to the introduction of homologous double stranded RNA (dsRNA) to specifically target a gene's product, resulting in null or hypomorphic phenotypes. Today RNA interference (RNAi), is a technique in which exogenous, double-stranded RNAs (dsRNAs) that are complimentary to known mRNA's, are introduced into a cell to specifically destroy that particular mRNA, thereby diminishing or abolishing gene expression. Thus, RNA interference (RNAi), is a gene-silencing technique used in studying the absence of normal gene action (by disrupting its activity in vivo, i.e., turning it off) in fruit flies, nematodes, and mammalian cells.

Solving the Mystery Methods: Discovered Gunnera genes responsible for flavonoid production.  Correctly insert genes w/n specialized RNAi constructs. Infect plant with construct via agrobacterium-mediated transfer. Grow up plant and subject to conditions conducive for symbiosis to occur. Last Summer Almost finish this step Functional analysis. How does my summer experience contribute to this project?

Acknowledgments God VCU’s Bioinformatics & Bioengineering Institute National Science Foundation Jeff Elhai, BBSI Director Wan-Ling Chiu, my mentor The Chiu Lab

Questions?