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Microarray Analysis of plants grown on the International Space Station. R.S. Pereira¹, A.J. Stimpson¹ and M.J. Correll¹.  ¹Dept. of Agricultural and Biological Engineering, University of Florida, Gainesville, FL.

   Most large-scale gene expression experiments with small seedlings are performed by pooling several hundred plants for the extraction of RNA. However, for the TROPI experiments which studied plant phototropism and gravitropism in microgravity on the International Space Station (ISS), the amount of seedlings (Arabidopsis thaliana) available for genetic analysis was limited and did not allow for pooling of large numbers of plants. Therefore, in order to conserve plant material for microarray studies, we tested the use of 1 to 4 plant seedlings on RNA extraction and microarray results.

   Tissue disruption of Arabidopsis (Ler) seedlings was performed using a mini mortar and pestle (Kontes, NJ).  The RNA was further isolated from the disrupted plant seedling using the RNeasy Plant Mini Kit (Qiagen, CA). Experiments were performed on a range of 1 to 30 plants (1-week-old Ler) to identify the minimum amount of material that will be needed for future microarray analyses.

   Approximately 0.505µg (Abs. 260/280 = 2.05) of total RNA was extracted from 1 seedling while 4.713µg (Abs. 260/280 = 2.22) was obtained from 30 seedlings. Further characterization of RNA quality was performed with a Bioanalyzer using a Pico LabChip (Agilent Technologies, CA). It was found that adequate quality and quantity of RNA could be obtained with as little as 4 plants.

   Ultimately, our goal is to use only one 5-day-old seedling grown on the ISS for microarray studies. Results from these microarray experiments will be compared to previous studies that pooled roots from ~500-1000 seedlings for analyses (Molas et. al. 2006).

(Supported by NASA: NCC2-1200)

Molas ML, Kiss JZ, Correll MJ (2006).  J. Exp. Bot. 2006; 57(12): 3217-29.