Growth Conditions and Inoculations: All experiments were performed as previously described (Vogel and Somerville, 2000, Proc. Natl. Acad. 97: 1897-1902). Arabidopsis thaliana and Hybrid Kuta squash (Park Seed, Greenwood, SC) were grown in growth chambers at 22o C with a 14 hr photoperiod and a light intensity of approximately 125 µEinsteins m-2 s-1 provided by Phillips F32T8 fluorescent lamps. Powdery mildew (Erysiphe cichoracearum UCSC1) was cultured on squash for 10-12 days and was then applied to Arabidopsis using 1.3 m settling towers. Plants were 3 weeks old at the time of inoculation.
RNA and Microarray Methods: Total RNA was extracted from the plants using the Trizol method (Invitrogen, Ramonell et al. (2002) Mol. Plant Pathol. 3: 301) and purified with a silica membrane column (Qiagen, RNeasy). Twenty micrograms biotinylated complementary RNA (cRNA) was prepared as described (Hernan et al. (2003) Cancer Res. 63, 140) from the purified total RNA. The resulting cRNA was used to hybridize ATH1 Arabidopsis GeneChips (Affymetrix) using the manufacturer’s protocols. The array images were analyzed with the Affymetrix Microarray Suite 5.0 software with the target intensity set to 500. These data were imported into GeneSpring 4.2. To remove chip-to-chip signal variation, the reference data set, consisting of the intensity values for each gene averaged over four replicates of Columbia-1, uninoculated, was normalized by the intensity values of the top 50th percentile of genes on this array. The normalized values for the reference data set (Normalized Value of Control) are reported along with the intensity values for this array.
As defined by Affymetrix, these are the probe set identifiers, each of which is unique to a specific probe set defining a specific region of a single gene or set
VALUE
This is the final calculated measurement for each probe set identifier that has been made comparable across all samples and rows
ABS_CALL
A qualitative measurement indicating if the probe set is detected (Present; P), not detected (Absent; A), or marginally detected (Marginal;M)
Detection p-value
A p-value indicating the significance of the Detection call. A Detection p-value measures the probability that the discrimination scores of all probe pairs in the probe set are above a certain level, and that the target is likely to be Present
Normalized Value of Control
A normalized measurement of control arrays for each probe set calculated in GeneSpring 4.2
Shown on the paper
A symbol indicating if the probe set is shown on the paper (Y), or not shown on the paper (N)
