Expression of WRKY transcription factors in M. truncatula cell cultures. A, induction of WRKYs by YE as revealed by oligonucleotide array analysis. The double apostrophes represent minutes and the single apostrophes represent hours. B, WRKY transcript levels in YE and MJ treated cells determined by Affymetrix array analysis. C, Detailed time course for WRKY gene transcript levels in response to YE, as determined by RT-PCR. Actin is shown as loading control.