Gene expression during oosporogenesis in Phytophthora

A screen for genes induced during sexual development was performed in the heterothallic oomycete Phytophthora infestans, the potato blight agent. Of 15,644 unigenes on the Affymetrix chip, 87 were induced >10-fold during mating, with 28 induced >100-fold. This was subsequently validated in independent matings using RNA blots and RT-PCR. Keywords: Developmental stage comparison RNA was harvested from nonmating cultures of an A1 mating type strain and an A2 mating type strain, and from mixtures of the A1 and A2 strains (3 and 10 day mating cultures). For each treatment, triplicate cultures were prepared on different days. The RNA from the three replicates was pooled to make the probe for each of the four chips, thereby providing pseudobiological replicates but no technical replicates.