Generation of a transcriptome catalog for global analysis of gene expression in Ampelomyces quisqualis during mycoparasitization

In this work, 454 pyrosequencing was used to build up a 3’ cDNA fragment library from a normalized library constructed from pooled RNA samples extracted at different stages of A. quisqualis mycoparasitization process (recognition, early and late parasitization). An extensive catalogue of unique transcripts was compiled and used to develop a microarray for large-scale analysis of genes involved in this mycoparasitism. We examined the transcriptomic changes that occur during the first stage of mycoparasitism (conidial germination). Our results showed that 1,776 transcripts are regulated during germination in the presence of powdery mildew. A striking feature of the gene catalogue was the presence of a number of genes predicted to encode proteins involved in the production of, glucanases, chitinases and extracellular proteases. This suggests that A. quisqualis causes the degradation of powdery mildew macromolecular constituents to provide the carbon skeletons and energy for the synthesis of proteins and other components destined for the developing of the mycelium. Microarray oligo probes were designed based on 454 sequencing of 3'-ends of transcripts of a sample constituted by pooling RNAs extracted at different stages of A. quisqualis mycoparasitization process (recognition, early and late parasitization)