The transcriptome of the arbuscular mycorrhizal fungus Glomus intraradices

The virtual transcriptome of G. intraradices (based on >430,000 reads) served as the basis for the design of an EST expresson array and for a number of analyses of gene expression in germinating spores, extraradical mycelium (ERM) and symbiotic root tissues. The G. intraradices EST expression array (4 x 72K) manufactured by Roche NimbleGen Systems Limited (Madison, WI) (http://www.nimblegen.com/products/exp/index.html) contained three independent, non identical, 60-mer probes per sequence. Included in the oligoarray were 22,402 G. intraradices sequences, 5785 random 60-mer control probes and labeling controls. We performed 12 hybridisations with samples from germinating spores (three biological replicates), extraradical mycelium (three biological replicates), symbiotic root tissues from Medicago (three biological replicates) and rice (1 replicate) as well as from microdissected arbuscule-colonized cortical cells of Medicago and rice (1 replicate each).