Altered PtAIL1 expression is accompanied by significant transcriptome changes during adventitious rooting induction

Oligoarray analysis was used to identify genes differentially expressed in 2 mm sections of the basal stem region of wild type T89, PtAIL1 over-expressing or PtAIL1 RNAi lines of P. tremula x Populus tremuloides 24h and 72h after adventitious rooting induction. The Populus trichocarpa custom-exon expression array (12x135K) manufactured by Roche NimbleGen Systems Limited (Madison, WI) (http://www.nimblegen.com/products/exp/index.html) contained three independent, nonidentical, 60-mer probes per gene model coding sequence. Included in the oligoarray were 43,929 annotated gene models (Populus trichocarpa genome v2 ; Phytozome 5.0), 5,859 random 60-mer control probes and labelling controls. We performed 27 hybridizations from wildtype, PtAIL1 over-expressing or PtAIL1 RNAi lines of P. tremula x Populus tremuloides at time 0, 24h and 72h after adventitious rooting induction. For each timepoint we performed three biological replicates.