title: Maize (B73) primary root transcriptome under water deficit (B73-6h-0.2-1.bc8)
design: For this transcriptome study seeds of the maize inbred line B73 were surface sterilized and germinated in moist germination paper. Seedlings with a primary root length of 2 to 4 cm were transferred to new paper rolls soaked with polyethylene glycol (PEG8000) solutions with a water potential of -0.2 MPa and -0.8 MPa for mild and severe water deficit, respectively, or distilled water for control experiments. Paper rolls with seedlings were incubated in PEG solutions or distilled water for 6 and 24h. Experiments were performed in four biological replicates resulting in 24 samples (4x 6h control, 4x 6h mild water deficit, 4x 6h severe water deficit, 4x 24h control, 4x 24h mild water deficit, 4x 24h severe water deficit). Each sample consisted of 10 pooled roots. These were harvested in liquid nitrogen and RNA extracted as described in Winz & Baldwin 2001. cDNA libraries were constructed according to the Illumina TruSeq RNA Sample Preparation Protocol. For sequencing four libraries were pooled in one flow cell lane. Each library per lane was indexed by one of the adapters AR001 (bc1), AR008 (bc8), AR010 (bc10), or AR011 (bc11). Pooled libraries ware loaded on a flow cell according to an incomplete block design. Cluster preparation and single read sequencing were performed with an Illumina HiSeq 2000.