title: Comparison of the rhizosphere bacterial communities of Zigongdongdou soybean and a high-methionine transgenic line of this cultivar
design: In the current study, we assessed the dynamics of the structures of the bacterial communities that inhabit the rhizospheres of transgenic soybean (ZD91) and non-transgenic soybean (ZD). An experimental field - Nanchong (30°48′N, 106°04′E), Sichuan Province, China, in which a completely randomized block design was set out in 2011, was used. For each soybean cultivar, four replicate plots which were randomly distributed over the field were used. ZD_1, ZD_2, ZD_3 and ZD_4 are the four replicates of ZD; ZD91_1, ZD91_2, ZD91_3 and ZD91_4 are the four replicates of ZD91; and Bulk means bulk soil which collected and pooled at the start of the growth season. The rhizosphere soil samples were collected at the pod-setting stage of the two soybean cultivars and bulk soil sample was sampled at the start of the growth season. Soil DNA was extracted from all bulk and rhizosphere soil samples by employing the FastDNA® SPIN Kit for Soil (MP Biomedicals, USA) as recommended by the manufacturer. The 16S rDNA gene (V4 region) was amplified using the barcode primers 515F and 926R. The PCR products from different samples were then mixed in equal ratios (7.2 ng per sample) for pyrosequencing with a Roche Genome Sequencer GS-FLX Titanium platform.