Insights into the Mondia whitei microbiome across geographic regions in Eastern Africa
A 5 g sample of root with attached rhizosphere were transferred into sterile stomacher bag containing 5 mL of 0.85% sodium chloride. The bags were shaken for 30 s using a bag mixer (Interscience, St. Nom, France) to dislodge the rhizosphere. The rhizosphere solution was transferred into 15-mL tubes, centrifuged (5,000 g, 10 min) to obtain the rhizosphere pellet. After dislodging the rhizosphere, root samples were further washed with 0.85% sodium chloride solution, pulverized with liquid nitrogen and ground with a mortar and pestle. The rhizosphere pellet and the crushed root samples were stored at -70 C for DNA extraction. The DNA was extracted using FastDNA Spin Kit for Soil (MO BIO Laboratories, USA), following the manufacturers instructions. The DNA was extracted from 0.5 g of the processed root, and 0.2 to 0.8 g rhizosphere pellet samples. The DNA concentration was estimated using the NanoDropTM 2000 spectrophotometer (Thermo Fischer Scientific, Germany), and the DNA was stored at -20 C. The same samples were used for GC-MS (Supplementary Method 1) and HPLC-MS analyses (Supplementary Method 2).