Germinating rice seeds shape rhizospheric bacteria via releasing benzaldehyde

Seeds of rice were sown on paddy soil collected from a rice field in Shenzhen, China. Five seeds were distributed evenly in each square pot with soil fully moistened using double-distilled water. Since most (>85%) seeds completed germination in 3 days after sowing (DAS3), germinated and non-germinated seeds on DAS3 were separately used for bacteria collection. Four replicates of 50 seeds each were rinsed roughly in 100 mL Phosphate Buffered Saline (PBS, pH =7.2) solution. The PBS eluent was passed through a 0.22 membrane (MF MilliporeTM, Darmstadt, Germany) to enrich the bacterial cells. Bacterial DNA was extracted using FastDNA Spin Kit (MP Biomedical, Santa Ana, USA) according to the default protocol. Afterwards, the V4-V5 region of the 16S rDNA gene was amplified using primers 515F and 907R . The amplicon product was purified and then subjected to shotgun library creation and Illumina high-throughput sequencing using PE250 technique on the NovaSeq 6000 at Novogene Co., Ltd. (Beijing, China).