Quantitative RT-PCR Analysis of S. sanxanigenens

The S. sanxanigenens strains shown in Table 1 were cultured in NK medium, and then collected when cultivated at 24 h. The crude total DNA-free RNA of S. sanxanigenens strains was extracted using the RNAiso Plus (Takara, Dalian, China) and RNAprep Pure Cell/Bacteria Kit (Tiangen, China). The cDNA was amplified using FastKing RT Kit (Tiangen, Beijing, China) with the total mRNA as the template. Samples were then analyzed using Agilent 6820 (Agilent, America) with RealMasterMix (SYBR Green I) (Tiangen, Beijing, China). Quantity real-time PCR amplification primers were listed in Table 2. For data analysis, the 16 S gene was selected as the internal standard for normalization between samples, and three biological replicates were performed. The obtained data were analyzed by using the 2^−ΔΔCt method [11 (link)].