Cefotaxime

Within 24 h of expulsion, each fecal sample was diluted 1:10 in buffered peptone water (Oxoid) and spread plated on MacConkey agar (Oxoid) laced with two mg/L cefotaxime (Gold Biotechnology), and then incubated overnight at 37°C. From each sample, one presumptive E. coli isolate was randomly picked using Harrison’s disk method. The identity was confirmed through their signature metallic green sheen morphology on Eosin Methylene Blue Agar.

For gene expression construct, the coding sequence of Glyma02g07650 (GmFT7) was amplified (with XhoI and BamHI restriction enzyme sites on 5′ and 3′ end, respectively) and ligated to pGEM-T Easy vector (Promega). The vector was digested, and gene fragment was ligated to pRT101 at Xho I and Bam HI sites, to obtain 35S promoter and polyA terminator. Then the 35S:GmFT7:polyA cassette was excised using Hind III and ligated to pUQC10255 expression vector (Supplementary Fig. S4). Transformation of Arabidopsis Col (WT) and ft-10 mutant was performed using the floral dip method^{53 (link)}.
Bragg cultivar was used for soybean transformation following the protocol by Li et al.^{40 (link)} with modifications; selection on SIM medium containing 4 mg/L glufosinate (Sigma, USA) was started during the second subculture step SIM and continued till SEM medium. 100 mg/L Cefotaxime (GoldBio, USA), 50 mg/L Vancomycin (GoldBio, USA) and 50 mg/L Ticarcillin (GoldBio, USA) were used instead of carbenicillin on SIM, SEM and RM medium. Five independent experiments were conducted using an average of 110 seed explants per experiment and recovered five transgenic shoots. However, one-line produced seeds. The transgenic seeds were multiplied and selected for the Bar gene. Three T2 lines were used for analysis.