*2.2. Collection of Bacterial Strains and Broth*

ACC deaminase producing PGPRs *S. maltophilia* (ACC deaminase activity = 71.78 μmol α-ketobutyrate mg−<sup>1</sup> protein h<sup>−</sup>1) and *A. fabrum* (ACC deaminase activity = 432.6 μmol α-ketobutyrate mg−<sup>1</sup> protein h−1) were taken from the Laboratory of Soil Microbiology, Department of Soil Science. Both PGPRs were documented Cd tolerant previously, i.e., survive over 5.0 mg Cd kg−<sup>1</sup> soil toxicity [25]. For seeds inoculation, Dworkin and Foster (DF) media without agar was used for inoculum preparation [47]. Loop of each rhizobacteria was taken in the sterilized flask and incubated at 25 ± 3 ◦C and 100 rpm for 48 h. After that, broth optical density (OD) was measured by spectrophotometer (540 nm wavelength). Finally, dilution was made with sterilized distilled water to achieve 0.45 nm OD, to achieve a uniform population of 107–108 colony forming units (CFU) mL–1.

## *2.3. Seeds Sterilization and Sowing*

HgCl2 (0.1%) solution was used for sterilization of seeds. All seeds were placed for 5 min in the solution followed by, three times, washing with sterilized deionized water [48]. Moreover, 1mL respective PGPR inoculum was used for seeds inoculation along with sugar (30% sucrose), peat, and clay (1:1) in 1:2:6 ratio for 100 g seeds. Four inoculated seeds were sown in each pot. Sowing of bitter gourd seeds was done by hand. After 20 days of sowing, only three healthy seedlings were maintained in each pot by thinning.
