IAA production assay

1. Inoculate a single isolated colony to isolate appropriate 1/10 diluted rich medium supplemented with 0.5% L-tryptophan.
2. Incubate up to 5 days at 25^o^C with shaking.
3. After incubation, removed 1 mL of bacterial culture and transfer to sterile micro-centrifuge tube.
4. Centrifuge tubes for 2 min at full speed (~10,000xg) in a table-top centrifuge.
5. Remove supernate, being careful not to remove bacteria from pellet, and transfer to fresh test tube.
6. Add 2 mL Salkowski’s reagent
7. Incubate solution for 30 min at room temperature in the dark.
8. After incubation, measure optical density at 530 nm.

IAA standard curve

1. prepare 5 solutions of 10, 20, 50, 100, and 150 ug/ml IAA
2. Mix 1 ml of each solution with 2 mL Salkowski’s reagent
3. Incubate for 30 min at room temperature in the dark.
4. After incubation measure optical density at 530 nm.

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Citations

• Goswami and Deka 2020. Isolation of a novel rhizobacteria having multiple plant growth promoting traits and antifungal activity against certain phytopathogens
• Bric et al 1991 Rapid In Situ Assay for Indoleacetic Acid Production by Bacteria Immobilized on a Nitrocellulose Membrane
• Ahmad et al 2008 Screening of free-living rhizospheric bacteria for their multiple plant growth promoting activities
• Bal et al 2013 ACC deaminase and IAA producing growth promoting bacteria from the rhizosphere soil of tropical rice plants
• Joseph et al 2007 Characterization of plant growth promoting rhizobacteria associated with chickpea (Cicer arietinum L.)