Indole-3-acetic acid (IAA) production trait, a useful screening to select endophytic and rhizosphere competent bacteria for rice growth promoting agents.

Plants select plant growth promoting rhizobacteria (PGPR) that are competitively fit to occupy compatible niches without causing pathological stress on them. However, when screening bacteria for plant growth promoting (PGP) agents, it is better to select bacteria for achieving the most promising isolates having suitable colonization and PGP traits. In most researches, it has been seen that following incubation, bacterial flora are taken at random from petri dishes for further study. However, this type of selection may remove some superior bacteria in terms of PGP traits and high colonization ability. Therefore, it is essential to study all the isolated bacteria in an economic way and select the best bacteria in terms of PGP traits and high colonization rate. A simple screening method to detect endophytic and rhizosphere bacteria, isolated from the plants in rotation with rice, for rice PGP agents based on a root colonization bioassay and a PGP trait is characterized. •Selected bacterial isolates based on their IAA producing trait have the potential for more PGP and colonization of rice plant.•IAA may be the first PGP trait for screening bacteria isolated from plant rotated with rice for rice PGP agents.•The screening procedure appears to be very effective and less time consuming.