Serial enrichment incubation technique (SEIT) for rapid isolation of plant growth-promoting bacteria: Saving researcher time and lab resources.

Traditional methods of Plant growth-promoting bacteria (PGPB) isolation involve serial dilution and spreading on common or specific media, which leads to more than 10 bacteria per sample, and screening of these bacteria for a desired potential bacterium takes much time (4-6 months) and lab resources. The current improved protocol, termed Serial Enrichment Incubation Technique (SEIT), involves incubating the sample in a specific nutrient medium for 5 days, then transferring it into a fresh medium twice for five days each, and finally serially diluting the final tube and spreading the suspension onto Petriplates containing specific media. This protocol gives the desired nutrient-transforming bacteria compared to traditional published protocols within 20 days. Isolation of the siderophore-producing bacteria (SPB) by incubating in an iron-free succinate medium allows the elimination of non-siderophore-producers, and these isolates are also potential candidates for biocontrol against phytopathogens. Soil nutrient solubilizers can be isolated rapidly using SEIT. • SPB can be isolated by incubating in iron-free succinate media and could be used for iron nutrition and biocontrol against phytopathogens. • Efficient PGPB could be isolated through SEIT in less than 20 days. • Slow-growing and less populated PGPB can be isolated, and its inoculation would increase soil microbial diversity.