Screening of potential PGPR candidates as future biofertilizers-A strategic approach from lab to field

Abstract

A vast increase in population, urbanization and industrialization has shrunken agriculture land and thus, affected demand vs. food supply ratio. Exploitation and manipulation of beneficial bacteria-plant association can be most effective and eco-friendly to enhance plant growth and productivity in sustainable manner. Various bioinoculants tested in several crops are found to be effective under laboratory conditions but showed inconsistencies in field studies. Therefore, present study aimed to adopt a systematic approach from lab to natural conditions for providing better and stable bioinoculants. In addition, to broaden the application of selected bacterial inoculants, cross infection studies were performed. Ability of endophytic bacteria to promote growth of pearl millet plant was tested at laboratory, greenhouse and field condition. They were screened and sorted out for various levels on the basis of various plant growth parameters. Bioinoculants of field trial were inoculated to wheat plants to confirm their endophytic nature and cross-infection capability using species-specific PCR. Most of the bio-inoculants promoted plant growth better in sterilized than unsterilized soil. In microcosm studies, some of the isolates showed synergistic effect on plant growth. In field studies, PM10461 was the best and consistent inoculant followed by PM9404 and PM9426. Cross-infection capability and endophytic colonization of these strains in wheat broaden the application to other crops. In future studies, various formulations (consortia) which showed better plant growth promotion in microcosm studies, can be tested at field level and efficient inoculants can be converted into commercial biofertilizer for wide usage and industrial production.