Laponite® clay/poly(ethylene oxide) gel beads for delivery of plant growth-promoting rhizobacteria

Hydrogels have been extensively used for crop improvement and this study presents a novel and facile synthesis method of clay nanocomposite hydrogel beads for encapsulation of plant probiotic bacteria. The nanocomposite used in the study consists of poly(ethylene oxide) and laponite clay. The hydrogel beads were prepared in a one-step synthesis technique to encapsulate five Pseudomonas strains both alone and as a consortium. The effects of this polymer nanocomposite (PNC) gel/plant growth-promoting rhizobacteria (PGPR) in various combinations were studied using Vigna unguiculata by evaluating its growth parameters. Here, significant improvement of leaf length, leaf number and shoot length could be observed for the consortium-encapsulated PNC hydrogel beads treated plants when compared with the untreated as well as single strain bacteria treated. In addition, the microbial viability studies indicated the PGPR to be stable up to 60 days within the PNC beads. The results of the study indicate great potential of the PNC beads mediated delivery of plant probiotic bacteria for the replacement of chemically synthesised and environmentally hazardous fertilisers.