Nano-Encapsulation of Plant Growth-Promoting Rhizobacteria and Their Metabolites Using Alginate-Silica Nanoparticles and Carbon Nanotube Improves UCB1 Pistachio Micropropagation

Abstract

UCB-1 is the commercial rootstock of pistachio. Reproduction of this rootstock by tissue culture is limited by low levels of proliferation rate. Therefore, any compound that improves the proliferation rate and the quality of the shoots can be used in the process of commercial reproduction of this rootstock. Use of plant growth-promoting bacteria is one of the best ideas. Given the beneficial effects of nanoparticles in enhancement of the growth in plant tissue cultures, the aim of the present study was to investigate the effects of nanoencapsulation of plant growth-promoting rhizobacteria (using silica nanoparticles and carbon nanotubes) and their metabolites in improving UCB1 pistachio micropropagation. The experiment was conducted in a completely randomized design with three replications. Before planting, treatments on the DKW medium were added. The results showed that the use of Pseudomonas fluorescens VUPF5 and Bacillus subtilis VRU1 nanocapsules significantly enhanced the root length and proliferation. The nanoformulation of the VUPF5 metabolite led to the highest root length (6.26 cm) and the largest shoot (3.34 cm). Inoculation of explants with the formulation of the metabolites (both bacterial strains) significantly elevated the average shoot length and the fresh weight of plant compared to the control. The explants were dried completely using both bacterial strains directly and with capsule coating after the three days.

Potential Role and Utilization of Plant Growth Promoting Microbes in Plant Tissue Culture

“…Beside these classical plant hormones, other PRGs such as polyamines, analogs of diphenyl urea, salicylic acid, jasmonates, sterols, brassinosteroids, strigolactones oligosaccharins, phosphoinositosides, systemins, and florigen were discovered more recently. Among all PGRs, auxin and cytokinin classes are usually considered to be the most important phytohormones in plant growth regulation because they regulate many metabolic processes (Pour et al, 2019). PGPMs have the potential to produce these two hormones.…”

Biopolymers for Biological Control of Plant Pathogens: Advances in Microencapsulation of Beneficial Microorganisms

“…In fact, encapsulation tends to stabilize and maintain cells against biotic and abiotic soil stresses. Several studies have pointed to various encapsulation techniques to increase the viability of microbial (Table 1), [18,30,[52][53][54][55]. Encapsulation of material into carriers can be achieved by various technology such as emulsification, lyophilization, extrusion coating, spray chilling, fluidized-bed coating, coacervation, spray drying, and thermal gelation.…”

“…The emulsion is a chemical method for the encapsulation of living cells. An emulsifier, a surfactant, and a hardening agent (such as CaCl 2 ) are required for encapsulation by emulsification [55]. This method can be used to keep bacteria alive on a larger scale [79].…”

Towards Better Understanding of the Interactions and Efficient Application of Plant Beneficial Prebiotics, Probiotics, Postbiotics and Synbiotics

“…Therefore, before applying plant beneficial metabolites directly after the fermentation production process or in purified form, formulation operations should be performed to ensure their efficient release into soil. Encapsulation and nanoencapsulation of microbial metabolites was reported as an effective tool in enhancing proliferation of shoots and rooting (Pour et al, 2019). In this case, the inclusion of carbon nanotubes and SiO nanoparticles in the alginate-gelatin nanocapsules increased the overall beneficial effect of the formulated cell-free product.…”