Bacillus megaterium-Mediated Synthesis of Selenium Nanoparticles and Their Antifungal Activity against Rhizoctonia solani in Faba Bean Plants

Abstract

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.

Essential Oil of Foeniculum vulgare Mill. as a Green Fungicide and Defense-Inducing Agent against Fusarium Root Rot Disease in Vicia faba L.

“…In this research, inhibition of the fungal activity using essential oil of fennel led to a significant increase in the fresh and dry weight of the shoot and root system of Vicia faba L. plants. There was a clear significantly negative relationship ( Figure 6 ) between the degree of disease severity and fresh plant weight, indicating that infection with F. solani KHA10 was the main growth-limiting factor in all plants in the present and previous studies [ 1 , 25 ].…”

“…Radial growth of F. solani was evaluated at different concentrations of FSEO (25,50,100,200 and 400 µL/mL) according to method used by Hashem et al [1], with minor changes. The fennel essential oil was mixed well with the molten CZA medium at the desired final concentrations.…”

“…The assay was repeated 3 times. DPPH percentage inhibition was estimated based on the control reading [ 1 ]. DPPH scavenged (%) = (A cont.…”

“…Vicia faba L., commonly known as faba bean or broad bean, is an economical legume grain that widely contributes to human consumption, animal fodder and silage making [ 1 ]. Faba beans have high nutritional value due to their high protein content, minerals, vitamins and considerable amounts of bioactive compounds [ 2 ].…”

Special Issue: Fungal Nanotechnology

“…For example, Rhizopus oryaze metabolites were utilized as a biocatalyst for the green synthetization of magnesium oxide (MgO-NPs) nanoparticles [5]. Additionally, biogenic selenium nanoparticles (Se-NPs) was produced by Bacillus megaterium and was used as an antifungal agent against R. solani, the causal organisms of damping and root rot disease in Vicia faba, as well as for induction of plant growth [6]. Bacillus-mediated AgNPs with an onion-isolated endophytic bacteria Bacillus endophyticus strain H3, bactriosynthesized AgNPs with a concentration of 40 µg/mL, had a high rice-blast antifungal activity with an inhibition rate of 88% mycelial.…”