Elucidating the efficacy of functionalized multi-walled carbon nanotube in the biogenesis of L-Dopa and antioxidant metabolites in cell cultures of Hybanthus enneaspermus.

Hybanthus enneaspermus (L.)F.Muell. is a highly indispensable medicinal herb yielding L-Dopa, deemed the gold standard drug among the therapeutic options for Parkinson's disease. This investigation is the first attempt to evaluate the eliciting influence of carboxylic acid functionalized multi-walled carbon nanotube (MWCNT-COOH) on the biosynthesis of L-Dopa and on biomass aggregation and antioxidant metabolites in H. enneaspermus cell suspension cultures. Suspension cells were accomplished from friable calli generated from the nodal segments of H. enneaspermus in Murashige and Skoog (MS) liquid medium infused with 2 mg L-1 2, 4-Dichlorophenoxyacetic acid (2, 4-D), and 0.3 mg L-1meta-Topolin (mT). The influence of MWCNTs on L-Dopa synthesis, biomass accumulation, and biochemical parameters was examined on the basis of the exposure time and in a concentration-dependent manner of MWCNTs. The inclusion of 30 mg L-1 MWCNTs increased the biomass and the L-Dopa level by 2.00 and 16.37-folds, respectively, compared with that of the control. Furthermore, the effect of MWCNTs on physiological parameters such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), ascorbate peroxidase (APX), hydrogen peroxide (H2O2), malondialdehyde (MDA) content, 2-diphenylpicrylhydrazyl (DPPH), and ferric-reducing ability of plasma (FRAP) was examined over the elicited cells. Among the antioxidant enzymatic activities, CAT enhanced 8.0 fold compared with that of the control. MDA and DPPH content enhanced 2.60 and 1.12 folds, respectively, compared with that of the control. The current study showed that MWCNTs offer new possibilities for their usage over in vitro by acting as potential innovative plant metabolite elicitors and stress-protecting entities.

Synthesis of Nickel-Chitosan Nanoparticles for Controlling Blast Diseases in Asian Rice.

Rice blast caused by Pyricularia oryzae is one of most devastating fungal diseases in rice, reducing the annual yield of rice worldwide. As an alternative to fungicide for curbing rice blast, synthesis of nickel-chitosan nanoparticles (Ni-Ch NPs) was performed with nickel chloride and assessed its efficacy in inflating plant growth and hindrance of Pyricularia oryzae (blast pathogen). Characterization of Ni-Ch NPs from SEM, TEM, and DLS analyses showed smooth- and spherical-shaped nanoparticles in the range of 20-70 nm. Colloidal stability of NPs was revealed from Zeta potential exhibiting polydispersity index of 0.22. EDX spectroscopy corroborated the presence of nickel (14.05%) in synthesized Ni-Ch NPs. A significant increase in germination and growth attributes in terms of shoot and root length and number of lateral roots over control was observed in paddy seeds on the treatment with Ni-Ch NPs. Furthermore, the application of NPs in paddy plants under glasshouse condition demonstrated a remarkable improvement in plant growth. Protein profiling of NP-treated plants revealed new polypeptides (Rubisco units) enlightening the enhanced photosynthetic rate. Also, Asian rice exhibited reduced blast symptoms on leaves treated with NPs under glasshouse condition while displaying 64% mycelia inhibition in Petri plates. All these results suggest that nickel-chitosan nanoparticles could be exploited as an effective plant growth promoter cohort in controlling rice blast disease.

Protection of turmeric plants from rhizome rot disease under field conditions by ß-D-glucan nanoparticle.

The rhizome rot caused by Pythium aphanidermatum is one of the most devastating diseases of the turmeric crop. Fungicides are unable to control the rapidly evolving P. aphanidermatum and new control strategies are urgently needed. This study examined the effect of ß-d-glucan nanoparticles (GNP) in turmeric plants under field condition by the foliar spray method. Enhanced plant growth, rhizome yield, and curcumin content demonstrate the positive effect of the GNP on turmeric plants. Rapid activation of various defense enzymes was also observed in leaves and rhizomes of treated plants. GNP-treated plants showed a decreased rot incidence. It may be possible that increased defense enzymes might have played a role in reducing the colonization of pathogen.

Foliar application of ß-D-glucan nanoparticles to control rhizome rot disease of turmeric.

The soilborne Oomycete Pythium aphanidermatum is the causal agent of rhizome rot disease, one of the most serious threats to turmeric crops. At present, effective fungicides are not available. Researches on nanoparticles in a number of crops have evidenced the positive changes in gene expression indicating their potential use in crop improvement. Hence, experiments were carried out to determine the effect of ß-D-glucan nanoparticles (nanobiopolymer) in protection of turmeric plants against rot disease by the way of products that reinforce plant's own defense mechanism. Foliar spray of ß-D-glucan nanoparticles (0.1%, w/v) elicited marked increase in the activity of defense enzymes such as peroxidases (E.C.1.11.1.7), polyphenol oxidases (E.C.1.14.18.1), protease inhibitors (E.C.3.4.21.1) and ß-1,3-glucanases (E.C.3.2.1.39) at various age levels. Constitutive and induced isoforms of these enzymes were investigated during this time-course study. ß-D-glucan nanoparticles (GNPs) significantly reduced the rot incidence offering 77% protection. Increased activities of defense enzymes in GNPs-applied turmeric plants may play a role in restricting the development of disease symptoms. These results demonstrated that GNPs could be used as an effective resistance activator in turmeric for control of rhizome rot disease.

ß-D-Glucan nanoparticle pre-treatment induce resistance against Pythium aphanidermatum infection in turmeric.

In vitro experiments were carried out to test the efficacy of GNP (ß-D-glucan nanoparticle prepared from mycelium of Pythium aphanidermatum) against rhizome rot disease of turmeric (Curcuma longa L.) caused by P. aphanidermatum. GNP (0.1%, w/v) was applied to rhizome prior to inoculation with P. aphanidermatum (0 h, 24 h). Cell death, activities of defense enzymes such as peroxidase, polyphenol oxidase, protease inhibitor and ß-1,3 glucanase were monitored. Prior application of GNP (24 h) to turmeric rhizome effectively controls P. aphanidermatum infection. The increase in defense enzyme activities occurred more rapidly and was enhanced in P. aphanidermatum infected rhizomes that were pre-treated with GNP. Pre-treatment also induced new isoforms of defense enzymes. Increased activities of defense enzymes suggest that they play a key role in restricting the development of disease symptoms in the rhizomes as evidenced by a reduction in cell death. The results demonstrated that GNP can be used as a potential agent for control of rhizome rot disease.

Preparation of ß-D-glucan nanoparticles and its antifungal activity.

This work demonstrates the preparation of ß-D-glucan (isolated from the cell wall of Pythium aphanidermatum) nanoparticles through the addition of 2% (w/v) sodium hydroxide to ß-D-glucan solution with constant stirring at 90°C. Addition of sodium tripolyphosphate (TPP) aids the stable formation of nanoparticles. Fourier transform infrared (FTIR) spectroscopy confirmed phosphoric groups of TPP linked with OH group of ß-D-glucan in the nanoparticles. The formation of nanoparticles was observed by the peak at 386 nm using UV-vis spectroscopy. The average size of nanoparticle as determined by Zetasizer was about 60 nm, while the zeta potential was negative. Scanning electron microscope image showed spherical, smooth and almost homogenous structure for nanoparticles with size ranging from 20 to 50 nm. Further analysis by TEM, indicated polydispersity with an average size of 20-30 nm. The XRD analysis confirmed the crystalline structure of ß-glucan nanoparticle. The prepared nanoparticles exhibited antifungal activity against P. aphanidermatum, a devastating fungus which affects major crop plants.

Effect of Chitosan on Rhizome Rot Disease of Turmeric Caused by Pythium aphanidermatum.

Chitosan was evaluated for its potential to induce antifungal hydrolases in susceptible turmeric plant (Curcuma longa L.). Under field conditions, the application of chitosan (crab shell) to turmeric plants by foliar spray method induces defense enzymes such as chitinases and chitosanases. Such an increase in enzyme activity was enhanced by spraying chitosan (0.1% w/v) on leaves of turmeric plants at regular intervals. Gel electrophoresis revealed new chitinase and chitosanase isoforms in leaves of turmeric plants treated with chitosan. Treated turmeric plants showed increased resistance towards rhizome rot disease caused by Pythium aphanidermatum, whereas control plants expressed severe rhizome rot disease. Increased activity of defense enzymes in leaves of chitosan treated turmeric plants may play a role in restricting the development of disease symptoms. The eliciting properties of chitosan make chitosan a potential antifungal agent for the control of rhizome rot disease of turmeric.