Green Fabrication, Characterization of Zinc Oxide Nanoparticles Using Plant Extract of Momordica charantia and Curcuma zedoaria and Their Antibacterial and Antioxidant Activities.

In recent years, the rapid increase in the resistance of microorganisms to antibiotics has produced major health issues. Novel applications for these compounds have been developed by integrating modern technologies such as nanotechnology and material science with the innate antibacterial activity of metals. The current study demonstrated the synthesis of zinc oxide nanoparticles (ZnO NPs) from Momordica charantia and Curcuma zedoaria plant extracts, as well as their antibacterial properties. The synthesis of ZnO NPs was confirmed via UV-visible spectroscopy, showing clear peaks at 375 and 350 nm for M. charantia and C. zedoaria, respectively. Scanning electron microscopy (SEM) analysis revealed crystals of irregular shapes for the majority of the nanoparticles synthesized from both plants. The existence of ZnO NPs was confirmed using X-ray diffraction while the particle size was calculated using Scherrer's equation, which was 19.65 for C. zedoaria and 17.02 for M. charantia. Different functional groups were detected through Fourier transform infrared spectroscopy analysis. The antibacterial activity of the ZnO NPs at three different concentrations (250, 500, and 1000 µg/ml) was assessed against three different bacterial strains, i.e., Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa), using disc diffusion methods. The ZnO nanoparticles showed promising antibacterial activity against bacterial strains. For C. zedoaria, the highest growth inhibition was observed at a concentration of 1000 µg/ml, which was 18, 19, and 18 mm as compared to antibiotics (15, 11, and 15.6 mm) against E. coli, P. aeruginosa, and S. aureus, respectively. Similarly, at 1000 µg/ml of NPs, M. charantia showed the highest growth inhibition (18, 15, and 17 mm) as compared to antibiotics (15, 11, and 14.6 mm) against E. coli, P. aeruginosa, and S. aureus, respectively. In conclusion, compared to pure plant extract and antibiotics, ZnO NPs at a higher concentration (1000 µg/ml) exhibited a significant difference in zone of inhibition against all the bacterial strains. Different concentrations of ZnO using M. charantia and C. zedoaria caused increments in the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The nanoparticles extracted using C. zedoaria exhibited higher antioxidant activity than M. charantia. Greenly synthesized ZnO nanoparticles have remarkable antibacterial properties and antioxidant activity, making them a promising contender for future pharmaceutical application.

Characterization of Endophytic Fungi, Acremonium sp., from Lilium davidii and Analysis of Its Antifungal and Plant Growth-Promoting Effects.

The present study was aimed at isolating endophytic fungi from the Asian culinary and medicinal plant Lilium davidii and analyzing its antifungal and plant growth-promoting effects. In this study, the fungal endophyte Acremonium sp. Ld-03 was isolated from the bulbs of L. davidii and identified through morphological and molecular analysis. The molecular and morphological analysis confirmed the endophytic fungal strain as Acremonium sp. Ld-03. Antifungal effects of Ld-03 were observed against Fusarium oxysporum, Botrytis cinerea, Botryosphaeria dothidea, and Fusarium fujikuroi. The highest growth inhibition, i.e., 78.39 ± 4.21%, was observed for B. dothidea followed by 56.68 ± 4.38%, 43.62 ± 3.81%, and 20.12 ± 2.45% for B. cinerea, F. fujikuroi, and F. oxysporum, respectively. Analysis of the ethyl acetate fraction through UHPLC-LTQ-IT-MS/MS revealed putative secondary metabolites which included xanthurenic acid, valyl aspartic acid, gancidin W, peptides, and cyclic dipeptides such as valylarginine, cyclo-[L-(4-hydroxy-Pro)-L-leu], cyclo(Pro-Phe), and (3S,6S)-3-benzyl-6-(4-hydroxybenzyl)piperazine-2,5-dione. Other metabolites included (S)-3-(4-hydroxyphenyl)-2-((S)-pyrrolidine-2-carboxamido)propanoic acid, dibutyl phthalate (DBP), 9-octadecenamide, D-erythro-C18-Sphingosine, N-palmitoyl sphinganine, and hydroxypalmitoyl sphinganine. The strain Ld-03 showed indole acetic acid (IAA) production with or without the application of exogenous tryptophan. The IAA ranged from 53.12 ± 3.20 µg ml-1 to 167.71 ± 7.12 µg ml-1 under different tryptophan concentrations. The strain was able to produce siderophore, and its production was significantly decreased with increasing Fe(III) citrate concentrations in the medium. The endophytic fungal strain also showed production of organic acids and phosphate solubilization activity. Plant growth-promoting effects of the strain were evaluated on in vitro seedling growth of Allium tuberosum. Application of 40% culture dilution resulted in a significant increase in root and shoot length, i.e., 24.03 ± 2.71 mm and 37.27 ± 1.86 mm, respectively, compared to nontreated control plants. The fungal endophyte Ld-03 demonstrated the potential of conferring disease resistance and plant growth promotion. Therefore, we conclude that the isolated Acremonium sp. Ld-03 should be further investigated before utilization as a biocontrol agent and plant growth stimulator.

Introduction of Arabidopsis's heat shock factor HsfA1d mitigates adverse effects of heat stress on potato (Solanum tuberosum L.) plant.

Thermal stress induces a wide array of morphological and physiological changes in potato affecting its development and economic yield. Response to thermal stress in plants is mostly regulated by heat shock factors (hsfs). The current study aimed at improving heat tolerance by transforming potato plant with heat shock factor, HsfA1d, using Agrobacterium. Gateway cloning strategy was adopted for isolation of HsfA1d from Arabidopsis thaliana and cloning into plant expression vector. The target gene was introduced into potato by infecting internodal explants with Agrobacterium strain GV3101 carrying pGWB402Ω-HsfA1d construct. Upon exposure to heat stress, the wild-type plants turned yellowish, whereas no phenotypic effect on transgenic plants was observed. Expression of HsfA1d in transgenic plants was increased by 5.8-fold under thermal stress compared to room temperature. Transgenic plants exhibited 6-fold increase in the expression of downstream HSP70 under thermal stress compared to wild-type plants. Both chlorophyll a and b were significantly decreased in wild-type plants while no such decrease was recorded in transgenic plants under thermal stress. Heat stress was found to have no significant effect on carotenoid pigments of both wild-type and transgenic plants. Significantly lower electrolyte leakage from transgenic plants was witnessed compared to wild type upon exposure to thermal stress. Transgenic plants accumulated significantly higher proline content compared to wild-type plants under heat stress. It is concluded that HsfA1d plays a vital role in plant thermotolerance and hence can be effectively used to enhance the resistance of crop plants against heat stress.