Management of Ralstonia solanacearum in Tomato Using ZnO Nanoparticles Synthesized Through Matricaria chamomilla.

Matricaria chamomilla flower extract was used as a biocompatible material for synthesis of zinc oxide nanoparticles (ZnONPs). The synthesized NPs were evaluated for their antibacterial potential in vitro and in vivo against the Gram-negative bacterium Ralstonia solanacearum, which causes devastating bacterial wilt disease in tomato and other crops. Synthesized ZnONPs were further analyzed by UV-visible spectroscopy, Fourier transform infrared spectroscopy, x-ray diffraction, transmission electron microscopy, and scanning electron microscopy with energy-dispersive spectroscopy. The synthesized polydisperse ZnONPs were found to be in the size range of 8.9 to 32.6 nm, and at 18.0 µg ml-1 exhibited maximum in vitro growth inhibition of the pathogen R. solanacearum. Scanning electron microscopy analysis of affected bacterial cells showed morphological deformation such as disruption of the cell membrane and wall, and the leakage of cell contents. Results of in vivo studies also showed that application of ZnONPs to the artificially inoculated tomato plants with the pathogen R. solanacearum significantly enhanced the plant growth by reducing bacterial soil population and disease severity as compared with the untreated control. Biosynthesized ZnONPs could be an effective approach to control the bacterium R. solanacearum.

Eco-friendly Management of Bacterial Wilt in Tomato Using Dried Powder of the Wild Arid-Land Medicinal Shrub Rhazya stricta.

Bacterial wilt (BW) disease caused by Ralstonia solanacearum species complex is a devastating plant disease that inflicts heavy losses to the large number of economic host plants it infects. In this study, the potential of dried powder of the arid-land medicinal shrub Rhazya stricta to control BW of tomato was explored. Both, in vitro and in planta studies were conducted, using different concentrations of dried powder of plant parts, and applied (surface mulched or mixed) to infested soil at 0, 10, and 20 days before transplanting (DBT). Aqueous extract of leaves (16% w/v) was found to be as effective as streptomycin (100 ppm) in inhibiting the in vitro growth of R. solanacearum. As evident from the scanning electron micrograph, 16% aqueous extract of leaves produced severe morphological changes, such as rupture of the bacterial cell walls. Results from the greenhouse experiments demonstrated that the higher powder dose (succulent shoot), namely, 30 g/kg of soil mixed with infested soil 20 DBT, was found to be the most effective in controlling BW. It increased root length (cm), shoot length (cm), and plant fresh biomass (g) by 55, 42, and 40%, respectively, over control plants. Mixing of plant powder with the artificially infested (35 ml of 108 CFU/ml per kilogram of soil) pot soil was better than surface mulching. The 30 g/kg of soil dose mixed with soil increased root length (cm), shoot length (cm), and plant fresh biomass (g) of treated plants by 67, 36, and 46%, respectively, over control plants. A 37% decrease in disease severity over the control was observed with drench application of 30 g of powder per kilogram of soil applied once at 20 DBT. Our results indicated that the dried powder (30 g/kg of soil) of leaves or succulent shoots of R. stricta, thoroughly mixed with soil, 20 DBT, could act as an effective control method against BW.

The chemistry and pharmacology of alkaloids and allied nitrogen compounds from Artemisia species: A review.

Several reviews have been published on Artemisia's derived natural products, but it is the first attempt to review the chemistry and pharmacology of more than 80 alkaloids and allied nitrogen compounds obtained from various Artemisia species (covering the literature up to June 2018). The pharmacological potential and unique skeleton types of certain Artemisia's alkaloids provoke the importance of analyzing Artemisia species for bioactive alkaloids and allied nitrogen compounds. Among the various types of bioactive Artemisia's alkaloids, the main classes were the derivatives of rupestine (pyridine-sesquiterpene), lycoctonine (diterpene), pyrrolizidine, purines, polyamine, peptides, indole, piperidine, pyrrolidine, alkamides, and flavoalkaloids. The rupestine derivatives are Artemisia's characteristic alkaloids, whereas the rest are common alkaloids found in the family Asteraceae and chemotaxonomically links the genus Artemisia with the tribes Anthemideae. The most important biological activities of Artemisia's alkaloids are including hepatoprotective, local anesthetic, ß-galactosidase, and antiparasitic activities; treatment of angina pectoris, opening blocked arteries, as a sleep-inducing agents and inhibition of HIV viral protease, CYP450, melanin biosynthesis, human carbonic anhydrase, [3H]-AEA metabolism, kinases, and DNA polymerase ß1 . Some of the important nitrogen metabolites of Artemisia include pellitorine, zeatin, tryptophan, rupestine, and aconitine analogs, which need to be optimized and commercialized further.

Mini review on photosensitization by plants in grazing herbivores.

Photosensitization is severe dermatitis or oxidative/chemical changes in the epidermal tissues activated by the light-induced excitation of molecules within the tissue. It is a series of reactions mediated through light receptors and is more common when the plant-produced metabolites are heterocyclic/polyphenols in nature. The areas affected are exposed body parts and mostly non-pigmented areas with least ultraviolet protection. Similarly, cellular alteration also occurs in the affected animal's dermal tissues and body parts and grazing animals by the accumulation and activation of photodynamic molecules. Photo-oxidation can also occur within the plant due to the generation of reactive oxygen species causing damage and degradation in the form of free radicals and DNA. During the last few decades, many new tropical grass species have been introduced in the grazing lands which are genetically modified, and the animals grazing on them are facing various forms of toxicity including photosensitization. The plant's secondary metabolites/drugs may cause toxicity when bacteria, viral agents, fungi (Pithomyces chartarum), or neoplasia injures the liver and prevents the phylloerythrin excretion. All these may disturb the liver enzymes and blood profile causing a decrease in weight and production (wool and milk etc.) with severe dermal, digestive, and nervous problems. Recent advancements in OMICS (cellomics, ethomics, metabolomics, metabonomics, and glycomics) have enabled us to detect and identify the plants' secondary metabolites and changes in the animal's physiology and histopathology as a causative of photosensitivity. The review focuses on types of photosensitization, reasons, secondary metabolic compounds, chemistry, and environmental effect on plants.

A new irregular monoterpene acetate along with eight known compounds with antifungal potential from the aerial parts of Artemisia incisa Pamp (Asteraceae).

A new compound named as santolinylol-3-acetate (4-(2-hydroxypropan-2-yl)-2-methylhexa-1,5-dien-3-yl acetate) (3), along with seven known compounds; linoleic acid (1), benzoic acid (2), santolinylol (4), ethyl-(E)-p-hydroxy cinnamate (5), scopoletin (6), esculetin (7) isofraxidin (8) and eupatorin (9), were isolated from the aerial parts (ethanolic extract) of endangered species: Artemisia incisa Pamp (Asteraceae). The compounds' structures were determined through modern spectroscopic techniques, and comparison of data (physicochemical constants) with the literature. The relative stereochemistry of santolinylol-3-acetate (3) was determined by comparing its data of NOESY, and specific rotation with its diol analogue; santolinylol (4), isolated from the same plant; A. incisa. The results of the antifungal activity showed that coumarins are as whole less active compounds. Compounds 3 (25 and 300 µg/mL), and 4 (12.5 and 300 µg/mL), showed good activities against Candida albicans, and Aspergillus flavus, respectively, which justifies A. incisa as a traditional medicine for curing the said fungal infections.

Nematicidal activity of nonacosane-10-ol and 23a-homostigmast-5-en-3ß-ol isolated from the roots of Fumaria parviflora (Fumariaceae).

Two bioactive nematicidal phytochemicals, viz., nonacosane-10-ol and 23a-homostigmast-5-en-3ß-ol, were isolated from the n-hexane fraction of the roots of Fumaria parviflora through activity-guided isolation. The structures of the compounds were elucidated using ¹³C and ¹H nuclear magnetic resonance. Activity of the two compounds against eggs and juveniles (J2s) of Meloidogyne incognita was evaluated in vitro at the concentrations of 50, 100, 150, and 200 µg mL⁻¹. Over 120 h of incubation, the cumulative percent mortality and hatch inhibition of both of the compounds tested ranged from 20 to 100% and from 15 to 95.0%, respectively. In pot trials with tomato cultivar Riogrande, the two compounds, applied as soil drenches at the concentrations of 100, 200, and 300 mg/kg, significantly decreased the nematodes and plant growth parameters. Nonacosane-10-ol and 23a-homostigmast-5-en-3ß-ol reduced the numbers of galls (42.6 and 60.3), galling index (1.6 and 2.8), females per gram of root (37.3 and 57.0), eggs per gram of root (991.3 and 1273.0), reproduction factor (Rf) (0.1 and 0.2), and fresh root weight (14.33 and 17.0 g) at 300 mg/kg concentration and increased fresh shoot weight (49.0 and 48.4 g), dry shoot weight (28.0 and 25.3 g), and plant height (53.5 and 49.6 cm), respectively. These compounds could provide new insight in the search for novel nematicides against M. incognita.