Modulation of callus growth and secondary metabolites in different Thymus species and Zataria multiflora micropropagated under ZnO nanoparticles stress

Abstract

Thymus species are aromatic plants with diverse applications in food industries and medicine. This study was conducted to evaluate the potential effect of ZnO nanoparticles (NPs) on callus proliferation and thymol and carvacrol production in three Thymus species, that is, T. vulgaris, T. daenensis, and T. kotschyanus, and Zataria multiflora. For this purpose, callus induction was performed on Murashige and Skoog (MS) medium containing different plant growth regulators (PGRs). After optimization of callus growth, the effects of different concentrations of ZnO NPs (100 and 150 mg L −1 ) were investigated. MS containing 2 mg L −1 of 2, 4-dichlorophenoxy acetic acid (2,4-D) and 1 mg L −1 of kinetin (Kin) revealed significantly highest fresh weight (0.18 g) of callus in T.kotschyanus. Callus growth rate (0.079 mm day −1 ) was found highest in T. vulgaris under similar conditions. Moreover, highest callus induction (92.50%) was achieved by T. kotschyanus in MS containing 2.5 mg L −1 of 2,4-D. Regarding the highest content of thymol (22.8 mg L −1 ) and carvacrol (0.68 mg L −1 ) evaluated by high-performance liquid chromatography, best results were achieved under 150 mg L −1 of ZnO NPs in T. kotschyanus and T. daenesis, respectively. This is simple and cost-effective method to be applied on industrial level for production of enhanced secondary metabolites content. potent chemical elicitors as signaling agents that effect a great diversity of physiological and biochemical processes in plant metabolism and plant secondary metabolites production [1,2]. NPs are capable of increasing cell membrane permeability, stimulating defensive mechanisms in plant cells, and subsequent increase in secondary metabolites content [2,3]. Zinc oxide (ZnO) NPs as an inorganic micronutrient have a beneficial effect on plant growth, cell division, and structure and function of membrane because of their high electron mobility, large surface area, and catalytic activity [4]. Most of the recent studies are focused on the effects of NPs on seed germination [5], plant growth rate [6] physiological responses [3][4][5][6], and secondary metabolites production [2][3][4][5]. Recent studies have shown that plant growth, development, and physiology are significantly affected by NPs; however, their role on plant secondary metabolism, especially regarding callus culture, is still obscure [2]. The inclusion of NPs to tissue culture media could enhance

Nanoparticles induce genetic, biochemical, and ultrastructure variations in Salvadora persica callus

“…On the other hand, BITC accumulation slightly increased in callus treated with 2 mg/l SiO 2 NPs for 45 days, while no changes were observed in 30-day-old callus treated with the same NP concentration. Similar findings were reported for the accumulation of thymol and carvacrol in thyme callus stressed with different concentrations of ZnO NPs [37]. By comparing the growth of callus with the accumulation of BITC, it was observed that due to the application of NPs at different concentrations, Fe 3 O 4 NPs at both concentrations and SiO 2 at 0.5 mg/l decreased the callus growth and secondary metabolism, as a nonessential mechanism of plant life, also decreased by increasing exposure time, while SiO 2 NPs at 2 mg/l and ZnO NPs stimulated callus growth.…”

Effects of Biogenic Zinc Oxide Nanoparticles on Growth and Oxidative Stress Response in Flax Seedlings vs. In Vitro Cultures: A Comparative Analysis

“…Accordingly, the concentration of Zn provided to plants should be precisely controlled for optimal plant development [ 24 ]. On the contrary, zinc oxide nanoparticles (ZnONPs) elicitation capability has been used to promote the production of bioactive secondary metabolites in medicinal plants [ 25 , 26 ].…”

Engineered ZnO and CuO Nanoparticles Ameliorate Morphological and Biochemical Response in Tissue Culture Regenerants of Candyleaf (Stevia rebaudiana)

“…Employment of ENPs in the tissue/cell culture industry of medicinal plants is limited despite a lot of progress having been made in the last decade in the agricultural nanotechnology sector. The available literature suggests that ENPs evoke abiotic stress in tissue/cell culture raised medicinal plants [43][44][45][46][47][48]. These studies illustrate the effects induced by ENPs on the growth and secondary metabolism of plants of medicinal significance.…”