Red elemental selenium nanoparticles mediated substantial variations in growth, tissue differentiation, metabolism, gene transcription, epigenetic cytosine DNA methylation, and callogenesis in bittermelon (Momordica charantia); an in vitro experiment

Abstract

To gain a better insight into the selenium nanoparticle (nSe) benefits/toxicity, this experiment was carried out to address the behavior of bitter melon seedlings to nSe (0, 1, 4, 10, 30, and 50 mgL-1) or bulk form (selenate). Low doses of nSe increased biomass accumulation, while concentrations of 10 mgL-1 and above were associated with stem bending, impaired root meristem, and severe toxicity. Responses to nSe were distinct from that of bulk in that the nano-type exhibited a higher efficiency to stimulate growth and organogenesis than the bulk. The bulk form displayed higher phytotoxicity than the nano-type counterpart. According to the MSAP-based analysis, nSe mediated substantial variation in DNA cytosine methylation, reflecting the epigenetic modification. By increasing the concentration of nSe, the expression of the WRKY1 transcription factor linearly up-regulated (mean = 7.9fold). Transcriptions of phenylalanine ammonia-lyase (PAL) and 4-Coumarate: CoA-ligase (4CL) genes were also induced. The nSe treatments at low concentrations enhanced the activity of leaf nitrate reductase (mean = 52%) in contrast with the treatment at toxic concentrations. The toxic concentration of nSe increased leaf proline concentration by 80%. The nSe supplement also stimulated the activities of peroxidase (mean = 35%) and catalase (mean = 10%) enzymes. The nSe-treated seedlings exhibited higher PAL activity (mean = 39%) and soluble phenols (mean = 50%). The nSe toxicity was associated with a disrupted differentiation of xylem conducting tissue. The callus formation and performance of the explants originated from the nSe-treated seedlings had a different trend than that of the control. This experiment provides new insights into the nSe-associated advantage/ cytotoxicity

Comparative efficacy of selenate and selenium nanoparticles for improving growth, productivity, fruit quality, and postharvest longevity through modifying nutrition, metabolism, and gene expression in tomato; potential benefits and risk assessment

“…According to our findings, the potential benefits of nSe utilization toward improving plant growth, biomass accumulation, yield, nutrition, flowering time, fruit quality, and postharvest longevity were much higher than the use of selenate, and at the same time, the potential nSeassociated risks are fewer. These results are consistent with several recent reports [5,6,25,26]. The following mechanisms appear to mediate partly differential responses to nSe relative to the selenate; (I) variations in uptake kinetics (nSe inactive influx through aquaporins vs secondary active influx mechanism of selenate through symporter) [2], (II) differences in their interactions with biomolecules and metabolism into the organic forms [2,26], (III) differential physicochemical properties of nanoparticles by which a nSe interaction with biomolecules can be different from that of selenate [2,5,6,26], (IV) variation in a nSe-mediated change in phytohormones [3,4,27], and (V) epigenetic modification [5,6].…”

“…Se or nSe supplementation, especially the latter, stimulated enzymatic antioxidants, non-enzymatic antioxidant compounds, and secondary metabolism. In agreement with our results, the nSe treatment improved enzymatic antioxidants [5,6,25], non-enzymatic antioxidants [25], and accumulation of secondary metabolites [3]. However, previous reports have only reported physiological responses to nSe.…”

“…Herein, the provided anatomical evidence, for the first time, underlines the risk of Se at high concentration in restricting crop fertility through disrupting the development of pollen grains. It has been recently reported in pepper [6] and bitter melon [5] plants that in vitro toxicity of nSe is associated with impaired tissue differentiation and abnormalities in stem's apical meristem. Further anatomical and developmental investigations of Phyto-toxicological concerns of nanomaterials are required to improve our knowledge of plant responses to nanoproducts, especially nano-pesticides and nano-fertilizers [5,[35][36][37].…”

“…Taking nano-fertilizers and nanopesticides into account, nanotechnology has provided a great opportunity to improve crop productivity and crop protection and has solved some of the challenges that we face today in agriculture. It has been highlighted in recent studies that bioavailability and function of Se in plant growth and metabolism were significantly more efficient in form of nanoparticles (nSe) compared to other natural Se forms such as selenate and selenite [1][2][3][4][5][6]. On the other hand, there is evidence that nSe use could potentially compromise plant growth and development [3,5,6].…”

“…It has been highlighted in recent studies that bioavailability and function of Se in plant growth and metabolism were significantly more efficient in form of nanoparticles (nSe) compared to other natural Se forms such as selenate and selenite [ 1 – 6 ]. On the other hand, there is evidence that nSe use could potentially compromise plant growth and development [ 3 , 5 , 6 ]. However, the potential benefit or phytotoxicity of nSe is still controversial.…”