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.

Sara Rajaee Behbahani,Zahra Oraghi Ardebili,Mostafa Ebadi,Alireza Iranbakhsh,Ahmad Majd,Jen-Tsung Chen

doi:10.1371/journal.pone.0235556

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 = 7.9-fold). 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 and further highlights the necessity of designing convincing studies to introduce novel methods for plant cell/tissue cultures and agriculture.

Highlights

Nanoscience and nanotechnology as multidisciplinary fields provide breakthrough functions in plant and agriculture sciences [1]
It is well established that the physicochemical properties of nano-compounds play a determining role in their interaction with biological systems [24]
The results provide novel insights into the toxicity/advantage of nSe as an efficient elicitor in the culture medium

Summary

Introduction

Nanoscience and nanotechnology as multidisciplinary fields provide breakthrough functions in plant and agriculture sciences [1]. Due to the unique and outstanding physicochemical properties of nanoparticles, the nano-compounds induce differential responses in biological systems compared to the bulk substances [1,2,3]. In this regard, the synthetic method, concentration, physicochemical traits, and biological system species are major determining factors contributing to the potential advantages or risks of biological applications of nanoproducts [1,2,3]. Comparative convincing experiments on the interplay among bulk Se, nSe, and plant cells are rare and should be further investigated In this regard, ongoing experiments, under in vitro conditions, provide a great opportunity to fill the knowledge gaps in this area

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