Methyl Jasmonate and Salinity Increase Anthocyanin Accumulation in Radish Sprouts

Masaru Sakamoto,Takahiro Suzuki

doi:10.3390/horticulturae5030062

Abstract

Plant secondary metabolites with antioxidant properties, such as anthocyanins, are considered to have an important commercial value for some crops. Although anthocyanin concentration increases in response to various stimuli in plants, the mechanism of anthocyanin accumulation under multiple stimuli is not yet well understood. Here, we examined the effects of methyl jasmonate (MJ) and salinity on anthocyanin accumulation in radish (Raphanus sativus) sprouts. MJ treatments induced anthocyanin accumulation, which was enhanced by simultaneous treatment with salinity (200 mM NaCl), accompanied by growth restrictions. Sprouts treated with salinity alone did not induce anthocyanin accumulation, although sprout growth was restricted. Co-treatment with MJ and salinity increased hydrogen peroxide, total phenol content, and radical scavenging capacity more strongly than was achieved when each treatment was applied singly. Accumulation of anthocyanin was dependent on NaCl concentration and light intensity. Changing MJ and salinity treatment periods had different effects on anthocyanin accumulation and growth restriction, indicating that these phenomena might be differentially regulated. These results may provide an effective anthocyanin accumulation method without reducing plant biomass.

Highlights

Plants activate secondary metabolic pathways in response to various environmental stresses such as light, temperature, salinity, drought, and pathogens [1,2]
Red-colored pigments were observed on the abaxial surface of cotyledons of sprouts treated with methyl jasmonate (MJ) and MJ plus salinity (Figure 1c)
In MJ-treated sprouts, anthocyanins were restricted in a layer of abaxial cells under the vein whereas in sprouts co-treated with MJ and salinity, and anthocyanin was widely dispersed in a layer of many abaxial cells (Figure 1c)

Summary

Introduction

Plants activate secondary metabolic pathways in response to various environmental stresses such as light, temperature, salinity, drought, and pathogens [1,2]. Severe exposure to these stresses causes disruption of plant cellular homeostasis, which is accompanied by the production of reactive oxygen species (ROS). Plants initiate the synthesis of phenolic compounds and other antioxidants, and free radical scavenging enzymes to reduce ROS-mediated oxidative damage [6,7]. Production of anthocyanins, phenolic compounds that are well known as the principal plant pigments conferring red coloration, is induced in response to various stresses, and anthocyanins act as antioxidant molecules in plants to achieve tolerance of oxidative stress [11,12]. Salt-tolerant rice genotypes contained higher concentrations of anthocyanin and proline compared with salt-sensitive genotypes [16], indicating the importance of anthocyanins in plant salinity response

Methods

Results

Discussion

Conclusion