Presentation Information
[3Plant-02-KL]Enhancement of plant function by optimum irradiation of UV-LEDs
○Atsushi Okazawa1 (1. Osaka Met. Univ. (Japan))
Keywords:
Ultraviolet (UV),Light-emitting diodes (LEDs),Secondary metabolites,Plant immunity
[Purpose]
Plants have been evolving in response to the stresses of their habitats. Ultraviolet (UV) light has the highest energy in the sunlight spectrum and damages biomolecules. Accordingly, organisms had to adapt to UV radiation when they expanded into land. Plants have developed a unique system for UV radiation involving sensory photoreceptors and signal transduction.
Light-emitting diodes (LEDs) are highly efficient light sources, and the replacement of light sources with LEDs is progressing worldwide. In agriculture and plant-based bioproduction, efforts have been made to maximize plant production efficiency by selecting LED wavelengths. Compared with the visible and far-red wavelengths, the effects of narrow-band UV wavelengths on plants were less understood because of the difficulty in obtaining high-quality light sources. In this study, we prepared a series of narrow-band UV-LEDs and investigated plant responses to them.
[Method]
UV-LEDs, which have peak wavelengths across the UV wavelengths, were irradiated on Arabidopsis, grape berries, and so on. The effects of the irradiation on gene expression and metabolites were comprehensively analyzed by RNA-sequencing (RNA-Seq) and metabolomics.
[Results]
Arabidopsis responses to 280 and 310 nm UV-LED irradiation differed greatly in both the transcriptome and metabolome, suggesting that narrow-band UV-LEDs can be applied to control plant function.
When a high dose of 290 nm UV-LED was irradiated on grape berries, resveratrol in the skins was significantly increased. Interestingly, the increase was specific to stilbenoids with no effect on the amounts of other phenolic compounds, including anthocyanins. Then, we optimized the UV-LED irradiation conditions to increase the anthocyanins in grape berry skins. The optimized irradiation conditions promoted the coloring of not only grape berries but also other berries and red lettuce leaves.
Next, we tried to enhance plant immunity with UV-LED irradiation. The seedlings of transgenic Arabidopsis harboring PR1a::Fluc were irradiated with UV-LEDs with various wavelengths to obtain the action spectra of PR1a expression. DNA damage by the UV irradiation was also monitored by the formation of cyclobutene pyrimidine dimer (CPD) as an indicator. As a result, the UV-LED irradiation condition was optimized to efficiently enhance plant immunity with less DNA damage.
[Consideration]
We and many previous studies have shown that the UV responses of plants, manifested in various reactions, are wavelength dependent. The molecular basis of the dependence has been in a black box. Here, we obtained the action spectrum of plant immunity and DNA damage, which will help us understand complex plant UV responses.
[Conclusion]
UV-LEDs can control plant function by optimizing irradiation conditions. The enhancement of plant secondary metabolism and plant immunity achieved in this study demonstrates the potential application of this technology for plant-based bioproduction and sustainable plant protection.
A part of this research was supported by the Research and Implementation Promotion Program through Open Innovation Grants (JPJ011937) from the Project of the Bio-oriented Technology Research Advancement Institution (BRAIN).
Plants have been evolving in response to the stresses of their habitats. Ultraviolet (UV) light has the highest energy in the sunlight spectrum and damages biomolecules. Accordingly, organisms had to adapt to UV radiation when they expanded into land. Plants have developed a unique system for UV radiation involving sensory photoreceptors and signal transduction.
Light-emitting diodes (LEDs) are highly efficient light sources, and the replacement of light sources with LEDs is progressing worldwide. In agriculture and plant-based bioproduction, efforts have been made to maximize plant production efficiency by selecting LED wavelengths. Compared with the visible and far-red wavelengths, the effects of narrow-band UV wavelengths on plants were less understood because of the difficulty in obtaining high-quality light sources. In this study, we prepared a series of narrow-band UV-LEDs and investigated plant responses to them.
[Method]
UV-LEDs, which have peak wavelengths across the UV wavelengths, were irradiated on Arabidopsis, grape berries, and so on. The effects of the irradiation on gene expression and metabolites were comprehensively analyzed by RNA-sequencing (RNA-Seq) and metabolomics.
[Results]
Arabidopsis responses to 280 and 310 nm UV-LED irradiation differed greatly in both the transcriptome and metabolome, suggesting that narrow-band UV-LEDs can be applied to control plant function.
When a high dose of 290 nm UV-LED was irradiated on grape berries, resveratrol in the skins was significantly increased. Interestingly, the increase was specific to stilbenoids with no effect on the amounts of other phenolic compounds, including anthocyanins. Then, we optimized the UV-LED irradiation conditions to increase the anthocyanins in grape berry skins. The optimized irradiation conditions promoted the coloring of not only grape berries but also other berries and red lettuce leaves.
Next, we tried to enhance plant immunity with UV-LED irradiation. The seedlings of transgenic Arabidopsis harboring PR1a::Fluc were irradiated with UV-LEDs with various wavelengths to obtain the action spectra of PR1a expression. DNA damage by the UV irradiation was also monitored by the formation of cyclobutene pyrimidine dimer (CPD) as an indicator. As a result, the UV-LED irradiation condition was optimized to efficiently enhance plant immunity with less DNA damage.
[Consideration]
We and many previous studies have shown that the UV responses of plants, manifested in various reactions, are wavelength dependent. The molecular basis of the dependence has been in a black box. Here, we obtained the action spectrum of plant immunity and DNA damage, which will help us understand complex plant UV responses.
[Conclusion]
UV-LEDs can control plant function by optimizing irradiation conditions. The enhancement of plant secondary metabolism and plant immunity achieved in this study demonstrates the potential application of this technology for plant-based bioproduction and sustainable plant protection.
A part of this research was supported by the Research and Implementation Promotion Program through Open Innovation Grants (JPJ011937) from the Project of the Bio-oriented Technology Research Advancement Institution (BRAIN).
Comment
To browse or post comments, you must log in.Log in