Transcriptome and metabolome analyses revealed that narrowband 280 and 310\xa0nm UV-B induce distinctive responses in Arabidopsis

Tomohiro Tsurumoto,Daisaku Ohta,Yasuo Fujikawa,Atsushi Okazawa,Yukari Ochi,Yushi Onoda

doi:10.1038/s41598-022-08331-9

Tomohiro Tsurumoto, Daisaku Ohta + Show 4 more

Open Access

https://doi.org/10.1038/s41598-022-08331-9

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Abstract

In plants, the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) perceives UV-B and induces UV-B responses. UVR8 absorbs a range of UV-B (260–335 nm). However, the responsiveness of plants to each UV-B wavelength has not been intensively studied so far. Here, we performed transcriptome and metabolome analyses of Arabidopsis using UV light emitting diodes (LEDs) with peak wavelengths of 280 and 310 nm to investigate the differences in the wavelength-specific UV-B responses. Irradiation with both UV-LEDs induced gene expression of the transcription factor ELONGATED HYPOCOTYL 5 (HY5), which has a central role in the UVR8 signaling pathway. However, the overall transcriptomic and metabolic responses to 280 and 310 nm UV-LED irradiation were different. Most of the known UV-B-responsive genes, such as defense-related genes, responded only to 280 nm UV-LED irradiation. Lipids, polyamines and organic acids were the metabolites most affected by 280 nm UV-LED irradiation, whereas the effect of 310 nm UV-LED irradiation on the metabolome was considerably less. Enzymatic genes involved in the phenylpropanoid pathway upstream in anthocyanin biosynthesis were up-regulated only by 280 nm UV-LED irradiation. These results revealed that the responsivenesses of Arabidopsis to 280 and 310 nm UV-B were significantly different, suggesting that UV-B signaling is mediated by more complex pathways than the current model.

Highlights

The UV-B receptor UV RESISTANCE LOCUS 8 (UVR8) has been proposed as one of the factors mediating the transcriptional activation of ELONGATED HYPOCOTYL5 (HY5), a member of the bZIP transcription factor family, in response to UV-B4,6,8,9
Since a gene ontology (GO) term ’phenylpropanoid biosynthesis’ was enriched in differentially expressed genes (DEGs) in 280-2d, we focused on the gene expression of typical enzymes involved in flavonoid biosynthesis, ADT6, PAL1, cinnamate 4-hydroxylase (C4H), Chalcone synthase (CHS), CHI1, flavonol 3-hydroxylase (F3H), DFRA, LDOX and UGT75C1, which is one of anthocyanin glycosyltransferases (AGTs) (Fig. 7a,b)
We focused on the gene expression of transcription factors such as HY5, which is a key component in the UVR8 signaling pathway, HYH, a homologue of HY5, MEDs, and members in MBW complexes (MYBs, EGL3, GL3, TTG1, and TT8), which are involved in flavonoid biosynthesis (Fig. 7c)

Summary

Introduction

The sunlight that falls on the earth contains various wavelengths. Plants use the light as an energy source, and as signals for optimizing growth and development. Light is classified according to the wavelengths it contains, and the shortest-wavelength component of the sunlight that reaches the ground is UV. UV-B is the light that possesses the shortest wavelength and the highest energy in the sunlight that reaches the ground. Because nucleic acids and proteins, have absorption peaks near 260 and 280 nm, respectively, UV-B directly causes damage to the molecules. UV-B signaling requires monomerization of UVR8, which forms a homodimer in the ground s tate[8]. HY5 has a central role in UV-B signaling, regulating the expression of about half of UVR8-induced genes, including defense-related and anthocyanin biosynthetic g enes[13,14]

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