UV RESISTANCE LOCUS 8 From Chrysanthemum morifolium Ramat (CmUVR8) Plays Important Roles in UV-B Signal Transduction and UV-B-Induced Accumulation of Flavonoids

Abstract

UV Resistance Locus 8 (UVR8), an ultraviolet-B (UV-B; 280–315 nm) photoreceptor, participates in the regulation of various plant growth and developmental processes. UV-B radiation is an important factor enhancing the production of active components in medicinal plants. To-date, however, studies on UV-B photoreceptors have largely focused on Arabidopsis, and the functions of UVR8 in medicinal plants are still largely unknown. In the present study, a homolog of Arabidopsis UVR8, CmUVR8, was isolated from Chrysanthemum morifolium Ramat, and its structure and function were analyzed in detail. Protein sequence analysis showed that CmUVR8 contained nine conserved regulators of chromosome condensation 1 repeats, seven conserved bladed propellers, one C27 region, three “GWRHT” motifs and several crucial amino acid residues (such as 14 Trps and 2 Args), similar to AtUVR8. 3-D structural analysis of CmUVR8 indicated that its structure was similar to AtUVR8. Heterologous expression of CmUVR8 could rescued the deficient phenotype of uvr8-6, a mutant of UVR8 in Arabidopsis, indicating the role of CmUVR8 in the regulation of hypocotyl elongation and HY5 gene expression under UV-B irradiation. Moreover, CmUVR8 regulates UV-B-induced expression of four flavonoids biosynthesis-related genes and the UV-B-induced accumulation of flavonoids. Furthermore, the interaction between CmUVR8 and CmCOP1 were confirmed using a yeast two-hybrid assay. These results indicated that CmUVR8 plays important roles in UV-B signal transduction and the UV-B-induced accumulation of flavonoids, as a counterpart of AtUVR8.

Natural Holobiome Engineering by Using Native Extreme Microbiome to Counteract the Climate Change Effects

“…Studies conducted in recent years show that high UV-B irradiation can even decrease CO 2 assimilation, decrease photochemical efficiency of photosystem II (PSII), reduce electron transport rate (ETR) and limit the productivity of some crops (Basahi et al, 2014;Wang et al, 2015;González-Villagra et al, 2020). Our current knowledge has determined that plants can counteract the negative effect of UV-B through a series of morphological and molecular changes, such as, the biosynthesis of phenolic acids and flavonoids induced by a UV-B photoreceptor called UV RESISTANCE LOCUS 8 or UVR8 (Coffey et al, 2017;Yang et al, 2018;Kondou et al, 2019;Tossi et al, 2019). Nowadays, different research groups have proposed novel biotechnological methods to mitigate the effect of abiotic stress on agricultural crops, among them the use of PGPM are widely studied (Calvo-Polanco et al, 2016;Vurukonda et al, 2016;Ullah et al, 2017;Etesami and Maheshwari, 2018;Bernardo et al, 2019;Bahadur et al, 2019;Mathur et al, 2019;Mickan et al, 2019).…”

LED Illumination Spectrum Manipulation for Increasing the Yield of Sweet Basil (Ocimum basilicum L.)

“…For example, phytochromes (PHY), whose unique photosensory properties can profoundly have a major role in governing plant elongation, flowering time, and leaf expansion [ 24 ], perceives light strongly in the red (660~700 nm) and far-red regions (700~750 nm) [ 25 ]. In contrast, the phototropin (PHOTO), cryptochrome (CRY), and ZLT system absorb light actively in the blue (400~495 nm) and UV-A (315~400 nm) regions [ 26 ], predominantly regulates plants hypocotyl elongation, and play an indispensable role in blue light facilitated stomatal opening [ 27 , 28 ] and controls the prosperity of an effective photoperiodic blossoming inducer [ 28 ], while the UVB-resistance locus 8 (UVR8) system perceives light intensely in the UV-B (280~315 nm) regions [ 29 ], and controls the biosynthesis-related genes expressions [ 30 ]. On the other hand, the far-red and UV ranges have secondary impacts on specific plants’ growth.…”

iTRAQ-Based Protein Profiling Provides Insights into the Mechanism of Light-Induced Anthocyanin Biosynthesis in Chrysanthemum (Chrysanthemum × morifolium)

“…Negative regulators such as MYB4 and MYB5 [27,70] are active and repress anthocyanin biosynthesis. In light, the activated photoreceptor UVR8 (ultraviolet resistance locus 8) is ubiquitinated by COP1 and targeted for degradation [71]. COP1 is subsequently exported from nucleus allowing nuclear-localized TFs such as HY5, MYB6, and MYB7 [27,35,70] to accumulate and induce expression of structural anthocyanin genes including CHS, CHI, F3H, F3'H, DFR, 3GT, and 3MaT, to generate anthocyanins.…”