Beyond Arabidopsis: Differential UV-B Response Mediated by UVR8 in Diverse Species

Abstract

Ultraviolet-B radiation (UV-B, 280–315 nm) is an important environmental signal that regulates growth and development in plants. Two dose-dependent UV-B response pathways were described in plants: a specific one, mediated by UVR8 (the specific UV-B receptor) and an unspecific one, activated by the oxidative damage produced by radiation. The constitutively expressed receptor appears inactive as a dimer, with the two monomers dissociating upon UV-B irradiation. The monomer then interacts with COP1, an ubiquitin ligase, hindering its ability to poly-ubiquitinate transcriptional factor HY5, thus averting its degradation and activating the photomorphogenic response. HY5 induces the synthesis of proteins RUP1 and RUP2, which interact with UVR8, releasing COP1, and inducing the re-dimerization of UVR8. This mechanism has been thoroughly characterized in Arabidopsis, where studies have demonstrated that the UVR8 receptor is key in UV-B response. Although Arabidopsis importance as a model plant many mechanisms described in this specie differ in other plants. In this paper, we review the latest information regarding UV-B response mediated by UVR8 in different species, focusing on the differences reported compared to Arabidopsis. For instance, UVR8 is not only induced by UV-B but also by other agents that are expressed differentially in diverse tissues. Also, in some of the species analyzed, proteins with low homology to RUP1 and RUP2 were detected. We also discuss how UVR8 is involved in other developmental and stress processes unrelated to UV-B. We conclude that the receptor is highly versatile, showing differences among species.

Short-Term Pre-Harvest UV-B Supplement Enhances the Polyphenol Content and Antioxidant Capacity of Ocimum basilicum Leaves during Storage

“…However, we cannot exclude that the observed increment in the Flav Index at T S7 might be also due to the low temperature of the storage. In fact, protective responses against UV-B radiation can be observed as a possible pre-acclimation response to further abiotic stresses caused by a new exposure to UV radiations or to other factors [ 22 , 23 , 24 , 25 ]. Indeed, the increment in phenolic compounds caused by low temperatures is already described in the literature [ 26 ] and can be attributed to the cold-induced activity of phenylalanine ammoniumlyase (PAL) and chalcone-synthase (CHS) enzymes [ 27 , 28 ].…”

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

“…This is important to consider due to Bais et al (2015) estimated that by the end of the 21st century the most populated areas of the northern hemisphere could increase 10-20% in UV radiation. Sunlight provides the energy necessary for plant growth through photosynthesis, however, high energy light and, in particular, UV-A (315-400 nm) and UV-B (280-315 nm) can produce damage to plants through structural modifications in DNA, protein denaturation, damage to membranous organelles (chloroplasts, mitochondria and nucleus) and cause oxidative stress (Müller-Xing et al, 2014;Sharma et al, 2017;Tossi et al, 2019). UV-B has been considered as the most harmful type of radiation for plants, morphological changes have been observed as thicker leaves, shorter petioles and lower chlorophyll content (Zhu et al, 2010;Inostroza-Blancheteau et al, 2014;Robson et al, 2015).…”

“…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).…”

Rocket Science: The Effect of Spaceflight on Germination Physiology, Ageing, and Transcriptome of Eruca sativa Seeds

“…Expression of components of the NER pathway was also elevated by CAAT and/or spaceflight, including XPB, DDB1, XAB2, and SSRP1 ( Figure 6). Whilst photolyases were not significantly affected by CAAT or spaceflight (Supplementary Data File), other components involved in regulating the photoreactivation repair (PR) repair pathway including UVR8, COP1, and HY5 [68][69][70] were identified as DEGs (Figure 6). HY5, a transcription factor involved in expression of photolyases, was induced by CAAT in Earth and Space seeds; it was also induced by spaceflight in dry Space seeds ( Figure 6).…”

“…Some components of the photoactivation repair (PR) pathway are also upregulated in rocket seeds upon CAAT, but except for HY5 no elevated transcript abundances were evident in dry Space seeds ( Figure 6). The UV-B photoreceptor (UVR8) signaling can induce expression of photolyases involved in DNA repair, in part via a HY5-dependent pathway; in the absence of UV-B, COP1 can antagonize this response [68][69][70]. Taken together, the Space rocket seeds were shielded against UV irradiation on board the ISS but experienced low-level ionizing radiation from galactic cosmic rays, trapped protons, and solar energetic particles which may have caused the upregulation of DSB (ATM) and NER (XBP) DNA pathway transcripts ( Figure 6), indicating that DNA is a target of the partial seed ageing.…”