Fig 2
Different plant photoreceptors mediate inactivation and activation of COP1 and HY5, respectively. Light activation of the photoreceptors leads to inhibition of the COP1-SPA E3 ubiquitin ligase complex, which releases HY5 from its repression through ubiquitination and proteasomal degradation. While activated PHYs and CRYs interact with SPA proteins for the disruption and inactivation of the COP1/SPA complexes, FKF1 interact with COP1 to disrupt the COP1 homodimerization. PHYB though a positive regulator of HY5 in red light acts as its negative regulator in
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Light acts catalytically to initiate a cascade of events to eventually regulate different aspects of plant development. The cascade of light signal transduction involves several components that can be broadly grouped as photoreceptors, early signaling factors, central integrators and downstream effectors. ELONGATED HYPOCOTYL 5 (HY5), a bZIP transcr...
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... association ( Zuo et al. 2011). In addition, FKF1, ZTL and LKP2 also interact with COP1 to disrupt the COP1 homodimerization, leading to the suppression of COP1 activity and protein stability ( Lee et al. 2017Lee et al. , 2019. Moreover, CRYs and UVR8 compete with COP1 substrates for COP1 binding as both possess similar valine-proline (VP) motif (Fig. 2) ( Lau et al. 2019;Ponnu et al. 2019). COP1 and SPA1 can form a bigger complex with other components of E3 ubiquitin ligase complex and then regulate other proteins ( Paik et al. 2019). CUL4 acts as a scaffold protein in large multimeric CUL4 based E3 ligases. With the help of an adaptor protein DDB1 (DNA DAMAGE BINDING PROTEIN1), a ...
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... HY5 from proteolysis ( Ren et al. 2019). Moreover, it has been shown that HY5 accumulates more at the illuminated side of etiolated seedlings in response to UV-B light resulting in phototropin-independent bending toward UV-B (Vandenbussche and Van der Straeten 2014). Therefore, HY5 and COP1 are an indispensable part of UV-B signaling in plants (Fig. ...
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... binding to the chromatins of the BIC promoters ( Wang et al. 2017). It also attenuates FHY3/FAR1-activated FHY1/FHL expression, required for light-regulated PHYA nuclear accumulation and subsequent PHYA signaling processes ( Li et al. 2010). PHYB, on the other hand, helps in degradation of HY5 by promoting nuclear accumulation of SPA1 under FR ( Fig. 2) ( Zheng et al. ...
Citations
... HY5 and COP1 proteins act antagonistically in regulation of the seedling development (Osterlund et al. 2000), as COP1 negatively modulates the activity of HY5 (Ang et al. 1998). The COP1/HY5 regulatory pathway is the central hub of photomorphogenesis (Bhatnagar et al. 2020), with HY5 affecting the activity of most phytohormones, including ABA, auxin, gibberellins, brassinosteroids and ethylene. In addition to COP1, the large COP9 signalosome, which performs proteolytic degradation, also participates in light signaling and controls plant development in the dark toward skotomorphogenesis (Deng et al. 1991;Chamowitz et al. 1996;Ma et al. 2002;Qin et al. 2020). ...
Daily changes in the content of phytohormones accumulating in the hypocotyls of young sunflower seedlings that grow under a 14/10-h light-to-dark (LD) photoperiod were followed using LC–MS. The objective of the work was to investigate whether the presence of light and light transitions lead to visible changes visible in phytohormone levels on the sixth day after the onset of germination. The LC–MS technique used allowed the simultaneous detection of more than one hundred individual phytohormone derivatives, of which the daily accumulation patterns were determined for nearly fifty members. The daily changes in phytohormone levels followed specific patterns for each phytohormone. There were differences between the daytime and nighttime levels, most likely reflecting the effects of light on phytohormone metabolism. A significant difference was found between cytokinins (CKs) and all other phytohormones, so that CK group of phytohormones may be considered to have a separate role in hypocotyl elongation. Prolonged daytime (postponed dusk) resulted in a rapid disruption of rhythmic hypocotyl elongation and it triggered an acute light stress response that was evident in increased levels of a number of important phytohormones from all groups except CKs. However, this light stress, termed ARELD (Acute Response to Extended Light Duration), was not present in control plants grown under continuous light conditions. The data suggest that sunflower has means to adapt to the potentially stressful conditions of continuous light (LL). The qPCR-RT study of the isoforms of circadian clock-associated genes HaLHY, HaTOC1, HaELF3, and HaPIF3 revealed diurnal rhythms under both LD and LL conditions in which the peaks were synchronized and shifted toward the subjective dawn.
... The E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), and the basic leucine-zipper (bZIP) factor ELONGATED HYPOCOTYL 5 (HY5), constitutes the COP1-HY5 module and centers in the cascade [23]. When shaded, the shade signals (low red/far-red light ratio, low blue/green light ratio, and low UV-B signal) are perceived by photoreceptors (PHYTOCHORMES (PHYs), CRYPTOCHROMES (CRYs), and UV RESISTANCE LOCUS 8 (UVR8)), COP1 rapidly re-accumulates in the nucleus, and COP1 activity increases and enhances HY5 degradation [24,25]. ...
The medicinal plant Spatholobus suberectus Dunn is easily exposed to shade stress during growth, but its shade responses and shade stress resistant mechanisms have not been clarified. In this study, shade treatments including four attenuated sunlight intensities (100%, 60%, 40%, and 10%) and three shade durations (30 d, 45 d, and 60 d) were applied to S. suberectus. The shade-induced morphological indicators, phytohormonal regulations, metabolic flavonoids contents, transcriptomic flavonoid pathway gene expressions, and stress physiological changes of S. suberectus were analyzed. The putative promoter cis-regulatory elements (CREs) of 18 flavonoid biosynthetic pathway genes were identified. Results showed the stem growth indicators of S. suberectus were better at 40% light intensity. Phytohormones were involved in the shade-induced responses. Short-term shade (30 d) increased total flavonoids, gallated catechins and especially epigallocatechin gallate contents and favored for boosting medicinal value. Long-term shade (45 d, 60 d) tended to decrease flavonoids. The shade-induced flavonoids changes were attributed to their corresponding biosynthesizing genes expression variations. The high antioxidant capacity and the presence of phytohormone-, stress-, and development-related CREs provided the basis for stress resistance. In conclusion, the multiple responses under shade and the CREs analysis elucidated S. suberectus’ shade tolerance.
... COP1 localizes into the nucleus, where it targets degradation of a long list of photomorphogenesis-promoting factors, including ELONGATED HYPOCOTYL 5 (HY5) (41)(42)(43). HY5 is a master regulator of photomorphogenesis that triggers a large number of light-dependent developmental programs upon exposure to light (44)(45)(46). Although the function of HY5 in transcriptional regulation remains elusive, a recent study showed that HY5 likely functions as a transcriptional activator by directly partnering with various light-dependent transcription factors (47). ...
Light is a crucial environmental factor that impacts various aspects of plant development. Phytochromes, as light sensors, regulate myriads of downstream genes to mediate developmental reprogramming in response to changes in environmental conditions. CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) is an E3 ligase for a number of substrates in light signaling, acting as a central repressor of photomorphogenesis. The interplay between phytochrome B (phyB) and COP1 forms an antagonistic regulatory module that triggers extensive gene expression reprogramming when exposed to light. Here, we uncover a role of COP1 in light-dependent chromatin remodeling through the regulation of VIL1 (VIN3-LIKE 1)/VERNALIZATION 5, a Polycomb protein. VIL1 directly interacts with phyB and regulates photomorphogenesis through the formation of repressive chromatin loops at downstream growth-promoting genes in response to light. Furthermore, we reveal that COP1 governs light-dependent formation of chromatin loop and limiting a repressive histone modification to fine-tune expressions of growth-promoting genes during photomorphogenesis through VIL1.
... The stabilities of PIFs and HY5 are regulated by COP1/SPA and DET1, which are components of the E3 ubiquitin ligase complexes 13 . COP1, SPA, and DET1 are repressors of light-mediated responses in plants 7,13,14 . The E3 ligase activity of COP1 depends on its interaction with SPA 13 . ...
Biosynthesis of specialized metabolites (SM), including phenolics, terpenoids, and alkaloids, is stimulated by many environmental factors including light. In recent years, significant progress has been made in understanding the regulatory mechanisms involved in light-stimulated SM biosynthesis at the transcriptional, posttranscriptional, and posttranslational levels of regulation. While several excellent recent reviews have primarily focused on the impacts of general environmental factors, including light, on biosynthesis of an individual class of SM, here we highlight the regulation of three major SM biosynthesis pathways by light-responsive gene expression, microRNA regulation, and posttranslational modification of regulatory proteins. In addition, we present our future perspectives on this topic.
... HY5 is a transcription factor of the bZIP family. In Arabidopsis, it acts as a growth regulator -it inhibits the growth of the hypocotyl and lateral roots, and its action is light-dependent (Gangappa and Botto, 2016;Bhatnagar et al., 2020). Recently, the role of HY5 in stomata development has been further investigated. ...
Stomata, key gatekeepers of plant hydration, have long been known to play a pivotal role in mitigating the impacts of abiotic stressors. However, the complex molecular mechanisms underscoring this role remain unresolved fully and continue to be the subject of research. In the context of water-use efficiency (WUE), a key indicator of a plant’s ability to conserve water, this aspect links intrinsically with stomatal behavior. Given the pivotal role of stomata in modulating water loss, it can be argued that the complex mechanisms governing stomatal development and function will significantly influence a plant’s WUE under different abiotic stress conditions. Addressing these calls for a concerted effort to strengthen plant adaptability through advanced, targeted research. In this vein, recent studies have illuminated how specific stressors trigger alterations in gene expression, orchestrating changes in stomatal pattern, structure, and opening. This reveals a complex interplay between stress stimuli and regulatory sequences of essential genes implicated in stomatal development, such as MUTE, SPCH, and FAMA. This review synthesizes current discoveries on the molecular foundations of stomatal development and behavior in various stress conditions and their implications for WUE. It highlights the imperative for continued exploration, as understanding and leveraging these mechanisms guarantee enhanced plant resilience amid an ever-changing climatic landscape.
... Thus, the stability of HY5 and the degradation of PIFs inhibit hypocotyl elongation. COP1 is also involved in the regulation of the circadian clock (Bhatnagar et al., 2020). A weak cop1 mutant showed a short circadian clock gene expression cycle and an early flowering phenotype under short daylight [9,15,[22][23][24]. ...
... COP1 is also involved in the regulation of the circadian clock (Bhatnagar et al., 2020). A weak cop1 mutant showed a short circadian clock gene expression cycle and an early flowering phenotype under short daylight [9,15,[22][23][24]. Hormones such as BR (brassinolide), JA (jasmonic acid) and ETH (ethylene) play important roles in the regulation of morphogenesis. ...
... HY5 and HY5L have been reported to interact with COP1 to inhibit the morphogenesis of the hypocotyl elongation of Arabidopsis seedlings [9,22]. To understand whether ZmHY5 is regulated by ZmCOP1, we detected the expressions of ZmHY5 and ZmHY5L in the 5-day-old etiolated seedlings. ...
The morphogenesis of crops is critical to their yield performance. COP1 (constitutively photomorphogenic1) is one of the core regulators in plant morphogenesis and has been deeply studied in Arabidopsis thaliana. However, the function of COP1 in maize is still unclear. Here, we found that the mesocotyl lengths of zmcop1 loss-of-function mutants were shorter than those of wild-type B73 in darkness, while the mesocotyl lengths of lines with ZmCOP1 overexpression were longer than those of wild-type B104. The plant height with zmcop1 was shorter than that of B73 in both short- and long-day photoperiods. Using transcriptome RNA sequencing technology, we identified 33 DEGs (differentially expressed genes) between B73′s etiolated seedlings and those featuring zmcop1, both in darkness. The DEGs were mainly enriched in the plant phytohormone pathways. Our results provide direct evidence that ZmCOP1 functions in the elongation of etiolated seedlings in darkness and affects plant height in light. Our data can be applied in the improvement of maize plant architecture.
... The COP1 and SUPPRESSOR OF PHYA-105 (SPA) ubiquitin E3 ligase complex is a key regulator of shade avoidance response, ubiquitinating and promoting the degradation of positive regulators of photomorphogenesis, such as ELONGATED HYPOCOTYL 5 (HY5), HY5-HOMOLOG (HYH), LONG AFTER FAR-RED LIGHT 1 (LAF1), LONG HYPOCOTYL IN FAR-RED (HFR1), and PHYTOCHROME RAPIDLY REGULATED1/2 (PAR1/2) (Fig. 2a, b) (Liu et al. 2011;Bhatnagar et al. 2020;Zhou et al. 2014;Holm et al. 2002;Seo et al. 2003). The cop1 mutants showed greatly reduced hypocotyl elongation under shade conditions, indicating a vital role for COP1 in mediating the shade-avoidance response (Pacín et al. 2013). ...
The shade avoidance syndrome (SAS) in soybean can have destructive effects on yield, as essential carbon resources reserved for yield are diverted to the petiole and stem for exaggerated elongation, resulting in lodging and susceptibility to disease. Despite numerous attempts to reduce the unfavorable impacts of SAS for the development of cultivars suitable for high-density planting or intercropping, the genetic bases and fundamental mechanisms of SAS remain largely unclear. The extensive research conducted in the model plant Arabidopsis provides a framework for understanding the SAS in soybean. Nevertheless, recent investigations suggest that the knowledge obtained from model Arabidopsis may not be applicable to all processes in soybean. Consequently, further efforts are required to identify the genetic regulators of SAS in soybean for molecular breeding of high-yield cultivars suitable for density farming. In this review, we present an overview of the recent developments in SAS studies in soybean and suggest an ideal planting architecture for shade-tolerant soybean intended for high-yield breeding.
... HY5 (a bZIP TF) was a signaling hub acting downstream of several photoreceptors and a key mediator of photo-morphogenesis, which interacted with COP1 (E3 ubiquitinprotein ligase RFWD2; a negative regulator of photomorphogenesis) (Anita et al., 2018). The HY5-COP1 module acted a common signaling node that mediated cross-talk among multiple pathways, thereby, enhancing the plant phenotypic plasticity (Akankshaa et al., 2020). Our results also confirmed this conclusion, the expression patterns of identified four HY5 (Zm00001d015743, Zm00001d046402, Zm00001d008734, and Zm00001d039658) and two COP1 (Zm00001d014990 and Zm00001d052138) DEGs were same in both tissues under four light exposures (Figure 4; Supplementary Table 4). ...
The plastic elongation of mesocotyl (MES) and coleoptile (COL), which can be repressed by light exposure, plays a vital role in maize seedling emergence and establishment under adverse environmental conditions. Understanding the molecular mechanisms of light-mediated repression of MES and COL elongation in maize will allow us to develop new strategies for genetic improvement of these two crucial traits in maize. A maize variety, Zheng58, was used to monitor the transcriptome and physiological changes in MES and COL in response to darkness, as well as red, blue, and white light. The elongation of MES and COL was significantly inhibited by light spectral quality in this order: blue light > red light > white light. Physiological analyses revealed that light-mediated inhibition of maize MES and COL elongation was closely related to the dynamics of phytohormones accumulation and lignin deposition in these tissues. In response to light exposure, the levels of indole-3-acetic acid, trans-zeatin, gibberellin 3, and abscisic acid levels significantly decreased in MES and COL; by contrast, the levels of jasmonic acid, salicylic acid, lignin, phenylalanine ammonia-lyase, and peroxidase enzyme activity significantly increased. Transcriptome analysis revealed multiple differentially expressed genes (DEGs) involved in circadian rhythm, phytohormone biosynthesis and signal transduction, cytoskeleton and cell wall organization, lignin biosynthesis, and starch and sucrose metabolism. These DEGs exhibited synergistic and antagonistic interactions, forming a complex network that regulated the light-mediated inhibition of MES and COL elongation. Additionally, gene co-expression network analysis revealed that 49 hub genes in one and 19 hub genes in two modules were significantly associated with the elongation plasticity of COL and MES, respectively. These findings enhance our knowledge of the light-regulated elongation mechanisms of MES and COL, and provide a theoretical foundation for developing elite maize varieties with improved abiotic stress resistance.
... HY5 is one of the most studied signaling transcription factors, which sometimes acts redundantly with its closely related homolog HYH (HY5 HOMOLOG) [20,26]. The interaction between HY5 and COP1 is involved in many developmental processes [26]. ...
... HY5 is one of the most studied signaling transcription factors, which sometimes acts redundantly with its closely related homolog HYH (HY5 HOMOLOG) [20,26]. The interaction between HY5 and COP1 is involved in many developmental processes [26]. In photomorphogenesis, COP1 acts as a negative factor to promote the degradation of HY5 [26]. ...
... The interaction between HY5 and COP1 is involved in many developmental processes [26]. In photomorphogenesis, COP1 acts as a negative factor to promote the degradation of HY5 [26]. However, it has been reported that, in UV-B signaling, COP1 positively regulates HY5, and HY5 then mediates UV-B-induced stomatal closure [13,20]. ...
RING-finger-type ubiquitin E3 ligase Constitutively Photomorphogenic 1 (COP1) and floral integrators such as FLOWERING LOCUS T (FT), TWIN SISTER OF FT (TSF) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) have been identified as regulators of stomatal movement. However, little is known about their roles and relationship in dark-induced stomatal closure. Here, we demonstrated that COP1 is required for dark-induced stomatal closure using cop1 mutant. The cop1 mutant closed stomata in response to exogenous nitric oxide (NO) but not hydrogen peroxide (H2O2), and H2O2 but not NO accumulated in cop1 in darkness, further indicating that COP1 acts downstream of H2O2 and upstream of NO in dark-induced stomatal closure. Expression of FT, TSF and SOC1 in wild-type (WT) plants decreased significantly with dark duration time, but this process was blocked in cop1. Furthermore, ft, tsf, and soc1 mutants accumulated NO and closed stomata faster than WT plants in response to darkness. Altogether, our results indicate that COP1 transduces H2O2 signaling, promotes NO accumulation in guard cells by suppressing FT, TSF and SOC1 expression, and consequently leads to stomatal closure in darkness. These findings add new insights into the mechanisms of dark-induced stomatal closure.
... The biological functions of CRYs have been well demonstrated in Arabidopsis, involving in a variety of physiological and biochemical processes, including de-etiolation, flowering, magnetic field induction and drought stress response (Hammad et al., 2020;Liu et al., 2017;Mao et al., 2005;Yu et al., 2010). AtCRYs directly interact with the E3 ubiquitin ligase Constitutively Photomorphogenic 1 (COP1) and inhibits the degradation of the downstream ELONGATED HYPOCOTYL 5 (HY5) or CONSTANS (CO) protein, which are the main positive regulator of photomorphogenesis and flowering regulation (Bhatnagar et al., 2020;Zuo et al., 2011). AtCRYs also directly interact with some transcription regulators such as Auxin/Indole-3-acetic acids (AUX/IAAs), Phytochrome interacting factors (PIFs), Calcium and integrin binding protein 1 (CIB1), BES interacting Myc-like protein 1 (BIM1) and Auxin response factor 6/8 (ARF6/ARF8) to regulate shade avoidance, flowering time, photomorphogenesis and hormone signals (Liu et al., 2013;Mao et al., 2020;Pedmale et al., 2016;Wang et al., 2018;Xu et al., 2018). ...
As a plant blue light receptor, CRY2 plays pleotropic roles in regulating photomorphogenesis, flowering time and stress response. However, the function of CRY2 in the octoploid cultivated strawberry (Fragaria × ananassa Duch.) has not been identified. In this study, certain variation and functional divergences of the FaCRY2 protein were found in compared with its homologs in diploid model plants (AtCRY2 and SlCRY2). Quantitative RT-PCR analysis of the FaCRY2 showed the highest expression level in the leaf and flower tissues. The subcellular localization results indicate that the FaCRY2 was a nucleus-localized protein. The cry2 mutants, silenced by artificial micro-interfering RNA interference (AmiRNAi) using 'Benihoppe' strawberry as genetic background, showed a growth retardation, including dwarf phenotype, decreased free IAA content, delayed flowering time, deepened the lignification degree of petiole cells, decreased stomatal conductance and transpiration rate. RNA-seq analysis showed that there were 910 significantly differentially expressed genes (DEGs) between wild-type (WT) and cry2. They were mainly enriched in hormone regulation, cell development and stress response, etc. The decrease of IAA accumulation could be the main factor responsible for the delayed growth of cry2. Taken together, our results suggested the complex roles of FaCRY2 in the plant growth regulation in cultivated strawberry.
