Lycopene, one of the strongest natural antioxidants known and the main carotene in ripe tomato, is very important for human health. Light is well known to be one of the most important environmental stimuli influencing...Lycopene, one of the strongest natural antioxidants known and the main carotene in ripe tomato, is very important for human health. Light is well known to be one of the most important environmental stimuli influencing lycopene biosynthesis; specifically, red light induces higher lycopene content in tomato. However, whether blue light promotes lycopene synthesis remains elusive and exactly how light stimulation promotes lycopene synthesis remains unclear. We applied supplemental blue and red lighting on tomato plants at anthesis to monitor the effect of supplemental blue and red lighting on lycopene synthesis. Our results showed that supplemental blue/red lighting induced higher lycopene content in tomato fruits; furthermore, we found that the expression of key genes in the lycopene synthesis pathway was induced by supplemented blue/red light. The expression of light signaling components, such as red-light receptor phytochromes(PHYs), blue-light receptor cryptochromes(CRYs) and light interaction factors, phytochrome-interacting factors(PIFs) and ELONGATED HYPOCOTYL 5(HY5) were up-or down-regulated by blue/red lighting. Thus, blue and red light increased lycopene content in tomatoes by inducing light receptors that modulate HY5 and PIFs activation to mediate phytoene synthase 1(PSY1) gene expression. These results provide a sound theoretical basis for further elucidation of the light regulating mechanism of lycopene synthesis in tomatoes, and for instituting a new generation of technological innovations for the enhancement of lycopene accumulation in crop production.展开更多
It is well-documented that phytochromes can control plant growth and development from germination to flowering. Additionally, these photoreceptors have been shown to modulate both biotic and abiotic stress. This has l...It is well-documented that phytochromes can control plant growth and development from germination to flowering. Additionally, these photoreceptors have been shown to modulate both biotic and abiotic stress. This has led to a series of studies exploring the molecular and biochemical basis by which phytochromes modulate stresses, such as salinity, drought, high light or herbivory. Evidence for a role of phytrochromes in plant stress tolerance is explored and reviewed.展开更多
A subfamily of four Phytochrome （phy）-Interacting bHLH transcription Factors （PIFs） collectively promote skotomorphogenic development in dark-grown seedlings. This activity is reversed upon exposure to light, by p...A subfamily of four Phytochrome （phy）-Interacting bHLH transcription Factors （PIFs） collectively promote skotomorphogenic development in dark-grown seedlings. This activity is reversed upon exposure to light, by photoacti- vated phy molecules that induce degradation of the PIFs, thereby triggering the transcriptional changes that drive a tran- sition to photomorphogenesis. The PIFs function both redundantly and partially differentially at the morphogenic level in this process, To identify the direct targets of PIF transcriptional regulation genome-wide, we analyzed the DNA-binding sites for all four PIFs by ChlP-seq analysis, and defined the genes transcriptionally regulated by each PIF, using RNA-seq analysis of pif mutants. Despite the absence of detectable differences in DNA-binding-motif recognition between the PIFs, the data show a spectrum of regulatory patterns, ranging from single PIF dominance to equal contributions by all four. Similarly, a broad array of promoter architectures was found, ranging from single PIF-binding sites, containing single sequence motifs, through multiple PIF-binding sites, each containing one or more motifs, with each site occupied prefer- entially by one to multiple PIFs. Quantitative analysis of the promoter occupancy and expression level induced by each PIF revealed an intriguing pattern. Although there is no robust correlation broadly across the target-gene population, examination of individual genes that are shared targets of multiple PIFs shows a gradation in correlation from strongly positive, through uncorrelated, to negative. This finding suggests a dual-layered mechanism of transcriptional regulation, comprising both a continuum of binding-site occupancy by each PIF and a superimposed layer of local regulation that acts differentially on each PIF, to modulate its intrinsic transcriptional activation capacity at each site, in a quantitative pattern that varies between the individual PIFs from gene to gene. These findings provide a framework for probing the mecha-展开更多
The stomatal pores of plant leaves, situated in the epidermis and surrounded by a pair of guard cells, allow CO2 uptake for photosynthesis and water loss through transpiration. Blue light is one of the dominant enviro...The stomatal pores of plant leaves, situated in the epidermis and surrounded by a pair of guard cells, allow CO2 uptake for photosynthesis and water loss through transpiration. Blue light is one of the dominant environmental signals that control stomatal movements in leaves of plants in a natural environment. This blue light response is mediated by blue/UV A light-absorbing phototropins （phots） and cryptochromes （crys）. Red/far-red light-absorbing phytochromes （phys） also play a role in the control of stomatal aperture. The signaling components that link the perception of light signals to the stomatal opening response are largely unknown. This review discusses a few newly discovered nuclear genes, their function with respect to the phot-, cry-, and phy-mediated signal transduction cascades, and possible involve- ment of circadian clock.展开更多
Separately, it is well-documented that phytochromes (phys), gibberellin (GA) and abscisic acid (ABA) strongly control the seed germination in tomato. However, we hipothesized that phys interact with GA or ABA during t...Separately, it is well-documented that phytochromes (phys), gibberellin (GA) and abscisic acid (ABA) strongly control the seed germination in tomato. However, we hipothesized that phys interact with GA or ABA during this response. Thus, we make an analysis of seed germination of ABA deficient (sit), GA constitutive response (pro), phytochrome deficient (au) mutants as well as, specially, au sit and au pro double mutants of tomato?incubated in the dark or light conditions during 120 h [12 h intervals (i)]. Compared to au, which severely?reduced percentage germination (Gi%) and pro, which did not alter Gi%, au pro showed in the light enhanced Gi% and germination speed index (GSI) besides the reduced average germination time (AGT). Moreover, in the dark, germination of au pro was similar to pro. These results indicate that the mechanisms by which GA modulate germination in tomato are light dependent through the phy signaling, whereas intermediary values of Gi%, GSI and AGT in dark and light of au sit compared to au and sit single mutants indicate an additive effect of the au and sit mutations, suggesting that ABA and phy may act through the parallel signaling pathway.展开更多
Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified i...Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified in the last decade many far-red light signaling mutants and several red and blue light signaling mutants, suggesting the existence of distinct red, far-red, or blue light signaling pathways downstream of phytochromes and cryptochromes. However, genetic screens have also identified mutants with defective de-etiolation responses under multiple wavelengths. Thus, the opti- mal de-etiolation responses of a plant depend on coordination among the different light signaling pathways. This review intends to discuss several recently identified signaling components that have a potential role to integrate red, far-red, and blue light signalings. This review also highlights the recent discoveries on proteolytic degradation in the desensitization of light signal transmission, and the tight connection of light signaling with photoperiodic flowering and circadian rhythm. Studies on the controlling mechanisms of de-etiolation, photoperiodic flowering, and circadian rhythm have been the fascinating topics in Arabidopsis research. The knowledge obtained from Arabidopsis can be readily applied to food crops and ornamental species, and can be contributed to our general understanding of signal perception and transduction in all organisms.展开更多
Previous studies demonstrated that cryptochromes are involved in blue light-induced coiling and prehaustoria development in young de-etiolated dodder seedlings. In this study, we suggest that carotenoids and chlorophy...Previous studies demonstrated that cryptochromes are involved in blue light-induced coiling and prehaustoria development in young de-etiolated dodder seedlings. In this study, we suggest that carotenoids and chlorophyll are not the blue light absorbing chromophores involved in the mediation of prehaustoria development to blue light. Norflurazon-bleached dodder segments coiled and formed prehaustoria under blue light. However, norflurazon significantly reduced prehaustoria number （62%） under a mixture of red and far-red light, suggesting that phytochromes could be altered by norflurazon.展开更多
基金supported by the National Key Research and Development Program of China (2017YFD0701500)the Teamwork Projects Funded by Guangdong Natural Science Foundation, China (S2013030012842)the Guangzhou Science & Technology Project, China (201704020058)
文摘Lycopene, one of the strongest natural antioxidants known and the main carotene in ripe tomato, is very important for human health. Light is well known to be one of the most important environmental stimuli influencing lycopene biosynthesis; specifically, red light induces higher lycopene content in tomato. However, whether blue light promotes lycopene synthesis remains elusive and exactly how light stimulation promotes lycopene synthesis remains unclear. We applied supplemental blue and red lighting on tomato plants at anthesis to monitor the effect of supplemental blue and red lighting on lycopene synthesis. Our results showed that supplemental blue/red lighting induced higher lycopene content in tomato fruits; furthermore, we found that the expression of key genes in the lycopene synthesis pathway was induced by supplemented blue/red light. The expression of light signaling components, such as red-light receptor phytochromes(PHYs), blue-light receptor cryptochromes(CRYs) and light interaction factors, phytochrome-interacting factors(PIFs) and ELONGATED HYPOCOTYL 5(HY5) were up-or down-regulated by blue/red lighting. Thus, blue and red light increased lycopene content in tomatoes by inducing light receptors that modulate HY5 and PIFs activation to mediate phytoene synthase 1(PSY1) gene expression. These results provide a sound theoretical basis for further elucidation of the light regulating mechanism of lycopene synthesis in tomatoes, and for instituting a new generation of technological innovations for the enhancement of lycopene accumulation in crop production.
文摘It is well-documented that phytochromes can control plant growth and development from germination to flowering. Additionally, these photoreceptors have been shown to modulate both biotic and abiotic stress. This has led to a series of studies exploring the molecular and biochemical basis by which phytochromes modulate stresses, such as salinity, drought, high light or herbivory. Evidence for a role of phytrochromes in plant stress tolerance is explored and reviewed.
文摘A subfamily of four Phytochrome （phy）-Interacting bHLH transcription Factors （PIFs） collectively promote skotomorphogenic development in dark-grown seedlings. This activity is reversed upon exposure to light, by photoacti- vated phy molecules that induce degradation of the PIFs, thereby triggering the transcriptional changes that drive a tran- sition to photomorphogenesis. The PIFs function both redundantly and partially differentially at the morphogenic level in this process, To identify the direct targets of PIF transcriptional regulation genome-wide, we analyzed the DNA-binding sites for all four PIFs by ChlP-seq analysis, and defined the genes transcriptionally regulated by each PIF, using RNA-seq analysis of pif mutants. Despite the absence of detectable differences in DNA-binding-motif recognition between the PIFs, the data show a spectrum of regulatory patterns, ranging from single PIF dominance to equal contributions by all four. Similarly, a broad array of promoter architectures was found, ranging from single PIF-binding sites, containing single sequence motifs, through multiple PIF-binding sites, each containing one or more motifs, with each site occupied prefer- entially by one to multiple PIFs. Quantitative analysis of the promoter occupancy and expression level induced by each PIF revealed an intriguing pattern. Although there is no robust correlation broadly across the target-gene population, examination of individual genes that are shared targets of multiple PIFs shows a gradation in correlation from strongly positive, through uncorrelated, to negative. This finding suggests a dual-layered mechanism of transcriptional regulation, comprising both a continuum of binding-site occupancy by each PIF and a superimposed layer of local regulation that acts differentially on each PIF, to modulate its intrinsic transcriptional activation capacity at each site, in a quantitative pattern that varies between the individual PIFs from gene to gene. These findings provide a framework for probing the mecha-
文摘The stomatal pores of plant leaves, situated in the epidermis and surrounded by a pair of guard cells, allow CO2 uptake for photosynthesis and water loss through transpiration. Blue light is one of the dominant environmental signals that control stomatal movements in leaves of plants in a natural environment. This blue light response is mediated by blue/UV A light-absorbing phototropins （phots） and cryptochromes （crys）. Red/far-red light-absorbing phytochromes （phys） also play a role in the control of stomatal aperture. The signaling components that link the perception of light signals to the stomatal opening response are largely unknown. This review discusses a few newly discovered nuclear genes, their function with respect to the phot-, cry-, and phy-mediated signal transduction cascades, and possible involve- ment of circadian clock.
文摘Separately, it is well-documented that phytochromes (phys), gibberellin (GA) and abscisic acid (ABA) strongly control the seed germination in tomato. However, we hipothesized that phys interact with GA or ABA during this response. Thus, we make an analysis of seed germination of ABA deficient (sit), GA constitutive response (pro), phytochrome deficient (au) mutants as well as, specially, au sit and au pro double mutants of tomato?incubated in the dark or light conditions during 120 h [12 h intervals (i)]. Compared to au, which severely?reduced percentage germination (Gi%) and pro, which did not alter Gi%, au pro showed in the light enhanced Gi% and germination speed index (GSI) besides the reduced average germination time (AGT). Moreover, in the dark, germination of au pro was similar to pro. These results indicate that the mechanisms by which GA modulate germination in tomato are light dependent through the phy signaling, whereas intermediary values of Gi%, GSI and AGT in dark and light of au sit compared to au and sit single mutants indicate an additive effect of the au and sit mutations, suggesting that ABA and phy may act through the parallel signaling pathway.
文摘Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified in the last decade many far-red light signaling mutants and several red and blue light signaling mutants, suggesting the existence of distinct red, far-red, or blue light signaling pathways downstream of phytochromes and cryptochromes. However, genetic screens have also identified mutants with defective de-etiolation responses under multiple wavelengths. Thus, the opti- mal de-etiolation responses of a plant depend on coordination among the different light signaling pathways. This review intends to discuss several recently identified signaling components that have a potential role to integrate red, far-red, and blue light signalings. This review also highlights the recent discoveries on proteolytic degradation in the desensitization of light signal transmission, and the tight connection of light signaling with photoperiodic flowering and circadian rhythm. Studies on the controlling mechanisms of de-etiolation, photoperiodic flowering, and circadian rhythm have been the fascinating topics in Arabidopsis research. The knowledge obtained from Arabidopsis can be readily applied to food crops and ornamental species, and can be contributed to our general understanding of signal perception and transduction in all organisms.
基金the National Natural Science Fouindation of China(Grant No.30270689)the Science Fundifor Distinguished Young Scholars of Hcnan Province(Grant No.0312001600the Ministry or Science,SporIs.and Culture of Japan(Grant No.13139202 to K.S.).
文摘Previous studies demonstrated that cryptochromes are involved in blue light-induced coiling and prehaustoria development in young de-etiolated dodder seedlings. In this study, we suggest that carotenoids and chlorophyll are not the blue light absorbing chromophores involved in the mediation of prehaustoria development to blue light. Norflurazon-bleached dodder segments coiled and formed prehaustoria under blue light. However, norflurazon significantly reduced prehaustoria number （62%） under a mixture of red and far-red light, suggesting that phytochromes could be altered by norflurazon.
