Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that underg...Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that undergoes blue-light-dependent phosphorylation, ubiquitination, photobody formation, and degradation in the nucleus, but the relationship between these blue-light-dependent events remains unclear. It has been proposed that CRY2 phosphorylation triggers a conformational change responsible for the subsequent ubiquitination and photobody formation, leading to CRY2 function and/or degradation. We tested this hypothesis by a structure-function study, using mutant CRY2-GFP fusion proteins expressed in transgenic Arabidopsis. We show that changes of lysine residues of the NLS （Nuclear Localization Signal） sequence of CRY2 to arginine residues partially impair the nuclear importation of the CRY2Ks41R and CRY2K554/sR mutant proteins, resulting in reduced phosphorylation, physiological activities, and degradation in response to blue light. In contrast to the wild-type CRY2 protein that forms photobodies exclusively in the nucleus, the CRY2K541R and CRY2K554/sR mutant proteins form protein bodies in both the nucleus and cytosol in response to blue light. These results suggest that photoexcited CRY2 molecules can aggregate to form photobody-like structure without the nucleus-dependent protein modifications or the association with the nuclear CRY2-interacting proteins. Taken together, the observation that CRY2 forms photobodies markedly faster than CRY2 phosphorylation in response to blue light, we hypothesize that the photoexcited cryptochromes form oligomers, preceding other biochemical changes of CRY2, to facilitate photobody formation, signal amplification, and propagation, as well as desensitization by degradation.展开更多
Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In thi...Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In this study,we demonstrated that GL promotes atypical photomorphogenesis in Arabidopsis thaliana via the dual regulations of phytochrome B(phyB)and phyA.Although the Pr-to-Pfr conversion rates of phyB and phyA under GL were lower than those under red light(RL)in a fluence rate-dependent and time-dependent manner,long-term treatment with GL induced high Pfr/Pr ratios of phyB and phyA.Moreover,GL induced the formation of numerous small phyB photobodies in the nucleus,resulting in atypical photomorphogenesis,with smaller cotyledon opening angles and longer hypocotyls in seedlings compared to RL.The abundance of phyA significantly decreased after short-and long-term GL treatments.We determined that four major PHYTOCHROME-INTERACTING FACTORs(PIFs:PIF1,PIF3,PIF4,and PIF5)act downstream of phyB in GL-mediated cotyledon opening.In addition,GL plays opposite roles in regulating different PIFs.For example,under continuous GL,the protein levels of all PIFs decreased,whereas the transcript levels of PIF4 and PIF5 strongly increased compared with dark treatment.Taken together,our work provides a detailed molecular framework for understanding the role of the antagonistic regulations of phyB and phyA in GL-mediated atypical photomorphogenesis.展开更多
Soybean(Glycine max(L.) Merr.), grown for its plant oils and proteins, is one of the most important crops throughout the world.Generating stable and heritable transgenic soybeans is relatively inefficient;therefore, t...Soybean(Glycine max(L.) Merr.), grown for its plant oils and proteins, is one of the most important crops throughout the world.Generating stable and heritable transgenic soybeans is relatively inefficient;therefore, there is an urgent need for a simple and high-efficient transient transformation method by which to enable the investigation of gene functions in soybeans, which will facilitate the elucidation and improvement of the molecular mechanisms regulating the associated agronomic traits. We established a system of transient expression in soybean mesophyll protoplasts and obtained a high level of protoplast transfection efficiency(up to 83.5%). The subcellular activity of the protoplasts was well preserved, as demonstrated by the dynamic formation of GmCRY nucleus photobodies(NPs) and/or cytoplasmic photobody-like structures(CPs) in response to blue light.In addition, we showed that GmCRY1b CPs colocalized with GmCOP1b, a co-ortholog of Arabidopsis thaliana CONSTITUTIVE PHOTOMORPHOGENIC 1(COP1), which provided new insight into the potential roles of GmCRY1s in the cytoplasm.展开更多
基金the National Institute of Health，the National Natural Science Foundation of China，National Transgenic Crop Initiative
文摘Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that undergoes blue-light-dependent phosphorylation, ubiquitination, photobody formation, and degradation in the nucleus, but the relationship between these blue-light-dependent events remains unclear. It has been proposed that CRY2 phosphorylation triggers a conformational change responsible for the subsequent ubiquitination and photobody formation, leading to CRY2 function and/or degradation. We tested this hypothesis by a structure-function study, using mutant CRY2-GFP fusion proteins expressed in transgenic Arabidopsis. We show that changes of lysine residues of the NLS （Nuclear Localization Signal） sequence of CRY2 to arginine residues partially impair the nuclear importation of the CRY2Ks41R and CRY2K554/sR mutant proteins, resulting in reduced phosphorylation, physiological activities, and degradation in response to blue light. In contrast to the wild-type CRY2 protein that forms photobodies exclusively in the nucleus, the CRY2K541R and CRY2K554/sR mutant proteins form protein bodies in both the nucleus and cytosol in response to blue light. These results suggest that photoexcited CRY2 molecules can aggregate to form photobody-like structure without the nucleus-dependent protein modifications or the association with the nuclear CRY2-interacting proteins. Taken together, the observation that CRY2 forms photobodies markedly faster than CRY2 phosphorylation in response to blue light, we hypothesize that the photoexcited cryptochromes form oligomers, preceding other biochemical changes of CRY2, to facilitate photobody formation, signal amplification, and propagation, as well as desensitization by degradation.
基金supported by the Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province(2023AH030049)Anhui Agricultural University Startup Fund(grant no.rc422115,to J.J.L.)Anhui Province Fund for University Development(22103103)。
文摘Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In this study,we demonstrated that GL promotes atypical photomorphogenesis in Arabidopsis thaliana via the dual regulations of phytochrome B(phyB)and phyA.Although the Pr-to-Pfr conversion rates of phyB and phyA under GL were lower than those under red light(RL)in a fluence rate-dependent and time-dependent manner,long-term treatment with GL induced high Pfr/Pr ratios of phyB and phyA.Moreover,GL induced the formation of numerous small phyB photobodies in the nucleus,resulting in atypical photomorphogenesis,with smaller cotyledon opening angles and longer hypocotyls in seedlings compared to RL.The abundance of phyA significantly decreased after short-and long-term GL treatments.We determined that four major PHYTOCHROME-INTERACTING FACTORs(PIFs:PIF1,PIF3,PIF4,and PIF5)act downstream of phyB in GL-mediated cotyledon opening.In addition,GL plays opposite roles in regulating different PIFs.For example,under continuous GL,the protein levels of all PIFs decreased,whereas the transcript levels of PIF4 and PIF5 strongly increased compared with dark treatment.Taken together,our work provides a detailed molecular framework for understanding the role of the antagonistic regulations of phyB and phyA in GL-mediated atypical photomorphogenesis.
基金supported by the National Key Research and Development Plan (2016YFD0101005)the National Natural Science Foundation of China (31871705 and 31422041)the Central Public-Interest Scientific Institution Basal Research Fund (Y2016JC13)
文摘Soybean(Glycine max(L.) Merr.), grown for its plant oils and proteins, is one of the most important crops throughout the world.Generating stable and heritable transgenic soybeans is relatively inefficient;therefore, there is an urgent need for a simple and high-efficient transient transformation method by which to enable the investigation of gene functions in soybeans, which will facilitate the elucidation and improvement of the molecular mechanisms regulating the associated agronomic traits. We established a system of transient expression in soybean mesophyll protoplasts and obtained a high level of protoplast transfection efficiency(up to 83.5%). The subcellular activity of the protoplasts was well preserved, as demonstrated by the dynamic formation of GmCRY nucleus photobodies(NPs) and/or cytoplasmic photobody-like structures(CPs) in response to blue light.In addition, we showed that GmCRY1b CPs colocalized with GmCOP1b, a co-ortholog of Arabidopsis thaliana CONSTITUTIVE PHOTOMORPHOGENIC 1(COP1), which provided new insight into the potential roles of GmCRY1s in the cytoplasm.
