Osmotic stress caused by drought and high salinity is a significant environmental threat that limits plant growth and agricultural yield. Redox regulation plays an important role in plant stress responses, but the mec...Osmotic stress caused by drought and high salinity is a significant environmental threat that limits plant growth and agricultural yield. Redox regulation plays an important role in plant stress responses, but the mechanisms by which plants perceive and transduce redox signals are still underexplored. Here, we report a critical function for the thiol peroxidase GPX1 in osmotic stress response in rice, where it serves as a redox sensor and transducer. GPX1 is quickly oxidized upon exposure to osmotic stress and forms an intramolecular disulfide bond, which is required for the activation of bZIP68, a VRE-like basic leucine zipper (bZIP) transcription factor involved in the ABA-independent osmotic stress response pathway. The disulfide exchange between GPX1 and bZIP68 induces homo-tetramerization of bZIP68 and thus positively regulates osmotic stress response by regulating osmotic-responsive gene expression. Furthermore, we discovered that the nuclear translocation of GPX1 is regulated by its acetylation under osmotic stress. Taken together, our findings not only uncover the redox regulation of the GPX1-bZIP68 module during osmotic stress but also highlight the coordination of protein acetylation and redox signaling in plant osmotic stress responses.展开更多
In photosynthetic organisms, tetrapyrrole-mediated retrograde signals are proposed to contribute to a bal- anced nuclear gene expression （NGE） in response to metabolic activity in chloroplasts. We followed an experi...In photosynthetic organisms, tetrapyrrole-mediated retrograde signals are proposed to contribute to a bal- anced nuclear gene expression （NGE） in response to metabolic activity in chloroplasts. We followed an experimental short- term approach that allowed the assessment of modified NGE during the first hours of specifically modified enzymatic steps of the Mg branch of tetrapyrrole biosynthesis, when pleiotropic effects of other signals can be avoided. In response to 24-h-induced silencing of CHLH, CHLM, and CHL27 encoding the CHLH subunit of Mg chelatase, the Mg protoporphyrin methyltransferase and Mg protoporphyrin monomethylester cyclase, respectively, deactivated gene expression rapidly led to reduced activity of the corresponding enzymes and altered Mg porphyrin levels. But NGE was not substantially altered. When these three genes were continuously inactivated for up to 4 d, changes of transcript levels of nuclear genes were determined. CHL27 silencing for more than 24h results in necrotic leaf lesions and modulated transcript levels of oxidative stress-responsive and photosynthesis-associated nuclear genes （PhANGs）. The prolonged deactivation of CHLH and CHLM results in slightly elevated transcript levels of PhANGs and tetrapyrrole-associated genes. These time-resolved studies indicate a complex scenario for the contribution of tetrapyrrole biosynthesis on NGE mediated by IO2-induced signaling and feedback-regulated ALA synthesis.展开更多
Plastid-to-nucleus signaling is essential for the coordination and adjustment of cellular metabolism in response to environmental and developmental cues of plant cells. A variety of operational retrograde signaling pa...Plastid-to-nucleus signaling is essential for the coordination and adjustment of cellular metabolism in response to environmental and developmental cues of plant cells. A variety of operational retrograde signaling path- ways have been described that are thought to be triggered by reactive oxygen species, photosynthesis redox imbalance, tetrapyrrole intermediates, and other metabolic traits. Here we report a meta-analysis based on transcriptome and pro- tein interaction data. Comparing the output of these pathways reveals the commonalities and peculiarities stimulated by six different sources impinging on operational retrograde signaling. Our study provides novel insights into the interplay of these pathways, supporting the existence of an as-yet unknown core response module of genes being regulated under all conditions tested. Our analysis further highlights affiliated regulatory cis-elements and classifies abscisic acid and auxin-based signaling as secondary components involved in the response cascades following a plastidial signal. Our study provides a global analysis of structure and interfaces of different pathways involved in plastid-to-nucleus signaling and a new view on this complex cellular communication network.展开更多
Protein phosphorylation is a well-established post-translational mechanism that regulates protein functions and metabolic pathways.It is known that several plant mitochondrial proteins are phosphorylated in a reversib...Protein phosphorylation is a well-established post-translational mechanism that regulates protein functions and metabolic pathways.It is known that several plant mitochondrial proteins are phosphorylated in a reversible manner.However,the identities of the protein kinases/phosphatases involved in this mech-anism and their roles in the regulation of the tricarboxylic acid(TCA)cycle remain unclear.In this study,we isolated and characterized plants lacking two mitochondrially targeted phosphatases(Sal2 and PP2c63)along with pyruvate dehydrogenase kinase(PDK),Protein-protein interaction analysis,quantitative phos-phoproteomics,and enzymatic analyses revealed that PDK specifically regulates pyruvate dehydrogenase complex(PDC),while PP2c63 nonspecifically regulates PDC.When recombinant PP2c63 and Sal2 proteins were added to mitochondria isolated from mutant plants,protein-protein interaction and enzymatic analyses showed that PP2c63 directly phosphorylates and modulates the activity of PDC,while Sal2 only indirectly affects TCA cycle enzymes.Characterization of steady-state metabolite levels and fluxes in the mutant lines further revealed that these phosphatases regulate flux through the TCA cycle,and that altered metabolism in the sa/2 pp2c63 double mutant compromises plant growth.These results are discussed in the context of current models of the control of respiration in plants.展开更多
基金supported by grants from the National Natural Science Foundation of Jiangsu Province(BK20200561)the National Natural Science Foundation of China(32101671 and 31670255)+3 种基金the National Natural Science Foundation of Jiangsu Province(BK20200282 and BK20161447)the National Science Fund for Outstanding Young Scholars(21922702)the China Postdoctoral Science Foundation(2019M661860)the Fundamental Research Funds for the Central Universities(KYZ201859).
文摘Osmotic stress caused by drought and high salinity is a significant environmental threat that limits plant growth and agricultural yield. Redox regulation plays an important role in plant stress responses, but the mechanisms by which plants perceive and transduce redox signals are still underexplored. Here, we report a critical function for the thiol peroxidase GPX1 in osmotic stress response in rice, where it serves as a redox sensor and transducer. GPX1 is quickly oxidized upon exposure to osmotic stress and forms an intramolecular disulfide bond, which is required for the activation of bZIP68, a VRE-like basic leucine zipper (bZIP) transcription factor involved in the ABA-independent osmotic stress response pathway. The disulfide exchange between GPX1 and bZIP68 induces homo-tetramerization of bZIP68 and thus positively regulates osmotic stress response by regulating osmotic-responsive gene expression. Furthermore, we discovered that the nuclear translocation of GPX1 is regulated by its acetylation under osmotic stress. Taken together, our findings not only uncover the redox regulation of the GPX1-bZIP68 module during osmotic stress but also highlight the coordination of protein acetylation and redox signaling in plant osmotic stress responses.
文摘In photosynthetic organisms, tetrapyrrole-mediated retrograde signals are proposed to contribute to a bal- anced nuclear gene expression （NGE） in response to metabolic activity in chloroplasts. We followed an experimental short- term approach that allowed the assessment of modified NGE during the first hours of specifically modified enzymatic steps of the Mg branch of tetrapyrrole biosynthesis, when pleiotropic effects of other signals can be avoided. In response to 24-h-induced silencing of CHLH, CHLM, and CHL27 encoding the CHLH subunit of Mg chelatase, the Mg protoporphyrin methyltransferase and Mg protoporphyrin monomethylester cyclase, respectively, deactivated gene expression rapidly led to reduced activity of the corresponding enzymes and altered Mg porphyrin levels. But NGE was not substantially altered. When these three genes were continuously inactivated for up to 4 d, changes of transcript levels of nuclear genes were determined. CHL27 silencing for more than 24h results in necrotic leaf lesions and modulated transcript levels of oxidative stress-responsive and photosynthesis-associated nuclear genes （PhANGs）. The prolonged deactivation of CHLH and CHLM results in slightly elevated transcript levels of PhANGs and tetrapyrrole-associated genes. These time-resolved studies indicate a complex scenario for the contribution of tetrapyrrole biosynthesis on NGE mediated by IO2-induced signaling and feedback-regulated ALA synthesis.
文摘Plastid-to-nucleus signaling is essential for the coordination and adjustment of cellular metabolism in response to environmental and developmental cues of plant cells. A variety of operational retrograde signaling path- ways have been described that are thought to be triggered by reactive oxygen species, photosynthesis redox imbalance, tetrapyrrole intermediates, and other metabolic traits. Here we report a meta-analysis based on transcriptome and pro- tein interaction data. Comparing the output of these pathways reveals the commonalities and peculiarities stimulated by six different sources impinging on operational retrograde signaling. Our study provides novel insights into the interplay of these pathways, supporting the existence of an as-yet unknown core response module of genes being regulated under all conditions tested. Our analysis further highlights affiliated regulatory cis-elements and classifies abscisic acid and auxin-based signaling as secondary components involved in the response cascades following a plastidial signal. Our study provides a global analysis of structure and interfaces of different pathways involved in plastid-to-nucleus signaling and a new view on this complex cellular communication network.
基金the Max Planck Society(A.R.F.and Y.Z)and the European Union's Horizon 2020 Research and Innovation program,project PlantaSYST(A.R.F.and Y.Z.)Deutsche For-schungsgemeinschaft(FI 1655/3-1 and INST 211/744-1 FUGG for I.F).
文摘Protein phosphorylation is a well-established post-translational mechanism that regulates protein functions and metabolic pathways.It is known that several plant mitochondrial proteins are phosphorylated in a reversible manner.However,the identities of the protein kinases/phosphatases involved in this mech-anism and their roles in the regulation of the tricarboxylic acid(TCA)cycle remain unclear.In this study,we isolated and characterized plants lacking two mitochondrially targeted phosphatases(Sal2 and PP2c63)along with pyruvate dehydrogenase kinase(PDK),Protein-protein interaction analysis,quantitative phos-phoproteomics,and enzymatic analyses revealed that PDK specifically regulates pyruvate dehydrogenase complex(PDC),while PP2c63 nonspecifically regulates PDC.When recombinant PP2c63 and Sal2 proteins were added to mitochondria isolated from mutant plants,protein-protein interaction and enzymatic analyses showed that PP2c63 directly phosphorylates and modulates the activity of PDC,while Sal2 only indirectly affects TCA cycle enzymes.Characterization of steady-state metabolite levels and fluxes in the mutant lines further revealed that these phosphatases regulate flux through the TCA cycle,and that altered metabolism in the sa/2 pp2c63 double mutant compromises plant growth.These results are discussed in the context of current models of the control of respiration in plants.
