Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit th...Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit the stress signals within cells as well as between cells and tissues,and make appropriate adjustments in their growth and development in order to survive and reproduce.In recent years,significant progress has been made on many fronts of the stress signaling research,particularly in understanding the downstream signaling events that culminate at the activation of stress-and nutrient limitation-responsive genes,cellular ion homeostasis,and growth adjustment.However,the revelation of the early events of stress signaling,particularly the identification of primary stress sensors,still lags behind.In this review,we summarize recent work on the genetic and molecular mechanisms of plant abiotic stress and nutrient limitation sensing and signaling and discuss new directions for future studies.展开更多
Iron plays a key role in Parkinson＇s disease （PD）. Increased iron content of the substantia nigra （SN） has been found in PD patients, and divalent metal transporter 1 （DMT1） has been shown to be up-regulated in...Iron plays a key role in Parkinson＇s disease （PD）. Increased iron content of the substantia nigra （SN） has been found in PD patients, and divalent metal transporter 1 （DMT1） has been shown to be up-regulated in the SN of both MPTP-induced PD models and PD patients. However, the mechanisms underlying DMT1 up-regulation are largely unknown. In the present study, we observed that in the SN of 6-hydroxydopamine （6-OHDA）-induced PD rats, DMT1 with the iron responsive element （IRE, DMTI＋IRE）, but not DMT1 without IRE （DMTI-IRE）, was up- regulated, suggesting that increased DMTI＋IRE expression might account for nigral iron accumulation in PD rats. This possibility was further assessed in an in vitro study using 6-OHDA-treated and DMTl＋IRE-over-expressing MES23.5 cells. In 6-OHDA-treated MES23.5 cells, increased iron regulatory protein （IRP） 1 and IRP2 expression was observed, while silencing of IRPs dramatically diminished 6-OHDA-indueed DMTI＋IRE up-regulation. Pre- treatment with N-acetyl-L-cysteine fully suppressed IRPs up-regulation by inhibition of 6-OHDA-indueed oxidative stress. Increased DMTI＋IRE expression resulted in increased iron influx by MES23.5 cells. Our data provide direct evidence that DMTI＋IRE up-regulation can account for IRE/IRP-dependent 6-OHDA-induced iron accumulation initiated by 6-OHDA-induced intracellular oxidative stress and that increased levels of intracellular iron result in ag- gravated oxidative stress. The results of this study provide novel evidence supporting the use of anti-oxidants in the treatment of PD, with the goal of inhibiting iron accumulation by regulation of DMT1 expression.展开更多
Manganese （Mn） is an essential catalytic metal in the Mn-cluster that oxidizes water to produce oxygen dur- ing photosynthesis. However, the transport protein（s） responsible for Mn2＋ import into the chloroplast r...Manganese （Mn） is an essential catalytic metal in the Mn-cluster that oxidizes water to produce oxygen dur- ing photosynthesis. However, the transport protein（s） responsible for Mn2＋ import into the chloroplast re- mains unknown. Here, we report the characterization ofArabidopsis CMT1 （Chloroplast Manganese Trans- porter 1）, an evolutionarily conserved protein in the Uncharacterized Protein Family 0016 （UPFO016）, that is required for manganese accumulation into the chloroplast. CMT1 is expressed primarily in green tissues, and its encoded product is localized in the inner envelope membrane of the chloroplast. Disruption of CMT1 in the T-DNA insertional mutant cmtl-1 resulted in stunted plant growth, defective thylakoid stacking, and severe reduction of photosystem II complexes and photosynthetic activity. Consistent with reduced oxy- gen evolution capacity, the mutant chloroplasts contained less manganese than the wild-type ones. In sup- port of its function as a Mn transporter, CMT1 protein supported the growth and enabled Mn2＋ accumula- tion in the yeast cells of Mn2＋-uptake deficient mutant （3smfl）. Taken together, our results indicate that CMT1 functions as an inner envelope Mn transporter responsible for chloroplast Mn2＋ uptake.展开更多
Trace metals such as manganese(Mn),copper(Cu),zinc(Zn),and iron(Fe)are essential for many biological processes in plant life cycles.However,in excess,they can be toxic and disrupt plant growth processes,which is econo...Trace metals such as manganese(Mn),copper(Cu),zinc(Zn),and iron(Fe)are essential for many biological processes in plant life cycles.However,in excess,they can be toxic and disrupt plant growth processes,which is economically undesirable for crop production.For this reason,processes such as homeostasis and transport control of these trace metals are of constant interest to scientists studying heavily contaminated habitats.Phytoremediation is a promising cleanup technology for soils polluted with heavy metals.However,this technique has some disadvantages,such as the slow growth rate of metal-accumulating plant species,low bioavailability of heavy metals,and long duration of remediation.Microbial-assisted phytoremediation is a promising strategy for hyperaccumulating,detoxifying,or remediating soil contaminants.Arbuscular mycorrhizal fungi(AMF)are found in association with almost all plants,contributing to their healthy performance and providing resistance against environmental stresses.They colonize plant roots and extend their hyphae to the rhizosphere region,assisting in mineral nutrient uptake and regulation of heavy metal acquisition.Endophytic fungi exist in every healthy plant tissue and provide enormous services to their host plants,including growth enhancement by nutrient acquisition,detoxification of heavy metals,secondary metabolite regulation,and enhancement of abiotic/biotic stress tolerance.The aim of the present work is to review the recent literature regarding the role of AMF and endophytic fungi in plant heavy metal tolerance in terms of its regulation in highly contaminated conditions.展开更多
【目的】Heavy metal ATPase(HMA)基因家族广泛参与植物对金属元素的吸收和转运,系统鉴定番茄HMA基因家族成员及其特征,并研究其在应对镉胁迫过程中的功能,为解析番茄重金属转运机制及番茄低镉积累种质创新提供理论依据。【方法】通过...【目的】Heavy metal ATPase(HMA)基因家族广泛参与植物对金属元素的吸收和转运,系统鉴定番茄HMA基因家族成员及其特征,并研究其在应对镉胁迫过程中的功能,为解析番茄重金属转运机制及番茄低镉积累种质创新提供理论依据。【方法】通过生物信息学鉴定番茄HMA基因家族成员,并分析其系统进化树、蛋白理化性质、基因结构、顺式作用元件、基因表达模式等,通过酵母功能互补试验研究SlHMA1的镉转运活性。【结果】番茄基因组中存在8个SlHMAs,分属2个亚组。在基因结构方面,各SlHMAs间及与拟南芥和水稻的同源基因之间都存在显著差异。SlHMAs成员启动子区域含有较多逆境响应相关的顺式作用元件,RT-qPCR结果也揭示大多数SlHMAs表达对镉胁迫有不同程度的组织特异性响应。酵母功能互补试验表明SlHMA1蛋白具有镉转运活性,进化分析表明HMA1广泛存在于植物界,且其ATP水解酶活性相关的氨基酸保守基序DKTGT也在植物界高度保守。【结论】番茄SlHMAs具有HMA家族基因的典型特征,同时也存在功能多样性。SlHMAs及其氨基酸保守基序DKTGT与金属离子转运及镉胁迫响应密切相关,在低镉作物育种方面具有重要应用潜力。展开更多
Cadmium (Cd) is one of the most toxic elements and can be accumulated in plants easily; meanwhile, eIF5A is a highly conserved protein in all eukaryotic organisms. The present work tried to investigate whether eIF5A i...Cadmium (Cd) is one of the most toxic elements and can be accumulated in plants easily; meanwhile, eIF5A is a highly conserved protein in all eukaryotic organisms. The present work tried to investigate whether eIF5A is involved in Cd accumulation and sensitivity in Arabidopsis (Arabidopsis thaliana L.) by comparing the wild-type Columbia-0 (Col-0) with a knockdown mutant of AteIF5A-2, fbr12-3 under Cd stress conditions. The results showed that the mutant fbr12-3 accumulated more Cd in roots and shoots and had significantly lower chlorophyll content, shorter root length, and smaller biomass, suggesting that downregulation of AteIF5A-2 makes the mutant more Cd sensitive. Real-time polymerase chain reaction revealed that the expressions of metal transporters involved in Cd uptake and translocation including IRT1, ZIP1, AtNramp3, and AtHMA4 were significantly increased but the expressions of PCS1 and PCS2 related to Cd detoxification were decreased notably in fbr12-3 compared with Col-0. As a result, an increase in MDA and H<sub>2</sub>O<sub>2</sub> content but decrease in root trolox, glutathione and proline content under Cd stress was observed, indicating that a severer oxidative stress occurs in the mutant. All these results demonstrated for the first time that AteIF5A influences Cd sensitivity by affecting Cd uptake, accumulation, and detoxification in Arabidopsis.展开更多
Zinc(Zn) is an essential trace mineral that is required for plant growth and development. A number of protein transporters, which are involved in Zn uptake, translocation and distribution, are finely regulated to main...Zinc(Zn) is an essential trace mineral that is required for plant growth and development. A number of protein transporters, which are involved in Zn uptake, translocation and distribution, are finely regulated to maintain Zn homeostasis in plant. In this study, we functionally characterized an ATP-binding cassette(ABC) transporter gene, OsPDR7, which is involved in Zn homeostasis. Os PDR7 encodes a plasma membrane-localized protein that is expressed mainly in the exodermis and xylem in the rice root.ospdr7 mutants resulted in higher Zn accumulation compared with the wild type. Heterogeneous expression of OsPDR7 in a yeast mutant rescued the Zn-deficiency phenotype, implying transport activity of OsPDR7 to Zn in yeast. However, no ZIP genes except for OsZIP9 showed change in expression profile in the ospdr7 mutants, which suggested that OsPDR7 maintains cellular Zn homeostasis through regulating Os ZIP9 expression. RNA-Seq analysis further revealed a set of differentially expressed genes between the wild type and ospdr7 mutants that allowed us to propose a possible OsPDR7-associated signaling network involving transporters, hormone responsive genes, and transcription factors. Our results revealed a novel transporter involved in the regulation of Zn homeostasis and will pave the way toward a better understanding of the fine-tuning of gene expression in the network of transporter genes.展开更多
文摘Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth,productivity and quality.Plants have evolved mechanisms to perceive these environmental challenges,transmit the stress signals within cells as well as between cells and tissues,and make appropriate adjustments in their growth and development in order to survive and reproduce.In recent years,significant progress has been made on many fronts of the stress signaling research,particularly in understanding the downstream signaling events that culminate at the activation of stress-and nutrient limitation-responsive genes,cellular ion homeostasis,and growth adjustment.However,the revelation of the early events of stress signaling,particularly the identification of primary stress sensors,still lags behind.In this review,we summarize recent work on the genetic and molecular mechanisms of plant abiotic stress and nutrient limitation sensing and signaling and discuss new directions for future studies.
基金We thank Dr Wei-dong Le for providing the MES23.5 cell line. This work was supported by grants from the National Program of Basic Research sponsored by the Ministry of Science and Tech- nology of China （2006CB500704）, the National Natural Science Foundation of China （30930036, 30770757, 30870858） and the Natural Science Fund of Shandong Province for Distinguished Young Scholars （JQ200807）.
文摘Iron plays a key role in Parkinson＇s disease （PD）. Increased iron content of the substantia nigra （SN） has been found in PD patients, and divalent metal transporter 1 （DMT1） has been shown to be up-regulated in the SN of both MPTP-induced PD models and PD patients. However, the mechanisms underlying DMT1 up-regulation are largely unknown. In the present study, we observed that in the SN of 6-hydroxydopamine （6-OHDA）-induced PD rats, DMT1 with the iron responsive element （IRE, DMTI＋IRE）, but not DMT1 without IRE （DMTI-IRE）, was up- regulated, suggesting that increased DMTI＋IRE expression might account for nigral iron accumulation in PD rats. This possibility was further assessed in an in vitro study using 6-OHDA-treated and DMTl＋IRE-over-expressing MES23.5 cells. In 6-OHDA-treated MES23.5 cells, increased iron regulatory protein （IRP） 1 and IRP2 expression was observed, while silencing of IRPs dramatically diminished 6-OHDA-indueed DMTI＋IRE up-regulation. Pre- treatment with N-acetyl-L-cysteine fully suppressed IRPs up-regulation by inhibition of 6-OHDA-indueed oxidative stress. Increased DMTI＋IRE expression resulted in increased iron influx by MES23.5 cells. Our data provide direct evidence that DMTI＋IRE up-regulation can account for IRE/IRP-dependent 6-OHDA-induced iron accumulation initiated by 6-OHDA-induced intracellular oxidative stress and that increased levels of intracellular iron result in ag- gravated oxidative stress. The results of this study provide novel evidence supporting the use of anti-oxidants in the treatment of PD, with the goal of inhibiting iron accumulation by regulation of DMT1 expression.
文摘Manganese （Mn） is an essential catalytic metal in the Mn-cluster that oxidizes water to produce oxygen dur- ing photosynthesis. However, the transport protein（s） responsible for Mn2＋ import into the chloroplast re- mains unknown. Here, we report the characterization ofArabidopsis CMT1 （Chloroplast Manganese Trans- porter 1）, an evolutionarily conserved protein in the Uncharacterized Protein Family 0016 （UPFO016）, that is required for manganese accumulation into the chloroplast. CMT1 is expressed primarily in green tissues, and its encoded product is localized in the inner envelope membrane of the chloroplast. Disruption of CMT1 in the T-DNA insertional mutant cmtl-1 resulted in stunted plant growth, defective thylakoid stacking, and severe reduction of photosystem II complexes and photosynthetic activity. Consistent with reduced oxy- gen evolution capacity, the mutant chloroplasts contained less manganese than the wild-type ones. In sup- port of its function as a Mn transporter, CMT1 protein supported the growth and enabled Mn2＋ accumula- tion in the yeast cells of Mn2＋-uptake deficient mutant （3smfl）. Taken together, our results indicate that CMT1 functions as an inner envelope Mn transporter responsible for chloroplast Mn2＋ uptake.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFD-0800807)the National Nature Science Foundation of China(Nos.31702003 and 31902105)+3 种基金the Young Elite Scientists Sponsorship Program of China Association for Science and Technology(CAST)(No.2017QNRC001)the China Postdoctoral Science Foundation(No.2019 M651505)the“Chenguang Program”of the Shanghai Education Development Foundation and Shanghai Municipal Education Commission,China(No.17CG07)the Shanghai Agriculture Science and Technology Development Project,China(No.2018-4-13).
文摘Trace metals such as manganese(Mn),copper(Cu),zinc(Zn),and iron(Fe)are essential for many biological processes in plant life cycles.However,in excess,they can be toxic and disrupt plant growth processes,which is economically undesirable for crop production.For this reason,processes such as homeostasis and transport control of these trace metals are of constant interest to scientists studying heavily contaminated habitats.Phytoremediation is a promising cleanup technology for soils polluted with heavy metals.However,this technique has some disadvantages,such as the slow growth rate of metal-accumulating plant species,low bioavailability of heavy metals,and long duration of remediation.Microbial-assisted phytoremediation is a promising strategy for hyperaccumulating,detoxifying,or remediating soil contaminants.Arbuscular mycorrhizal fungi(AMF)are found in association with almost all plants,contributing to their healthy performance and providing resistance against environmental stresses.They colonize plant roots and extend their hyphae to the rhizosphere region,assisting in mineral nutrient uptake and regulation of heavy metal acquisition.Endophytic fungi exist in every healthy plant tissue and provide enormous services to their host plants,including growth enhancement by nutrient acquisition,detoxification of heavy metals,secondary metabolite regulation,and enhancement of abiotic/biotic stress tolerance.The aim of the present work is to review the recent literature regarding the role of AMF and endophytic fungi in plant heavy metal tolerance in terms of its regulation in highly contaminated conditions.
文摘【目的】Heavy metal ATPase(HMA)基因家族广泛参与植物对金属元素的吸收和转运,系统鉴定番茄HMA基因家族成员及其特征,并研究其在应对镉胁迫过程中的功能,为解析番茄重金属转运机制及番茄低镉积累种质创新提供理论依据。【方法】通过生物信息学鉴定番茄HMA基因家族成员,并分析其系统进化树、蛋白理化性质、基因结构、顺式作用元件、基因表达模式等,通过酵母功能互补试验研究SlHMA1的镉转运活性。【结果】番茄基因组中存在8个SlHMAs,分属2个亚组。在基因结构方面,各SlHMAs间及与拟南芥和水稻的同源基因之间都存在显著差异。SlHMAs成员启动子区域含有较多逆境响应相关的顺式作用元件,RT-qPCR结果也揭示大多数SlHMAs表达对镉胁迫有不同程度的组织特异性响应。酵母功能互补试验表明SlHMA1蛋白具有镉转运活性,进化分析表明HMA1广泛存在于植物界,且其ATP水解酶活性相关的氨基酸保守基序DKTGT也在植物界高度保守。【结论】番茄SlHMAs具有HMA家族基因的典型特征,同时也存在功能多样性。SlHMAs及其氨基酸保守基序DKTGT与金属离子转运及镉胁迫响应密切相关,在低镉作物育种方面具有重要应用潜力。
基金supported by Program for Innovative Research Team in Universities (IRT1185)the Fundamental Research Funds for the Central Universities
文摘Cadmium (Cd) is one of the most toxic elements and can be accumulated in plants easily; meanwhile, eIF5A is a highly conserved protein in all eukaryotic organisms. The present work tried to investigate whether eIF5A is involved in Cd accumulation and sensitivity in Arabidopsis (Arabidopsis thaliana L.) by comparing the wild-type Columbia-0 (Col-0) with a knockdown mutant of AteIF5A-2, fbr12-3 under Cd stress conditions. The results showed that the mutant fbr12-3 accumulated more Cd in roots and shoots and had significantly lower chlorophyll content, shorter root length, and smaller biomass, suggesting that downregulation of AteIF5A-2 makes the mutant more Cd sensitive. Real-time polymerase chain reaction revealed that the expressions of metal transporters involved in Cd uptake and translocation including IRT1, ZIP1, AtNramp3, and AtHMA4 were significantly increased but the expressions of PCS1 and PCS2 related to Cd detoxification were decreased notably in fbr12-3 compared with Col-0. As a result, an increase in MDA and H<sub>2</sub>O<sub>2</sub> content but decrease in root trolox, glutathione and proline content under Cd stress was observed, indicating that a severer oxidative stress occurs in the mutant. All these results demonstrated for the first time that AteIF5A influences Cd sensitivity by affecting Cd uptake, accumulation, and detoxification in Arabidopsis.
基金jointly supported by the Key Research and Development Plan of Jiangsu Province,China (Grant No. BE2020318-2)the National Natural Science Foundation of China (Grant No. U19A2026)。
文摘Zinc(Zn) is an essential trace mineral that is required for plant growth and development. A number of protein transporters, which are involved in Zn uptake, translocation and distribution, are finely regulated to maintain Zn homeostasis in plant. In this study, we functionally characterized an ATP-binding cassette(ABC) transporter gene, OsPDR7, which is involved in Zn homeostasis. Os PDR7 encodes a plasma membrane-localized protein that is expressed mainly in the exodermis and xylem in the rice root.ospdr7 mutants resulted in higher Zn accumulation compared with the wild type. Heterogeneous expression of OsPDR7 in a yeast mutant rescued the Zn-deficiency phenotype, implying transport activity of OsPDR7 to Zn in yeast. However, no ZIP genes except for OsZIP9 showed change in expression profile in the ospdr7 mutants, which suggested that OsPDR7 maintains cellular Zn homeostasis through regulating Os ZIP9 expression. RNA-Seq analysis further revealed a set of differentially expressed genes between the wild type and ospdr7 mutants that allowed us to propose a possible OsPDR7-associated signaling network involving transporters, hormone responsive genes, and transcription factors. Our results revealed a novel transporter involved in the regulation of Zn homeostasis and will pave the way toward a better understanding of the fine-tuning of gene expression in the network of transporter genes.
基金Supported by"2009 Clinical and Basic Clinical Research Contest"of the Bureau for Clinical Research Support from the University of Chile Clinical Hospital
文摘AIM: To describe the variation that divalent metal transporter 1 (DMT1) shows in patients after Roux-en-Y gastric bypass (RYGB) surgery.
