Fig(Ficus carica L.)with purple-red peel cultivars are popular among consumers and exhibit better storability.While DNA methylation influences fruit ripening and color development,its specific role in fig fruit remain...Fig(Ficus carica L.)with purple-red peel cultivars are popular among consumers and exhibit better storability.While DNA methylation influences fruit ripening and color development,its specific role in fig fruit remains unclear.This study explores the impact of DNA methylation on the fig peel coloration.Enzymatic colorimetric detection revealed that the level of‘Purple Peel’fig DNA methylation decreases with fig fruit ripening and coloring.Treatment of young fruit with the DNA-methylation inhibitor azacytidine induced peel coloration,suggesting that a decrease in DNA-methylation level promotes fig peel coloration.Seven members of DNA methyltransferases and three members of DNA demethylases were identified from a high-level fig genome,highlighting FcMET1 and FcDRM2 as stable proteins,ensuring functional expression.Reference to the Arabidopsis protein interaction network map predicted that FcMET1 is in a central position,suggesting a crucial regulatory role in multiple biological processes.Correlation analysis revealed a positive correlation between FcMET1 expression during peel development and the level of total DNA methylation.Weighted gene co-expression network analysis identified co-expression of FcMET1 with the color-related transcription factors MYB,bHLH and WD40,as well as with eight structural genes in the flavonoid-biosynthesis pathway.The expression of FcUFGT3 was negatively correlated with that of FcMET1.McrBC-PCR and Bisulfite Sequencing detection showed that a low methylation level of the FcUFGT3 promoter corresponds with its high expression in colored fig.This investigation of the mechanism of DNA methylation provides a theoretical basis for understanding the role of DNA-methylation modifications in fig ripening and coloring.展开更多
Tea plant(Camellia sinensis(L.)O.Kuntze)is a cold-sensitive leaf-harvesting crop whose growth,yield,and processed tea quality are all inhibited by low temperatures.Therefore,identifying the regulatory genes involved i...Tea plant(Camellia sinensis(L.)O.Kuntze)is a cold-sensitive leaf-harvesting crop whose growth,yield,and processed tea quality are all inhibited by low temperatures.Therefore,identifying the regulatory genes involved in tea plant growth and freezing tolerance is crucial for genetic improvement.WRKY transcription factors regulate various plant processes,including growth and development,stress responses,and metabolite biosynthesis.However,the molecular network through which WRKY coordinates these pathways in tea plants remains unclear.In this study,we revealed that CsWRKY57L,a cold-inducible WRKY IIc subfamily member,positively regulated freezing tolerance by directly promoting flavonoid accumulation in tea plants.Transient suppression of CsWRKY57L weakened the freezing tolerance of tea plants by reducing flavonoid content and suppressing the C-repeat-binding factor(CBF)-cold-responsive(COR)gene pathway.In contrast,heterologous overexpression of CsWRKY57L in Arabidopsis had the opposite effect.Additionally,overexpression of CsWRKY57L inhibited reproductive development and accelerated senescence in Arabidopsis.Interaction analysis revealed that CsWRKY57L directly binds to the promoters of CsSWEET1a,CsSWEET15,and AtSWEET15,which encode sugar transporters essential for plant reproductive development,and inhibits their transcription.Overall,the study revealed a dual role of CsWRKY57L in promoting freezing tolerance via flavonoid biosynthesis and inhibiting reproductive development by regulating SWEETs expression.This study uncovers a novel mechanism whereby CsWRKY57L coordinately regulates both stress responses and growth in tea plants,providing a molecular basis for breeding low-temperature-tolerant varieties with restricted reproductive development.展开更多
Spinal cord ischemia-reperfusion injury,a severe form of spinal cord damage,can lead to sensory and motor dysfunction.This injury often occurs after traumatic events,spinal cord surgeries,or thoracoabdominal aortic su...Spinal cord ischemia-reperfusion injury,a severe form of spinal cord damage,can lead to sensory and motor dysfunction.This injury often occurs after traumatic events,spinal cord surgeries,or thoracoabdominal aortic surgeries.The unpredictable nature of this condition,combined with limited treatment options,poses a significant burden on patients,their families,and society.Spinal cord ischemia-reperfusion injury leads to reduced neuronal regenerative capacity and complex pathological processes.In contrast,mitophagy is crucial for degrading damaged mitochondria,thereby supporting neuronal metabolism and energy supply.However,while moderate mitophagy can be beneficial in the context of spinal cord ischemia-reperfusion injury,excessive mitophagy may be detrimental.Therefore,this review aims to investigate the potential mechanisms and regulators of mitophagy involved in the pathological processes of spinal cord ischemia-reperfusion injury.The goal is to provide a comprehensive understanding of recent advancements in mitophagy related to spinal cord ischemia-reperfusion injury and clarify its potential clinical applications.展开更多
Radish(Raphanus sativus L.)is an important cruciferous root vegetable,with bolting regulated by multiple genes.However,the genetic mechanisms underlying bolting regulation remain unclear.Here,the genome of the cultiva...Radish(Raphanus sativus L.)is an important cruciferous root vegetable,with bolting regulated by multiple genes.However,the genetic mechanisms underlying bolting regulation remain unclear.Here,the genome of the cultivar C60213 is assembled into a high-quality,gap-free telomere-to-telomere structure,spanning nine chromosomes and totaling 472.71 Mb,using a combination of Oxford Nanopore,PacBio,and Hi-C sequencing technologies.It identifies 49,768 protein-coding genes,97.38%of which are functionally annotated.Repetitive sequences constitute 59.72%of the genome,primarily comprising long terminal repeats.A high-density genetic linkage map is constructed using an F2 population derived from a cross between early-and late-bolting radishes,identifying seven major quantitative trait loci associated with bolting and flowering.RNA-seq and quantitative real-time PCR analysis reveal that the RsMIPS3 gene is found to be associated with bolting,with its expression decreasing during this process.Notably,RsMIPS3 overexpression in Arabidopsis delays bolting,confirming its role in regulating bolting time.These findings advance radish genome research and provide a valuable target for breeding late-bolting varieties.展开更多
Although both abscisic acid(ABA)and methyl jasmonate(MeJA)play significant roles in regulating the development and quality of grape(Vitis vinifera L.)berries,the regulatory effects and mechanisms of the combined appli...Although both abscisic acid(ABA)and methyl jasmonate(MeJA)play significant roles in regulating the development and quality of grape(Vitis vinifera L.)berries,the regulatory effects and mechanisms of the combined application of ABA and MeJA remain unclear.To further explore the optimal combination of these hormones for regulating the development of grape quality,combined ABA and MeJA treatments were carried out in this study,with‘Jumeigui’grape used as the material.The results indicated that the combined treatment of high-ABA and low-MeJA(HA+LM)increased the sugar-acid ratio,promoted the accumulation of phenolic substances in grape skins,and resulted in anthocyanin content 168.9%higher than that of the control,significantly enhancing coloration.Additionally,the combined treatment of low-ABA and low-MeJA(LA+LM)was more conducive to the accumulation of phenols in grape,especially phenolic acid and resveratrol,as the total phenolic content increased by 38.96%relative to that of the control.Moreover,the expressions of aroma-related genes were upregulated by the combined high-MeJA treatments.The combined treatment of high-ABA and high-MeJA(HA+HM)markedly increased terpene biosynthesis,followed by the LA+HM treatment,increasing the intensity of the rose flavor characteristics of the‘Jumeigui’grape.Therefore,the combination of MeJA and ABA at different concentrations had distinct effects on fruit quality and appropriate combinations can be selected according to the specific needs for the targeted metabolites.展开更多
L-茶氨酸(L-Theanine,LTA)是茶叶中独特的游离氨基酸,是茶汤鲜爽味的主要来源,具有多种生物活性,属于新食品原料。本文基于Citespace和VOSviewer对Web of Science核心数据库和中国知网数据库,对2014~2024年LTA相关文献进行可视化分析,...L-茶氨酸(L-Theanine,LTA)是茶叶中独特的游离氨基酸,是茶汤鲜爽味的主要来源,具有多种生物活性,属于新食品原料。本文基于Citespace和VOSviewer对Web of Science核心数据库和中国知网数据库,对2014~2024年LTA相关文献进行可视化分析,其中关键词密度和贡献图谱结果显示LTA相关研究集中在茶叶类型、胁迫反应、LTA的生物活性等方面。因此,本文综述了茶叶LTA含量的影响因素,并重点阐述LTA生物活性作用机制,包括抗氧化、抗热应激、抗抑郁、调节代谢、抗癌、调节免疫、调节肠道菌群、保护神经系统、保护肝脏和保护肠道的作用机制,发现LTA主要通过调控核因子κB(Nuclear factor kappa B,NF-κB)、c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)、信号传导及转录激活因子(Signal transducer and activator of transcription,STAT)和丝裂原活化蛋白激酶(Mitogen-activated protein kinase,MAPK)等信号通路发挥生物活性功能,并总结了当前LTA在食品产业中的实际应用。本文可为LTA的研究和发展提供方向,并为开发LTA功能性食品提供一定的参考。展开更多
NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-l...NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-like PRRSV evolved,named the L1A variant.The phylogenetics,epidemic status,and pathogenicity of the LA variants were subsequently comprehensively evaluated.Based on the results of the ORF5 phylogenetic analysis,the L1A variants were classified as NADC34-like PPRSV.All the strains had the same discontinuous 131-aa deletion in the NSP2 region(similar to that in the NADC30).Recombination analysis revealed that the L1A variants were recombinant viruses that contained an NADC30-like PRRSV skeleton,a nonstructural protein-encoding gene region obtained in part from JXA1-like PRRSV and a ORF2-ORF6 gene region partly obtained from NADC34-like PRRSV and that exhibited similar recombination patterns.We successfully isolated the L1A variant TZJ2756 from PAMs and Marc-145 cells.In animal experiments,TZJ2756 exhibited moderate pathogenicity in piglets,causing obvious clinical symptoms,namely,persistent fever,significantly reduced body weight,interstitial edema and severe interstitial pneumonia in the lungs,and prolonged high-load viremia.L1A variants have been detected in at least 12 provinces in China and share many similar epidemiological characteristics with the American L1C variant.This research will enhance our understanding of the prevalence of L1A variants and furnish valuable data for the ongoing monitoring of NADC34-like PRRSV in China.展开更多
The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tub...The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tubers is regulated remains poorly understood.In this study,we identified and functionally validated key transcription factors that regulate anthocyanin biosynthesis based on a comparative transcriptome and metabolome analysis of three D.alata cultivars with different colored tubers(dark purple,light purple,and white).The anthocyanin glycoside cyanidin-3-O-(2′′-O-glucosyl)glucoside was abundant during early tuber development,and we determined that its accumulation is regulated in opposite manners by two R2R3-MYB transcription factors:DaMYB75 and DaMYB56.Yeast two-hybrid and bimolecular fluorescence complementation assays in Nicotiana benthamiana and co-expression assays in D.alata demonstrated that DaMYB75 promotes anthocyanin biosynthesis by specifically activating the promoter of the late anthocyanin biosynthesis gene DaANS and enhancing its expression through an interaction with DabHLH72.By contrast,DaMYB56 is a negative regulator of anthocyanin biosynthesis that binds to the DaANS promoter together with DabHLH72.Furthermore,the methylation levels of the DaMYB75 promoter were significantly lower in purple tubers than in white tubers.These findings shed light on the regulation of anthocyanin biosynthesis by MYBs and provide the basis for genetically improving anthocyanin content in D.alata.展开更多
L-缬氨酸具有广泛市场需求,目前工业生产L-缬氨酸方法主要是微生物发酵法。随着代谢工程策略的不断组合叠加,理性改造菌株代谢L-缬氨酸遇到瓶颈导致产量提升受限;非理性改造策略作为提升目标产物合成效率的一种补充策略被广泛应用于生...L-缬氨酸具有广泛市场需求,目前工业生产L-缬氨酸方法主要是微生物发酵法。随着代谢工程策略的不断组合叠加,理性改造菌株代谢L-缬氨酸遇到瓶颈导致产量提升受限;非理性改造策略作为提升目标产物合成效率的一种补充策略被广泛应用于生物领域,然而非理性改造面临菌株突变文库庞大、传统高产菌株筛选方式耗时长、效率低等困境,因此需要一种快速高效筛选目标产物的工具缩短非理性改造菌株的周期。本研究基于一株经理性代谢工程改造的谷氨酸棒状杆菌L-缬氨酸生产菌SX-4,构建了一种与L-缬氨酸浓度呈正相关的生物传感器。通过更换不同强度的核糖体结合位点(ribosome binding site,RBS)序列优化响应精准度、拓宽响应范围;进一步利用常压室温等离子体诱变(atmospheric and room temperature plasma,ARTP)技术构建大量诱变菌株文库,并利用液滴微流控技术实现了L-缬氨酸高产菌株的高通量筛选。所获得的菌株A23于摇瓶培养48 h,L-缬氨酸产量为21.36 g/L,相较于出发菌株提升了46.5%。本研究为其他氨基酸非理性改造研究提供了理论基础与借鉴。展开更多
基金supported by 111 Project(Grant No.B17043)China Postdoctoral Science Foundation(Grant No.2022M723425).
摘要Fig(Ficus carica L.)with purple-red peel cultivars are popular among consumers and exhibit better storability.While DNA methylation influences fruit ripening and color development,its specific role in fig fruit remains unclear.This study explores the impact of DNA methylation on the fig peel coloration.Enzymatic colorimetric detection revealed that the level of‘Purple Peel’fig DNA methylation decreases with fig fruit ripening and coloring.Treatment of young fruit with the DNA-methylation inhibitor azacytidine induced peel coloration,suggesting that a decrease in DNA-methylation level promotes fig peel coloration.Seven members of DNA methyltransferases and three members of DNA demethylases were identified from a high-level fig genome,highlighting FcMET1 and FcDRM2 as stable proteins,ensuring functional expression.Reference to the Arabidopsis protein interaction network map predicted that FcMET1 is in a central position,suggesting a crucial regulatory role in multiple biological processes.Correlation analysis revealed a positive correlation between FcMET1 expression during peel development and the level of total DNA methylation.Weighted gene co-expression network analysis identified co-expression of FcMET1 with the color-related transcription factors MYB,bHLH and WD40,as well as with eight structural genes in the flavonoid-biosynthesis pathway.The expression of FcUFGT3 was negatively correlated with that of FcMET1.McrBC-PCR and Bisulfite Sequencing detection showed that a low methylation level of the FcUFGT3 promoter corresponds with its high expression in colored fig.This investigation of the mechanism of DNA methylation provides a theoretical basis for understanding the role of DNA-methylation modifications in fig ripening and coloring.
基金supported by the National Natural Science Foundation of China(Grant Nos.32072630,32372774,and U22A20499)the earmarked fund for CARS(Grant No.CARS-19-01A).
摘要Tea plant(Camellia sinensis(L.)O.Kuntze)is a cold-sensitive leaf-harvesting crop whose growth,yield,and processed tea quality are all inhibited by low temperatures.Therefore,identifying the regulatory genes involved in tea plant growth and freezing tolerance is crucial for genetic improvement.WRKY transcription factors regulate various plant processes,including growth and development,stress responses,and metabolite biosynthesis.However,the molecular network through which WRKY coordinates these pathways in tea plants remains unclear.In this study,we revealed that CsWRKY57L,a cold-inducible WRKY IIc subfamily member,positively regulated freezing tolerance by directly promoting flavonoid accumulation in tea plants.Transient suppression of CsWRKY57L weakened the freezing tolerance of tea plants by reducing flavonoid content and suppressing the C-repeat-binding factor(CBF)-cold-responsive(COR)gene pathway.In contrast,heterologous overexpression of CsWRKY57L in Arabidopsis had the opposite effect.Additionally,overexpression of CsWRKY57L inhibited reproductive development and accelerated senescence in Arabidopsis.Interaction analysis revealed that CsWRKY57L directly binds to the promoters of CsSWEET1a,CsSWEET15,and AtSWEET15,which encode sugar transporters essential for plant reproductive development,and inhibits their transcription.Overall,the study revealed a dual role of CsWRKY57L in promoting freezing tolerance via flavonoid biosynthesis and inhibiting reproductive development by regulating SWEETs expression.This study uncovers a novel mechanism whereby CsWRKY57L coordinately regulates both stress responses and growth in tea plants,providing a molecular basis for breeding low-temperature-tolerant varieties with restricted reproductive development.
基金supported by Cuiying Scientific and Technological Innovation Program of Second Hospital of Lanzhou University,Nos.CY2023-QN-B18(to YD),2020QN-16(to YZ)the Natural Science Foundation of Gansu Province,No.22JR11RA082(to YZ)Key R&D Plan of Gansu Provincial Department of Science and Technology-Social Development Projects,No.23YFFA0043(to XK).
摘要Spinal cord ischemia-reperfusion injury,a severe form of spinal cord damage,can lead to sensory and motor dysfunction.This injury often occurs after traumatic events,spinal cord surgeries,or thoracoabdominal aortic surgeries.The unpredictable nature of this condition,combined with limited treatment options,poses a significant burden on patients,their families,and society.Spinal cord ischemia-reperfusion injury leads to reduced neuronal regenerative capacity and complex pathological processes.In contrast,mitophagy is crucial for degrading damaged mitochondria,thereby supporting neuronal metabolism and energy supply.However,while moderate mitophagy can be beneficial in the context of spinal cord ischemia-reperfusion injury,excessive mitophagy may be detrimental.Therefore,this review aims to investigate the potential mechanisms and regulators of mitophagy involved in the pathological processes of spinal cord ischemia-reperfusion injury.The goal is to provide a comprehensive understanding of recent advancements in mitophagy related to spinal cord ischemia-reperfusion injury and clarify its potential clinical applications.
基金supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U22A20494)the 1+9 Open Competition Project of Sichuan Academy of Agricultural Sciences(1+9KJGGo02)+4 种基金the National Key R&D Program of China(2024YFA130670O)the“5+1”Agricultural Frontier Technology Research Initiative of Sichuan Academy of Agricultural Sciences(5+1QYGG003)the Project of Sichuan Province Engineering Technology Research Center of Vegetables(2023PZSC0303)the 14th Five-Year Plan Vegetable Breeding Project of Sichuan Province(2021YFYZ0022)the Experts of Sichuan Vegetable Innovation Team(SCCXTD-2025-05).
摘要Radish(Raphanus sativus L.)is an important cruciferous root vegetable,with bolting regulated by multiple genes.However,the genetic mechanisms underlying bolting regulation remain unclear.Here,the genome of the cultivar C60213 is assembled into a high-quality,gap-free telomere-to-telomere structure,spanning nine chromosomes and totaling 472.71 Mb,using a combination of Oxford Nanopore,PacBio,and Hi-C sequencing technologies.It identifies 49,768 protein-coding genes,97.38%of which are functionally annotated.Repetitive sequences constitute 59.72%of the genome,primarily comprising long terminal repeats.A high-density genetic linkage map is constructed using an F2 population derived from a cross between early-and late-bolting radishes,identifying seven major quantitative trait loci associated with bolting and flowering.RNA-seq and quantitative real-time PCR analysis reveal that the RsMIPS3 gene is found to be associated with bolting,with its expression decreasing during this process.Notably,RsMIPS3 overexpression in Arabidopsis delays bolting,confirming its role in regulating bolting time.These findings advance radish genome research and provide a valuable target for breeding late-bolting varieties.
基金supported by the Xi'an Key Research and Development Program(Grant No.24NYGG0057)the National Natural Science Foundation of China(Grant No.U22A20491)the Shaanxi Key Research and Development Program(Grant No.2024NC-YBXM-024).
摘要Although both abscisic acid(ABA)and methyl jasmonate(MeJA)play significant roles in regulating the development and quality of grape(Vitis vinifera L.)berries,the regulatory effects and mechanisms of the combined application of ABA and MeJA remain unclear.To further explore the optimal combination of these hormones for regulating the development of grape quality,combined ABA and MeJA treatments were carried out in this study,with‘Jumeigui’grape used as the material.The results indicated that the combined treatment of high-ABA and low-MeJA(HA+LM)increased the sugar-acid ratio,promoted the accumulation of phenolic substances in grape skins,and resulted in anthocyanin content 168.9%higher than that of the control,significantly enhancing coloration.Additionally,the combined treatment of low-ABA and low-MeJA(LA+LM)was more conducive to the accumulation of phenols in grape,especially phenolic acid and resveratrol,as the total phenolic content increased by 38.96%relative to that of the control.Moreover,the expressions of aroma-related genes were upregulated by the combined high-MeJA treatments.The combined treatment of high-ABA and high-MeJA(HA+HM)markedly increased terpene biosynthesis,followed by the LA+HM treatment,increasing the intensity of the rose flavor characteristics of the‘Jumeigui’grape.Therefore,the combination of MeJA and ABA at different concentrations had distinct effects on fruit quality and appropriate combinations can be selected according to the specific needs for the targeted metabolites.
摘要L-茶氨酸(L-Theanine,LTA)是茶叶中独特的游离氨基酸,是茶汤鲜爽味的主要来源,具有多种生物活性,属于新食品原料。本文基于Citespace和VOSviewer对Web of Science核心数据库和中国知网数据库,对2014~2024年LTA相关文献进行可视化分析,其中关键词密度和贡献图谱结果显示LTA相关研究集中在茶叶类型、胁迫反应、LTA的生物活性等方面。因此,本文综述了茶叶LTA含量的影响因素,并重点阐述LTA生物活性作用机制,包括抗氧化、抗热应激、抗抑郁、调节代谢、抗癌、调节免疫、调节肠道菌群、保护神经系统、保护肝脏和保护肠道的作用机制,发现LTA主要通过调控核因子κB(Nuclear factor kappa B,NF-κB)、c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)、信号传导及转录激活因子(Signal transducer and activator of transcription,STAT)和丝裂原活化蛋白激酶(Mitogen-activated protein kinase,MAPK)等信号通路发挥生物活性功能,并总结了当前LTA在食品产业中的实际应用。本文可为LTA的研究和发展提供方向,并为开发LTA功能性食品提供一定的参考。
基金supported by grants from the National Natural Science Foundation of China(32172890 and 32002315)the National Key Research and Development Program of China(2022YFF0711004)+3 种基金the Natural Science Foundation of Heilongjiang Province,China(YQ2022C042)the State Key Laboratory of Veterinary Biotechnology Foundation of China(SKLVBF202208)the Postdoctoral Fellowship Program of CPSF,China(GZC20233062)the National Center of Technology Innovation for Pigs,China(NCTIP-XD/C09)。
摘要NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-like PRRSV evolved,named the L1A variant.The phylogenetics,epidemic status,and pathogenicity of the LA variants were subsequently comprehensively evaluated.Based on the results of the ORF5 phylogenetic analysis,the L1A variants were classified as NADC34-like PPRSV.All the strains had the same discontinuous 131-aa deletion in the NSP2 region(similar to that in the NADC30).Recombination analysis revealed that the L1A variants were recombinant viruses that contained an NADC30-like PRRSV skeleton,a nonstructural protein-encoding gene region obtained in part from JXA1-like PRRSV and a ORF2-ORF6 gene region partly obtained from NADC34-like PRRSV and that exhibited similar recombination patterns.We successfully isolated the L1A variant TZJ2756 from PAMs and Marc-145 cells.In animal experiments,TZJ2756 exhibited moderate pathogenicity in piglets,causing obvious clinical symptoms,namely,persistent fever,significantly reduced body weight,interstitial edema and severe interstitial pneumonia in the lungs,and prolonged high-load viremia.L1A variants have been detected in at least 12 provinces in China and share many similar epidemiological characteristics with the American L1C variant.This research will enhance our understanding of the prevalence of L1A variants and furnish valuable data for the ongoing monitoring of NADC34-like PRRSV in China.
基金supported by the National Natural Science Foundation of China(32460767)Jiangxi Provincial Key Research and Development Program(20232BBF60007)Jiangxi Provincial Natural Science Foundation(20224BAB205024).
摘要The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tubers is regulated remains poorly understood.In this study,we identified and functionally validated key transcription factors that regulate anthocyanin biosynthesis based on a comparative transcriptome and metabolome analysis of three D.alata cultivars with different colored tubers(dark purple,light purple,and white).The anthocyanin glycoside cyanidin-3-O-(2′′-O-glucosyl)glucoside was abundant during early tuber development,and we determined that its accumulation is regulated in opposite manners by two R2R3-MYB transcription factors:DaMYB75 and DaMYB56.Yeast two-hybrid and bimolecular fluorescence complementation assays in Nicotiana benthamiana and co-expression assays in D.alata demonstrated that DaMYB75 promotes anthocyanin biosynthesis by specifically activating the promoter of the late anthocyanin biosynthesis gene DaANS and enhancing its expression through an interaction with DabHLH72.By contrast,DaMYB56 is a negative regulator of anthocyanin biosynthesis that binds to the DaANS promoter together with DabHLH72.Furthermore,the methylation levels of the DaMYB75 promoter were significantly lower in purple tubers than in white tubers.These findings shed light on the regulation of anthocyanin biosynthesis by MYBs and provide the basis for genetically improving anthocyanin content in D.alata.
摘要L-缬氨酸具有广泛市场需求,目前工业生产L-缬氨酸方法主要是微生物发酵法。随着代谢工程策略的不断组合叠加,理性改造菌株代谢L-缬氨酸遇到瓶颈导致产量提升受限;非理性改造策略作为提升目标产物合成效率的一种补充策略被广泛应用于生物领域,然而非理性改造面临菌株突变文库庞大、传统高产菌株筛选方式耗时长、效率低等困境,因此需要一种快速高效筛选目标产物的工具缩短非理性改造菌株的周期。本研究基于一株经理性代谢工程改造的谷氨酸棒状杆菌L-缬氨酸生产菌SX-4,构建了一种与L-缬氨酸浓度呈正相关的生物传感器。通过更换不同强度的核糖体结合位点(ribosome binding site,RBS)序列优化响应精准度、拓宽响应范围;进一步利用常压室温等离子体诱变(atmospheric and room temperature plasma,ARTP)技术构建大量诱变菌株文库,并利用液滴微流控技术实现了L-缬氨酸高产菌株的高通量筛选。所获得的菌株A23于摇瓶培养48 h,L-缬氨酸产量为21.36 g/L,相较于出发菌株提升了46.5%。本研究为其他氨基酸非理性改造研究提供了理论基础与借鉴。