The strawberry Fra a 1 proteins belong to the class 10 Pathogenesis-Related(PR-10)superfamily.In strawberry,a large number of members have been identified,but only a limited number is expressed in the fruits.In this o...The strawberry Fra a 1 proteins belong to the class 10 Pathogenesis-Related(PR-10)superfamily.In strawberry,a large number of members have been identified,but only a limited number is expressed in the fruits.In this organ,Fra a 1.01 and Fra a 1.02 are the most abundant Fra proteins in the green and red fruits,respectively,however,their function remains unknown.To know the function of Fra a 1.02 we have generated transgenic lines that silence this gene,and performed metabolomics,RNA-Seq,and hormonal assays.Previous studies associated Fra a 1.02 to strawberry fruit color,but the analysis of anthocyanins in the ripe fruits showed no diminution in their content in the silenced lines.Gene ontology(GO)analysis of the genes differentially expressed indicated that oxidation/reduction was the most represented biological process.Redox state was not apparently altered since no changes were found in ascorbic acid and glutathione(GSH)reduced/oxidized ratio,but GSH content was reduced in the silenced fruits.In addition,a number of glutathione-S-transferases(GST)were down-regulated as result of Fra a 1.02-silencing.Another highly represented GO category was transport which included a number of ABC and MATE transporters.Among the regulatory genes differentially expressed WRKY33.1 and WRKY33.2 were down-regulated,which had previously been assigned a role in strawberry plant defense.A reduced expression of the VQ23 gene and a diminished content of the hormones JA,SA,and IAA were also found.These data might indicate that Fra a 1.02 participates in the defense against pathogens in the ripe strawberry fruits.展开更多
Plants emit an overabundance of volatile compounds, which act in their producers either as appreciated attractants to lure beneficial animals or as repellent toxins to deter pests in a species-specific and concentrati...Plants emit an overabundance of volatile compounds, which act in their producers either as appreciated attractants to lure beneficial animals or as repellent toxins to deter pests in a species-specific and concentration-dependent manner. Plants have evolved solutions to provide sufficient volatiles without poisoning themselves. Uridine-diphosphate sugar-dependent glycosyltransferases （UGTs） acting on vola-tiles is one important part of this sophisticated system, which balances the levels of bioactive metabolites and prepares them for cellular and long-distance transport and storage but enables the remobilization of disarmed toxins for the benefit of plant protection. This review provides an overview of the research history of glycosidically bound volatiles （GBVs）, a relatively new group of plant secondary metabolites, and discusses the role of UGTs in the production of GBVs for plant protection.展开更多
The strawberry Fra a I allergen is a homolog of the major birch pollen allergen Bet v 1. It is synthesized by red ripe fruits of Fragaria x ananassa while white fruits of a mutant genotype, which is known to be tolera...The strawberry Fra a I allergen is a homolog of the major birch pollen allergen Bet v 1. It is synthesized by red ripe fruits of Fragaria x ananassa while white fruits of a mutant genotype, which is known to be tolerated by individuals affected by allergy, are devoid of it. Proteomic analyses have shown that Fra a 1 is down-regulated in the tolerated white- fruited genotype along with enzymes of the anthocyanin pigment pathway. In this study, we report the spatial and tem- poral expression of three Fra a genes that encode different isoforms, and the transient RNAi-mediated silencing of the Fra a genes in strawberry fruits of the red-fruited cultivar Elsanta with an ihpRNA construct. As a consequence of reduced levels of Fra a mRNAs, fruits were obtained that produced significantly decreased levels of anthocyanins and upstream metabolites. This effect is consistent with the parallel down-regulation of the phenylalanine ammonia lyase （FaPAL） and to a lesser extent of the chalcone synthase （FaCHS） transcript levels also found in these fruits. In naturally occurring white- fruited genotypes of F. chiloensis and F. vesca, Fra a transcript levels are higher than those of the red-fruited varieties, likely to compensate for the low expression levels of FaPAL and FaCHS in these mutant genotypes. The results demonstrate that Fra a expression is directly linked to flavonoid biosynthesis and show that the Fra a allergen has an essential biological function in pigment formation in strawberry fruit.展开更多
Uridine diphosphate-dependent glycosyltransferases(UGTs)mediate the glycosylation of plant metabolites,thereby altering their physicochemical properties and bioactivities.Plants possess numerous UGT genes,with the enc...Uridine diphosphate-dependent glycosyltransferases(UGTs)mediate the glycosylation of plant metabolites,thereby altering their physicochemical properties and bioactivities.Plants possess numerous UGT genes,with the encoded enzymes often glycosylating multiple substrates and some exhibiting substrate inhibition kinetics,but the biological function and molecular basis of these phenomena are not fully understood.The promiscuous monolignol/phytoalexin glycosyltransferase NbUGT72AY1 exhibits substrate inhibition(Ki)at 4 mM scopoletin,whereas the highly homologous monolignol StUGT72AY2 is inhibited at 190 mM.We therefore used hydrogen/deuterium exchange mass spectrometry and structure-based mutational analyses of both proteins and introduced NbUGT72AY1 residues into StUGT72AY2 and vice versa to study promiscuity and substrate inhibition of UGTs.A single F87I and chimeric mutant of NbUGT72AY1 showed significantly reducedscopoletin substrate inhibition,whereas its monolignolgly cosylation activity was almost unaffected.Reverse mutations in StUGT72AY2 resulted in increased scopoletin glycosylation,leading to enhanced promiscuity,which was accompanied by substrate inhibition.Studies of 3D structures identified open and closed UGT conformers,allowing visualization of the dynamics of conformational changes that occur during catalysis.Previously postulated substrate access tunnels likely serve as drainage channels.The results suggest a two-site model in which the second substrate molecule binds near the catalytic site and blocks product release.Mutational studies showed that minor changes in amino acid sequence can enhance the promiscuity of the enzyme and add new capabilities such as substrate inhibition without affecting existing functions.The proposed subfunctionalization mechanism of expanded promiscuity may play a role in enzyme evolution and highlights the importance of promiscuous enzymes in providing new functions.展开更多
Creativity is a design feature of human language.This paper presents a cognitive model of verbal creativity that draws on insights from the psychological research into creativity-particularly Glaveanu's 5A model t...Creativity is a design feature of human language.This paper presents a cognitive model of verbal creativity that draws on insights from the psychological research into creativity-particularly Glaveanu's 5A model that distinguishes five crucial perspectives on a creative act(actors,audience,artefacts,actions and affordances).The paper will outline a linguistic version of this model that adopts Construction Grammar as its theoretical foundation.The resulting"5C model of constructional creativity"argues that the central elements of linguistic creativity are constructors,co-constructors,constructs,constructional blending and the constructional network.展开更多
Hydrothermal carbonization(HTC)converts wet biomass into hydrochar and a process liquid,but aromatic compounds in the products have been reported as a roadblock for soil applications as they can inhibit germination,pl...Hydrothermal carbonization(HTC)converts wet biomass into hydrochar and a process liquid,but aromatic compounds in the products have been reported as a roadblock for soil applications as they can inhibit germination,plant growth,and soil microbial activity.Here,we compared HTC and hydrothermal humification(HTH)of cow manure digestate while varying the initial alkaline content by adding KOH.HTH converted 37.5 wt%of the feedstock to artificial humic acids(A-HAs)found in both solid and liquid,twice that of HTC.HTH reduced phenolic and furanic aromatic compounds by over 70%in solids and 90%in liquids.The A-HAs in HTH resemble natural humic acids(N-HA),based on FTIR,UV-vis spectra,and CHN and XRD analysis.The HTH liquid possesses 60%higher total organic carbon(TOC)than HTC.Although one-third of TOC can be precipitated as A-HA,a high TOC concentration remains in the liquid,which is shown to be mainly organic acids.Therefore,we also evaluated the HTC and HTH liquids for anaerobic biomethane production,and found that compared to the original cow manure digestate,the HTH liquids increased methane yield by 110.3 to 158.6%,a significant enhancement relative to the 17.2%increase seen with HTC liquid.The strong reduction in organic acids during biogas production from HTH liquid indicates the potential for converting soluble byproducts into methane,while maintaining high A-HAs levels in the solid product.展开更多
基金This work was supported by grants from the Spanish Ministry of Economy and Competitiveness(MINECO,BIO2013-44199-R)B.O-N.was supported by a FPI fellowship and C.M.by the RYC program of Spanish Ministry of Economy and CompetitivenessThe authors would like to thank and acknowledge the support of this work by the EU funded GoodBerry project(funded from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 679303).
文摘The strawberry Fra a 1 proteins belong to the class 10 Pathogenesis-Related(PR-10)superfamily.In strawberry,a large number of members have been identified,but only a limited number is expressed in the fruits.In this organ,Fra a 1.01 and Fra a 1.02 are the most abundant Fra proteins in the green and red fruits,respectively,however,their function remains unknown.To know the function of Fra a 1.02 we have generated transgenic lines that silence this gene,and performed metabolomics,RNA-Seq,and hormonal assays.Previous studies associated Fra a 1.02 to strawberry fruit color,but the analysis of anthocyanins in the ripe fruits showed no diminution in their content in the silenced lines.Gene ontology(GO)analysis of the genes differentially expressed indicated that oxidation/reduction was the most represented biological process.Redox state was not apparently altered since no changes were found in ascorbic acid and glutathione(GSH)reduced/oxidized ratio,but GSH content was reduced in the silenced fruits.In addition,a number of glutathione-S-transferases(GST)were down-regulated as result of Fra a 1.02-silencing.Another highly represented GO category was transport which included a number of ABC and MATE transporters.Among the regulatory genes differentially expressed WRKY33.1 and WRKY33.2 were down-regulated,which had previously been assigned a role in strawberry plant defense.A reduced expression of the VQ23 gene and a diminished content of the hormones JA,SA,and IAA were also found.These data might indicate that Fra a 1.02 participates in the defense against pathogens in the ripe strawberry fruits.
基金This work was supported by the Deutsche Forschungsgemeinschaft DFG （SCHW634/32-1） and National Natural Science Foundation of China （grant numbers 31870678）.
文摘Plants emit an overabundance of volatile compounds, which act in their producers either as appreciated attractants to lure beneficial animals or as repellent toxins to deter pests in a species-specific and concentration-dependent manner. Plants have evolved solutions to provide sufficient volatiles without poisoning themselves. Uridine-diphosphate sugar-dependent glycosyltransferases （UGTs） acting on vola-tiles is one important part of this sophisticated system, which balances the levels of bioactive metabolites and prepares them for cellular and long-distance transport and storage but enables the remobilization of disarmed toxins for the benefit of plant protection. This review provides an overview of the research history of glycosidically bound volatiles （GBVs）, a relatively new group of plant secondary metabolites, and discusses the role of UGTs in the production of GBVs for plant protection.
文摘The strawberry Fra a I allergen is a homolog of the major birch pollen allergen Bet v 1. It is synthesized by red ripe fruits of Fragaria x ananassa while white fruits of a mutant genotype, which is known to be tolerated by individuals affected by allergy, are devoid of it. Proteomic analyses have shown that Fra a 1 is down-regulated in the tolerated white- fruited genotype along with enzymes of the anthocyanin pigment pathway. In this study, we report the spatial and tem- poral expression of three Fra a genes that encode different isoforms, and the transient RNAi-mediated silencing of the Fra a genes in strawberry fruits of the red-fruited cultivar Elsanta with an ihpRNA construct. As a consequence of reduced levels of Fra a mRNAs, fruits were obtained that produced significantly decreased levels of anthocyanins and upstream metabolites. This effect is consistent with the parallel down-regulation of the phenylalanine ammonia lyase （FaPAL） and to a lesser extent of the chalcone synthase （FaCHS） transcript levels also found in these fruits. In naturally occurring white- fruited genotypes of F. chiloensis and F. vesca, Fra a transcript levels are higher than those of the red-fruited varieties, likely to compensate for the low expression levels of FaPAL and FaCHS in these mutant genotypes. The results demonstrate that Fra a expression is directly linked to flavonoid biosynthesis and show that the Fra a allergen has an essential biological function in pigment formation in strawberry fruit.
文摘Uridine diphosphate-dependent glycosyltransferases(UGTs)mediate the glycosylation of plant metabolites,thereby altering their physicochemical properties and bioactivities.Plants possess numerous UGT genes,with the encoded enzymes often glycosylating multiple substrates and some exhibiting substrate inhibition kinetics,but the biological function and molecular basis of these phenomena are not fully understood.The promiscuous monolignol/phytoalexin glycosyltransferase NbUGT72AY1 exhibits substrate inhibition(Ki)at 4 mM scopoletin,whereas the highly homologous monolignol StUGT72AY2 is inhibited at 190 mM.We therefore used hydrogen/deuterium exchange mass spectrometry and structure-based mutational analyses of both proteins and introduced NbUGT72AY1 residues into StUGT72AY2 and vice versa to study promiscuity and substrate inhibition of UGTs.A single F87I and chimeric mutant of NbUGT72AY1 showed significantly reducedscopoletin substrate inhibition,whereas its monolignolgly cosylation activity was almost unaffected.Reverse mutations in StUGT72AY2 resulted in increased scopoletin glycosylation,leading to enhanced promiscuity,which was accompanied by substrate inhibition.Studies of 3D structures identified open and closed UGT conformers,allowing visualization of the dynamics of conformational changes that occur during catalysis.Previously postulated substrate access tunnels likely serve as drainage channels.The results suggest a two-site model in which the second substrate molecule binds near the catalytic site and blocks product release.Mutational studies showed that minor changes in amino acid sequence can enhance the promiscuity of the enzyme and add new capabilities such as substrate inhibition without affecting existing functions.The proposed subfunctionalization mechanism of expanded promiscuity may play a role in enzyme evolution and highlights the importance of promiscuous enzymes in providing new functions.
文摘Creativity is a design feature of human language.This paper presents a cognitive model of verbal creativity that draws on insights from the psychological research into creativity-particularly Glaveanu's 5A model that distinguishes five crucial perspectives on a creative act(actors,audience,artefacts,actions and affordances).The paper will outline a linguistic version of this model that adopts Construction Grammar as its theoretical foundation.The resulting"5C model of constructional creativity"argues that the central elements of linguistic creativity are constructors,co-constructors,constructs,constructional blending and the constructional network.
文摘Hydrothermal carbonization(HTC)converts wet biomass into hydrochar and a process liquid,but aromatic compounds in the products have been reported as a roadblock for soil applications as they can inhibit germination,plant growth,and soil microbial activity.Here,we compared HTC and hydrothermal humification(HTH)of cow manure digestate while varying the initial alkaline content by adding KOH.HTH converted 37.5 wt%of the feedstock to artificial humic acids(A-HAs)found in both solid and liquid,twice that of HTC.HTH reduced phenolic and furanic aromatic compounds by over 70%in solids and 90%in liquids.The A-HAs in HTH resemble natural humic acids(N-HA),based on FTIR,UV-vis spectra,and CHN and XRD analysis.The HTH liquid possesses 60%higher total organic carbon(TOC)than HTC.Although one-third of TOC can be precipitated as A-HA,a high TOC concentration remains in the liquid,which is shown to be mainly organic acids.Therefore,we also evaluated the HTC and HTH liquids for anaerobic biomethane production,and found that compared to the original cow manure digestate,the HTH liquids increased methane yield by 110.3 to 158.6%,a significant enhancement relative to the 17.2%increase seen with HTC liquid.The strong reduction in organic acids during biogas production from HTH liquid indicates the potential for converting soluble byproducts into methane,while maintaining high A-HAs levels in the solid product.
