Trichome formation has been extensively studied as a mechanistic model for epidermal cell differentiation and cell morphogenesis in plants. However, the genetic and molecular mechanisms underlying trichome formation ...Trichome formation has been extensively studied as a mechanistic model for epidermal cell differentiation and cell morphogenesis in plants. However, the genetic and molecular mechanisms underlying trichome formation （i.e., initiation and elongation） in rice remain largely unclear. Here, we report an AP2/ERF transcription factor, Hairy Leaf 6 （HL6）, which controls trichome formation in rice. Functional analyses revealed that HL6 transcriptionally regulates trichome elongation in rice, which is dependent on functional OsWOX3B, a homeodomain-containing protein that acts as a key regulator in trichome initiation. Biochemical and molecular genetic analyses demonstrated that HL6 physically interacts with OsWOX3B, and both of them regulate the expression of some auxin-related genes during trichome formation, in which OsWOX3B likely enhances the binding ability of HL6 with one of its direct target gene, OsYUCCA5. Popu- lation genetic analysis indicated that HL6 was under negative selection during rice domestication. Taken together, our findings provide new insights into the molecular regulatory network of trichome formation in rice.展开更多
In plants, the meristem has to maintain a separate population of pluripotent cells that serve two main tasks, i.e., self-maintenance and organ initiation, which are separated spatially in meristem. Prior to our study,...In plants, the meristem has to maintain a separate population of pluripotent cells that serve two main tasks, i.e., self-maintenance and organ initiation, which are separated spatially in meristem. Prior to our study, WUS and WUS.like WOX genes had been reported as essential for the development of the SAM. In this study, the consequences of gain of WOX1 function are described. Here we report the identification of an Arabidopsis gain-of-function mutant woxl-D, in which the expression level of the WOX1 （WUSCHEL HOMEOBOX 1） was elevated and subtle defects in meristem development were observed. The woxl-D mutant phenotype is dwarfed and slightly bushy, with a smaller shoot apex. The woxl-D mutant also produced small and dark green leaves, and exhibited a failure in anther dehiscence and male sterility. Molecular evidences showed that the transcription of the stem cell marker gene CLV3 was down-regulated in the meristem of woxl-D but accumulated in the other regions, i.e., in the root-hypocotyl junction and at the sites for lateral root initiation. The fact that the organ size and cell size in leaves of woxl-D are smaller than those in wild type suggests that cell expansion is possibly affected in order to have partially retarded the development of lateral organs, possibly through alteration of CLV3 expression pattern in the meristem. An S-adenosylmethionine decarboxylase （SAMDC） protein, SAMDC1, was found able to interact with WOX1 by yeast two-hybrid and pull-down assays in vitro. HPLC analysis revealed a significant reduction of polyamine content in woxl-D. Our results suggest that WOX1 plays an important role in meristem development in Arabidopsis, possibly via regulation of SAMDC activity and polyamine homeostasis, and/or by regulating CLV3 expression.展开更多
Gene amplification followed by functional diversification is a major force in evolution. A typical example of this is seen in the WUSCHEL-RELATED HOMEOBOX （WOX） gene family, named after the Arabidopsis stem cell reg...Gene amplification followed by functional diversification is a major force in evolution. A typical example of this is seen in the WUSCHEL-RELATED HOMEOBOX （WOX） gene family, named after the Arabidopsis stem cell regulator WUSCHEL. Here we analyze functional divergence in the WOX gene family. Members of the WUS clade, except the cambium stem cell regulator WOX4, can substitute for WUS function in shoot and floral stem cell maintenance to different degrees. Stem cell function of WUS requires a canonical WUS-box, essential for interaction with TPL/TPR co-repressors, whereas the repressive EAR domain is dispensable and the acidic domain seems only to be required for female fertility. In contrast to the WUS clade, members of the ancient WOX13 and the WOX9 clades cannot support stem cell maintenance. Although the homeodomains are interchangeable between WUS and WOX9 clade members, a WUS- compatible homeodomain together with canonical WUS-box is not sufficient for stem cell maintenance. Our results suggest that WOX function in shoot and floral meristems of Arabidopsis is restricted to the modern WUS clade, suggesting that stem cell control is a derived function. Yet undiscovered functional domains in addition to the homeodomain and the WUS-box are necessary for this function.展开更多
Selective hydrogenolysis of glycerol to 1,3‐propanediol（1,3‐PD） is an important yet challenging method for the transformation of biomass into value‐added chemicals due to steric hindrance and unfavorable thermody...Selective hydrogenolysis of glycerol to 1,3‐propanediol（1,3‐PD） is an important yet challenging method for the transformation of biomass into value‐added chemicals due to steric hindrance and unfavorable thermodynamics. In previous studies, chemoselective performances were found de‐manding and sensitive to H2 pressure. In this regard, we manipulate the chemical/physical charac‐teristics of the catalyst supports via doping Nb into WOx and prepared 1D needle‐, 2D flake‐, and 3D sphere‐stack mesoporous structured Nb‐WOx with increased surface acid sites. Moreover, Nb dop‐ing can successfully inhibit the over‐reduction of active W species during glycerol hydrogenolysis and substantially broaden the optimal H2 pressure from 1 to 5 MPa. When Nb doping is 2%, sup‐ported Pt catalysts showed promising performance for the selective hydrogenolysis of glycerol to 1,3‐PD over an unprecedentedly wide H2 pressure range, which will guarantee better catalyst sta‐bility in the long run, as well as expand their applications to other hydrogen‐related reactions.展开更多
The use of H2SO4‐,HCl‐,H3PO4‐,and CH3COOH‐activated montmorillonite(Mt)and WOx/H3PO4‐activated Mt as catalysts for the gas‐phase dehydration of glycerol was investigated.The WOx/H3PO4‐activated Mt catalysts wer...The use of H2SO4‐,HCl‐,H3PO4‐,and CH3COOH‐activated montmorillonite(Mt)and WOx/H3PO4‐activated Mt as catalysts for the gas‐phase dehydration of glycerol was investigated.The WOx/H3PO4‐activated Mt catalysts were prepared by an impregnation method using H3PO4‐activated Mt(Mt‐P)as the support.The catalysts were characterized using powder X‐ray diffraction,Fourier‐transform infrared spectroscopy,N2adsorption‐desorption,diffuse reflectance ultraviolet‐visible spectroscopy,temperature‐programmed desorption of NH3,and thermogravimetric analysis.The acid activation of Mt and WOx loaded on Mt‐P affected the strength and number of acid sites arising from H+exchange,the leaching of octahedral Al3+cations from Mt octahedral sheets,and the types of WOx(2.7≤x≤3)species(i.e.,isolated WO4/WO6‐containing clusters,two‐dimensional[WO6]polytungstates,or three‐dimensional WO3crystals).The strong acid sites were weakened,and the weak and medium acid sites were strengthened when the W loading on Mt‐P was12wt%(12%W/Mt‐P).The12%W/Mt‐P catalyst showed the highest catalytic activity.It gave a glycerol conversion of89.6%and an acrolein selectivity of81.8%at320°C.Coke deposition on the surface of the catalyst led to deactivation.展开更多
The important antimalarial drug artemisinin is biosynthesized and stored in Artemisia annua glandular trichomes and the artemisinin content correlates with trichome density;however,the factors affecting trichome devel...The important antimalarial drug artemisinin is biosynthesized and stored in Artemisia annua glandular trichomes and the artemisinin content correlates with trichome density;however,the factors affecting trichome development are largely unknown.Here,we demonstrate that the A.annua R2R3 MYB transcription factor TrichomeLess Regulator 1(TLR1)negatively regulates trichome development.In A.annua,TLR1 overexpression lines had 44.7%–64.0%lower trichome density and 11.5%–49.4%lower artemisinin contents and TLR1-RNAi lines had 33%–93.3%higher trichome density and 32.2%–84.0%higher artemisinin contents compared with non-transgenic controls.TLR1 also negatively regulates the expression of anthocyanin biosynthetic pathway genes in A.annua.When heterologously expressed in Arabidopsis thaliana,TLR1 interacts with GLABROUS3a,positive regulator of trichome development,and represses trichome development.Yeast two-hybrid and pull-down assays indicated that TLR1 interacts with the WUSCHEL homeobox(WOX)protein AaWOX1,which interacts with the LEAFY-like transcription factor TLR2.TLR2 overexpression in Arabidopsis and A.annua showed that TLR2 reduces trichome development by reducing gibberellin levels.Furthermore,artemisinin contents were 19%–43%lower in TLR2-overexpressing A.annua plants compared to controls.These data indicate that TLR1 and TLR2 negatively regulate trichome density by lowering gibberellin levels and may enable approaches to enhance artemisinin yields.展开更多
Members of the WUSCHEL-related homeobox(WOX)transcription factor family are essential for determining cell fate and regulating diverse developmental processes in plants.Many WOX genes have been systematically investig...Members of the WUSCHEL-related homeobox(WOX)transcription factor family are essential for determining cell fate and regulating diverse developmental processes in plants.Many WOX genes have been systematically investigated in woody plants such as Populus trichocarpa,but not in Salix suchowensis.Whole-genome sequence data for S.suchowensis is now available for comprehensive study of WOX genes in S.suchowensis.We thus surveyed the genome of S.suchowensis and demonstrated active expression of 15 WOX genes.In a phylogenetic analysis of WOX genes,the 15 SsWOX genes clustered among the modern/WUS,intermediate and ancient clades similar to the WOX genes of Arabidopsis thaliana.Based on the conserved intron/exon structure,SsWOX genes in the same subgroup had similar conserved exon–intron structures and motif domains.Furthermore,among several SsWOX subgroups,WUS(Wuschel)-box and EAR(the ERF-associated amphiphilic repression)-like motifs were conserved.Expression profiles of WOX genes in roots,stems and leaves indicate that SsWOX genes have various conserved roles in the tissues.Comparative analysis of the expression patterns in Salix suchowensis with that of Arabidopsis suggests that different shoot regeneration abilities are controlled by different WOX genes in plants.The analysis provide an overview of differentially expressed SsWOX genes during shoot regeneration,but also contribute to understanding the evolution of WOX genes in Salicaceae and the interrelations of WOX genes and other transcription factors,providing targets for further study.展开更多
文摘Trichome formation has been extensively studied as a mechanistic model for epidermal cell differentiation and cell morphogenesis in plants. However, the genetic and molecular mechanisms underlying trichome formation （i.e., initiation and elongation） in rice remain largely unclear. Here, we report an AP2/ERF transcription factor, Hairy Leaf 6 （HL6）, which controls trichome formation in rice. Functional analyses revealed that HL6 transcriptionally regulates trichome elongation in rice, which is dependent on functional OsWOX3B, a homeodomain-containing protein that acts as a key regulator in trichome initiation. Biochemical and molecular genetic analyses demonstrated that HL6 physically interacts with OsWOX3B, and both of them regulate the expression of some auxin-related genes during trichome formation, in which OsWOX3B likely enhances the binding ability of HL6 with one of its direct target gene, OsYUCCA5. Popu- lation genetic analysis indicated that HL6 was under negative selection during rice domestication. Taken together, our findings provide new insights into the molecular regulatory network of trichome formation in rice.
基金supported by the National Natural Science Foundation of China(90717003 and 30625002 to L.-J. Q.)partially by the 111 Project
文摘In plants, the meristem has to maintain a separate population of pluripotent cells that serve two main tasks, i.e., self-maintenance and organ initiation, which are separated spatially in meristem. Prior to our study, WUS and WUS.like WOX genes had been reported as essential for the development of the SAM. In this study, the consequences of gain of WOX1 function are described. Here we report the identification of an Arabidopsis gain-of-function mutant woxl-D, in which the expression level of the WOX1 （WUSCHEL HOMEOBOX 1） was elevated and subtle defects in meristem development were observed. The woxl-D mutant phenotype is dwarfed and slightly bushy, with a smaller shoot apex. The woxl-D mutant also produced small and dark green leaves, and exhibited a failure in anther dehiscence and male sterility. Molecular evidences showed that the transcription of the stem cell marker gene CLV3 was down-regulated in the meristem of woxl-D but accumulated in the other regions, i.e., in the root-hypocotyl junction and at the sites for lateral root initiation. The fact that the organ size and cell size in leaves of woxl-D are smaller than those in wild type suggests that cell expansion is possibly affected in order to have partially retarded the development of lateral organs, possibly through alteration of CLV3 expression pattern in the meristem. An S-adenosylmethionine decarboxylase （SAMDC） protein, SAMDC1, was found able to interact with WOX1 by yeast two-hybrid and pull-down assays in vitro. HPLC analysis revealed a significant reduction of polyamine content in woxl-D. Our results suggest that WOX1 plays an important role in meristem development in Arabidopsis, possibly via regulation of SAMDC activity and polyamine homeostasis, and/or by regulating CLV3 expression.
文摘Gene amplification followed by functional diversification is a major force in evolution. A typical example of this is seen in the WUSCHEL-RELATED HOMEOBOX （WOX） gene family, named after the Arabidopsis stem cell regulator WUSCHEL. Here we analyze functional divergence in the WOX gene family. Members of the WUS clade, except the cambium stem cell regulator WOX4, can substitute for WUS function in shoot and floral stem cell maintenance to different degrees. Stem cell function of WUS requires a canonical WUS-box, essential for interaction with TPL/TPR co-repressors, whereas the repressive EAR domain is dispensable and the acidic domain seems only to be required for female fertility. In contrast to the WUS clade, members of the ancient WOX13 and the WOX9 clades cannot support stem cell maintenance. Although the homeodomains are interchangeable between WUS and WOX9 clade members, a WUS- compatible homeodomain together with canonical WUS-box is not sufficient for stem cell maintenance. Our results suggest that WOX function in shoot and floral meristems of Arabidopsis is restricted to the modern WUS clade, suggesting that stem cell control is a derived function. Yet undiscovered functional domains in addition to the homeodomain and the WUS-box are necessary for this function.
基金supported by the National Natural Science Foundation of China (2169008, 21690084, 21673228, 21303187, 21403218)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17020100)+1 种基金DICP ZZBS 201612Key Projects for Fundamental Research and Development of China (2016YFA0202801)~~
文摘Selective hydrogenolysis of glycerol to 1,3‐propanediol（1,3‐PD） is an important yet challenging method for the transformation of biomass into value‐added chemicals due to steric hindrance and unfavorable thermodynamics. In previous studies, chemoselective performances were found de‐manding and sensitive to H2 pressure. In this regard, we manipulate the chemical/physical charac‐teristics of the catalyst supports via doping Nb into WOx and prepared 1D needle‐, 2D flake‐, and 3D sphere‐stack mesoporous structured Nb‐WOx with increased surface acid sites. Moreover, Nb dop‐ing can successfully inhibit the over‐reduction of active W species during glycerol hydrogenolysis and substantially broaden the optimal H2 pressure from 1 to 5 MPa. When Nb doping is 2%, sup‐ported Pt catalysts showed promising performance for the selective hydrogenolysis of glycerol to 1,3‐PD over an unprecedentedly wide H2 pressure range, which will guarantee better catalyst sta‐bility in the long run, as well as expand their applications to other hydrogen‐related reactions.
基金supported by the National Natural Science Foundation of China(21373185,41672033,21506188,21404090)the Open Project Programs of Engineering Research Center of Non-metallic Minerals of Zhejiang Province(ZD2015k07)+2 种基金of State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology(GCTKF2014006)of Key Laboratory of High Efficient Processing of Bamboo of Zhejiang Province(2016)of State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology(CRE-2016-C-303)~~
文摘The use of H2SO4‐,HCl‐,H3PO4‐,and CH3COOH‐activated montmorillonite(Mt)and WOx/H3PO4‐activated Mt as catalysts for the gas‐phase dehydration of glycerol was investigated.The WOx/H3PO4‐activated Mt catalysts were prepared by an impregnation method using H3PO4‐activated Mt(Mt‐P)as the support.The catalysts were characterized using powder X‐ray diffraction,Fourier‐transform infrared spectroscopy,N2adsorption‐desorption,diffuse reflectance ultraviolet‐visible spectroscopy,temperature‐programmed desorption of NH3,and thermogravimetric analysis.The acid activation of Mt and WOx loaded on Mt‐P affected the strength and number of acid sites arising from H+exchange,the leaching of octahedral Al3+cations from Mt octahedral sheets,and the types of WOx(2.7≤x≤3)species(i.e.,isolated WO4/WO6‐containing clusters,two‐dimensional[WO6]polytungstates,or three‐dimensional WO3crystals).The strong acid sites were weakened,and the weak and medium acid sites were strengthened when the W loading on Mt‐P was12wt%(12%W/Mt‐P).The12%W/Mt‐P catalyst showed the highest catalytic activity.It gave a glycerol conversion of89.6%and an acrolein selectivity of81.8%at320°C.Coke deposition on the surface of the catalyst led to deactivation.
基金funded by the National Key R&D Program of China (2019YFC1711100)National Natural Science Foundation of China (32070332)+1 种基金Shanghai Natural Science Foundation in China (20ZR1453800)Shanghai local Science and Technology Development Fund Program guided by the Central Government (YDZX20203100002948)
文摘The important antimalarial drug artemisinin is biosynthesized and stored in Artemisia annua glandular trichomes and the artemisinin content correlates with trichome density;however,the factors affecting trichome development are largely unknown.Here,we demonstrate that the A.annua R2R3 MYB transcription factor TrichomeLess Regulator 1(TLR1)negatively regulates trichome development.In A.annua,TLR1 overexpression lines had 44.7%–64.0%lower trichome density and 11.5%–49.4%lower artemisinin contents and TLR1-RNAi lines had 33%–93.3%higher trichome density and 32.2%–84.0%higher artemisinin contents compared with non-transgenic controls.TLR1 also negatively regulates the expression of anthocyanin biosynthetic pathway genes in A.annua.When heterologously expressed in Arabidopsis thaliana,TLR1 interacts with GLABROUS3a,positive regulator of trichome development,and represses trichome development.Yeast two-hybrid and pull-down assays indicated that TLR1 interacts with the WUSCHEL homeobox(WOX)protein AaWOX1,which interacts with the LEAFY-like transcription factor TLR2.TLR2 overexpression in Arabidopsis and A.annua showed that TLR2 reduces trichome development by reducing gibberellin levels.Furthermore,artemisinin contents were 19%–43%lower in TLR2-overexpressing A.annua plants compared to controls.These data indicate that TLR1 and TLR2 negatively regulate trichome density by lowering gibberellin levels and may enable approaches to enhance artemisinin yields.
基金supported by the National Key Research and Development Plan of China(2016YFD0600101)the Fundamental Research Funds for the Central Non-Profit Research Institution of CAF(CAFYBB2014QB015)+3 种基金the National Natural Science Foundation of China(31570662,31500533,and 61401214)Jiangsu Provincial Department of Housing and Urban–Rural Development(2016ZD44)2017 Graduate Research and Innovation Program Projects in Jiangsu Province(KYCY17_0827)the PAPD(Priority Academic Program Development)program at Nanjing Forestry University
文摘Members of the WUSCHEL-related homeobox(WOX)transcription factor family are essential for determining cell fate and regulating diverse developmental processes in plants.Many WOX genes have been systematically investigated in woody plants such as Populus trichocarpa,but not in Salix suchowensis.Whole-genome sequence data for S.suchowensis is now available for comprehensive study of WOX genes in S.suchowensis.We thus surveyed the genome of S.suchowensis and demonstrated active expression of 15 WOX genes.In a phylogenetic analysis of WOX genes,the 15 SsWOX genes clustered among the modern/WUS,intermediate and ancient clades similar to the WOX genes of Arabidopsis thaliana.Based on the conserved intron/exon structure,SsWOX genes in the same subgroup had similar conserved exon–intron structures and motif domains.Furthermore,among several SsWOX subgroups,WUS(Wuschel)-box and EAR(the ERF-associated amphiphilic repression)-like motifs were conserved.Expression profiles of WOX genes in roots,stems and leaves indicate that SsWOX genes have various conserved roles in the tissues.Comparative analysis of the expression patterns in Salix suchowensis with that of Arabidopsis suggests that different shoot regeneration abilities are controlled by different WOX genes in plants.The analysis provide an overview of differentially expressed SsWOX genes during shoot regeneration,but also contribute to understanding the evolution of WOX genes in Salicaceae and the interrelations of WOX genes and other transcription factors,providing targets for further study.
