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| 1 | Overexpression of SHORT VEGETATIVE PHASE-LIKE (SVL) in Populus delays onset and reduces abundance of flowering in field-grown trees显示文摘The spread of transgenes and exotic germplasm from planted crops into wild or feral species is a difficult problem for public and regulatory acceptance of genetically engineered plants,particularly for wind-pollinated trees such as poplar.We report that overexpression of a poplar homolog of the floral repressor SHORT VEGETATIVE PHASE-LIKE(SVL),a homolog of the Arabidopsis MADS-box repressor SHORT VEGETATIVE PHASE(SVP),delayed the onset of flowering several years in three genotypes of field-grown transgenic poplars.Higher expression of SVL correlated with a delay in flowering onset and lower floral abundance,and did not cause morphologically obvious or statistically significant effects on leaf characteristics,tree form,or stem volume.Overexpression effects on reproductive and vegetative phenology in spring was modest and genotype-specific.Our results suggest that use of SVL and related floral repressors can be useful tools to enable a high level of containment for vegetatively propagated short-rotation woody energy or pulp crops. | Greg S.Goralogia Glenn T.Howe Amy M.Brunner Emily Helliwell Michael F.Nagle Cathleen Ma Haiwei Lu Amanda L.Goddard Anna C.Magnuson Amy L.Klocko Steven H.Strauss | 2021 | Horticulture Research2021，8，1： | 1 |
| 2 | Plasma Edge Kinetic-MHD Modeling in Tokamaks Using Kepler Workflow for Code Coupling,Data Management and Visualization显示文摘A new predictive computer simulation tool targeting the development of the H-mode pedestal at the plasma edge in tokamaks and the triggering and dynamics of edge localizedmodes(ELMs)is presented in this report.This tool brings together,in a coordinated and effective manner,several first-principles physics simulation codes,stability analysis packages,and data processing and visualization tools.A Kepler workflow is used in order to carry out an edge plasma simulation that loosely couples the kinetic code,XGC0,with an ideal MHD linear stability analysis code,ELITE,and an extended MHD initial value code such as M3D or NIMROD.XGC0 includes the neoclassical ion-electron-neutral dynamics needed to simulate pedestal growth near the separatrix.The Kepler workflow processes the XGC0 simulation results into simple images that can be selected and displayed via the Dashboard,a monitoring tool implemented in AJAX allowing the scientist to track computational resources,examine running and archived jobs,and view key physics data,all within a standard Web browser.The XGC0 simulation is monitored for the conditions needed to trigger an ELM crash by periodically assessing the edge plasma pressure and current density profiles using the ELITE code.If an ELM crash is triggered,the Kepler workflow launches the M3D code on a moderate-size Opteron cluster to simulate the nonlinear ELM crash and to compute the relaxation of plasma profiles after the crash.This process is monitored through periodic outputs of plasma fluid quantities that are automatically visualized with AVS/Express and may be displayed on the Dashboard.Finally,the Kepler workflow archives all data outputs and processed images using HPSS,as well as provenance information about the software and hardware used to create the simulation.The complete process of preparing,executing and monitoring a coupled-code simulation of the edge pressure pedestal buildup and the ELM cycle using the Kepler scientific workflow system is described in this paper. | J.Cummings A.Pankin N.Podhorszki G.Park S.Ku R.Barreto S.Klasky C.S.Chang H.Strauss L.Sugiyama P.Snyder D.Pearlstein B.Ludascher G.Bateman A.Kritz the CPES Team | 2008 | Communications in Computational Physics2008，4，8： | 1 |
| 3 | Diverse effects of overexpression of LEAFY and PTLF, a poplar (Populus) homolog of LEAFY/FLORICAULA, in transgenic poplar and Arabidopsis显示文摘 | William H.Rottmann RichardMeilan Lorraine A.Sheppard Amy M.Brunner Jeffrey S.Skinner CaipingMa ShupingCheng LiseJouanin GillesPilate Steven H.Strauss | 2001 | The Plant Journal2001，，3： | 1 |
| 4 | Reconfiguring Plant Metabolism for Biodegradable Plastic Production显示文摘For decades,plants have been the subject of genetic engineering to synthesize novel,value-added compounds.Polyhydroxyalkanoates(PHAs),a large class of biodegradable biopolymers naturally synthesized in eubacteria,are among the novel products that have been introduced to make use of plant acetyl-CoA metabolic pathways.It was hoped that renewable PHA production would help address environmental issues associated with the accumulation of nondegradable plastic wastes.However,after three decades of effort synthesizing PHAs,and in particular the simplest form polyhydroxybutyrate(PHB),and seeking to improve their production in plants,it has proven very difficult to reach a commercially profitable rate in a normally growing plant.This seems to be due to the growth defects associated with PHA production and accumulation in plant cells.Here,we review major breakthroughs that have been made in plant-based PHA synthesis using traditional genetic engineering approaches and discuss challenges that have been encountered.Then,from the point of view of plant synthetic biology,we provide perspectives on reprograming plant acetyl-CoA pathways for PHA production,with the goal of maximizing PHA yield while minimizing growth inhibition.Specifically,we suggest genetic elements that can be considered in genetic circuit design,approaches for nuclear genome and plastome modification,and the use of multiomics and mathematical modeling in understanding and restructuring plant metabolic pathways. | Haiwei Lu Guoliang Yuan Steven H.Strauss Timothy J.Tschaplinski Gerald A.Tuskan Jin-Gui Chen Xiaohan Yang | 2020 | BioDesign Research2020，，1： | 1 |
| 5 | UNIFORM RECIPROCAL APPROXIMATION SUBJECT TO COEFFICIENT CONSTRAINTS显示文摘In this paper best approximation by reciprocals of functions of a subspace Un=span(u1,…,un)satisfying coefficient constraints is considered.We present a characterization ofbest approximations.When(u1,…,un)is a Descartes system an explicit characterization ofbest approximations by equioscillations is given.Existence and uniqueness results are shown.Moreover,the theory is applied to best approximaitons by reciprocals of polynomials. | H.Strauss | 1992 | Analysis in Theory and Applications1992，8，2： | 0 |
| 6 | Genetic down-regulation of gibberellin results in semi-dwarf poplar but few non-target effects on chemical resistance and tolerance to defoliation显示文摘Aims Plant stature can be strongly modified via regulation of endog-enous levels and signalling of the plant hormone gibberellin(GA).Down-regulation of GA can produce semi-dwarf tree varieties with improved qualities such as reduced susceptibility to wind damage,enhanced root growth and more compact cultivation.However,these modifications may have unintended,non-target consequences for defence against herbivores,via either of two mechanisms:(i)reduced biomass production may cause trade-offs with chemical resistance traits,as predicted by the growth-differentiation balance hypothesis,and(ii)altered biomass allocation to either roots or pho-tosynthetic tissues may affect regrowth potential and thus tolerance to defoliation.Methods We studied GA down-regulated(GE)and non-transgenic wild-type hybrid poplar(Populus alba×P.tremula)in an outdoor,above-ground common garden and defoliated half of all replicate trees to simulate defoliation.We then quantified the independent and inter-active effects of genotype and defoliation on growth and chemical resistance-related traits,including phenolic glycosides(PGs),con-densed tannin and nitrogen.We also calculated tolerance to defo-liation as the differential in relative growth between undefoliated and defoliated trees.Important Findings Our results indicate that two of the four GA down-regulated geno-types had significantly reduced stem height,basal diameter,vol-ume(d2h),total biomass and increased allocation to leaves relative to the wild type.One of those two genotypes also had reduced allocation to roots.One and sometimes both of these same two genotypes also had at least 20%lower levels of condensed tannins and PGs and similar increases in lignin and nitrogen.Tolerance,as calculated by the differential in relative growth between unde-foliated and defoliated trees,was similar among all experimental genotypes.However,two GE genotypes flushed fewer leaves in response to defoliation relative to the wild type.Our results indi-cate that GA down-regulation strongly alters biomass production and allocation in poplar but does not necessarily compromise the ability of these trees to tolerate damage.However,some of the modifications we observed do have the potential to alter non-target resistance traits over time,and warrant further research,especially under plantation conditions. | Christine Buhl Steven H.Strauss Richard L.Lindroth | 2019 | Journal of Plant Ecology2019，12，1： | 0 |
| 7 | GWAS identifies candidate genes controlling adventitious rooting in Populus trichocarpa显示文摘Adventitious rooting(AR)is critical to the propagation,breeding,and genetic engineering of trees.The capacity for plants to undergo this process is highly heritable and of a polygenic nature;however,the basis of its genetic variation is largely uncharacterized.To identify genetic regulators of AR,we performed a genome-wide association study(GWAS)using 1148 genotypes of Populus trichocarpa.GWASs are often limited by the abilities of researchers to collect precise phenotype data on a high-throughput scale;to help overcome this limitation,we developed a computer vision system to measure an array of traits related to adventitious root development in poplar,including temporal measures of lateral and basal root length and area.GWAS was performed using multiple methods and significance thresholds to handle non-normal phenotype statistics and to gain statistical power.These analyses yielded a total of 277 unique associations,suggesting that genes that control rooting include regulators of hormone signaling,cell division and structure,reactive oxygen species signaling,and other processes with known roles in root development.Numerous genes with uncharacterized functions and/or cryptic roles were also identified.These candidates provide targets for functional analysis,including physiological and epistatic analyses,to better characterize the complex polygenic regulation of AR. | Michael F.Nagle Jialin Yuan Damanpreet Kaur Cathleen Ma Ekaterina Peremyslova Yuan Jiang Bahiya Zahl Alexa Niño de Rivera Wellington Muchero Li Fuxin Steven H.Strauss | 2023 | Horticulture Research2023，10，8： | 0 |
| 8 | Variation in floral form of CRISPR knock-outs of the poplar homologs of LEAFY and AGAMOUS after FT heat-induced early flowering显示文摘Plant migration and gene flow from genetically modified or exotic trees to nearby lands or by crossing with wild relatives is a major public and regulatory concern.Many genetic strategies exist to mitigate potential gene flow;however,the long delay in onset of flow-ering is a severe constraint to research progress.We used heat-induced FT overexpression to speed assessment of the expected floral phenotypes after CRISPR knockout of poplar homologs of the key floral genes,LEAFY and AGAMOUS.We selected events with previously characterized CRISPR-Cas9 induced biallelic changes then re-transformed them with the Arabidopsis thaliana FLOWERING LOCUS T(AtFT)gene under control of either a strong constitutive promoter or a heat-inducible promoter.We successfully obtained flowering in both a male and female clone of poplar,observing a wide range of inflorescence and floral forms among flowers,ramets,and insertion events.Overall,flowers obtained from the selected LFY and AG targeted events were consistent with what would be predicted for loss-of-function of these genes.LFY-targeted events showed small catkins with leaf-like organs,AG-targeted events had nested floral organs consistent with reduction in floral determinacy and absence of well-formed carpels or anthers.These findings demonstrate the great developmental plasticity of Populus flowers during genetically accelerated flowering,which may be of horticultural value.They also provide an informative early view of floral phenotypes and apparent sterility from knockouts of both these gene targets. | Amy L.Klocko Estefania Elorriaga Cathleen Ma Steven H.Strauss | 2023 | Horticulture Research2023，10，8： | 0 |
| 9 | 贵州台江下、中寒武统界线层型候选剖面碳同位素研究显示文摘在扬子地台贵州台江八郎下、中寒武统界线剖面界线附近,碳酸盐岩和干酪根碳同位素组成有规律变化。1δ3Cker(PDB)值在-33.4‰和-26.5‰间漂移与1δ3Ccarb(PDB)值在-2.7‰和+3.1‰间变化,反映了当时海水的碳同位素组成。无机和有机碳同位素组成之差的Δδ值,沿剖面不断变小,指示剖面上部样品可能受到热扰动和成岩后期作用影响。碳同位素规律的变化,反映了最初的沉积信息,特别是有机质埋藏量的变化,这些变化与早-中寒武世环境变化和生物组合差异有关。 | 郭庆军 刘丛强 H.Strauss 赵元龙 朱立军 皮道会 袁金良 | 2006 | 矿物学报2006，26，3： | 0 |
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