Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since ...Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.展开更多
Auxin,one of the first identified and most widely studied phytohormones,has been and will remain a hot topic in plant biology.After more than a century of passionate exploration,the mysteries of its synthesis,transpor...Auxin,one of the first identified and most widely studied phytohormones,has been and will remain a hot topic in plant biology.After more than a century of passionate exploration,the mysteries of its synthesis,transport,signaling,and metabolism have largely been unlocked.Due to the rapid development of new technologies,new methods,and new genetic materials,the study of auxin has entered the fast lane over the past 30 years.Here,we highlight advances in understanding auxin signaling,including auxin perception,rapid auxin responses,TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F-boxes(TIR1/AFBs)-mediated transcriptional and non-transcriptional branches,and the epigenetic regulation of auxin signaling.We also focus on feedback inhibition mechanisms that prevent the over-amplification of auxin signals.In addition,we cover the TRANSMEMBRANE KINASE-mediated non-canonical signaling,which converges with TIR1/AFBs-mediated transcriptional regulation to coordinate plant growth and development.The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field,leading to an increasingly deeper,more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development.展开更多
Lead sulfide(PbS)presents large potential in thermoelectric application due to its earth-abundant S element.However,its inferior average ZT(ZTave)value makes PbS less competitive with its analogs PbTe and PbSe.To prom...Lead sulfide(PbS)presents large potential in thermoelectric application due to its earth-abundant S element.However,its inferior average ZT(ZTave)value makes PbS less competitive with its analogs PbTe and PbSe.To promote its thermoelectric performance,this study implements strategies of continuous Se alloying and Cu interstitial doping to synergistically tune thermal and electrical transport properties in n-type PbS.First,the lattice parameter of 5.93Åin PbS is linearly expanded to 6.03Åin PbS_(0.5)Se_(0.5)with increasing Se alloying content.This expanded lattice in Se-alloyed PbS not only intensifies phonon scattering but also facilitates the formation of Cu interstitials.Based on the PbS_(0.6)Se_(0.4)content with the minimal lattice thermal conductivity,Cu interstitials are introduced to improve the electron density,thus boosting the peak power factor,from 3.88μW cm^(−1)K^(−2)in PbS_(0.6)Se_(0.4)to 20.58μW cm^(−1)K^(−2)in PbS0.6Se0.4−1%Cu.Meanwhile,the lattice thermal conductivity in PbS_(0.6)Se_(0.4)−x%Cu(x=0-2)is further suppressed due to the strong strain field caused by Cu interstitials.Finally,with the lowered thermal conductivity and high electrical transport properties,a peak ZT~1.1 and ZTave~0.82 can be achieved in PbS_(0.6)Se_(0.4)−1%Cu at 300–773K,which outperforms previously reported n-type PbS.展开更多
The sessile life style of plants creates the need to deal with an often adverse environment, in which water availability can change on a daily basis, challenging the cellular physiology and integrity. Changes in os- m...The sessile life style of plants creates the need to deal with an often adverse environment, in which water availability can change on a daily basis, challenging the cellular physiology and integrity. Changes in os- motic conditions disrupt the equilibrium of the plasma membrane： hypoosmotic conditions increase and hyperosmotic environment decrease the cell volume. Here, we show that short-term extracellular osmotic treatments are closely followed by a shift in the balance between endocytosis and exocytosis in root mer- istem cells. Acute hyperosmotic treatments （ionic and nonionic） enhance clathrin-mediated endocytosis simultaneously attenuating exocytosis, whereas hypoosmotic treatments have the opposite effects. In addition to clathrin recruitment to the plasma membrane, components of early endocytic trafficking are essential during hyperosmotic stress responses. Consequently, growth of seedlings defective in elements of clathrin or early endocytic machinery is more sensitive to hyperosmotic treatments. We also found that the endocytotic response to a change of osmotic status in the environment is dominant over the presum- ably evolutionary more recent regulatory effect of plant hormones, such as auxin. These results imply that osmotic perturbation influences the balance between endocytosis and exocytosis acting through clathrin- mediated endocytosis. We propose that tension on the plasma membrane determines the addition or removal of membranes at the cell surface, thus preserving cell integrity.展开更多
The phytohormone auxin plays a central role in shaping plant growth and development.With decades of genetic and biochemical studies,numerous core molecular components and their networks,underlying auxin biosynthesis,t...The phytohormone auxin plays a central role in shaping plant growth and development.With decades of genetic and biochemical studies,numerous core molecular components and their networks,underlying auxin biosynthesis,transport,and signaling,have been identified.Notably,protein phosphorylation,catalyzed by kinases and oppositely hydrolyzed by phosphatases,has been emerging to be a crucial type of post-translational modification,regulating physiological and developmental auxin output at all levels.In this review,we comprehensively discuss earlier and recent advances in our understanding of genetics,biochemistry,and cell biology of the kinases and phosphatases participating in auxin action.We provide insights into the mechanisms by which reversible protein phosphorylation defines developmental auxin responses,discuss current challenges,and provide our perspectives on future directions involving the integration of the control of protein phosphorylation into the molecular auxin network.展开更多
Protein abundance and localization at the plasma membrane(PM)shapes plant development and mediates adaptation to changing environmental conditions.It is regulated by ubiquitination,a post-translational modification cr...Protein abundance and localization at the plasma membrane(PM)shapes plant development and mediates adaptation to changing environmental conditions.It is regulated by ubiquitination,a post-translational modification crucial for the proper sorting of endocytosed PM proteins to the vacuole for subsequent degradation.To understand the significance and the variety of roles played by this reversible modification,the function of ubiquitin receptors,which translate the ubiquitin signature into a cellular response,needs to be elucidated.In this study,we show that TOL(TOM1-like)proteins function in plants as multivalent ubiquitin receptors,governing ubiquitinated cargo delivery to the vacuole via the conserved Endosomal Sorting Complex Required for Transport(ESCRT)pathway.TOL2 and TOL6 interact with components of the ESCRT machinery and bind to K63-linked ubiquitin via two tandemly arranged conserved ubiquitin-binding domains.Mutation of these domains results not only in a loss of ubiquitin binding but also altered localization,abolishing TOL6 ubiquitin receptor activity.Function and localization of TOL6 is itself regulated by ubiquitination,whereby TOL6 ubiquitination potentially modulates degradation of PM-localized cargoes,assisting in the fine-tuning of the delicate interplay between protein recycling and downregulation.Taken together,our findings demonstrate the function and regulation of a ubiquitin receptor that mediates vacuolar degradation of PM proteins in higher plants.展开更多
Winter plants rely on vernalization,a crucial process for adapting to cold conditions and ensuring successful reproduction.However,understanding the role of histone modifications in guiding the vernalization process i...Winter plants rely on vernalization,a crucial process for adapting to cold conditions and ensuring successful reproduction.However,understanding the role of histone modifications in guiding the vernalization process in winter wheat remains limited.In this study,we investigated the transcriptome and chromatin dynamics in the shoot apex throughout the life cycle of winter wheat in the field.Two core histone modifications,H3K27me3 and H3K36me3,exhibited opposite patterns on the key vernalization gene VERNALIZATION1(VRN1),correlating with its induction during cold exposure.Moreover,the H3K36me3 level remained high at VRN1 after cold exposure,which may maintain its active state.Mutations in FERTILIZATION-INDEPENDENT ENDOSPERM(TaFIE)and SET DOMAIN GROUP 8/EARLY FLOWERING IN SHORT DAYS(TaSDG8/TaEFS),components of the writer complex for H3K27me3 and H3K36me3,respectively,affected flowering time.Intriguingly,VRN1 lost its high expression after the cold exposure memory in the absence of H3K36me3.During embryo development,VRN1 was silenced with the removal of active histone modifications in both winter and spring wheat,with selective restoration of H3K27me3 in winter wheat.The mutant of Tafie-cr-87,a component of H3K27me3“writer”complex,did not influence the silence of VRN1during embryo development,but rather attenuated the cold exposure requirement of winter wheat.Integrating gene expression with H3K27me3 and H3K36me3 patterns identified potential regulators of flowering.This study unveils distinct roles of H3K27me3 and H3K36me3 in controlling vernalization response,maintenance,and resetting in winter wheat.展开更多
Photoisomerization and photoluminescence are two distinct energy dissipation path-ways in light-driven molecular motors.The photoisomerization properties of discrete molecular motors have been well established in solu...Photoisomerization and photoluminescence are two distinct energy dissipation path-ways in light-driven molecular motors.The photoisomerization properties of discrete molecular motors have been well established in solution,but their photoluminescent properties have been rarely reported-especially in aggregates.Here,it is shown that an overcrowded alkene-based molecular motor exhibits distinct dynamic prop-erties in solution and aggregate states,for example,gel and solid states.Despite the poor emissive properties of molecular motors in solution,a bright emission is observed in the aggregate states,including in gel and the crystalline solid.The emis-sion wavelength is highly dependent on the nature of the supramolecular packing and order in the aggregates.As a result,the fluorescent color can be readily tuned reversibly via mechanical grinding and vapor fuming,which provides a new platform for developing multi-stimuli functional materials.展开更多
Endophytic fungi can be beneficial to plant growth. However, the molecular mechanisms under-lying colonization of Acremonium spp. remain unclear. In this study, a novel endophytic Acremonium strain was isolated from t...Endophytic fungi can be beneficial to plant growth. However, the molecular mechanisms under-lying colonization of Acremonium spp. remain unclear. In this study, a novel endophytic Acremonium strain was isolated from the buds of Panax notoginseng and named Acremonium sp. D212. The Acremonium sp. D212 could colonize the roots of P. notoginseng, enhance the resistance of P. notoginseng to root rot disease, and promote root growth and saponin bio-synthesis in P. notoginseng. Acremonium sp. D212 could secrete indole-3-acetic acid (IAA) and jasmonic acid (JA), and inoculation with the fungus increased the endogenous levels of IAA and JA in P. noto-ginseng. Colonization of the Acremonium sp. D212 in the roots of the rice line Nipponbare was dependent on the concentration of methyl jasmonate (MeJA) (2–15μmol/L) and 1-naphthalenacetic acid (NAA) (10–20μmol/L). Moreover, the roots of the JA signaling-defective coi1-18 mutant were colonized by Acremonium sp. D212 to a lesser degree than those of the wild-type Nipponbare and miR393b-overexpressing lines, and the colonization was res-cued by MeJA but not by NAA. It suggests that the cross-talk between JA signaling and the auxin biosynthetic pathway plays a crucial role in the colonization of Acremonium sp. D212 in host plants.展开更多
The auxin signaling molecule controls a variety of growth and developmental processes in land plants. Auxin regulates gene expression through a nuclear auxin signaling pathway (NAP) consisting of the ubiquitin ligase ...The auxin signaling molecule controls a variety of growth and developmental processes in land plants. Auxin regulates gene expression through a nuclear auxin signaling pathway (NAP) consisting of the ubiquitin ligase auxin receptor TIR1/AFB, its Aux/IAA degradation substrate, and DNA-binding ARF transcription factors. Although extensive qualitative understanding of the pathway and its interactions has been obtained, mostly by studying the flowering plant Arabidopsis thaliana, it remains unknown how these translate to quantitative system behavior in vivo, a problem that is confounded by the large NAP gene families in most species. Here, we used the minimal NAP of the liverwort Marchantia polymorpha to quantitatively map NAP protein accumulation and dynamics in vivo through the use of knockin fluorescent fusion proteins. Beyond revealing the dynamic native accumulation profile of the entire NAP protein network, we discovered that the two central ARFs, MpARF1 and MpARF2, are proteasomally degraded. This auxin-independent degradation tunes ARF protein stoichiometry to favor gene activation, thereby reprogramming auxin response during the developmental progression. Thus, quantitative analysis of the entire NAP has enabled us to identify ARF degradation and the stoichiometries of activator and repressor ARFs as a potential mechanism for controlling gemma germination.展开更多
The phytohormone auxin,and its directional transport through tissues,plays a fundamental role in the development of higher plants.This polar auxin transport predominantly relies on PIN-FORMED(PIN)auxin exporters.Hence...The phytohormone auxin,and its directional transport through tissues,plays a fundamental role in the development of higher plants.This polar auxin transport predominantly relies on PIN-FORMED(PIN)auxin exporters.Hence,PIN polarization is crucial for development,but its evolution during the rise of morpho-logical complexity in land plants remains unclear.Here,we performed a cross-species investigation by observing the trafficking and localization of endogenous and exogenous PINs in two bryophytes,Physco-mitrium patens and Marchantia polymorpha,and in theflowering plant Arabidopsis thaliana.We confirmed that the GFP fusion did not compromise the auxin export function of all examined PINs by using a radioac-tive auxin export assay and by observing the phenotypic changes in transgenic bryophytes.Endogenous PINs polarize tofilamentous apices,while exogenous Arabidopsis PINs distribute symmetrically on the membrane in both bryophytes.In the Arabidopsis root epidermis,bryophytic PINs have no defined polarity.Pharmacological interference revealed a strong cytoskeletal dependence of bryophytic but not Arabidopsis PIN polarization.The divergence of PIN polarization and trafficking is also observed within the bryophyte clade and between tissues of individual species.These results collectively reveal the divergence of PIN traf-ficking and polarity mechanisms throughout land plant evolution and the co-evolution of PIN sequence-based and cell-based polarity mechanisms.展开更多
Hormone perception and signaling pathways have a fundamental regulatory function in the physiological processes of plants.Cytokinins,a class of plant hormones,regulate cell division and meristem maintenance.The cytoki...Hormone perception and signaling pathways have a fundamental regulatory function in the physiological processes of plants.Cytokinins,a class of plant hormones,regulate cell division and meristem maintenance.The cytokinin signaling pathway is well established in the model plant Arabidopsisthaliana.Several negative feedback mechanisms,tightly controlling cytokinin signaling output,have been described previously.In this study,we identified a new feedback mechanism executed through alternative splicing of the cytokinin receptor AHK4/CRE1.A novel splicing variant named CRE1int7 results from seventh intron retention,introducing a premature termination codon in the transcript.We showed that CRE1int7 is translated in planta into a truncated receptor lacking the C-terminal receiver domain essential for signal transduction.CRE1int7 can bind cytokinin but cannot activate the downstream cascade.We present a novel negative feedback mechanism of the cytokinin signaling pathway,facilitated by a decoy receptor that can inactivate canonical cytokinin receptors via dimerization and compete with them for ligand binding.Ensuring proper plant growth and development requires precise control of the cytokinin signaling pathway at several levels.CRE1int7 represents a so-far unknown mechanism for fine-tuning the cytokinin signaling pathway in Arabidopsis.展开更多
Dear Editor,Auxin is the major plant hormone regulating growth and development(Friml,2022).Forward genetic approaches have identified major components of auxin signaling and established the canonical mechanism mediati...Dear Editor,Auxin is the major plant hormone regulating growth and development(Friml,2022).Forward genetic approaches have identified major components of auxin signaling and established the canonical mechanism mediating transcriptional and thus developmental reprogramming in Arabidopsis thaliana.In this textbook view,TRANSPORT INHIBITOR RESPONSE 1(TIR1)/AUXIN-SIGNALING F-BOX(AFB)proteins are auxin receptors,which act as F-box subunits determining the substrate specificity of the Skp1-Cullin1-F box protein(SCF)type E3 ubiquitin ligase complex.Auxin acts as a"molecular glue,"increasing the affinity between TIR1/AFBs and the Auxin/lndole-3-Acetic Acid(Aux/IAA)repressors.Subsequently,Aux/IAAs are ubiquitinated and degraded,thus releasing auxin transcription factors from their repression and making them free to mediate transcription of auxin response genes(Yu et al.,2022).展开更多
Thermoelectric materials enable the direct conversion between heat and electricity,providing potential in power generation and cooling applications[1].The energy conversion efficiency is determined by the dimensionles...Thermoelectric materials enable the direct conversion between heat and electricity,providing potential in power generation and cooling applications[1].The energy conversion efficiency is determined by the dimensionless figure of merit ZT=S^(2)σT/κ_(tot),where S is the Seebeck coefficient;σis the electrical conductivity;T is the temperature in Kelvin;κ_(tot)is the total thermal conductivity.展开更多
The phytohormone auxin plays central roles in many growth and developmental processes in plants.Development of chemical tools targeting the auxin pathway is useful for both plant biology and agriculture.Here we reveal...The phytohormone auxin plays central roles in many growth and developmental processes in plants.Development of chemical tools targeting the auxin pathway is useful for both plant biology and agriculture.Here we reveal that naproxen,a synthetic compound with anti-inflammatory activity in humans,acts as an auxin transport inhibitor targeting PIN-FORMED(PIN)transporters in plants.Physiological experiments indicate that exogenous naproxen treatment affects pleiotropic auxin-regulated developmental processes.Additional cellular and biochemical evidence indicates that naproxen suppresses auxin transport,specifically PIN-mediated auxin efflux.Moreover,biochemical and structural analyses confirm that naproxen binds directly to PIN1 protein via the same binding cavity as the indole-3-acetic acid substrate.Thus,by combining cellular,biochemical,and structural approaches,this study clearly establishes that naproxen is a PIN inhibitor and elucidates the underlying mechanisms.Further use of this compound may advance our understanding of the molecular mechanisms of PIN-mediated auxin transport and expand our toolkit in auxin biology and agriculture.展开更多
Ethylene and cytokinin,two plant hormones with essential functions throughout the plant's life cycle,contribute to a wide spectrum of physiological,biochemical,and developmental processes.Over the last decades,the...Ethylene and cytokinin,two plant hormones with essential functions throughout the plant's life cycle,contribute to a wide spectrum of physiological,biochemical,and developmental processes.Over the last decades,the molecular mechanisms underlying their biosynthesis and metabolism as well as pathways mediating their perception and signal transduction have been deciphered.Although machineries controlling the activities of these two central hormonal regulators appear robust and autonomous,in the ever-changing environmental conditions that plants face,survival is dependent on their tight communication and mutually balanced activities.A recent work by Zdarska et al.(2019)is trying to address the challenging question regarding the mechanisms underlying the cytokinin and ethylene cross-talk.This study reveals an intriguing,multilayered nature of hormonal interaction,in which the EHYLENE RESISTANT 1(ETR1)receptor upon perceiving an ethylene signal activates a multistep phosphorelay(MSP)cytokinin transduction cascade,integrating ethylene and cytokinin in the control of root apical meristem size.In parallel,activation of canonical ethylene signaling adjusts the responsiveness of the cytokinin pathway by transcriptional upregulation of one of its key signaling components,the ARR10 response regulator(Figure 1).Importantly,unlike the canonical ethylene transduction machinery,ethylene input into the MSP is dependent on histidine kinase activity of ETR1 receptor.展开更多
Auxin is a key hormonal regulator,that governs plant growth and development in concert with other hormonal pathways.The unique feature of auxin is its polar,cell-to-cell transport that leads to the formation of local ...Auxin is a key hormonal regulator,that governs plant growth and development in concert with other hormonal pathways.The unique feature of auxin is its polar,cell-to-cell transport that leads to the formation of local auxin maxima and gradients,which coordinate initiation and patterning of plant organs.The molecular machinery mediating polar auxin transport is one of the important points of interaction with other hormones.Multiple hormonal pathways converge at the regulation of auxin transport and form a regulatory network that integrates various developmental and environmental inputs to steer plant development.In this review,we discuss recent advances in understanding the mechanisms that underlie regulation of polar auxin transport by multiple hormonal pathways.Specifically,we focus on the post-translational mechanisms that contribute to fine-tuning of the abundance and polarity of auxin transporters at the plasma membrane and thereby enable rapid modification of the auxin flow to coordinate plant growth and development.展开更多
In plants,the antagonism between growth and defense is hardwired by hormonal signaling.The perception of pathogen-associatedmolecularpatterns(PAMPs)frominvadingmicroorganismsinhibits auxin signalingand plant growth.Co...In plants,the antagonism between growth and defense is hardwired by hormonal signaling.The perception of pathogen-associatedmolecularpatterns(PAMPs)frominvadingmicroorganismsinhibits auxin signalingand plant growth.Conversely,pathogens manipulate auxin signaling to promote disease,but how this hormone inhibits immunity is not fully understood.Ustilago maydis is a maize pathogen that induces auxin signaling in its host.We characterized a U.maydis effector protein,Naked1(Nkd1),that is translocated into the host nucleus.Through its native ethylene-responsive element binding factor-associated amphiphilic repression(EAR)motif,Nkd1 binds to the transcriptional co-repressors TOPLESS/TOPLESS-related(TPL/TPRs)and prevents the recruitment of a transcriptional repressor involved in hormonal signaling,leading to the derepression of auxin and jasmonate signaling and thereby promoting susceptibility to(hemi)biotrophic pathogens.A moderate upregulation of auxin signaling inhibits the PAMP-triggered reactive oxygen species(ROS)burst,an early defense response.Thus,our findings establish a clear mechanism for auxin-induced pathogen susceptibility.Engineered Nkd1 variants with increased expression or increased EAR-mediated TPL/TPR binding trigger typical salicylic-acid-mediated defense reactions,leading to pathogen resistance.This implies that moderate binding of Nkd1 to TPL is a result of a balancing evolutionary selection process to enable TPL manipulation while avoiding host recognition.展开更多
Cotton(Gossypium spp.)is one of the most important economic crops in the world and also a major source of natural fiber,oil,and protein.The morphology of cotton species varies from trailing herbaceous perennials to tr...Cotton(Gossypium spp.)is one of the most important economic crops in the world and also a major source of natural fiber,oil,and protein.The morphology of cotton species varies from trailing herbaceous perennials to trees<10 m.Like other important crops,modern cotton cultivars are polyploids and have gone through polyploidization,evolution,and domestication.The cotton genus comprises approximately 45 diploid(2n=2x=26)and seven tetraploid species(2n=4x=52)(Guan et al.,2014).展开更多
Auxin, one of the plant hormones, is a key regulator of plant growth and development. At the cellular level, it controls different processes, such as cell expansion, division, and differentiation that are reflected by...Auxin, one of the plant hormones, is a key regulator of plant growth and development. At the cellular level, it controls different processes, such as cell expansion, division, and differentiation that are reflected by its regulatory role in a plethora of developmental mechanisms. An important feature of the auxin action is its differential distribution within tissues mediated by the polar auxin transport machinery, which can be dynamically regulated in response to internal and external stimuli. Receptors at the cell surface or cell interior are needed to sense and interpret fluctuations in the auxin distribution.展开更多
文摘Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
基金financially supported by the National Natural Science Foundation of China and the Israel Science Foundation(NSFC-ISF32061143005)+2 种基金National Natural Science Foundation of China(32000225)Natural Science Foundation of Shandong Province(ZR2020QC036)China Postdoctoral Science Foundation(2020M682165)。
文摘Auxin,one of the first identified and most widely studied phytohormones,has been and will remain a hot topic in plant biology.After more than a century of passionate exploration,the mysteries of its synthesis,transport,signaling,and metabolism have largely been unlocked.Due to the rapid development of new technologies,new methods,and new genetic materials,the study of auxin has entered the fast lane over the past 30 years.Here,we highlight advances in understanding auxin signaling,including auxin perception,rapid auxin responses,TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F-boxes(TIR1/AFBs)-mediated transcriptional and non-transcriptional branches,and the epigenetic regulation of auxin signaling.We also focus on feedback inhibition mechanisms that prevent the over-amplification of auxin signals.In addition,we cover the TRANSMEMBRANE KINASE-mediated non-canonical signaling,which converges with TIR1/AFBs-mediated transcriptional regulation to coordinate plant growth and development.The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field,leading to an increasingly deeper,more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development.
基金National Science Fund for Distinguished Young Scholars,Grant/Award Number:51925101National Natural Science Foundation of China,Grant/Award Number:52172236+1 种基金Fundamental Research Funds for the Central Universities,Grant/Award Number:xtr042021007Top Young Talents Programme of Xi'an Jiaotong University。
文摘Lead sulfide(PbS)presents large potential in thermoelectric application due to its earth-abundant S element.However,its inferior average ZT(ZTave)value makes PbS less competitive with its analogs PbTe and PbSe.To promote its thermoelectric performance,this study implements strategies of continuous Se alloying and Cu interstitial doping to synergistically tune thermal and electrical transport properties in n-type PbS.First,the lattice parameter of 5.93Åin PbS is linearly expanded to 6.03Åin PbS_(0.5)Se_(0.5)with increasing Se alloying content.This expanded lattice in Se-alloyed PbS not only intensifies phonon scattering but also facilitates the formation of Cu interstitials.Based on the PbS_(0.6)Se_(0.4)content with the minimal lattice thermal conductivity,Cu interstitials are introduced to improve the electron density,thus boosting the peak power factor,from 3.88μW cm^(−1)K^(−2)in PbS_(0.6)Se_(0.4)to 20.58μW cm^(−1)K^(−2)in PbS0.6Se0.4−1%Cu.Meanwhile,the lattice thermal conductivity in PbS_(0.6)Se_(0.4)−x%Cu(x=0-2)is further suppressed due to the strong strain field caused by Cu interstitials.Finally,with the lowered thermal conductivity and high electrical transport properties,a peak ZT~1.1 and ZTave~0.82 can be achieved in PbS_(0.6)Se_(0.4)−1%Cu at 300–773K,which outperforms previously reported n-type PbS.
文摘The sessile life style of plants creates the need to deal with an often adverse environment, in which water availability can change on a daily basis, challenging the cellular physiology and integrity. Changes in os- motic conditions disrupt the equilibrium of the plasma membrane： hypoosmotic conditions increase and hyperosmotic environment decrease the cell volume. Here, we show that short-term extracellular osmotic treatments are closely followed by a shift in the balance between endocytosis and exocytosis in root mer- istem cells. Acute hyperosmotic treatments （ionic and nonionic） enhance clathrin-mediated endocytosis simultaneously attenuating exocytosis, whereas hypoosmotic treatments have the opposite effects. In addition to clathrin recruitment to the plasma membrane, components of early endocytic trafficking are essential during hyperosmotic stress responses. Consequently, growth of seedlings defective in elements of clathrin or early endocytic machinery is more sensitive to hyperosmotic treatments. We also found that the endocytotic response to a change of osmotic status in the environment is dominant over the presum- ably evolutionary more recent regulatory effect of plant hormones, such as auxin. These results imply that osmotic perturbation influences the balance between endocytosis and exocytosis acting through clathrin- mediated endocytosis. We propose that tension on the plasma membrane determines the addition or removal of membranes at the cell surface, thus preserving cell integrity.
基金This work was supported by the European Union's Horizon 2020 Program(ERC grant agreement no.742985 to J.F.)S.T.was funded by a European Molecular Biology Organization(EMBO)long-term postdoctoral fellowship(ALTF 723-2015)C.L.is supported by the Austrian Science Fund(FWF,P 31493).
文摘The phytohormone auxin plays a central role in shaping plant growth and development.With decades of genetic and biochemical studies,numerous core molecular components and their networks,underlying auxin biosynthesis,transport,and signaling,have been identified.Notably,protein phosphorylation,catalyzed by kinases and oppositely hydrolyzed by phosphatases,has been emerging to be a crucial type of post-translational modification,regulating physiological and developmental auxin output at all levels.In this review,we comprehensively discuss earlier and recent advances in our understanding of genetics,biochemistry,and cell biology of the kinases and phosphatases participating in auxin action.We provide insights into the mechanisms by which reversible protein phosphorylation defines developmental auxin responses,discuss current challenges,and provide our perspectives on future directions involving the integration of the control of protein phosphorylation into the molecular auxin network.
基金This work has been supported by grants fromthe Austrian Science Fund(FWF P30850,V382 Richter-Programm to B.kFWF P31493 to C.L)by a Doc fellowship from the Austrian Academy of Sciences to L.D.-A.
文摘Protein abundance and localization at the plasma membrane(PM)shapes plant development and mediates adaptation to changing environmental conditions.It is regulated by ubiquitination,a post-translational modification crucial for the proper sorting of endocytosed PM proteins to the vacuole for subsequent degradation.To understand the significance and the variety of roles played by this reversible modification,the function of ubiquitin receptors,which translate the ubiquitin signature into a cellular response,needs to be elucidated.In this study,we show that TOL(TOM1-like)proteins function in plants as multivalent ubiquitin receptors,governing ubiquitinated cargo delivery to the vacuole via the conserved Endosomal Sorting Complex Required for Transport(ESCRT)pathway.TOL2 and TOL6 interact with components of the ESCRT machinery and bind to K63-linked ubiquitin via two tandemly arranged conserved ubiquitin-binding domains.Mutation of these domains results not only in a loss of ubiquitin binding but also altered localization,abolishing TOL6 ubiquitin receptor activity.Function and localization of TOL6 is itself regulated by ubiquitination,whereby TOL6 ubiquitination potentially modulates degradation of PM-localized cargoes,assisting in the fine-tuning of the delicate interplay between protein recycling and downregulation.Taken together,our findings demonstrate the function and regulation of a ubiquitin receptor that mediates vacuolar degradation of PM proteins in higher plants.
基金supported by National Natural Science Foundation(31970529)Beijing Natural Science Foundation Outstanding Youth Project(JQ23026)+1 种基金National Key Research and Development Program of China(2021YFD1201500)the Major Basic Research Program of Shandong Natural Science Foundation(ZR2019ZD15)。
文摘Winter plants rely on vernalization,a crucial process for adapting to cold conditions and ensuring successful reproduction.However,understanding the role of histone modifications in guiding the vernalization process in winter wheat remains limited.In this study,we investigated the transcriptome and chromatin dynamics in the shoot apex throughout the life cycle of winter wheat in the field.Two core histone modifications,H3K27me3 and H3K36me3,exhibited opposite patterns on the key vernalization gene VERNALIZATION1(VRN1),correlating with its induction during cold exposure.Moreover,the H3K36me3 level remained high at VRN1 after cold exposure,which may maintain its active state.Mutations in FERTILIZATION-INDEPENDENT ENDOSPERM(TaFIE)and SET DOMAIN GROUP 8/EARLY FLOWERING IN SHORT DAYS(TaSDG8/TaEFS),components of the writer complex for H3K27me3 and H3K36me3,respectively,affected flowering time.Intriguingly,VRN1 lost its high expression after the cold exposure memory in the absence of H3K36me3.During embryo development,VRN1 was silenced with the removal of active histone modifications in both winter and spring wheat,with selective restoration of H3K27me3 in winter wheat.The mutant of Tafie-cr-87,a component of H3K27me3“writer”complex,did not influence the silence of VRN1during embryo development,but rather attenuated the cold exposure requirement of winter wheat.Integrating gene expression with H3K27me3 and H3K36me3 patterns identified potential regulators of flowering.This study unveils distinct roles of H3K27me3 and H3K36me3 in controlling vernalization response,maintenance,and resetting in winter wheat.
基金National Natural Science Foundation of China,Grant/Award Numbers:22220102004,22025503Shanghai Municipal Science and Technology Major Project,Grant/Award Number:2018SHZDZX03+5 种基金Innovation Program of Shanghai Municipal Education Commission,Grant/Award Number:2023ZKZD40Fundamental Research Funds for the Central Universities,the Program of Introducing Talents of Discipline to Universities,Grant/Award Number:B16017Science and Technology Commission of Shanghai Municipality,Grant/Award Number:21JC1401700Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study,Grant/Award Number:SN-ZJU-SIAS-006China Scholarship Council,Grant/Award Number:202006745016Dutch Ministry of Education,Culture and Science,Grant/Award Number:024.001.035。
文摘Photoisomerization and photoluminescence are two distinct energy dissipation path-ways in light-driven molecular motors.The photoisomerization properties of discrete molecular motors have been well established in solution,but their photoluminescent properties have been rarely reported-especially in aggregates.Here,it is shown that an overcrowded alkene-based molecular motor exhibits distinct dynamic prop-erties in solution and aggregate states,for example,gel and solid states.Despite the poor emissive properties of molecular motors in solution,a bright emission is observed in the aggregate states,including in gel and the crystalline solid.The emis-sion wavelength is highly dependent on the nature of the supramolecular packing and order in the aggregates.As a result,the fluorescent color can be readily tuned reversibly via mechanical grinding and vapor fuming,which provides a new platform for developing multi-stimuli functional materials.
文摘Endophytic fungi can be beneficial to plant growth. However, the molecular mechanisms under-lying colonization of Acremonium spp. remain unclear. In this study, a novel endophytic Acremonium strain was isolated from the buds of Panax notoginseng and named Acremonium sp. D212. The Acremonium sp. D212 could colonize the roots of P. notoginseng, enhance the resistance of P. notoginseng to root rot disease, and promote root growth and saponin bio-synthesis in P. notoginseng. Acremonium sp. D212 could secrete indole-3-acetic acid (IAA) and jasmonic acid (JA), and inoculation with the fungus increased the endogenous levels of IAA and JA in P. noto-ginseng. Colonization of the Acremonium sp. D212 in the roots of the rice line Nipponbare was dependent on the concentration of methyl jasmonate (MeJA) (2–15μmol/L) and 1-naphthalenacetic acid (NAA) (10–20μmol/L). Moreover, the roots of the JA signaling-defective coi1-18 mutant were colonized by Acremonium sp. D212 to a lesser degree than those of the wild-type Nipponbare and miR393b-overexpressing lines, and the colonization was res-cued by MeJA but not by NAA. It suggests that the cross-talk between JA signaling and the auxin biosynthetic pathway plays a crucial role in the colonization of Acremonium sp. D212 in host plants.
基金Netherlands Organisation for Scientific Research,the Netherlands(grants ALWOP.402 and OCENW.M20.031 to J.W.B.)Human Frontiers Research Program(grant RGP0015/2022 to D.W.).
文摘The auxin signaling molecule controls a variety of growth and developmental processes in land plants. Auxin regulates gene expression through a nuclear auxin signaling pathway (NAP) consisting of the ubiquitin ligase auxin receptor TIR1/AFB, its Aux/IAA degradation substrate, and DNA-binding ARF transcription factors. Although extensive qualitative understanding of the pathway and its interactions has been obtained, mostly by studying the flowering plant Arabidopsis thaliana, it remains unknown how these translate to quantitative system behavior in vivo, a problem that is confounded by the large NAP gene families in most species. Here, we used the minimal NAP of the liverwort Marchantia polymorpha to quantitatively map NAP protein accumulation and dynamics in vivo through the use of knockin fluorescent fusion proteins. Beyond revealing the dynamic native accumulation profile of the entire NAP protein network, we discovered that the two central ARFs, MpARF1 and MpARF2, are proteasomally degraded. This auxin-independent degradation tunes ARF protein stoichiometry to favor gene activation, thereby reprogramming auxin response during the developmental progression. Thus, quantitative analysis of the entire NAP has enabled us to identify ARF degradation and the stoichiometries of activator and repressor ARFs as a potential mechanism for controlling gemma germination.
基金supported by the European Research Council Advanced Grant (ETAP-742985 to H.T.and J.F.)by the Ministry of Science and Technology (grant 110-2636-B-005-001 to K.-J.L.).
文摘The phytohormone auxin,and its directional transport through tissues,plays a fundamental role in the development of higher plants.This polar auxin transport predominantly relies on PIN-FORMED(PIN)auxin exporters.Hence,PIN polarization is crucial for development,but its evolution during the rise of morpho-logical complexity in land plants remains unclear.Here,we performed a cross-species investigation by observing the trafficking and localization of endogenous and exogenous PINs in two bryophytes,Physco-mitrium patens and Marchantia polymorpha,and in theflowering plant Arabidopsis thaliana.We confirmed that the GFP fusion did not compromise the auxin export function of all examined PINs by using a radioac-tive auxin export assay and by observing the phenotypic changes in transgenic bryophytes.Endogenous PINs polarize tofilamentous apices,while exogenous Arabidopsis PINs distribute symmetrically on the membrane in both bryophytes.In the Arabidopsis root epidermis,bryophytic PINs have no defined polarity.Pharmacological interference revealed a strong cytoskeletal dependence of bryophytic but not Arabidopsis PIN polarization.The divergence of PIN polarization and trafficking is also observed within the bryophyte clade and between tissues of individual species.These results collectively reveal the divergence of PIN traf-ficking and polarity mechanisms throughout land plant evolution and the co-evolution of PIN sequence-based and cell-based polarity mechanisms.
基金Czech Science Foundation via project 23-07363S(to D.Z.,J.H.,K.V.,and O.N.)Scientific Service Units(SSU)of ISTA through resources provided by the Imaging and Optics Facility and the Life Science Facility.
文摘Hormone perception and signaling pathways have a fundamental regulatory function in the physiological processes of plants.Cytokinins,a class of plant hormones,regulate cell division and meristem maintenance.The cytokinin signaling pathway is well established in the model plant Arabidopsisthaliana.Several negative feedback mechanisms,tightly controlling cytokinin signaling output,have been described previously.In this study,we identified a new feedback mechanism executed through alternative splicing of the cytokinin receptor AHK4/CRE1.A novel splicing variant named CRE1int7 results from seventh intron retention,introducing a premature termination codon in the transcript.We showed that CRE1int7 is translated in planta into a truncated receptor lacking the C-terminal receiver domain essential for signal transduction.CRE1int7 can bind cytokinin but cannot activate the downstream cascade.We present a novel negative feedback mechanism of the cytokinin signaling pathway,facilitated by a decoy receptor that can inactivate canonical cytokinin receptors via dimerization and compete with them for ligand binding.Ensuring proper plant growth and development requires precise control of the cytokinin signaling pathway at several levels.CRE1int7 represents a so-far unknown mechanism for fine-tuning the cytokinin signaling pathway in Arabidopsis.
基金the European Research Council Advanced Grant(ETAP-742985).
文摘Dear Editor,Auxin is the major plant hormone regulating growth and development(Friml,2022).Forward genetic approaches have identified major components of auxin signaling and established the canonical mechanism mediating transcriptional and thus developmental reprogramming in Arabidopsis thaliana.In this textbook view,TRANSPORT INHIBITOR RESPONSE 1(TIR1)/AUXIN-SIGNALING F-BOX(AFB)proteins are auxin receptors,which act as F-box subunits determining the substrate specificity of the Skp1-Cullin1-F box protein(SCF)type E3 ubiquitin ligase complex.Auxin acts as a"molecular glue,"increasing the affinity between TIR1/AFBs and the Auxin/lndole-3-Acetic Acid(Aux/IAA)repressors.Subsequently,Aux/IAAs are ubiquitinated and degraded,thus releasing auxin transcription factors from their repression and making them free to mediate transcription of auxin response genes(Yu et al.,2022).
基金supported by the National Science Fund for Distinguished Young Scholars(51925101)National Key Research and Development Program of China(2018YFA0702100)+1 种基金111 Project(B17002)Lise Meitner Project(M2889-N)。
文摘Thermoelectric materials enable the direct conversion between heat and electricity,providing potential in power generation and cooling applications[1].The energy conversion efficiency is determined by the dimensionless figure of merit ZT=S^(2)σT/κ_(tot),where S is the Seebeck coefficient;σis the electrical conductivity;T is the temperature in Kelvin;κ_(tot)is the total thermal conductivity.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB37020103 to Linfeng Sun)research funds from the Center for Advanced Interdisciplinary Science and Biomedicine of IHM,Division of Life Sciences and Medicine,University of Science and Technology of China(QYPY20220012 to S.T.)+4 种基金start-up funding from the University of Science and Technology of China and the Chinese Academy of Sciences(GG9100007007,KY9100000026,KY9100000051,KJ2070000079 to S.T.)the National Natural Science Foundation of China(31900885 to X.L.,31870732 to Linfeng Sun)the Natural Science Foundation of Anhui Province(2008085MC90 to X.L.,2008085J15 to Linfeng Sun)the Fundamental Research Funds for the Central Universities(WK9100000021 to S.T.,WK9100000031 to Linfeng Sun)and the USTC Research Funds of the Double First-Class Initiative(YD9100002016 to S.T.,YD9100002004 to Linfeng Sun).Linfeng Sun is supported by an Outstanding Young Scholar Award from the Qiu Shi Science and Technologies Foundation and a Young Scholar Award from the Cyrus Tang Foundation.
文摘The phytohormone auxin plays central roles in many growth and developmental processes in plants.Development of chemical tools targeting the auxin pathway is useful for both plant biology and agriculture.Here we reveal that naproxen,a synthetic compound with anti-inflammatory activity in humans,acts as an auxin transport inhibitor targeting PIN-FORMED(PIN)transporters in plants.Physiological experiments indicate that exogenous naproxen treatment affects pleiotropic auxin-regulated developmental processes.Additional cellular and biochemical evidence indicates that naproxen suppresses auxin transport,specifically PIN-mediated auxin efflux.Moreover,biochemical and structural analyses confirm that naproxen binds directly to PIN1 protein via the same binding cavity as the indole-3-acetic acid substrate.Thus,by combining cellular,biochemical,and structural approaches,this study clearly establishes that naproxen is a PIN inhibitor and elucidates the underlying mechanisms.Further use of this compound may advance our understanding of the molecular mechanisms of PIN-mediated auxin transport and expand our toolkit in auxin biology and agriculture.
文摘Ethylene and cytokinin,two plant hormones with essential functions throughout the plant's life cycle,contribute to a wide spectrum of physiological,biochemical,and developmental processes.Over the last decades,the molecular mechanisms underlying their biosynthesis and metabolism as well as pathways mediating their perception and signal transduction have been deciphered.Although machineries controlling the activities of these two central hormonal regulators appear robust and autonomous,in the ever-changing environmental conditions that plants face,survival is dependent on their tight communication and mutually balanced activities.A recent work by Zdarska et al.(2019)is trying to address the challenging question regarding the mechanisms underlying the cytokinin and ethylene cross-talk.This study reveals an intriguing,multilayered nature of hormonal interaction,in which the EHYLENE RESISTANT 1(ETR1)receptor upon perceiving an ethylene signal activates a multistep phosphorelay(MSP)cytokinin transduction cascade,integrating ethylene and cytokinin in the control of root apical meristem size.In parallel,activation of canonical ethylene signaling adjusts the responsiveness of the cytokinin pathway by transcriptional upregulation of one of its key signaling components,the ARR10 response regulator(Figure 1).Importantly,unlike the canonical ethylene transduction machinery,ethylene input into the MSP is dependent on histidine kinase activity of ETR1 receptor.
文摘Auxin is a key hormonal regulator,that governs plant growth and development in concert with other hormonal pathways.The unique feature of auxin is its polar,cell-to-cell transport that leads to the formation of local auxin maxima and gradients,which coordinate initiation and patterning of plant organs.The molecular machinery mediating polar auxin transport is one of the important points of interaction with other hormones.Multiple hormonal pathways converge at the regulation of auxin transport and form a regulatory network that integrates various developmental and environmental inputs to steer plant development.In this review,we discuss recent advances in understanding the mechanisms that underlie regulation of polar auxin transport by multiple hormonal pathways.Specifically,we focus on the post-translational mechanisms that contribute to fine-tuning of the abundance and polarity of auxin transporters at the plasma membrane and thereby enable rapid modification of the auxin flow to coordinate plant growth and development.
基金The research leading to these results received funding from the European Research Council under the European Union Seventh Framework Pro-gramme ERC-2013-STG grant agreement 335691the Austrian Science Fund(FWF)P27818-B22,I 3033-B22+1 种基金the Austrian Academy of Sciences(OEAW)the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy-EXC 2070-390732324.
文摘In plants,the antagonism between growth and defense is hardwired by hormonal signaling.The perception of pathogen-associatedmolecularpatterns(PAMPs)frominvadingmicroorganismsinhibits auxin signalingand plant growth.Conversely,pathogens manipulate auxin signaling to promote disease,but how this hormone inhibits immunity is not fully understood.Ustilago maydis is a maize pathogen that induces auxin signaling in its host.We characterized a U.maydis effector protein,Naked1(Nkd1),that is translocated into the host nucleus.Through its native ethylene-responsive element binding factor-associated amphiphilic repression(EAR)motif,Nkd1 binds to the transcriptional co-repressors TOPLESS/TOPLESS-related(TPL/TPRs)and prevents the recruitment of a transcriptional repressor involved in hormonal signaling,leading to the derepression of auxin and jasmonate signaling and thereby promoting susceptibility to(hemi)biotrophic pathogens.A moderate upregulation of auxin signaling inhibits the PAMP-triggered reactive oxygen species(ROS)burst,an early defense response.Thus,our findings establish a clear mechanism for auxin-induced pathogen susceptibility.Engineered Nkd1 variants with increased expression or increased EAR-mediated TPL/TPR binding trigger typical salicylic-acid-mediated defense reactions,leading to pathogen resistance.This implies that moderate binding of Nkd1 to TPL is a result of a balancing evolutionary selection process to enable TPL manipulation while avoiding host recognition.
基金supported by the Natural Science Basic Research Plan in the Shaanxi Province of China(2019JQ-062 and 2020JQ-410)Shaanxi Youth Entrusted Talent Program(20190205)+3 种基金Shaanxi Postdoctoral Project(2018BSHYDZZ76)Fundamental Research Funds for Central Universities(GK201903064,GK202002005and GK202001004)Young Elite Scientists Sponsorship Program by CAST(2019-2021QNRC001)State Key Laboratory of Cotton Biology Open Fund(CB2020A12).
文摘Cotton(Gossypium spp.)is one of the most important economic crops in the world and also a major source of natural fiber,oil,and protein.The morphology of cotton species varies from trailing herbaceous perennials to trees<10 m.Like other important crops,modern cotton cultivars are polyploids and have gone through polyploidization,evolution,and domestication.The cotton genus comprises approximately 45 diploid(2n=2x=26)and seven tetraploid species(2n=4x=52)(Guan et al.,2014).
文摘Auxin, one of the plant hormones, is a key regulator of plant growth and development. At the cellular level, it controls different processes, such as cell expansion, division, and differentiation that are reflected by its regulatory role in a plethora of developmental mechanisms. An important feature of the auxin action is its differential distribution within tissues mediated by the polar auxin transport machinery, which can be dynamically regulated in response to internal and external stimuli. Receptors at the cell surface or cell interior are needed to sense and interpret fluctuations in the auxin distribution.
