The phytohormone auxin exerts control over remarkable developmental processes in plants.It moves from cell to cell,resulting in the creation of both extracellular auxin and intracellular auxin,which are recognized by ...The phytohormone auxin exerts control over remarkable developmental processes in plants.It moves from cell to cell,resulting in the creation of both extracellular auxin and intracellular auxin,which are recognized by distinct auxin receptors.These two auxin signaling systems govern different auxin responses while working together to regulate plant development.In this review,we outline the latest research advancements in unraveling these auxin signaling pathways,encompassing auxin perception and signaling transductions.We emphasize the interaction between extracellular and intracellular auxin,which contributes to the intricate role of auxin in plant development.展开更多
The formation of root system architecture(RSA)plays a crucial role in plant growth.OsDRO1 is known to have a function in controlling RSA in rice,however,the role of potato StDRO2,a homolog of rice OsDRO1,in root growt...The formation of root system architecture(RSA)plays a crucial role in plant growth.OsDRO1 is known to have a function in controlling RSA in rice,however,the role of potato StDRO2,a homolog of rice OsDRO1,in root growth remains unclear.In this study,we obtained potato dro2 mutant lines by Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-Associated 9(CRISPR/Cas9)-mediated genome editing system.The mutant lines were generated from a splicing defect of the StDRO2 intron 1,which causes a nonsense mutation in StDRO2.Furthermore,the secondary structure of StDRO2 mRNA analyzed with RNAfold Web Server was altered in the dro2 mutant.Mutation of StDRO2 conveys potato adaptation through changing the RSA via alteration of auxin transport under drought stress.The potato dro2 lines showed higher plant height,longer root length,smaller root growth angle and increased tuber weight than the wild-type.The alteration of RSA was associated with a disturbance of IAA distribution in the dro2 mutant,and the levels of StPIN7 and StPIN10 detected by using real-time PCR were up-regulated in the roots of potato dro2 lines grown under drought stress.Moreover,the microRNAs(miRNAs)PmiREN024536 and PmiREN024486 targeted the StDRO2 gene,and auxin positively and negatively regulated the expression of StDRO2 and the miRNAs PmiREN024536 and PmiREN024486,respectively,in the potato roots.Our data shows that a regulatory network involving auxin,StDRO2,PmiREN024536 and PmiREN024486 can control RSA to convey potato fitness under drought stress.展开更多
Protein biosynthesis by the ribosome is a fundamental biological process in living systems.Recent studies suggest that ribosomal subunits also play essential roles in cell growth and differentiation beyond their roles...Protein biosynthesis by the ribosome is a fundamental biological process in living systems.Recent studies suggest that ribosomal subunits also play essential roles in cell growth and differentiation beyond their roles in protein translation.The ribosomal subunit RPS6 has been studied for more than 50 years in various organisms,but little is known about its specific roles in certain signaling pathways.In this study,we focused on the functions of Arabidopsis RPS6A in auxin-related root growth and development.The rps6a mutant presented a series of auxin-deficient phenotypes,such as shortened primary roots,reduced lateral root numbers,and defective vasculatures.Treatment of the rps6a mutant with various concentrations of auxin and its analogs did not restore the root defect phenotypes,suggesting a defect in the auxin signaling pathway.Further cell biological and global transcriptome analyses revealed that auxin signaling was weakened in the rps6a mutant and that there was a reduced abundance of PIN-FORMED(PIN)auxin transporters.Our work provides insights into the role of the protein biosynthesis pathway involved in auxin signaling.展开更多
Grafting is an effective technique for increasing the resistance of vegetables to biotic and abiotic stresses.It has been widely applied to produce solanaceous and melon vegetables.Temperature is an important external...Grafting is an effective technique for increasing the resistance of vegetables to biotic and abiotic stresses.It has been widely applied to produce solanaceous and melon vegetables.Temperature is an important external factor affecting graft formation.However,the molecular mechanism by which external ambient temperature affects tomato graft formation remains unclear.In this study,we demonstrated that elevating ambient temperature during grafting to 35℃ for more than 24 h after grafting accelerated vascular reconnection.We generated self-or heterografted combinations between phyB1B2 and pif4 loss-of-function mutant and wild-type plants,and were mutants unresponsive to graft formation at elevated ambient temperature.In addition,elevated ambient temperature induced SlPIF4 expression during grafting.SlPIF4 directly binds the promoters of auxin biosynthesis genes SlYUCCAs and activates their expression.Further investigation revealed auxin accumulation in the graft junction under elevated ambient temperature.The results illuminate the mechanism by which the PHYB-PIF4-auxin module promotes tomato graft formation in response to elevated ambient temperature.展开更多
Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis tha...Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.展开更多
Auxins were the first of the major plant hormones and played key roles in plant growth and development.Auxin triggered gene expression through several mechanisms.The canonical textbook model is that auxin binds to TIR...Auxins were the first of the major plant hormones and played key roles in plant growth and development.Auxin triggered gene expression through several mechanisms.The canonical textbook model is that auxin binds to TIR1/AFB receptors and stabilizes their interaction with Aux/IAA repressors,leading to their ubiquitination and degradation,which results in activation of ARFs transcription factors.The recent study published in Nature by JiíFriml and co-authors updated the view on gene expression regulated by auxin.The role of TIR-produced cAMP was confirmed to be the second messenger in transcriptional auxin signaling.The conclusions raised in this Nature article shift the paradigm about the regulation of plant growth and development by auxin to the modulation of cAMP production and its interaction with candidate targets.展开更多
Brassica napus(oilseed rape)is sensitive to boron(B)deficiency and exhibits young leaf curling in response to low-B stress at the seedling stage,which leads to reduced photosynthesis and plant growth.So far,no gene ha...Brassica napus(oilseed rape)is sensitive to boron(B)deficiency and exhibits young leaf curling in response to low-B stress at the seedling stage,which leads to reduced photosynthesis and plant growth.So far,no gene has been identified to be involved in B deficiency induced leaf curling.Our previous results showed the transcription factor BnaA1.WRKY53 might be involved in B-deficiency tolerance.However,altered BnaA1.WRKY53 expression does not influence B concentration in shoot,root and leaf cell walls,which suggests Bna A1.WRKY53 might be involved in other biological processes.Indeed,phenotypic and anatomical analyses revealed that BnaA1.WRKY53 negatively regulated the leaf curling induced by leaf epinasty by suppressing the overexpansion of palisade cells under B deficiency.Further transcriptome enrichment analysis of differentially expressed genes(DEGs)between wild-type and BnaA1.WRKY53overexpression line showed auxin response pathway was enriched.In addition,Arabidopsis DR5::GFP auxin reporter line showed B deficiency caused predominant auxin signal accumulation in the adaxial side and concomitant adaxial cell expansion,which indicated that B deficiency may induce leaf curling by altering auxin distribution.Phytohormone quantification and gene expression analysis demonstrated that BnaA1.WRKY53 prevent auxin overaccumulation in leaves by suppressing auxin biosynthetic genes under B deficiency.Furthermore,exogenous 1-naphthlcetic acid(NAA)treatment experiments revealed that high auxin could induce leaf curling and BnaA1.WRKY53 expression.Overall,these findings demonstrate that auxin and the transcription factor BnaA1.WRKY53 synergistically regulate leaf curling to maintain an optimal leaf area under B deficiency,and provide novel insights into the resistance mechanisms against B-deficiency-induced leaf curling in oilseed rape.展开更多
Grapevine(Vitis sp.)is one of the most important economic fruit crops all over the world,and the formation of adventitious roots(ARs)is crucial for the vegetative reproduction of grapes.However,studies on the regulato...Grapevine(Vitis sp.)is one of the most important economic fruit crops all over the world,and the formation of adventitious roots(ARs)is crucial for the vegetative reproduction of grapes.However,studies on the regulatory mechanisms of this process are currently lacking.In this study,we applied an efficient and convenient leave-petiole(LP)system for studying ARs,revealing a significant inhibition of root primordia formation under continuous-light treatment.The results showed that isolated ARs of grapevine were induced and originated from ray cells near the vascular cambium,with the process categorized into induction,initiation,and extension stages.LP samples under light and dark conditions were used for transcriptome sequencing and endogenous hormone measurements at three critical time points of AR formation.A total of 37155 transcripts were obtained,and 7041 genes showed significantly different expression levels in the petiole.An integrated analysis,including Gene Ontology(GO)enrichment analysis,weighted gene co-expression network analysis(WGCNA),and hormonal content determination,showed that several genes(ARF4,LAX1,PIN1,SUS2,APX1,TPXL1,CHS3,etc.)associated with hormone signals,sugar synthesis and transport,reactive oxygen species(ROS)scavenging,cell wall biogenesis,flavonoid biosynthesis,microtubule remodeling,and some transcription factors(HY5,COP1,ERF2,MYB15,etc)played vital roles in light-induced AR formation.A hypothetical model was initially constructed,which illustrated the centrality of auxin in HY5-dependent AR formation and the complex crosstalk among various factors.The results of this study provided abundant genetic resources and a novel perspective for understanding the molecular mechanisms of AR formation in grapevine.展开更多
In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates r...In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates redox metabolism and promotes the accumulation of nitric oxide(NO)in various tissues and physiological contexts.NO functions as a redox signaling molecule,exerting its effects in part through the reversible oxidation of cysteine residues via a post-translational modification known as S-nitrosylation.Recent findings highlight a dynamic interplay between S-nitrosylation and the ubiquitination machinery,shaping critical aspects of auxin-mediated plant responses.In this review,we summarize current knowledge on redox regulation of UPS components involved in auxinmediated pathways and propose new perspectives on the integration of hormonal and redox signaling in plants.We describe and discuss the complexity of the latest evidence supporting the role of NO as a second messenger in auxin signaling,with S-nitrosylation acting as a regulatory mechanism that fine-tunes the UPS to control developmental outcomes.We focused on the direct effects of NO that include S-nitrosylation of specific cysteine residues of substrates,adaptors,and substrate receptors belonging to different CULLIN1-and CULLIN4-based E3 ubiquitin ligase complexes.展开更多
Arogenate dehydratase(ADT)catalyzes the final step in phenylalanine synthesis and is crucial for plant development and metabolism.Previously,we demonstrated that the ADT/prephenate dehydratase ZmADT2 is essential for ...Arogenate dehydratase(ADT)catalyzes the final step in phenylalanine synthesis and is crucial for plant development and metabolism.Previously,we demonstrated that the ADT/prephenate dehydratase ZmADT2 is essential for maize resistance to Ustilago maydis and for overall plant development.In this study,we explored the role of ZmADT2 in maize kernel development.The mmsu mutant,a dysfunctional ZmADT2 variant,exhibits delayed embryo and endosperm development,along with deficiencies in carbohydrate and protein storage.Transcriptome analysis revealed differential expression of many kernel compartment-specific genes between mmsu and wild-type(WT)kernels,with impaired nutrient accumulation and auxin signaling pathway in the mmsu endosperm.Compared to WT,ZmADT2 mutation led to reduced auxin levels and smaller endosperm cell size.Exogenous auxin rescued the small kernel phenotype of mmsu.Additionally,auxin distribution was reduced in the basal endosperm transfer layer(BETL),causing defects in its development and function,including reduced transfer cell elongation,cell wall ingrowth and nutrient uptake.These findings suggest that ZmADT2 mediated mediates an auxin signaling pathway that is essential for maize kernel development.展开更多
[Objective] The aim was to study the effect of different kinds of exogenous auxin on the growth of rice roots under cadmium stress.[Method] Oryza sativa L.cv Zhonghua No.11 was used as experimental materials to detect...[Objective] The aim was to study the effect of different kinds of exogenous auxin on the growth of rice roots under cadmium stress.[Method] Oryza sativa L.cv Zhonghua No.11 was used as experimental materials to detect the effect of different kinds of exogenous auxin on the growth of rice roots.[Result] The results showed that 0.1 mmol/L Cd treatment could not only increase primary,adventitious and lateral root length but also lateral root number,whereas the shoot growth was inhibited.When supplemented with different concentrations of NAA,IAA,IBA and 2,4-D,the growth of root system varied and similar change trend had been found.At the auxin concentration of 10^-9-10^-7 mol/L in particular 10^-8 mol/L,all four kinds of auxin promoted the elongation growth of primary and adventitious roots,but inhibition was observed when auxin was higher than 10^-7 mol/L.The decreased shoot growth caused by Cd could not be counteracted by supplementing with the four kinds of auxin.However,at the auxin concentration of 10^-9-10^-8 mol/L,NAA could improve rice growth under Cd stress condition.The formation and development of lateral roots on primary and adventitious roots was not only similar but also different after applying the same concentration of four auxins.[Conclusion] The addition of suitable amount of auxin under cadmium stress （such as 10^-9-10^-8 mol/L of NAA and so on） could ease the damage of cadmium on plants to a certain extent.展开更多
Protein post-translational modifications(PTMs),such as ubiquitination,phosphorylation,and small ubiquitin-like modifier(SUMO)ylation,are crucial for regulating protein stability,activity,subcellular localization,and b...Protein post-translational modifications(PTMs),such as ubiquitination,phosphorylation,and small ubiquitin-like modifier(SUMO)ylation,are crucial for regulating protein stability,activity,subcellular localization,and binding with cofactors.Such modifications remarkably increase the variety and complexity of proteomes,which are essential for regulating numerous cellular and physiological processes.The regulation of auxin signaling is finely tuned in time and space to guide various plant growth and development.Accumulating evidence indicates that PTMs play critical roles in auxin signaling regulations.Thus,a thorough and systematic review of the functions of PTMs in auxin signal transduction will improve our profound comprehension of the regulation mechanism of auxin signaling and auxin-mediated various processes.This review discusses the progress of protein ubiquitination,phosphorylation,histone acetylation and methylation,SUMOylation,and S-nitrosylation in the regulation of auxin signaling.展开更多
Rice(Oryza sativa)plant architecture and grain shape,which determine grain quality and yield,are modulatedby auxin and brassinosteroid via regulation of cell elongation and proliferation.We review the signaltransducti...Rice(Oryza sativa)plant architecture and grain shape,which determine grain quality and yield,are modulatedby auxin and brassinosteroid via regulation of cell elongation and proliferation.We review the signaltransduction of these hormones and the crosstalk between their signals on the regulation of rice plantarchitecture and grain shape.展开更多
Indole-3-acetamide(IAM)is the first confirmed auxin biosynthetic intermediate in some plant pathogenic bacteria.Exogenously applied IAM or production of IAM by overexpressing the bacterial iaaM gene in Arabidopsis cau...Indole-3-acetamide(IAM)is the first confirmed auxin biosynthetic intermediate in some plant pathogenic bacteria.Exogenously applied IAM or production of IAM by overexpressing the bacterial iaaM gene in Arabidopsis causes auxin overproduction phenotypes.However,it is still inconclusive whether plants use IAM as a key precursor for auxin biosynthesis.Herein,we reported the isolation IAM HYDROLASE 1(IAMH1)gene in Arabidopsis from a forward genetic screen for IAM-insensitive mutants that display normal auxin sensitivities.IAMH1 has a close homolog named IAMH2 that is located right next to IAMH1on chromosomeⅣin Arabidopsis.We generated iamh1 iamh2 double mutants using our CRISPR/Cas9gene editing technology.We showed that disruption of the IAMH genes rendered Arabidopsis plants resistant to IAM treatments and also suppressed the iaaM overexpression phenotypes,suggesting that IAMH1 and IAMH2 are the main enzymes responsible for converting IAM into indole-3-acetic acid(IAA)in Arabidopsis.The iamh double mutants did not display obvious developmental defects,indicating that IAM does not play a major role in auxin biosynthesis under normal growth conditions.Our findings provide a solid foundation for clarifying the roles of IAM in auxin biosynthesis and plant development.展开更多
Study on the role of quereentin in polar auxin transportation. Arabidopsis was cultured on medium supplemented with quereetin to observe the growth of hypoeotyls, ^14C-IAA transport assays were conducted to measure th...Study on the role of quereentin in polar auxin transportation. Arabidopsis was cultured on medium supplemented with quereetin to observe the growth of hypoeotyls, ^14C-IAA transport assays were conducted to measure the auxin transport activity. The results showed that Arabidopsis mutant auxl which had been deficient in auxin influx transportion obviously recovered the ability after eultured on the medium with quercetin. The polar auxin transport was promoted by the addition of quereetin. These results indicated that quereetin could promote polar auxin transport in vivo.展开更多
Based on the sequence information of Arabidopsis PIN1, two cDNAs encoding PIN homologues from Brassica juncea, Bjpin2 and Bjpin3, were isolated through cDNA library screening. Bjpin2 and Bjpin3 encoded proteins contai...Based on the sequence information of Arabidopsis PIN1, two cDNAs encoding PIN homologues from Brassica juncea, Bjpin2 and Bjpin3, were isolated through cDNA library screening. Bjpin2 and Bjpin3 encoded proteins containing 640 and 635 amino acid residues, respectively, which shared 97.5% identities with each other and were highly homologous to Arabidopsis PIN1, PIN2 and other putative PIN proteins. BJPIN2 and BjPIN3 had similar structures as AtPIN proteins. Northern blot analysis indicated that Bjpin2 was expressed in stem, leaf and floral tissues, while Bjpin3 was expressed predominantly in stem and hypocotyls. Two promoter fragments of pin genes, Bjpin-X and Bjpin-Z, were isolated by 'genome walking' technique using primers at 5'-end of pin cDNA. Promoter-gus fusion studies revealed the GUS activities driven by Bjpin-X were at internal side of xylem and petal; while those driven by Bjpin-Z were detected at leaf vein, epidermal cell and cortex of stem, vascular tissues and anther. Results of the pin genes with different expression patterns in B. juncea suggested the presence of a gene family.展开更多
Auxin has been suggested to play an essential role in regulating apple fruit maturation and ripening, though the molecular function of auxin and its interaction with ethylene during apple fruit development are largely...Auxin has been suggested to play an essential role in regulating apple fruit maturation and ripening, though the molecular function of auxin and its interaction with ethylene during apple fruit development are largely unknown. To understand the function of auxin during apple fruit maturation and ripening, auxin efflux carrier and IAA-amido synthetase encoding genes were identified from the apple genome based on the results of previous microarray analysis. The expression patterns of these genes were analyzed using qRT-PCR during 10 - 12 weeks of fruit maturation for two apple cultivars: “Golden Delicious” (GD) and “Cripps Pink” (CP), which have the distinct patterns of maturation progression. Our results showed that the expressions of auxin efflux carrier and IAA-amido synthetase genes have a correlation with the timing of ethylene biosynthesis pathway activation in both cultivars. The earlier and stronger expression of MdGH3.102 and MdAECFP1 in the fruit of GD, a mid-season cultivar, correlates with the earlier activation of a pre-climacteric ethylene biosynthesis gene of MdACS3, compared with that in CP, a late-ripening apple cultivar. Results of exogenous IAA treatment indicated that the expression patterns of the genes were regulated in a fruit maturity dependent manner. Our results suggested that the dynamics of the auxin level in apple fruit cortex could be one of the key factors influencing the timing of ethylene biosynthesis pathway activation and consequently contributed to the control of the apple maturation progression.展开更多
The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of mo...The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of molecules,including the natural auxin indole-3-acetic acid(IAA),as well as other phytoregulators.However,several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria.The effects of A.brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction.The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure,accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots.An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants.However,after five days of bacterization,the response disappeared in the primary root meristems.The role of polar auxin transport(PAT)in auxins relocation involved the PGP1,AXR4-1,and BEN2 proteins,which apparently mediated A.brasilense-induced root branching of Arabidopsis seedlings.展开更多
ENOX (ECTO-NOX) proteins of the external surface of the plasma membrane catalyze oxidation of both NADH and hydroquinones and protein disulfide-thiol interchange. They exhibit both prion-like and time-keeping (clock) ...ENOX (ECTO-NOX) proteins of the external surface of the plasma membrane catalyze oxidation of both NADH and hydroquinones and protein disulfide-thiol interchange. They exhibit both prion-like and time-keeping (clock) properties. The oxidative and interchange activities alternate to generate a regular period of 24 min in length. Here we report the cloning, expression and characterization of a constitutive plant ENOX protein activated by both natural (Indole-3-acetic acid, IAA) and synthetic (2,4-dichlorophenoxyacetic acid, 2,4-D) auxin plant growth regulators with an optimum of about 1 μM, higher concentrations being less effective. The gene encoding the 213 amino acid protein (ABP20) is found in EMBL accession number U81162. Functional motifs characteristic of ENOX1 proteins, previously identified by site-directed mutagenesis, are present in the candidate auxin-activated ENOX (dNOX, ENOX5), including adenine nucleotide and copper binding motifs along with essential cysteines and a motif having homology with a previously identified auxin-binding motif. Periodicity was exhibited by both the oxidative and protein disulfide-thiol inter-change activities as is characteristic for other ENOX proteins. Activity was blocked by the ENOX2-specific quassinoid inhibitor glaucarubolone and other ENOX2 inhibitors but not by the ENOX1-specific quassinoid inhibitor simalikalactone D. Activity required both auxin and bound copper. The inactive auxin 2,3-D was without effects.展开更多
TiO_(2) nanoparticles(nano-TiO_(2))are widely used in the world,and a considerable amount of nano-TiO_(2) is released into the environment,with toxic effects on organisms.In the various species of higher plants,growth...TiO_(2) nanoparticles(nano-TiO_(2))are widely used in the world,and a considerable amount of nano-TiO_(2) is released into the environment,with toxic effects on organisms.In the various species of higher plants,growth,including seed germination,root elongation,and biomass accumulation,is affected by nano-TiO_(2).However,the underlying molecular mechanisms remain to be elucidated.In this study,we observed that nano-TiO_(2) promoted root elongation in a dose-dependent manner.Furthermore,we found that nano-TiO_(2) elevated auxin accumulation in the root tips of the auxin marker lines DII-VENUS and DR5::GUS,and,correspondingly,quantitative real-time PCR analysis revealed that nano-TiO_(2) increased the expression levels of auxin biosynthesis-and transport-related genes.GFP fluorescence observation using transgenic PIN2-GFP indicated that nano-TiO_(2) promoted root growth by inducing PIN2 accumulation.Thus,we propose that nano-TiO_(2) promote root growth in Arabidopsis thaliana by altering the expression levels of auxin biosynthesis-and transport-related genes.展开更多
基金supported by the National Natural Science Foundation of China(32130010).
文摘The phytohormone auxin exerts control over remarkable developmental processes in plants.It moves from cell to cell,resulting in the creation of both extracellular auxin and intracellular auxin,which are recognized by distinct auxin receptors.These two auxin signaling systems govern different auxin responses while working together to regulate plant development.In this review,we outline the latest research advancements in unraveling these auxin signaling pathways,encompassing auxin perception and signaling transductions.We emphasize the interaction between extracellular and intracellular auxin,which contributes to the intricate role of auxin in plant development.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.32260085,31860064,31660501,31970609,32260718 and 31901870)the Key Projects of the Applied Basic Research Plan of Yunnan Province(Grant No.202301AS070082)+3 种基金the Start-up fund from Xishuangbanna Tropical Botanical Garden,the‘Top Talents Program in Science and Technology’from Yunnan Province,the Major Science and Technology Project in Yunnan Province(Grant Nos.202102AE090042 and 202202AE090036)the Young and Middle-Aged Academic and Technical Leaders Reserve Talent Program in Yunnan Province(Grant No.202205AC160076)China Postdoctoral Science Foundation(Grant No.2019M653849XB)the High-level Talents Introduction Plan of Yunnan Province-Young Talents Special Project。
文摘The formation of root system architecture(RSA)plays a crucial role in plant growth.OsDRO1 is known to have a function in controlling RSA in rice,however,the role of potato StDRO2,a homolog of rice OsDRO1,in root growth remains unclear.In this study,we obtained potato dro2 mutant lines by Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-Associated 9(CRISPR/Cas9)-mediated genome editing system.The mutant lines were generated from a splicing defect of the StDRO2 intron 1,which causes a nonsense mutation in StDRO2.Furthermore,the secondary structure of StDRO2 mRNA analyzed with RNAfold Web Server was altered in the dro2 mutant.Mutation of StDRO2 conveys potato adaptation through changing the RSA via alteration of auxin transport under drought stress.The potato dro2 lines showed higher plant height,longer root length,smaller root growth angle and increased tuber weight than the wild-type.The alteration of RSA was associated with a disturbance of IAA distribution in the dro2 mutant,and the levels of StPIN7 and StPIN10 detected by using real-time PCR were up-regulated in the roots of potato dro2 lines grown under drought stress.Moreover,the microRNAs(miRNAs)PmiREN024536 and PmiREN024486 targeted the StDRO2 gene,and auxin positively and negatively regulated the expression of StDRO2 and the miRNAs PmiREN024536 and PmiREN024486,respectively,in the potato roots.Our data shows that a regulatory network involving auxin,StDRO2,PmiREN024536 and PmiREN024486 can control RSA to convey potato fitness under drought stress.
基金supported by the National Natural Science Foundation of China(32321001)the Forestry Bureau of Anhui Province(AHLYJBGS-2024-01)+3 种基金the Center for Advanced Interdisciplinary Science and Biomedicine of IHM,the Division of Life Sciences and Medicine,the University of Science and Technology of China(QYPY20220012)the USTC Research Funds of the Double First-Class Initiative(YD9100002016)start-up funding from the University of Science and Technology of China and the Chinese Academy of Sciences(GG9100007007,KY9100000026,KY9100000051,KJ2070000079)the Fundamental Research Funds for the Central Universities(WK9100000021)。
文摘Protein biosynthesis by the ribosome is a fundamental biological process in living systems.Recent studies suggest that ribosomal subunits also play essential roles in cell growth and differentiation beyond their roles in protein translation.The ribosomal subunit RPS6 has been studied for more than 50 years in various organisms,but little is known about its specific roles in certain signaling pathways.In this study,we focused on the functions of Arabidopsis RPS6A in auxin-related root growth and development.The rps6a mutant presented a series of auxin-deficient phenotypes,such as shortened primary roots,reduced lateral root numbers,and defective vasculatures.Treatment of the rps6a mutant with various concentrations of auxin and its analogs did not restore the root defect phenotypes,suggesting a defect in the auxin signaling pathway.Further cell biological and global transcriptome analyses revealed that auxin signaling was weakened in the rps6a mutant and that there was a reduced abundance of PIN-FORMED(PIN)auxin transporters.Our work provides insights into the role of the protein biosynthesis pathway involved in auxin signaling.
基金supported by China Agriculture Research System of MOF and MARA(Grant No.CARS23-B10)The Major Science and Technology Projects in Hainan Province(Grant No.ZDKJ2021005)+1 种基金Key R&D projects in Shandong Province(Grant No.LJNY202106)Central Public-interest Scientific Institution Basal Research Fund(Grant No.IVF-BRF2023006)。
文摘Grafting is an effective technique for increasing the resistance of vegetables to biotic and abiotic stresses.It has been widely applied to produce solanaceous and melon vegetables.Temperature is an important external factor affecting graft formation.However,the molecular mechanism by which external ambient temperature affects tomato graft formation remains unclear.In this study,we demonstrated that elevating ambient temperature during grafting to 35℃ for more than 24 h after grafting accelerated vascular reconnection.We generated self-or heterografted combinations between phyB1B2 and pif4 loss-of-function mutant and wild-type plants,and were mutants unresponsive to graft formation at elevated ambient temperature.In addition,elevated ambient temperature induced SlPIF4 expression during grafting.SlPIF4 directly binds the promoters of auxin biosynthesis genes SlYUCCAs and activates their expression.Further investigation revealed auxin accumulation in the graft junction under elevated ambient temperature.The results illuminate the mechanism by which the PHYB-PIF4-auxin module promotes tomato graft formation in response to elevated ambient temperature.
文摘Auxin influences a variety of developmental and physiological processes. Early reports, suggested that auxin might affect plant stress response. We have identified a number of auxin responsive genes in Arabidopsis thaliana (L.) Heynh. by using cDNA an-ay and found that stress responsive genes, such as,Arabidopsis homolog of MEK kinase 1 (ATMEKK1), ReL/SpoT homolog 3 ( At-RSH3), Catalase 1 ( Cat1) and Ferritin 1 (Fer1), were down-regulated by auxin, indicating that auxin regulates ale expression of stress responsive genes. We also demonstrated that nitrilase genes, nitrilase I ( NIT]) and nitrilase 2 (NIT2) involving in indole-3-acetic acid (IAA) biosynthesis, were induced by salinity stress, suggesting that the level of IAA might increase in response to salinity stress. To dissect the signal pathway involved in the interaction, two auxin insensitive mutants, auxin resistant 2 (axr2) and auxin resistant 1-3 (axrl-3) were used. Stress responsive genes were induced by salt stress in wild type and axr2, but not in axr1-3. The result suggests that die interaction between auxin and stress responses may be linked in the ubiquitin pathway.
基金the National Key Research and Development Program of China(2024YFE0102300)National Natural Science Foundation of China(32470578)to Chunli Chen+1 种基金the funding support from the Fundamental Research Funds for the Central Universities(Program No.2662023LXPY003)to Sisi LiuDr.Junli Liu from Durham University for his reviewing on the manuscript.
文摘Auxins were the first of the major plant hormones and played key roles in plant growth and development.Auxin triggered gene expression through several mechanisms.The canonical textbook model is that auxin binds to TIR1/AFB receptors and stabilizes their interaction with Aux/IAA repressors,leading to their ubiquitination and degradation,which results in activation of ARFs transcription factors.The recent study published in Nature by JiíFriml and co-authors updated the view on gene expression regulated by auxin.The role of TIR-produced cAMP was confirmed to be the second messenger in transcriptional auxin signaling.The conclusions raised in this Nature article shift the paradigm about the regulation of plant growth and development by auxin to the modulation of cAMP production and its interaction with candidate targets.
基金supported by the National Natural Science Foundation of China(32002122,32372805)。
文摘Brassica napus(oilseed rape)is sensitive to boron(B)deficiency and exhibits young leaf curling in response to low-B stress at the seedling stage,which leads to reduced photosynthesis and plant growth.So far,no gene has been identified to be involved in B deficiency induced leaf curling.Our previous results showed the transcription factor BnaA1.WRKY53 might be involved in B-deficiency tolerance.However,altered BnaA1.WRKY53 expression does not influence B concentration in shoot,root and leaf cell walls,which suggests Bna A1.WRKY53 might be involved in other biological processes.Indeed,phenotypic and anatomical analyses revealed that BnaA1.WRKY53 negatively regulated the leaf curling induced by leaf epinasty by suppressing the overexpansion of palisade cells under B deficiency.Further transcriptome enrichment analysis of differentially expressed genes(DEGs)between wild-type and BnaA1.WRKY53overexpression line showed auxin response pathway was enriched.In addition,Arabidopsis DR5::GFP auxin reporter line showed B deficiency caused predominant auxin signal accumulation in the adaxial side and concomitant adaxial cell expansion,which indicated that B deficiency may induce leaf curling by altering auxin distribution.Phytohormone quantification and gene expression analysis demonstrated that BnaA1.WRKY53 prevent auxin overaccumulation in leaves by suppressing auxin biosynthetic genes under B deficiency.Furthermore,exogenous 1-naphthlcetic acid(NAA)treatment experiments revealed that high auxin could induce leaf curling and BnaA1.WRKY53 expression.Overall,these findings demonstrate that auxin and the transcription factor BnaA1.WRKY53 synergistically regulate leaf curling to maintain an optimal leaf area under B deficiency,and provide novel insights into the resistance mechanisms against B-deficiency-induced leaf curling in oilseed rape.
基金supported by National Key Research and Development Program of China(Grant No.2021YFD1200200)Scientific Research Fund of Hunan Provincial Education Department(Grant No.23A0190)。
文摘Grapevine(Vitis sp.)is one of the most important economic fruit crops all over the world,and the formation of adventitious roots(ARs)is crucial for the vegetative reproduction of grapes.However,studies on the regulatory mechanisms of this process are currently lacking.In this study,we applied an efficient and convenient leave-petiole(LP)system for studying ARs,revealing a significant inhibition of root primordia formation under continuous-light treatment.The results showed that isolated ARs of grapevine were induced and originated from ray cells near the vascular cambium,with the process categorized into induction,initiation,and extension stages.LP samples under light and dark conditions were used for transcriptome sequencing and endogenous hormone measurements at three critical time points of AR formation.A total of 37155 transcripts were obtained,and 7041 genes showed significantly different expression levels in the petiole.An integrated analysis,including Gene Ontology(GO)enrichment analysis,weighted gene co-expression network analysis(WGCNA),and hormonal content determination,showed that several genes(ARF4,LAX1,PIN1,SUS2,APX1,TPXL1,CHS3,etc.)associated with hormone signals,sugar synthesis and transport,reactive oxygen species(ROS)scavenging,cell wall biogenesis,flavonoid biosynthesis,microtubule remodeling,and some transcription factors(HY5,COP1,ERF2,MYB15,etc)played vital roles in light-induced AR formation.A hypothetical model was initially constructed,which illustrated the centrality of auxin in HY5-dependent AR formation and the complex crosstalk among various factors.The results of this study provided abundant genetic resources and a novel perspective for understanding the molecular mechanisms of AR formation in grapevine.
基金supported by grants from CONICET(PIP 0237 to MCT)Agencia Nacional de Promoción Científica y Tecnológica(ANPCYT,grant PICT-2020-0178 to MJI)Universidad Nacional deMar del Plata(EXA 1217/24 and 1179/24 to MCT).
文摘In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates redox metabolism and promotes the accumulation of nitric oxide(NO)in various tissues and physiological contexts.NO functions as a redox signaling molecule,exerting its effects in part through the reversible oxidation of cysteine residues via a post-translational modification known as S-nitrosylation.Recent findings highlight a dynamic interplay between S-nitrosylation and the ubiquitination machinery,shaping critical aspects of auxin-mediated plant responses.In this review,we summarize current knowledge on redox regulation of UPS components involved in auxinmediated pathways and propose new perspectives on the integration of hormonal and redox signaling in plants.We describe and discuss the complexity of the latest evidence supporting the role of NO as a second messenger in auxin signaling,with S-nitrosylation acting as a regulatory mechanism that fine-tunes the UPS to control developmental outcomes.We focused on the direct effects of NO that include S-nitrosylation of specific cysteine residues of substrates,adaptors,and substrate receptors belonging to different CULLIN1-and CULLIN4-based E3 ubiquitin ligase complexes.
基金funded by the National Natural Science Foundation of China(32071921)Key R&D Program of Shandong Province,China(2021LZGC022)Taishan Scholars Project(ts201712024).
文摘Arogenate dehydratase(ADT)catalyzes the final step in phenylalanine synthesis and is crucial for plant development and metabolism.Previously,we demonstrated that the ADT/prephenate dehydratase ZmADT2 is essential for maize resistance to Ustilago maydis and for overall plant development.In this study,we explored the role of ZmADT2 in maize kernel development.The mmsu mutant,a dysfunctional ZmADT2 variant,exhibits delayed embryo and endosperm development,along with deficiencies in carbohydrate and protein storage.Transcriptome analysis revealed differential expression of many kernel compartment-specific genes between mmsu and wild-type(WT)kernels,with impaired nutrient accumulation and auxin signaling pathway in the mmsu endosperm.Compared to WT,ZmADT2 mutation led to reduced auxin levels and smaller endosperm cell size.Exogenous auxin rescued the small kernel phenotype of mmsu.Additionally,auxin distribution was reduced in the basal endosperm transfer layer(BETL),causing defects in its development and function,including reduced transfer cell elongation,cell wall ingrowth and nutrient uptake.These findings suggest that ZmADT2 mediated mediates an auxin signaling pathway that is essential for maize kernel development.
基金Supported by National Natural Science Foundation of China(30671126)~~
文摘[Objective] The aim was to study the effect of different kinds of exogenous auxin on the growth of rice roots under cadmium stress.[Method] Oryza sativa L.cv Zhonghua No.11 was used as experimental materials to detect the effect of different kinds of exogenous auxin on the growth of rice roots.[Result] The results showed that 0.1 mmol/L Cd treatment could not only increase primary,adventitious and lateral root length but also lateral root number,whereas the shoot growth was inhibited.When supplemented with different concentrations of NAA,IAA,IBA and 2,4-D,the growth of root system varied and similar change trend had been found.At the auxin concentration of 10^-9-10^-7 mol/L in particular 10^-8 mol/L,all four kinds of auxin promoted the elongation growth of primary and adventitious roots,but inhibition was observed when auxin was higher than 10^-7 mol/L.The decreased shoot growth caused by Cd could not be counteracted by supplementing with the four kinds of auxin.However,at the auxin concentration of 10^-9-10^-8 mol/L,NAA could improve rice growth under Cd stress condition.The formation and development of lateral roots on primary and adventitious roots was not only similar but also different after applying the same concentration of four auxins.[Conclusion] The addition of suitable amount of auxin under cadmium stress （such as 10^-9-10^-8 mol/L of NAA and so on） could ease the damage of cadmium on plants to a certain extent.
基金supported by the National Natural Science Foundation of China(32061143005,32170313,and 32100266)Shandong Provincial Natural Science Foundation(ZR2021QC022 and ZR2022QC059).
文摘Protein post-translational modifications(PTMs),such as ubiquitination,phosphorylation,and small ubiquitin-like modifier(SUMO)ylation,are crucial for regulating protein stability,activity,subcellular localization,and binding with cofactors.Such modifications remarkably increase the variety and complexity of proteomes,which are essential for regulating numerous cellular and physiological processes.The regulation of auxin signaling is finely tuned in time and space to guide various plant growth and development.Accumulating evidence indicates that PTMs play critical roles in auxin signaling regulations.Thus,a thorough and systematic review of the functions of PTMs in auxin signal transduction will improve our profound comprehension of the regulation mechanism of auxin signaling and auxin-mediated various processes.This review discusses the progress of protein ubiquitination,phosphorylation,histone acetylation and methylation,SUMOylation,and S-nitrosylation in the regulation of auxin signaling.
基金the National Natural Science Foundation of China(32370248)the Jiangsu Seed Industry Revitalization Project(JBGS[2021]001)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Rice(Oryza sativa)plant architecture and grain shape,which determine grain quality and yield,are modulatedby auxin and brassinosteroid via regulation of cell elongation and proliferation.We review the signaltransduction of these hormones and the crosstalk between their signals on the regulation of rice plantarchitecture and grain shape.
文摘Indole-3-acetamide(IAM)is the first confirmed auxin biosynthetic intermediate in some plant pathogenic bacteria.Exogenously applied IAM or production of IAM by overexpressing the bacterial iaaM gene in Arabidopsis causes auxin overproduction phenotypes.However,it is still inconclusive whether plants use IAM as a key precursor for auxin biosynthesis.Herein,we reported the isolation IAM HYDROLASE 1(IAMH1)gene in Arabidopsis from a forward genetic screen for IAM-insensitive mutants that display normal auxin sensitivities.IAMH1 has a close homolog named IAMH2 that is located right next to IAMH1on chromosomeⅣin Arabidopsis.We generated iamh1 iamh2 double mutants using our CRISPR/Cas9gene editing technology.We showed that disruption of the IAMH genes rendered Arabidopsis plants resistant to IAM treatments and also suppressed the iaaM overexpression phenotypes,suggesting that IAMH1 and IAMH2 are the main enzymes responsible for converting IAM into indole-3-acetic acid(IAA)in Arabidopsis.The iamh double mutants did not display obvious developmental defects,indicating that IAM does not play a major role in auxin biosynthesis under normal growth conditions.Our findings provide a solid foundation for clarifying the roles of IAM in auxin biosynthesis and plant development.
基金Key Project of Conditions Platform of National Science and Technology (2005DKA21002-15)~~
文摘Study on the role of quereentin in polar auxin transportation. Arabidopsis was cultured on medium supplemented with quereetin to observe the growth of hypoeotyls, ^14C-IAA transport assays were conducted to measure the auxin transport activity. The results showed that Arabidopsis mutant auxl which had been deficient in auxin influx transportion obviously recovered the ability after eultured on the medium with quercetin. The polar auxin transport was promoted by the addition of quereetin. These results indicated that quereetin could promote polar auxin transport in vivo.
基金Studies were supported by the National NaturalSciences Foundation of China (No. 30070073, 95-Yu-29-7) and State Key Project of Basic Research (No.G1999011604). We greatly thank Dr. K1aus Palme for providing the Atpinl nucleotide sequences.
文摘Based on the sequence information of Arabidopsis PIN1, two cDNAs encoding PIN homologues from Brassica juncea, Bjpin2 and Bjpin3, were isolated through cDNA library screening. Bjpin2 and Bjpin3 encoded proteins containing 640 and 635 amino acid residues, respectively, which shared 97.5% identities with each other and were highly homologous to Arabidopsis PIN1, PIN2 and other putative PIN proteins. BJPIN2 and BjPIN3 had similar structures as AtPIN proteins. Northern blot analysis indicated that Bjpin2 was expressed in stem, leaf and floral tissues, while Bjpin3 was expressed predominantly in stem and hypocotyls. Two promoter fragments of pin genes, Bjpin-X and Bjpin-Z, were isolated by 'genome walking' technique using primers at 5'-end of pin cDNA. Promoter-gus fusion studies revealed the GUS activities driven by Bjpin-X were at internal side of xylem and petal; while those driven by Bjpin-Z were detected at leaf vein, epidermal cell and cortex of stem, vascular tissues and anther. Results of the pin genes with different expression patterns in B. juncea suggested the presence of a gene family.
文摘Auxin has been suggested to play an essential role in regulating apple fruit maturation and ripening, though the molecular function of auxin and its interaction with ethylene during apple fruit development are largely unknown. To understand the function of auxin during apple fruit maturation and ripening, auxin efflux carrier and IAA-amido synthetase encoding genes were identified from the apple genome based on the results of previous microarray analysis. The expression patterns of these genes were analyzed using qRT-PCR during 10 - 12 weeks of fruit maturation for two apple cultivars: “Golden Delicious” (GD) and “Cripps Pink” (CP), which have the distinct patterns of maturation progression. Our results showed that the expressions of auxin efflux carrier and IAA-amido synthetase genes have a correlation with the timing of ethylene biosynthesis pathway activation in both cultivars. The earlier and stronger expression of MdGH3.102 and MdAECFP1 in the fruit of GD, a mid-season cultivar, correlates with the earlier activation of a pre-climacteric ethylene biosynthesis gene of MdACS3, compared with that in CP, a late-ripening apple cultivar. Results of exogenous IAA treatment indicated that the expression patterns of the genes were regulated in a fruit maturity dependent manner. Our results suggested that the dynamics of the auxin level in apple fruit cortex could be one of the key factors influencing the timing of ethylene biosynthesis pathway activation and consequently contributed to the control of the apple maturation progression.
基金supported by the Coordinación de la Investigación Científica UMSNH.E.C.-F.and J.A.-R.were fellows of CONACYT-México.
文摘The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of molecules,including the natural auxin indole-3-acetic acid(IAA),as well as other phytoregulators.However,several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria.The effects of A.brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction.The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure,accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots.An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants.However,after five days of bacterization,the response disappeared in the primary root meristems.The role of polar auxin transport(PAT)in auxins relocation involved the PGP1,AXR4-1,and BEN2 proteins,which apparently mediated A.brasilense-induced root branching of Arabidopsis seedlings.
文摘ENOX (ECTO-NOX) proteins of the external surface of the plasma membrane catalyze oxidation of both NADH and hydroquinones and protein disulfide-thiol interchange. They exhibit both prion-like and time-keeping (clock) properties. The oxidative and interchange activities alternate to generate a regular period of 24 min in length. Here we report the cloning, expression and characterization of a constitutive plant ENOX protein activated by both natural (Indole-3-acetic acid, IAA) and synthetic (2,4-dichlorophenoxyacetic acid, 2,4-D) auxin plant growth regulators with an optimum of about 1 μM, higher concentrations being less effective. The gene encoding the 213 amino acid protein (ABP20) is found in EMBL accession number U81162. Functional motifs characteristic of ENOX1 proteins, previously identified by site-directed mutagenesis, are present in the candidate auxin-activated ENOX (dNOX, ENOX5), including adenine nucleotide and copper binding motifs along with essential cysteines and a motif having homology with a previously identified auxin-binding motif. Periodicity was exhibited by both the oxidative and protein disulfide-thiol inter-change activities as is characteristic for other ENOX proteins. Activity was blocked by the ENOX2-specific quassinoid inhibitor glaucarubolone and other ENOX2 inhibitors but not by the ENOX1-specific quassinoid inhibitor simalikalactone D. Activity required both auxin and bound copper. The inactive auxin 2,3-D was without effects.
基金This work is supported by the National Science Foundation of China(No.31970289).
文摘TiO_(2) nanoparticles(nano-TiO_(2))are widely used in the world,and a considerable amount of nano-TiO_(2) is released into the environment,with toxic effects on organisms.In the various species of higher plants,growth,including seed germination,root elongation,and biomass accumulation,is affected by nano-TiO_(2).However,the underlying molecular mechanisms remain to be elucidated.In this study,we observed that nano-TiO_(2) promoted root elongation in a dose-dependent manner.Furthermore,we found that nano-TiO_(2) elevated auxin accumulation in the root tips of the auxin marker lines DII-VENUS and DR5::GUS,and,correspondingly,quantitative real-time PCR analysis revealed that nano-TiO_(2) increased the expression levels of auxin biosynthesis-and transport-related genes.GFP fluorescence observation using transgenic PIN2-GFP indicated that nano-TiO_(2) promoted root growth by inducing PIN2 accumulation.Thus,we propose that nano-TiO_(2) promote root growth in Arabidopsis thaliana by altering the expression levels of auxin biosynthesis-and transport-related genes.
