The effects of neodymium nitrate (Nd^3+) on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3+ (5 μmol/L) to culture medium significantly increased rooting fre...The effects of neodymium nitrate (Nd^3+) on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3+ (5 μmol/L) to culture medium significantly increased rooting frequency. Histological investigation showed that Nd^3+ did not change the process of root initiation. Nd^3+ did not influence total endogenous cytokinin levels, but significantly increased the level of endogenous indole-3-acetic acid (IAA) in the base of shoot cuttings. Compared to the control, the ratio of IAA/cytokinins was very high in the Nd^3+ treatment. These results suggested that the enhanced rooting frequency may be related to the increase in endogenous IAA level in Nd^3+ treatment. Analysis of enzyme activities showed that the enhanced accumulation of the endogenous IAA by Nd^3+ should not be attributed to inhibition of IAA decomposition by IAA oxidase or promotion of cytokinin decomposition by cytokinin oxidase. Besides, Nd^3+ increased the ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG) in the process of adventitious rooting while the ratio of ascorbate (ASC) to dehydroascorbate (DHA) was not affected.展开更多
In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radia...In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata. However, the capability of produce adventitious roots in gymnosperms decreases with aging. While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level. This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities. Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process. It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting. According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively. Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.展开更多
Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the facto...Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the factors that affect the rooting of hybrid larch shoots-activated carbon,vitamin B1,sucrose,glycine,glutamic acid(Glu),cysteine,pH,and induction time in the dark and indole-3-butyric acid(IBA).Variance analysis showed that the effects of sucrose concentration on rooting rate,survival rate,and average root number,pH on the average number of roots;and Glu on survival rate were all significant(p<0.05)when compared to the mock treatments.Among all of the 45 treatments,the highest rooting rate was 90%,the highest survival rate was 100%,and the highest average root number was 11.8.The theoretically optimal procedure of in vitro root induction of hybrid larch shoots is shoot induction on L9 modified medium(pH 6.7)containing 2 mg.L^(-1)naphthalene acetic acid,0.25 mg.L^(-1)IBA,1/3 macroelements,7.5 g.L^(-1)sucrose,and 5 mg.L^(-1)Glu for 8 days,and then root induction on L9 modified medium without auxin.展开更多
In Arabidopsis thaliana,canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR(ARF)family that interact with auxin/indole acetic acid repressors(Aux/IAAs),whic...In Arabidopsis thaliana,canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR(ARF)family that interact with auxin/indole acetic acid repressors(Aux/IAAs),which themselves form co-receptor complexes with one of six TRANSPORT INHIBITOR*!/AUXIN-SIGNALLING F-BOX(TIR1/AFB)proteins.Different combinations of co-receptors drive specific sensing outputs,allowing auxin to control a myriad of processes.ARF6 and ARF8 are positive regulators of adventitious root initiation upstream of jasmonate,but the exact auxin co-receptor complexes controlling the transcriptional activity of these proteins has remained unknown.Here,using loss-of-function mutants we show that three Aux/IAA genes,IAA6,IAA9,and IAA17,act additively in the control of adventitious root(AR)initiation.These three IAA proteins interact with ARF6 and/or ARF8 and likely repress their activity in AR development.We show that TIR1 and AFB2 are positive regulators of AR formation and TIR1 plays a dual role in the control of jasmonic acid(JA)biosynthesis and conjugation,as several JA biosynthesis genes are up-regulated in the tir1-1 mutant.These results lead us to propose that in the presence of auxin,TIR1 and AFB2 form specific sensing complexes with IAA6,IAA9,and/or IAA17 to modulate JA homeostasis and control AR initiation.展开更多
Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs i...Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs is mediated by K^(+)transporters named K^(+)transporter(KT),K^(+)uptake(KUP),or high-affinity K^(+)(HAK).This study aimed to identify members of the HAK gene family in apples and to characterize the effects of K^(+)supply on adventitious root formation and on the expression of HAK genes and the genes that putatively control auxin transport,signaling,and cell fate during adventitious root formation.In this study,34 HAK genes(MdHAKs)were identified in the apple(Malus×domestica‘Golden Delicious’)genome.A phylogenetic analysis divided MdHAKs into four clusters(Ⅰ,Ⅱ,Ⅲ,andⅣ),comprising 16,1,4,and 13 genes,respectively.The syntenic relationships revealed that 62.5%of the total MdHAK genes arise from genomic duplication events.Chromosome location,domain structure,motif analysis,and physico-chemical characteristics were subsequently investigated.Furthermore,the application of K^(+)indicated the emergence of adventitious roots at 8 d and produced more adventitious roots at 16 d than the K^(+)-free control(CK)treatment.In addition,various MdHAKs showed root-specific expression in B9 apple rootstock stem cuttings and enhanced expression during the initiation and emergence stages of adventitious root formation in response to K^(+)treatment.Additionally,K^(+)treatment enhanced the expression levels of MdPIN1,MdPIN2,and MdAUX1.Further data indicated that a higher expression of MdWOX11,MdLBD16,and MdLBD29 and of cell cycle-related genes contributed to the auxin-stimulated adventitious root formation in response to K^(+).展开更多
Plant regeneration is a self-repair of the plant body in response to adverse conditions or damaged structures,and root regeneration allows the plant body to better adapt to its environment by supplementing the roots’...Plant regeneration is a self-repair of the plant body in response to adverse conditions or damaged structures,and root regeneration allows the plant body to better adapt to its environment by supplementing the roots’structure.Previous research has shown that adventitious roots can be made to occur from scratch in two ways.Studies that simulate adventitious root regeneration through natural conditions allow the regeneration process to be broadly divided into three stages:the perception of early signals,the massive accumulation of auxin,and the transformation of cell fate.The strength of regeneration,in turn,is influenced by wounding,stress,hormones,etc.This study mainly reviews the molecular mechanisms of de novo adventitious roots and discusses how the environment,hormones,and its own development in Arabidopsis thaliana.展开更多
The fibrous root system in cereals comprises primarily adventitious roots (ARs), which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development...The fibrous root system in cereals comprises primarily adventitious roots (ARs), which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development is still limited. We report here the isolation of four rice (Oryza sativa L.) mutants, from different genetic backgrounds, all of which were defective in AR formation. These mutants exhibited reduced numbers of lateral roots (LRs) and partial loss of gravitropism. The mutants also displayed enhanced sensitivity to N-l-naphthylphthalamic acid, an inhibitor of polar auxin transport (PAT), indicating that the mutations affected auxin transport. Positional cloning using one of the four mutants revealed that it was caused by loss-of-function of a guanine nucleotide exchange factor for ADP- ribosylation factor (OsGNOM1). RT-PCR and analysis of promoter::GUS transgenic plants showed that OsGNOM1 is expressed in AR primordia, vascular tissues, LRs, root tips, leaves, anthers and lemma veins, with a distribution pattern similar to that of auxin. In addition, the expressions of OsPIN2, OsPIN5b and OsPIN9 were altered in the mutants. Taken together, these findings indicate that OsGNOM1 affects the formation of ARs through regulating PAT.展开更多
Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mech- nisms of the adventitious rooting and the regulation of rooting processes are the principles ...Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mech- nisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstructures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated soft- wood shoots of Paeonia suffkuticosa 'Yinfen Jinlin'. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages: shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protru- sion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043 nmol·g^-1 FW on the bases of shoots, respectively. CTKs which included isopentenyl adenine (iPA), zeatin riboside (ZR) and dihy- drozeatin riboside (DHZR) were 0.949, 0.695 and 2.034 nmol·g^-1 FW, respectively. DHZR is active among CTKs. The ratio of IAA to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primor- dium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. ]AA levels in the treated shoots increased gradually to its highest level (three times of control) at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10:1.展开更多
The plant-specific WUSCHEL-related homeobox(WOX)genes are crucial for plant growth and development.Here,we systematically identified the MdWOX gene family in apple at the genome-wide level,and analyzed the phylogeneti...The plant-specific WUSCHEL-related homeobox(WOX)genes are crucial for plant growth and development.Here,we systematically identified the MdWOX gene family in apple at the genome-wide level,and analyzed the phylogenetic relationships,conserved motifs,gene structure,and syntenic relationships of the MdWOX genes.A total of 18 MdWOX genes were identified and phylogenetic analysis placed them into three clades.The phylogenetic relationships among the WOXs were further supported by the analyses of gene structure and conserved motifs.Chromosomal distribution and synteny analysis revealed that whole-genome and segmental duplications have played key roles in MdWOX gene family expansion.Moreover,the MdWOX genes exhibit tissue-specific expression patterns and MdWOX4a,MdWOX4b,MdWOX5b,MdWOX11/12a,and MdWOX11/12b may play essential roles in adventitious root development.The adventitious rooting ability was enhanced in MdWOX4b transgenic tobacco lines.The results of this study provide useful information for future functional studies on MdWOXs in the development of apple rootstocks.展开更多
Ontogenetic aging of tissues and the gradual decrease of adventitious rooting are known challenges for the clonal propagation of woody species,hampering clonal forestry programs.This study examined possible signatures...Ontogenetic aging of tissues and the gradual decrease of adventitious rooting are known challenges for the clonal propagation of woody species,hampering clonal forestry programs.This study examined possible signatures of tissue rejuvenation/reinvigoration in different propagated materials of Eucalyptus microcorys by analyzing the total protein profile,peroxidase activity,macro-and micronutrient contents,and adventitious rooting of mini cuttings.The analyses were performed on E.microcorys shoots which were successfully obtained by seminal and grafting propagation,micropropagation with epicormic shoots,and indirect organogenesis.Among four mature trees used in the propagation,tissues from the one with the best propagation results were investigated for signs of tissue rejuvenation and/or reinvigoration.Five individuals from each technique were randomly selected and transferred to a semi-hydroponic"channel"system.After four weeks in the seedbed,the total protein,peroxidase activity,nutrient content and rooting of the mini cuttings were evaluated.SDS-PAGE enabled the differentiation of leaf samples obtained by grafting from the other propagation techniques,as revealed by two distinct bands.Materials obtained by micropropagation with epicormic shoots showed the highest peroxidase activity,while those obtained by seminal propagation and from the selected mature tree showed the lowest peroxidase activity.A portable X-ray fluorescence spectroscope(pXRF)identified adequate nutrient content in most of the nutrients tested in materials obtained by seminal and grafting propagation,and by indirect organogenesis.The analysis of adventitious rooting showed that the highest rooting percentage was observed in mini cuttings from seminal propagation(75%)followed by indirect organogenesis(35%).Based on principal component analysis,it was concluded that rooting of mini cuttings from both seminal propagation and indirect organogenesis was associated with phosphorous,sulphur,and potassium contents,which suggests a higher level of tissue rejuvenation/reinvigoration in these propagated plants.Further studies are recommended to search for other methods that present similarities with the responses to adventitious rooting in forest species and thus optimize the rescue and propagation of plants with distinct ontogenetic stages.展开更多
Khaya anthotheca is a hardwood species from Africa and recently introduced to Brazil. This species yields high-quality wood for diverse applications, but little has been done toward an effective propagation method for...Khaya anthotheca is a hardwood species from Africa and recently introduced to Brazil. This species yields high-quality wood for diverse applications, but little has been done toward an effective propagation method for large-scale production in nurseries. We evaluated the effects of different concentrations of macro and micronutrients(i.e., 100, 50 and 25% of the concentration of a referenced solution) combined with indole-3-butyric acid(IBA) at 0 and 2 g L-1 on the survival rate of mini-stumps and the survival and adventitious rooting of K. anthotheca mini-cuttings. The mini-stumps were grown from a source of seeds imported from Ghana, West Africa. The ministumps survived at a high rate(97%). Consistently high shoot yields were obtained from the mini-stumps(average of 1.8 per mini-stump). High survival percentage of minicuttings and adventitious rooting were observed when solutions with 100 and 50% of the nutrients concentration were combined with 2 g L-1 IBA. Histological sections analyzed through optical microscopy indicated the tissues from mini-cutting stems were juvenile, which might have stimulated adventitious rooting. These results have important implications for further work aimed at establishing propagation strategies for K. anthotheca, which are of prime importance for assisting breeding programs of this species.展开更多
Apuleia leiocarpa is an environmentally and economically significant Atlantic Forest species threat-ened by ongoing exploitation.The vegetative propagation of the species could be a step forward to enable implanta-tio...Apuleia leiocarpa is an environmentally and economically significant Atlantic Forest species threat-ened by ongoing exploitation.The vegetative propagation of the species could be a step forward to enable implanta-tion of clonal seed orchards and multiplication of selected trees but remains unknown to date.This study assessed the mini-cutting technique for propagation of A.leiocarpa and determined the time required for rooting and viable mini-cutting type and sizes.The results show that it is possible to propagate A.leiocarpa with mini-cuttings derived from mini-stumps produced with seeds;the mini-stumps pre-sented regrowth capacity and remained constantly produc-tive for 1 year;10-cm A.leiocarpa mini-cuttings should remain under misting conditions for at least 40 days,and the vegetative propagation of A.leiocarpa with intermediate 7-to 10-cm mini-cuttings resulted in more vigorous clonal seedlings than smaller mini-cuttings.展开更多
A protocol for micropropagation using nodal explants from mature Pinus massoniana trees has been developed. Time of explant collection is crucial for the initial success of aseptic culture. Explants collected in early...A protocol for micropropagation using nodal explants from mature Pinus massoniana trees has been developed. Time of explant collection is crucial for the initial success of aseptic culture. Explants collected in early March gave the highest percentage of explant survival (64.5%) and shoot-forming percentage (52.3%). Thidiazuron (TDZ) concentration significantly influenced shoot formation; 4 mu M TDZ was optimum, with 4.8 shoots produced per explant with a mean length of 7.1 cm after 120 days of culture. Regenerated shoots rooted for 60 days in basic medium with 1 mu M NAA were ready for growth in pots. This is the first report on plantlet regeneration in vitro from mature trees of P. massoniana that provides a reliable method for propagating selected elites.展开更多
Chinquapin(Castanea henryi) is a dual-purpose tree species in China valued for as a source of timber and starch.We investigated the effect of four cutting mediums(pure vermiculite;peat:river sand at 3:1 v/v;peat:krasn...Chinquapin(Castanea henryi) is a dual-purpose tree species in China valued for as a source of timber and starch.We investigated the effect of four cutting mediums(pure vermiculite;peat:river sand at 3:1 v/v;peat:krasnozem at 1:1 v/v;and pure krasnozem) and three stem cutting periods(March,May,and July) on rooting performance of C.henryi cuttings.Different cutting periods and cutting mediums greatly influenced the rooting rate of C.henryi,ranging from 3.35 to 77.31%.Principal component analysis indicated that the best combination of cutting period and cutting medium was semi-hardwood cuttings(May cuttings)+krasnozem.Histological evidence indicated that adventitious root initials were present by week 5-6,and that the site of root primordia initiation was observed in the vascular cambium.Stem anatomical structures observed at different periods indicated that a xylem/radius ratio of29.90-37.42% and a fractured phloem fiber ring are indicative of rooting success.The relational model between rooting index and medium properties indicated that nutrient content and porosity significantly influenced callus production.However,pH strongly affected C.henryi root formation,with the Pearson correlation coefficients for May and July cuttings of-0.856 and-0.947,respectively.Our protocol is helpful to achieve mass clone propagation of improved C.henryi genotypes,thus overcoming a common hurdle in chinquapin breeding programs.展开更多
MicroRNAs(miRNAs) are small(ca. 20-24 nucleotides) non-coding RNAs that have recently been recognized as key post-transcriptional modulators of gene expression;and they are involved in many biological processes in pla...MicroRNAs(miRNAs) are small(ca. 20-24 nucleotides) non-coding RNAs that have recently been recognized as key post-transcriptional modulators of gene expression;and they are involved in many biological processes in plants, such as root growth and development. The miRNAs regulate root elongation, lateral root(LR) formation and adventitious root(AR) development in response to hormone signaling, nutrient uptake and biotic/abiotic stress. This review provides multiple perspectives on the involvement of miRNAs in regulating root growth and development in plants. We also discuss several crucial mechanisms of miRNAs, their relationships with transcription factors and the target gene-mediated hormone signaling interactions in the regulation of root growth and development.展开更多
Auxin response factors(ARFs) are transcription factors that activate or repress the expression of primary/early auxin response genes by binding to auxin-responsive elements(Aux REs) in their promoter regions. The ARFs...Auxin response factors(ARFs) are transcription factors that activate or repress the expression of primary/early auxin response genes by binding to auxin-responsive elements(Aux REs) in their promoter regions. The ARFs play important roles in diverse developmental processes.To explore the ARF gene family in hot pepper(Capsicum annuum L.), we performed a genome-wide identification and expression analysis. In this study, 19 pepper ARF genes(Ca ARFs) clustered into three phylogenetic groups(I, II, and III) were comprehensively analyzed. Conserved domain analysis showed that all Ca ARFs contained a B3 DNA-binding domain and a middle domain, but two members lacked the carboxyterminal dimerization(CTD) domain. The number of introns in Ca ARF genes ranged from 1 to 13 and the gene structure was similar among genes in the same phylogenetic group. Additionally, prediction of Ca ARFs promoter elements and putative targets for micro RNAs suggested that the regulation of Ca ARFs may occur at both transcriptional and posttranscriptional levels. Most Ca ARFs were expressed in more than one tested tissue, and most Ca ARFs were identified as being responsive to exogenous auxin. Moreover, time-course transcription profiles of Ca ARFs revealed their roles in adventitious rooting of hypocotyl cuttings from pepper seedlings. Therefore, our results will provide a foundation for better understanding the regulatory mechanisms and molecular functions of Ca ARFs in hot pepper.展开更多
Objective To increase the ultimate yield of periplocin in Periploca sepium adventitious root cultures by a two-stage culture based on nitrogen source.Methods Firstly,the effects of nitrogen source(NH4+-NO3-) at differ...Objective To increase the ultimate yield of periplocin in Periploca sepium adventitious root cultures by a two-stage culture based on nitrogen source.Methods Firstly,the effects of nitrogen source(NH4+-NO3-) at different ratios and different total initial nitrogen amounts on the accumulation of biomass and secondary metabolites in adventitious root cultures of P.sepium were investigated,and growth and production media for the two-stage culture based on the above results were established.Results The highest biomass and periplocin content were obtained in the culture medium of 15 mmol/L total nitrogen amount with NH4+-NO3-(1:2) and 30 mmol/L total nitrogen amount with nitrate as the sole nitrogen source.By adopting a fed-batch cultivation strategy,the dry weight adventitious root,periplocin content and yield were increased by 136%,108%,and 389%,respectively when compared with those of the control,reaching up to 8.13 g/L,157.15 μg/g,and 1277.63 μg/L,respectively.Furthermore,it was found that in the process of two-stage culture,the adventitious roots grew thicker significantly after they were transferred into production medium directly.Conclusion The ultimate yield of periplocin in P.sepium adventitious root cultures could be significantly increased by a two-stage culture based on nitrogen source.展开更多
Adventitious roots form from non-root tissues as part of normal development or in response to stress or wounding.The root primordia form in the source tissue,and during emergence the adventitious roots penetrate the i...Adventitious roots form from non-root tissues as part of normal development or in response to stress or wounding.The root primordia form in the source tissue,and during emergence the adventitious roots penetrate the inner cell layers and the epidermis;however,the mechanisms underlying this emergence remain largely unexplored.Here,we report that a regulatory module composed of the AP2/ERF transcription factor ABSCISIC ACID INSENSITIVE 4(ABI4),the MAP kinases MPK3 and MPK6,and the phosphatase PP2C12 plays an important role in the emergence of junction adventitious roots(J-ARs)from the root-hypocotyl junctions in Arabidopsis thaliana.ABI4 negatively regulates J-AR emergence,preventing the accumulation of reactive oxygen species and death of epidermal cells,which would otherwise facilitate J-AR emergence.Phosphorylation by MPK3/MPK6 activates ABI4 and dephosphorylation by PP2C12 inactivates ABI4.MPK3/MPK6 also directly phosphorylate and inactivate PP2C12 during J-AR emergence.We propose that this"double-check"mechanism increases the robustness of MAP kinase signaling and finely regulates the local programmed cell death required for J-AR emergence.展开更多
Objective To identify the genes of WRKY transcription factors(TFs) from roots of Bupleurum chinense and genes that potentially regulate saikosaponin(SS) biosynthesis.Methods Firstly,the subfamily cluster analysis ...Objective To identify the genes of WRKY transcription factors(TFs) from roots of Bupleurum chinense and genes that potentially regulate saikosaponin(SS) biosynthesis.Methods Firstly,the subfamily cluster analysis was mainly based on Arabidopsis thaliana WRKYs for 27 putative WRKY TFs selected from previous transcriptome sequencing data.Secondly,qPCR was used to screen such genes of WRKY TFs that could be induced by NaCI and PEG6000 in adventitious roots of B.chinense.Meanwhile,saikosaponins(SSs) in treated adventitious roots were determined by HPLC.The roots were collected at 0,2,4,8,12,24,48,and 72 h after treatments,and 120 h only for PEG.Finally,the tissue-specific expression was analyzed on screened genes by qPCR.Results The 27 genes were grouped into three categories:There were nine in Group Ⅰ,15 in Group Ⅱ,and two in Group Ⅲ.Four genes of WRKYTFs,BCWRKY6,BCWRKY16,BCWRKY32,and BCWRKY35 were obviously induced by NaCI in adventitious roots of B.chinense,while only BCWRKY32 was induced by PEG.The content of SSs increased at different levels in NaCI and PEG6000 treatment.Three genes including BCWRKY6,BCWRKY32,and BCWRKY35,expressed most in roots,were similar to the accumulation pattern of SS.Conclusion The three WRKY genes,BCWRKY6,BCWRKY32,and BCWRKY35,may be involved in the biosynthesis of SS.展开更多
Objective:In order to elucidate the biological activity of the Co-cultured adventitious roots(ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application,and the antiinflammatory...Objective:In order to elucidate the biological activity of the Co-cultured adventitious roots(ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application,and the antiinflammatory activities and potential mechanisms of Co-cultured ARs were studied.Methods:The experimental materials were obtained by bioreactor co-culture technology and used in the activity research.In this study,mouse macrophages induced by lipopolysaccharide(LPS) were used as in vitro model.Different concentrations of AR extract(50-400 g/mL) were used to treat cells.The expression of pro-inflammatory cytokines was determined using enzyme linked immunosorbent assay.The inducible nitric oxide synthase and cyclooxygenase-2 expression,mitogen-activated protein kinase(MAPK) phosphorylation,and the inhibitor of nuclear factor-kappa B-a levels were determined by the Western blot analysis.Results:In the co-cultured ARs,total flavonoids and total caffeic acid were determined,and the contents of both bioactive compounds were significantly higher than those ARs from the single-species culture.Compared with the control group,the large amount of pro-inflammatory mediators was released after LPS stimulation.However,in the extract groups with different concentrations(25,50,and 100 g/mL),the production of these pro-inflammatory mediators was inhibited in a dose-dependent manner.Furthermore,the levels of phosphorylation of MAPK proteins,including p-p38, p-c-Jun N-terminal kinase,and p-extracellular regulated protein kinases were significantly(P <0.05) decreased in the extract groups,revealing that the AR extract probably involved in regulating the MAPK signaling pathway.Conclusion:Collectively,our findings suggested that the co-cultured ARs of E.pallida and E.purpurea can inhibit production of pro-inflammatory mediators in mouse peritoneal macrophages and possess the anti-inflammatory effect by regulating MAPK signaling pathways.展开更多
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060359006)
文摘The effects of neodymium nitrate (Nd^3+) on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3+ (5 μmol/L) to culture medium significantly increased rooting frequency. Histological investigation showed that Nd^3+ did not change the process of root initiation. Nd^3+ did not influence total endogenous cytokinin levels, but significantly increased the level of endogenous indole-3-acetic acid (IAA) in the base of shoot cuttings. Compared to the control, the ratio of IAA/cytokinins was very high in the Nd^3+ treatment. These results suggested that the enhanced rooting frequency may be related to the increase in endogenous IAA level in Nd^3+ treatment. Analysis of enzyme activities showed that the enhanced accumulation of the endogenous IAA by Nd^3+ should not be attributed to inhibition of IAA decomposition by IAA oxidase or promotion of cytokinin decomposition by cytokinin oxidase. Besides, Nd^3+ increased the ratio of reduced glutathione (GSH) and oxidized glutathione (GSSG) in the process of adventitious rooting while the ratio of ascorbate (ASC) to dehydroascorbate (DHA) was not affected.
文摘In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata. However, the capability of produce adventitious roots in gymnosperms decreases with aging. While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level. This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities. Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process. It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting. According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively. Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.
基金This research was funded by The National Key Research and Development Program of China(Project No.2017YFD0600401).
文摘Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the factors that affect the rooting of hybrid larch shoots-activated carbon,vitamin B1,sucrose,glycine,glutamic acid(Glu),cysteine,pH,and induction time in the dark and indole-3-butyric acid(IBA).Variance analysis showed that the effects of sucrose concentration on rooting rate,survival rate,and average root number,pH on the average number of roots;and Glu on survival rate were all significant(p<0.05)when compared to the mock treatments.Among all of the 45 treatments,the highest rooting rate was 90%,the highest survival rate was 100%,and the highest average root number was 11.8.The theoretically optimal procedure of in vitro root induction of hybrid larch shoots is shoot induction on L9 modified medium(pH 6.7)containing 2 mg.L^(-1)naphthalene acetic acid,0.25 mg.L^(-1)IBA,1/3 macroelements,7.5 g.L^(-1)sucrose,and 5 mg.L^(-1)Glu for 8 days,and then root induction on L9 modified medium without auxin.
文摘In Arabidopsis thaliana,canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR(ARF)family that interact with auxin/indole acetic acid repressors(Aux/IAAs),which themselves form co-receptor complexes with one of six TRANSPORT INHIBITOR*!/AUXIN-SIGNALLING F-BOX(TIR1/AFB)proteins.Different combinations of co-receptors drive specific sensing outputs,allowing auxin to control a myriad of processes.ARF6 and ARF8 are positive regulators of adventitious root initiation upstream of jasmonate,but the exact auxin co-receptor complexes controlling the transcriptional activity of these proteins has remained unknown.Here,using loss-of-function mutants we show that three Aux/IAA genes,IAA6,IAA9,and IAA17,act additively in the control of adventitious root(AR)initiation.These three IAA proteins interact with ARF6 and/or ARF8 and likely repress their activity in AR development.We show that TIR1 and AFB2 are positive regulators of AR formation and TIR1 plays a dual role in the control of jasmonic acid(JA)biosynthesis and conjugation,as several JA biosynthesis genes are up-regulated in the tir1-1 mutant.These results lead us to propose that in the presence of auxin,TIR1 and AFB2 form specific sensing complexes with IAA6,IAA9,and/or IAA17 to modulate JA homeostasis and control AR initiation.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFD1000101,2019YFD1000803)Shaanxi Apple Industry Science and Technology Project(Grant No.2020zdzx03-01-04)+1 种基金Tang Scholar by Cyrus Tang Foundation(Grant No.C200022002)The China Apple Research System(Grant No.CARS-27).
文摘Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs is mediated by K^(+)transporters named K^(+)transporter(KT),K^(+)uptake(KUP),or high-affinity K^(+)(HAK).This study aimed to identify members of the HAK gene family in apples and to characterize the effects of K^(+)supply on adventitious root formation and on the expression of HAK genes and the genes that putatively control auxin transport,signaling,and cell fate during adventitious root formation.In this study,34 HAK genes(MdHAKs)were identified in the apple(Malus×domestica‘Golden Delicious’)genome.A phylogenetic analysis divided MdHAKs into four clusters(Ⅰ,Ⅱ,Ⅲ,andⅣ),comprising 16,1,4,and 13 genes,respectively.The syntenic relationships revealed that 62.5%of the total MdHAK genes arise from genomic duplication events.Chromosome location,domain structure,motif analysis,and physico-chemical characteristics were subsequently investigated.Furthermore,the application of K^(+)indicated the emergence of adventitious roots at 8 d and produced more adventitious roots at 16 d than the K^(+)-free control(CK)treatment.In addition,various MdHAKs showed root-specific expression in B9 apple rootstock stem cuttings and enhanced expression during the initiation and emergence stages of adventitious root formation in response to K^(+)treatment.Additionally,K^(+)treatment enhanced the expression levels of MdPIN1,MdPIN2,and MdAUX1.Further data indicated that a higher expression of MdWOX11,MdLBD16,and MdLBD29 and of cell cycle-related genes contributed to the auxin-stimulated adventitious root formation in response to K^(+).
文摘Plant regeneration is a self-repair of the plant body in response to adverse conditions or damaged structures,and root regeneration allows the plant body to better adapt to its environment by supplementing the roots’structure.Previous research has shown that adventitious roots can be made to occur from scratch in two ways.Studies that simulate adventitious root regeneration through natural conditions allow the regeneration process to be broadly divided into three stages:the perception of early signals,the massive accumulation of auxin,and the transformation of cell fate.The strength of regeneration,in turn,is influenced by wounding,stress,hormones,etc.This study mainly reviews the molecular mechanisms of de novo adventitious roots and discusses how the environment,hormones,and its own development in Arabidopsis thaliana.
基金Acknowledgments This work was supported by the Key Basic Research Special Foundation of China (2005CB20900), the National High Technology Research and Development Program (2007AA021403, 2006AA10Z 175), the National Natural Science Foundation of China (30471118 and 30770191) and the Specialized Research Fund for the Doctoral Program of Higher Education (20070335081).
文摘The fibrous root system in cereals comprises primarily adventitious roots (ARs), which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development is still limited. We report here the isolation of four rice (Oryza sativa L.) mutants, from different genetic backgrounds, all of which were defective in AR formation. These mutants exhibited reduced numbers of lateral roots (LRs) and partial loss of gravitropism. The mutants also displayed enhanced sensitivity to N-l-naphthylphthalamic acid, an inhibitor of polar auxin transport (PAT), indicating that the mutations affected auxin transport. Positional cloning using one of the four mutants revealed that it was caused by loss-of-function of a guanine nucleotide exchange factor for ADP- ribosylation factor (OsGNOM1). RT-PCR and analysis of promoter::GUS transgenic plants showed that OsGNOM1 is expressed in AR primordia, vascular tissues, LRs, root tips, leaves, anthers and lemma veins, with a distribution pattern similar to that of auxin. In addition, the expressions of OsPIN2, OsPIN5b and OsPIN9 were altered in the mutants. Taken together, these findings indicate that OsGNOM1 affects the formation of ARs through regulating PAT.
文摘Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mech- nisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstructures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated soft- wood shoots of Paeonia suffkuticosa 'Yinfen Jinlin'. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages: shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protru- sion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043 nmol·g^-1 FW on the bases of shoots, respectively. CTKs which included isopentenyl adenine (iPA), zeatin riboside (ZR) and dihy- drozeatin riboside (DHZR) were 0.949, 0.695 and 2.034 nmol·g^-1 FW, respectively. DHZR is active among CTKs. The ratio of IAA to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primor- dium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. ]AA levels in the treated shoots increased gradually to its highest level (three times of control) at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10:1.
基金funded by the National Natural Science Foundation of China(31801824)the Breeding Plan of Shandong Provincial Qingchuang Research Team,China(2019)the Scientific Research Funds for Highlevel Personnel of Qingdao Agricultural University,China(663/1118036 and 663/1119046)。
文摘The plant-specific WUSCHEL-related homeobox(WOX)genes are crucial for plant growth and development.Here,we systematically identified the MdWOX gene family in apple at the genome-wide level,and analyzed the phylogenetic relationships,conserved motifs,gene structure,and syntenic relationships of the MdWOX genes.A total of 18 MdWOX genes were identified and phylogenetic analysis placed them into three clades.The phylogenetic relationships among the WOXs were further supported by the analyses of gene structure and conserved motifs.Chromosomal distribution and synteny analysis revealed that whole-genome and segmental duplications have played key roles in MdWOX gene family expansion.Moreover,the MdWOX genes exhibit tissue-specific expression patterns and MdWOX4a,MdWOX4b,MdWOX5b,MdWOX11/12a,and MdWOX11/12b may play essential roles in adventitious root development.The adventitious rooting ability was enhanced in MdWOX4b transgenic tobacco lines.The results of this study provide useful information for future functional studies on MdWOXs in the development of apple rootstocks.
基金supported by the Coordination for the Improvement of Higher Education Personnel–Brazil (CAPES)the National Council for Scientific and Technological Development (CNPq)the Research Support Foundation of the State of Minas (FAPEMIG)。
文摘Ontogenetic aging of tissues and the gradual decrease of adventitious rooting are known challenges for the clonal propagation of woody species,hampering clonal forestry programs.This study examined possible signatures of tissue rejuvenation/reinvigoration in different propagated materials of Eucalyptus microcorys by analyzing the total protein profile,peroxidase activity,macro-and micronutrient contents,and adventitious rooting of mini cuttings.The analyses were performed on E.microcorys shoots which were successfully obtained by seminal and grafting propagation,micropropagation with epicormic shoots,and indirect organogenesis.Among four mature trees used in the propagation,tissues from the one with the best propagation results were investigated for signs of tissue rejuvenation and/or reinvigoration.Five individuals from each technique were randomly selected and transferred to a semi-hydroponic"channel"system.After four weeks in the seedbed,the total protein,peroxidase activity,nutrient content and rooting of the mini cuttings were evaluated.SDS-PAGE enabled the differentiation of leaf samples obtained by grafting from the other propagation techniques,as revealed by two distinct bands.Materials obtained by micropropagation with epicormic shoots showed the highest peroxidase activity,while those obtained by seminal propagation and from the selected mature tree showed the lowest peroxidase activity.A portable X-ray fluorescence spectroscope(pXRF)identified adequate nutrient content in most of the nutrients tested in materials obtained by seminal and grafting propagation,and by indirect organogenesis.The analysis of adventitious rooting showed that the highest rooting percentage was observed in mini cuttings from seminal propagation(75%)followed by indirect organogenesis(35%).Based on principal component analysis,it was concluded that rooting of mini cuttings from both seminal propagation and indirect organogenesis was associated with phosphorous,sulphur,and potassium contents,which suggests a higher level of tissue rejuvenation/reinvigoration in these propagated plants.Further studies are recommended to search for other methods that present similarities with the responses to adventitious rooting in forest species and thus optimize the rescue and propagation of plants with distinct ontogenetic stages.
基金supported by CNPq(National Council for Scientific and Technological Development,Brazil)CAPES(Coordination for the Improvement of Higher Level Personnel,Brazil)
文摘Khaya anthotheca is a hardwood species from Africa and recently introduced to Brazil. This species yields high-quality wood for diverse applications, but little has been done toward an effective propagation method for large-scale production in nurseries. We evaluated the effects of different concentrations of macro and micronutrients(i.e., 100, 50 and 25% of the concentration of a referenced solution) combined with indole-3-butyric acid(IBA) at 0 and 2 g L-1 on the survival rate of mini-stumps and the survival and adventitious rooting of K. anthotheca mini-cuttings. The mini-stumps were grown from a source of seeds imported from Ghana, West Africa. The ministumps survived at a high rate(97%). Consistently high shoot yields were obtained from the mini-stumps(average of 1.8 per mini-stump). High survival percentage of minicuttings and adventitious rooting were observed when solutions with 100 and 50% of the nutrients concentration were combined with 2 g L-1 IBA. Histological sections analyzed through optical microscopy indicated the tissues from mini-cutting stems were juvenile, which might have stimulated adventitious rooting. These results have important implications for further work aimed at establishing propagation strategies for K. anthotheca, which are of prime importance for assisting breeding programs of this species.
基金This study was funded by Fundação de AmparoàPesquisa do Estado do Rio de Janeiro”-FAPERJ(E26/111.612/2010)Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq(486471/2011-0).
文摘Apuleia leiocarpa is an environmentally and economically significant Atlantic Forest species threat-ened by ongoing exploitation.The vegetative propagation of the species could be a step forward to enable implanta-tion of clonal seed orchards and multiplication of selected trees but remains unknown to date.This study assessed the mini-cutting technique for propagation of A.leiocarpa and determined the time required for rooting and viable mini-cutting type and sizes.The results show that it is possible to propagate A.leiocarpa with mini-cuttings derived from mini-stumps produced with seeds;the mini-stumps pre-sented regrowth capacity and remained constantly produc-tive for 1 year;10-cm A.leiocarpa mini-cuttings should remain under misting conditions for at least 40 days,and the vegetative propagation of A.leiocarpa with intermediate 7-to 10-cm mini-cuttings resulted in more vigorous clonal seedlings than smaller mini-cuttings.
基金funded by the Science Research and Technology Development from the Department of Science and Technology of Guangxi(14125008-2-17,1598006-5-7)the Natural Science Foundation of China(31360178)+1 种基金the Key Program of Guangxi Forestry Bureau([2015]7)as an independent project by the Key Laboratory of Gaungxi Fine Timber Forest Resources Cultivation(13A-01-01)
文摘A protocol for micropropagation using nodal explants from mature Pinus massoniana trees has been developed. Time of explant collection is crucial for the initial success of aseptic culture. Explants collected in early March gave the highest percentage of explant survival (64.5%) and shoot-forming percentage (52.3%). Thidiazuron (TDZ) concentration significantly influenced shoot formation; 4 mu M TDZ was optimum, with 4.8 shoots produced per explant with a mean length of 7.1 cm after 120 days of culture. Regenerated shoots rooted for 60 days in basic medium with 1 mu M NAA were ready for growth in pots. This is the first report on plantlet regeneration in vitro from mature trees of P. massoniana that provides a reliable method for propagating selected elites.
基金funded by the National Natural Science Foundation of China (Grant Nos.31870674,31500554)the Natural Science Foundation of Hunan Province (Grant No.2018JJ3870)。
文摘Chinquapin(Castanea henryi) is a dual-purpose tree species in China valued for as a source of timber and starch.We investigated the effect of four cutting mediums(pure vermiculite;peat:river sand at 3:1 v/v;peat:krasnozem at 1:1 v/v;and pure krasnozem) and three stem cutting periods(March,May,and July) on rooting performance of C.henryi cuttings.Different cutting periods and cutting mediums greatly influenced the rooting rate of C.henryi,ranging from 3.35 to 77.31%.Principal component analysis indicated that the best combination of cutting period and cutting medium was semi-hardwood cuttings(May cuttings)+krasnozem.Histological evidence indicated that adventitious root initials were present by week 5-6,and that the site of root primordia initiation was observed in the vascular cambium.Stem anatomical structures observed at different periods indicated that a xylem/radius ratio of29.90-37.42% and a fractured phloem fiber ring are indicative of rooting success.The relational model between rooting index and medium properties indicated that nutrient content and porosity significantly influenced callus production.However,pH strongly affected C.henryi root formation,with the Pearson correlation coefficients for May and July cuttings of-0.856 and-0.947,respectively.Our protocol is helpful to achieve mass clone propagation of improved C.henryi genotypes,thus overcoming a common hurdle in chinquapin breeding programs.
基金funded by the Science and Technology Department of Henan Province,China(212102110046)the State Tobacco Monopoly Administration of China(110202101005(JY-05))+1 种基金the Science and Technology Project of China National Tobacco Corporation Henan Tobacco Company,China(2018410000270095)the Undergraduate Innovation and Entrepreneurship Project of Henan Province,China(202110466042)。
文摘MicroRNAs(miRNAs) are small(ca. 20-24 nucleotides) non-coding RNAs that have recently been recognized as key post-transcriptional modulators of gene expression;and they are involved in many biological processes in plants, such as root growth and development. The miRNAs regulate root elongation, lateral root(LR) formation and adventitious root(AR) development in response to hormone signaling, nutrient uptake and biotic/abiotic stress. This review provides multiple perspectives on the involvement of miRNAs in regulating root growth and development in plants. We also discuss several crucial mechanisms of miRNAs, their relationships with transcription factors and the target gene-mediated hormone signaling interactions in the regulation of root growth and development.
基金supported by the National Natural Science Foundation of China (31172001)the Special Fund for Agro-scientific Research in the Public Interest (201303014)+1 种基金the China Agriculture Research System (CARS-25)the Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences (CAAS-ASTIP-IVFCAAS)
文摘Auxin response factors(ARFs) are transcription factors that activate or repress the expression of primary/early auxin response genes by binding to auxin-responsive elements(Aux REs) in their promoter regions. The ARFs play important roles in diverse developmental processes.To explore the ARF gene family in hot pepper(Capsicum annuum L.), we performed a genome-wide identification and expression analysis. In this study, 19 pepper ARF genes(Ca ARFs) clustered into three phylogenetic groups(I, II, and III) were comprehensively analyzed. Conserved domain analysis showed that all Ca ARFs contained a B3 DNA-binding domain and a middle domain, but two members lacked the carboxyterminal dimerization(CTD) domain. The number of introns in Ca ARF genes ranged from 1 to 13 and the gene structure was similar among genes in the same phylogenetic group. Additionally, prediction of Ca ARFs promoter elements and putative targets for micro RNAs suggested that the regulation of Ca ARFs may occur at both transcriptional and posttranscriptional levels. Most Ca ARFs were expressed in more than one tested tissue, and most Ca ARFs were identified as being responsive to exogenous auxin. Moreover, time-course transcription profiles of Ca ARFs revealed their roles in adventitious rooting of hypocotyl cuttings from pepper seedlings. Therefore, our results will provide a foundation for better understanding the regulatory mechanisms and molecular functions of Ca ARFs in hot pepper.
文摘Objective To increase the ultimate yield of periplocin in Periploca sepium adventitious root cultures by a two-stage culture based on nitrogen source.Methods Firstly,the effects of nitrogen source(NH4+-NO3-) at different ratios and different total initial nitrogen amounts on the accumulation of biomass and secondary metabolites in adventitious root cultures of P.sepium were investigated,and growth and production media for the two-stage culture based on the above results were established.Results The highest biomass and periplocin content were obtained in the culture medium of 15 mmol/L total nitrogen amount with NH4+-NO3-(1:2) and 30 mmol/L total nitrogen amount with nitrate as the sole nitrogen source.By adopting a fed-batch cultivation strategy,the dry weight adventitious root,periplocin content and yield were increased by 136%,108%,and 389%,respectively when compared with those of the control,reaching up to 8.13 g/L,157.15 μg/g,and 1277.63 μg/L,respectively.Furthermore,it was found that in the process of two-stage culture,the adventitious roots grew thicker significantly after they were transferred into production medium directly.Conclusion The ultimate yield of periplocin in P.sepium adventitious root cultures could be significantly increased by a two-stage culture based on nitrogen source.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciencesthe Ministry of Agriculture of China(grant no.2016ZX08009003-005).
文摘Adventitious roots form from non-root tissues as part of normal development or in response to stress or wounding.The root primordia form in the source tissue,and during emergence the adventitious roots penetrate the inner cell layers and the epidermis;however,the mechanisms underlying this emergence remain largely unexplored.Here,we report that a regulatory module composed of the AP2/ERF transcription factor ABSCISIC ACID INSENSITIVE 4(ABI4),the MAP kinases MPK3 and MPK6,and the phosphatase PP2C12 plays an important role in the emergence of junction adventitious roots(J-ARs)from the root-hypocotyl junctions in Arabidopsis thaliana.ABI4 negatively regulates J-AR emergence,preventing the accumulation of reactive oxygen species and death of epidermal cells,which would otherwise facilitate J-AR emergence.Phosphorylation by MPK3/MPK6 activates ABI4 and dephosphorylation by PP2C12 inactivates ABI4.MPK3/MPK6 also directly phosphorylate and inactivate PP2C12 during J-AR emergence.We propose that this"double-check"mechanism increases the robustness of MAP kinase signaling and finely regulates the local programmed cell death required for J-AR emergence.
基金CAMS Innovation Fund for Medical Sciences(CIFMS)(2016-I2M-2-003)
文摘Objective To identify the genes of WRKY transcription factors(TFs) from roots of Bupleurum chinense and genes that potentially regulate saikosaponin(SS) biosynthesis.Methods Firstly,the subfamily cluster analysis was mainly based on Arabidopsis thaliana WRKYs for 27 putative WRKY TFs selected from previous transcriptome sequencing data.Secondly,qPCR was used to screen such genes of WRKY TFs that could be induced by NaCI and PEG6000 in adventitious roots of B.chinense.Meanwhile,saikosaponins(SSs) in treated adventitious roots were determined by HPLC.The roots were collected at 0,2,4,8,12,24,48,and 72 h after treatments,and 120 h only for PEG.Finally,the tissue-specific expression was analyzed on screened genes by qPCR.Results The 27 genes were grouped into three categories:There were nine in Group Ⅰ,15 in Group Ⅱ,and two in Group Ⅲ.Four genes of WRKYTFs,BCWRKY6,BCWRKY16,BCWRKY32,and BCWRKY35 were obviously induced by NaCI in adventitious roots of B.chinense,while only BCWRKY32 was induced by PEG.The content of SSs increased at different levels in NaCI and PEG6000 treatment.Three genes including BCWRKY6,BCWRKY32,and BCWRKY35,expressed most in roots,were similar to the accumulation pattern of SS.Conclusion The three WRKY genes,BCWRKY6,BCWRKY32,and BCWRKY35,may be involved in the biosynthesis of SS.
基金supported by grants the Jilin Scientific and Technological Development Program (20180101278JC) for the financial supportthe National Natural Science Foundation of China (31370388 and 31660080)。
文摘Objective:In order to elucidate the biological activity of the Co-cultured adventitious roots(ARs) of Echinacea pallida and Echinacea purpurea and provide theoretical basis for its application,and the antiinflammatory activities and potential mechanisms of Co-cultured ARs were studied.Methods:The experimental materials were obtained by bioreactor co-culture technology and used in the activity research.In this study,mouse macrophages induced by lipopolysaccharide(LPS) were used as in vitro model.Different concentrations of AR extract(50-400 g/mL) were used to treat cells.The expression of pro-inflammatory cytokines was determined using enzyme linked immunosorbent assay.The inducible nitric oxide synthase and cyclooxygenase-2 expression,mitogen-activated protein kinase(MAPK) phosphorylation,and the inhibitor of nuclear factor-kappa B-a levels were determined by the Western blot analysis.Results:In the co-cultured ARs,total flavonoids and total caffeic acid were determined,and the contents of both bioactive compounds were significantly higher than those ARs from the single-species culture.Compared with the control group,the large amount of pro-inflammatory mediators was released after LPS stimulation.However,in the extract groups with different concentrations(25,50,and 100 g/mL),the production of these pro-inflammatory mediators was inhibited in a dose-dependent manner.Furthermore,the levels of phosphorylation of MAPK proteins,including p-p38, p-c-Jun N-terminal kinase,and p-extracellular regulated protein kinases were significantly(P <0.05) decreased in the extract groups,revealing that the AR extract probably involved in regulating the MAPK signaling pathway.Conclusion:Collectively,our findings suggested that the co-cultured ARs of E.pallida and E.purpurea can inhibit production of pro-inflammatory mediators in mouse peritoneal macrophages and possess the anti-inflammatory effect by regulating MAPK signaling pathways.