The artemisinin accumulation in the hairy root cultures of Artemisia annua L. was enhanced via a treatment of three fungal elicitors separately ( Verticillium dahliae Kleb., Rhizopus stolonifer (Ehrenb. ex ...The artemisinin accumulation in the hairy root cultures of Artemisia annua L. was enhanced via a treatment of three fungal elicitors separately ( Verticillium dahliae Kleb., Rhizopus stolonifer (Ehrenb. ex Fr.) Vuill and Colletotrichum dematium (Pers.) Grove). Among these three elicitors, V. dahliae had the highest inducing efficiency, but none of them manifests any noticeable effects on the cell growth of the hairy root cultures. The artemisinin content of the hairy root cultures treated with V. dahliae elicitor was 1.12 mg/g DW, which was 45% higher than the control (0.77 mg/g DW). The results showed that elicitation was dependent on the elicitor concentration, the incubation period and the physiological stage at which the hairy root cultures were treated. In addition, the authors found that for V. dahliae , the optimum concentration was 0.4 mg carbohydrate per millilitre medium, the strongest response of A. annua hairy root cultures to the elicitation was at the late exponential growth stage, and the highest artemisinin content of the hairy root cultures was on the 4th day post treatment.展开更多
NAD(P)H oxidases were detected in suspension cultured cells of ginseng (Panax ginseng C. A. Meyer). The activities of these enzymes were induced by an elicitor (Cle) extracted from cell walls of Col-letotrichum lagera...NAD(P)H oxidases were detected in suspension cultured cells of ginseng (Panax ginseng C. A. Meyer). The activities of these enzymes were induced by an elicitor (Cle) extracted from cell walls of Col-letotrichum lagerarium. In addition, Cle induced an oxidative burst and enhanced the synthesis of saponin, activity of phenylalanine ammonialyase (PAL) , accumulation of chalcone synthase (CHS) and the transcription of a hydroxyproline-rich glycoprotein gene ( hrgp ) . Pre-treatments with DPI and quinacrine (two inhibitors of mammalian neutrophil plasma membrane NADPH oxidase) for 30 min prior to Cle addition blocked the NAD(P)H oxidase activity induced by Cle. These inhibitors also inhibited the release of H2C2, the synthesis of saponin, PAL activity and CHS accumulation. Our data revealed homology between plasma membrane NAD(P)H oxidases of mammalian neutrophil cells and ginseng suspension cells. They also indicated that deactivated NAD(P)H oxidases catalysed the release of H2O2 and that H2O2 was functioning as a second messenger stimulating PAL activity, saponin synthesis and hrgp transcription. Elevations of Ca2 + and protein phos-phorylation/dephosphorylation were required for this defense process. We propose that NAD(P)H oxidases mediate the processes of Cle-induced defense responses in ginseng suspensions, and postulate the existence of a signalling cascade including extracellular Cle stimulation, activation of plasma membrane NAD(P)H oxidases, release of H2O2, and the intracellular responses of metabolism and gene transcription in ginseng suspension cells.展开更多
Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidas...Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidase activity of isolated plasma membranes and stimulated in vivo H2O2 generation in ginseng cell suspensions. CDW also increased the activity of phenylalanine ammonia lyase (PAL), expression of a P. ginseng squalene epoxidase (sqe) gene and saponin synthesis. NADPH oxidase inhibitors inhibited both in vitro NADPH oxidase activity and in vivo H2O2 generation. Induction of PAL activity, saponin synthesis and sqe gene expression were all inhibited by such inhibitor treatments and reduced by incubation with catalase and HA scavengers. These data indicate that activation of NADPH oxidase and generation of H2O2 are essential signalling events mediating defence responses induced by the endogenous elicitor(s) present in CDW.展开更多
To optimize the technique of rapid propagation of Dendrobium hybrida seedlings and to explore a hormone-free tissue culture method for D.hybrida,six kinds of mycorrhizal fungi which were isolated from the wild orchids...To optimize the technique of rapid propagation of Dendrobium hybrida seedlings and to explore a hormone-free tissue culture method for D.hybrida,six kinds of mycorrhizal fungi which were isolated from the wild orchids were made into fungal elicitors.These fungal elicitors were added into the DE medium with concentrations of 40,60 and 80 ml/L,respectively.After a 90-d culturing,the effects of fungal elicitors on the growth of D.hybrida cultivar ‘088＇ tissue culture seedlings were studied.The results showed that treatment 13（T13） extremely significantly increased the fresh weight,but other treatment groups had no significant effects.In addition,T1,T5,T9,T11 and T13 extremely significantly influenced the contents of chlorophyll a and chlorophyll a ＋ b.However,T1 and T11 had extremely significantly effect on the content of chlorophyll b.Combining the effects on fresh weight and chlorophyll content,it could be concluded T13（40 ml/L of Y05） has promoting effects on the growth of D.hybrida tissue culture seedlings.展开更多
In this study, using Taxus cuspidata as a raw material, we obtained stable high-yielding cell lines by subculturing and quantified paclitaxel content using ultra- sonic extraction combined with TLC-UV spectrophotom- e...In this study, using Taxus cuspidata as a raw material, we obtained stable high-yielding cell lines by subculturing and quantified paclitaxel content using ultra- sonic extraction combined with TLC-UV spectrophotom- etry. In single factor and multiple factors tests to optimize design and study the effects of elicitors, precursors, and metabolic inhibitors on paclitaxel production by Taxus cuspidata cells, paclitaxel production reached 4.32 mg/L when 100 μmol/L methyl jasmonate, 20 mg/L salicylic acid, 400 mg/L phenylalanine and 2 mg/L gibberellin （GA3） were added to the culture medium of suspension cells. When adding metabolic adjustment factors on the 7th day of culture, extra- and intracellular paclitaxel production was the highest at 4.855 mg/L, paclitaxel release rate was 10.48 %, fresh mass and paclitaxel production of cell increased, respectively, by 6.08 and 11.57 %. By controlling the anabolism of paclitaxel, paclitaxel yield was significantly improved.展开更多
The expression of a protein elicitor from Magnaporthe griesea and its biological function in activating resistance in rice （Oryza safiva L） were reported. The gene of elicitor was expressed in Escherichia colicells ...The expression of a protein elicitor from Magnaporthe griesea and its biological function in activating resistance in rice （Oryza safiva L） were reported. The gene of elicitor was expressed in Escherichia colicells and produced a His6-fusion protein with 42 kD apparent molecular weight on SDS-PAGE. The purified protein could induce the resistance to blast disease, with the control efficiency of 46.47% and 36.41% at the 14^th day and the 21^st day after blast inoculation, respectively. After treatment with the expressed protein, the phenylalanine ammonia-lyase （PAL） and peroxidase （POD） activities were promoted in rice plants, meanwhile, the transcription levels of STKM, FAD, PBZ1 and PR1 genes were increased in rice plants. Moreover, after comparing the profile of total rice leaf proteins on two-dimensional electrophoresis gel, about 14 proteins were found to be increased in expression level after the expressed protein treatment. All the results indicated that the expressed protein could act as an elicitor to trigger the resistance in rice.展开更多
Callus cultures of Origanum vulgare L. were established from leaf discus on Murashige and Skoog （MS） medium containing different levels of growth regulators, i.e., 2,4-Dichlorophenoxyacetic acid （2,4-D）, Naphthale...Callus cultures of Origanum vulgare L. were established from leaf discus on Murashige and Skoog （MS） medium containing different levels of growth regulators, i.e., 2,4-Dichlorophenoxyacetic acid （2,4-D）, Naphthalene acetic acid （NAA）, Benzyl Adenine （BA） and Kinetin （Kn） and incubated under dark condition. Callus tissues were employed to study the influence of abiotic elicitors on the production of thymol. Constant weights of callus （300 mg） were cultured on accumulation medium treated separately with each one of elicitors used （50 g/L sucrose, 200 mg/L NaC1 and 50 or 100 mg/L proline）. The fresh and dry weights of callus were recorded after six weeks. The result indicated that maximum production of fresh and dry callus weight were 1,014 mg and 46.20 mg respectively achieved at 0.5 mg/L 2,4-D and 3 mg/L BA adding to the medium. Dry callus tissues were extracted with 70% methanol and analyzed by HPLC to determine the concentrations of thymol. The addition of abiotic elicitors to MS medium caused significant reduction in fresh weight of callus compared with control treatment. The concentration of thymol in the callus cultured on control treatment was 146.6 ppm. The data showed that 50 or 100 mg/L proline produced the highest yield of thymol 181.48 ppm and 174.58 ppm respectively, followed by sucrose 162.9 ppm, whereas the treatment with NaCI caused reduction in thymol concentration to percentage of 50.56% compared with the control.展开更多
The recognition of oligosaccharide elicitors,which originate from both pathogens and hosts,by membrane-localized receptors is of fundamental importance for triggering host immunity and disease resistance.It is therefo...The recognition of oligosaccharide elicitors,which originate from both pathogens and hosts,by membrane-localized receptors is of fundamental importance for triggering host immunity and disease resistance.It is therefore a topic of utmost significance for agricultural and botanical research.This review provides a comprehensive analysis of our current understanding of the types of oligosaccharide elicitors.We explore their diverse immunological functions,aiming to uncover the underlying mechanisms.We then detail the known recognition receptors for these oligosaccharide elicitors and describe the immune signaling pathways in which they participate.We outline the counter-defense strategies used by pathogens in response to oligosaccharide-induced immunity,offering insight into the complex interactions between plants and pathogens.Finally,we discuss challenges and limitations in the field of oligosaccharidebased immunity and propose directions for future research.A holistic view of oligosaccharide elicitors can facilitate the development of more effective strategies for enhancing plant disease resistance by leveraging mechanisms of oligosaccharide-induced immunity,ultimately promoting more sustainable agricultural practices and a better understanding of plant-pathogen interactions.展开更多
Nitric oxide (NO) has emerged as a key signaling molecule in plant secondary metabolite biosynthesis recently. In order to investigate the molecular basis of NO signaling in elicitor-induced secondary metabolite biosy...Nitric oxide (NO) has emerged as a key signaling molecule in plant secondary metabolite biosynthesis recently. In order to investigate the molecular basis of NO signaling in elicitor-induced secondary metabolite biosynthesis of plant cells, we determined the contents of NO, salicylic acid (SA), jasmonic acid (JA), and puerarin in Pueraria thomsonii Benth. suspension cells treated with the elicitors prepared from cell walls of Penicillium citrinum. The results showed that the fungal elicitor induced NO burst, SA accumulation and puerarin production of P. thomsonii Benth. cells. The elicitor-induced SA accumulation and puerarin production was suppressed by nitric oxide specific scavenger cPITO, indicating that NO was essential for elicitor-induced SA and puerarin biosynthesis in P. thomsonii Benth. cells. In transgenic NahG P. thomsonii Benth. cells, the fungal elicitor also induced puerarin biosynthesis, NO burst, and JA accumulation, though the SA biosynthe-sis was impaired. The elicitor-induced JA accumulation in transgenic cells was blocked by cPITO, which suggested that JA acted downstream of NO and its biosynthesis was controlled by NO. External application of NO via its donor sodium nitroprusside (SNP) enhanced puerarin biosynthesis in trans-genic NahG P. thomsonii Benth. cells, and the NO-triggered puerarin biosynthesis was suppressed by JA inhibitors IBU and NDGA, which indicated that NO induced puerarin production through a JA-dependent signal pathway in the transgenic cells. Exogenous application of SA suppressed the elicitor-induced JA biosynthesis and reversed the inhibition of IBU and NDGA on elicitor-induced pu-erarin accumulation in transgenic cells, which indicated that SA inhibited JA biosynthesis in the cells and that SA might be used as a substitute for JA to mediate the elicitor- and NO-induced puerarin biosynthesis. It was, therefore, concluded that NO might mediate the elicitor-induced puerarin bio-synthesis through SA- and JA-dependent signal pathways in wildtype P. thomsonii Benth. cells and transgenic NahG cells respectively.展开更多
Plants can produce animal cytokine-like immune peptides,among which plant elicitor peptides(Peps)derive from the C termini of their precursors(PROPEPs).Recently,the functions of Peps have been expanded beyond plant im...Plants can produce animal cytokine-like immune peptides,among which plant elicitor peptides(Peps)derive from the C termini of their precursors(PROPEPs).Recently,the functions of Peps have been expanded beyond plant immunity.However,a long-standing enigma is how PROPEPs are processed into Peps.Here,we report that the Ca2+-dependent type-ll metacaspases(MCs)constitute the proteolytic enzymes to mediate PROPEP processing in Arabidopsis.In protoplasts,co-expression of PROPEP1 with type-ll MCs,including MC4 to MC9,can promote the generation of processed Pep1.Destruction of the catalytic cysteine residue in MC4 or the conserved arginine residue preceding the Pep1 sequence blocks PROPEP1 cleavage,whereas the bacterial elicitor flg22 enhances the MC4-mediated PROPEP1 processing.MC4 cleaves PROPEP1 in vitro and also cleaves PROPEP2 to PROPEP8,but,surprisingly,not PROPEP6 in protoplasts.Domain swapping between PROPEP1 and PROPEP6 suggests a hidden role of the sequence context upstream of the Pep sequence for PROPEP processing.flg22-induced PROPEP1 processing and B otrytis cinerea resistance are severely impaired in the m c4/5/6/7 quadruple-mutant plants.Taken together,our study identifies the type-ll MCs as new players in Pep signaling,and lays the foundation for understanding the regulation of multifaceted functions of Peps in plant immunity and beyond.展开更多
Hymexazol （3-Hydroxy-5-methylisoxazole） as the main ingredients of HI （elicitor） was used to screen salt-tolerant species from 122 salt-tolerant rice （Oryza sativa L.） cultivars under specific inducement. The re...Hymexazol （3-Hydroxy-5-methylisoxazole） as the main ingredients of HI （elicitor） was used to screen salt-tolerant species from 122 salt-tolerant rice （Oryza sativa L.） cultivars under specific inducement. The results showed that the local species R6 is highly induce-sensitive. R6 showed salt tolerance during the whole growth period by using 1.0% NaCI solution after HI treatment. Cyclosporin A （CsA） and verapamil （VP） as P-glycoprotein （PGP） inhibitors and rifampin （RFP） as a PGP elicitor were used to treat R6. The morphological traits, structure of the root, physiological characteristics of leaf and root systems, the content of endog- enous hormones indole-3-acetic acid （IAA） and abscisic acid （ABA） etc. show that CsA, VP and RFP had remarkable effects on the rice＇s salt tolerance. Hymexazol inducement （HI） can improve the rice＇s salt tolerance greatly and make it more salt-resistant.展开更多
The phytoalexin elicitor β-(1→3)-branched β-(1→6)-linked glucohexatose has been regie- and stereospeciflcally synthesized by coupling of the 3, 6-branched gluco-trisaccharide Schmidt reagent 10 with a mixture of m...The phytoalexin elicitor β-(1→3)-branched β-(1→6)-linked glucohexatose has been regie- and stereospeciflcally synthesized by coupling of the 3, 6-branched gluco-trisaccharide Schmidt reagent 10 with a mixture of multiol 3,6-branched gluco-trisac-charides 13 which consists of free 5,6'-OH trisaccharide, free 5,2' ,6'-OH trisaccharide, free 5,3' ,6'-OH trisaccharide and so on. The compounds 10 and 13 were prepared from 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, 2, 3, 4, 6-tetra-O-ben-zoyl-α-D-glucopyranosyl trichloroacetimidate, and 2,3,4,6-te-tra-O-acetyl-α-D-glucopyranosyl trichloroacetimidate through re-gio- and stereoselective manners.展开更多
Magnaporthe grisea special races 98-186-1G1 and 97-23-2D1 induce incompatible and compatible reactions respectively with rice Xiushui? The elicitor from the cell wall of M. grisea race 98-186-1G1, termed IE, strongly ...Magnaporthe grisea special races 98-186-1G1 and 97-23-2D1 induce incompatible and compatible reactions respectively with rice Xiushui? The elicitor from the cell wall of M. grisea race 98-186-1G1, termed IE, strongly in-duced the HR response in suspension cultures of rice Xiushui? including increased PAL activity, transcription of pal , pr1, chi, cell death and the generation of NO. The elici-tor prepared from the cell wall of M. grisea race 97-23-2D1, named CE, was much less efficient at inducing such effects. The NOS enzyme inhibitors L-NAA and PBITU suppressed the production of NO induced by IE in Xiushui?rice. The increased PAL activity and transcription of pr1, pal, chi genes induced by IE were blocked by L-NAA, PBITU or CPTIO pretreatment. Direct treatment of rice cultures with the NO donor (SNP) also induced the transcription of pr1, pal and chi genes. These data implicated that NO acted as a signal mediating the HR induced by IE in rice and showed that NO, in combination with H2O2, is necessary for induc-tion of cell death by IE in rice suspension cells.展开更多
Elicitor prepared from the cell walls of Peni-cillium citrinum induces multiple responses of Taxuschinensis cells, including nitric oxide (NO) generation, se-quentially followed by the activation of PAL and synthesis ...Elicitor prepared from the cell walls of Peni-cillium citrinum induces multiple responses of Taxuschinensis cells, including nitric oxide (NO) generation, se-quentially followed by the activation of PAL and synthesis oftaxol. NO scavenger cPITO and nitric oxide synthase (NOS)inhibitor PBITU prevent the latter two reactions, all of whichare triggered in the absence of elicitor by NO donor sodiumnitroprusside (SNP). The elicitor-induced NO release ofTaxus chinensis suspension cells is strongly inhibited byPBITU. These results demonstrate a causal relationship be-tween NO generation and the latter two reactions of Taxus chinensis cells to the elicitor, and also indicate that NO, pro-duced via NOS in Taxus chinensis cells treated with fungalelicitor, might act as an essential signaling molecule for trig-gering the activation of PAL and synthesis of taxol.展开更多
The protein elicitor PB90 secreted by Phytophthora boehmeriae is an efficient elicitor inducing the hypersensitive response and systemic acquired resistance in tobacco plants. Here, we observed cell death in suspensio...The protein elicitor PB90 secreted by Phytophthora boehmeriae is an efficient elicitor inducing the hypersensitive response and systemic acquired resistance in tobacco plants. Here, we observed cell death in suspension-cultured cells of Nicotiana tabacum BY-2 with PB90 treatment using Trypan blue staining method. And this cell death could be suppressed by cycloheximide, an inhibitor of proteins synthesis, which implies that PB90-induced cell death was an active cell death process requiring new protein synthesis. DAPI staining revealed that PB90 induce rapid chromatin condensation, margination, apoptotic bodies' formation and DNA laddering, further TUNEL assay also observed the specific breakage of 3′-OH ends. All of the above common morphological characteristics indicated that PB90 induced apoptosis in suspension cultures of tobacco, suggesting that hypersensitive response induced by PB90 is an apoptotic process.展开更多
文摘The artemisinin accumulation in the hairy root cultures of Artemisia annua L. was enhanced via a treatment of three fungal elicitors separately ( Verticillium dahliae Kleb., Rhizopus stolonifer (Ehrenb. ex Fr.) Vuill and Colletotrichum dematium (Pers.) Grove). Among these three elicitors, V. dahliae had the highest inducing efficiency, but none of them manifests any noticeable effects on the cell growth of the hairy root cultures. The artemisinin content of the hairy root cultures treated with V. dahliae elicitor was 1.12 mg/g DW, which was 45% higher than the control (0.77 mg/g DW). The results showed that elicitation was dependent on the elicitor concentration, the incubation period and the physiological stage at which the hairy root cultures were treated. In addition, the authors found that for V. dahliae , the optimum concentration was 0.4 mg carbohydrate per millilitre medium, the strongest response of A. annua hairy root cultures to the elicitation was at the late exponential growth stage, and the highest artemisinin content of the hairy root cultures was on the 4th day post treatment.
文摘NAD(P)H oxidases were detected in suspension cultured cells of ginseng (Panax ginseng C. A. Meyer). The activities of these enzymes were induced by an elicitor (Cle) extracted from cell walls of Col-letotrichum lagerarium. In addition, Cle induced an oxidative burst and enhanced the synthesis of saponin, activity of phenylalanine ammonialyase (PAL) , accumulation of chalcone synthase (CHS) and the transcription of a hydroxyproline-rich glycoprotein gene ( hrgp ) . Pre-treatments with DPI and quinacrine (two inhibitors of mammalian neutrophil plasma membrane NADPH oxidase) for 30 min prior to Cle addition blocked the NAD(P)H oxidase activity induced by Cle. These inhibitors also inhibited the release of H2C2, the synthesis of saponin, PAL activity and CHS accumulation. Our data revealed homology between plasma membrane NAD(P)H oxidases of mammalian neutrophil cells and ginseng suspension cells. They also indicated that deactivated NAD(P)H oxidases catalysed the release of H2O2 and that H2O2 was functioning as a second messenger stimulating PAL activity, saponin synthesis and hrgp transcription. Elevations of Ca2 + and protein phos-phorylation/dephosphorylation were required for this defense process. We propose that NAD(P)H oxidases mediate the processes of Cle-induced defense responses in ginseng suspensions, and postulate the existence of a signalling cascade including extracellular Cle stimulation, activation of plasma membrane NAD(P)H oxidases, release of H2O2, and the intracellular responses of metabolism and gene transcription in ginseng suspension cells.
文摘Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidase activity of isolated plasma membranes and stimulated in vivo H2O2 generation in ginseng cell suspensions. CDW also increased the activity of phenylalanine ammonia lyase (PAL), expression of a P. ginseng squalene epoxidase (sqe) gene and saponin synthesis. NADPH oxidase inhibitors inhibited both in vitro NADPH oxidase activity and in vivo H2O2 generation. Induction of PAL activity, saponin synthesis and sqe gene expression were all inhibited by such inhibitor treatments and reduced by incubation with catalase and HA scavengers. These data indicate that activation of NADPH oxidase and generation of H2O2 are essential signalling events mediating defence responses induced by the endogenous elicitor(s) present in CDW.
基金Supported by National Nonprofit Institute Research Grant of CATAS-TCGRI(1630032014027)Special Fund for Agro-scientific Research in the Public Interest(201203071)Special Project for Scientific and Technological Achievements Demonstration and Promotion in Hainan Province(SQ2013CGSF0006)~~
文摘To optimize the technique of rapid propagation of Dendrobium hybrida seedlings and to explore a hormone-free tissue culture method for D.hybrida,six kinds of mycorrhizal fungi which were isolated from the wild orchids were made into fungal elicitors.These fungal elicitors were added into the DE medium with concentrations of 40,60 and 80 ml/L,respectively.After a 90-d culturing,the effects of fungal elicitors on the growth of D.hybrida cultivar ‘088＇ tissue culture seedlings were studied.The results showed that treatment 13（T13） extremely significantly increased the fresh weight,but other treatment groups had no significant effects.In addition,T1,T5,T9,T11 and T13 extremely significantly influenced the contents of chlorophyll a and chlorophyll a ＋ b.However,T1 and T11 had extremely significantly effect on the content of chlorophyll b.Combining the effects on fresh weight and chlorophyll content,it could be concluded T13（40 ml/L of Y05） has promoting effects on the growth of D.hybrida tissue culture seedlings.
基金supported by development plan project during ‘‘the 12th Five Year Plan’’ Nation Science and Technology in rural area(No.2012AA10A506-04 and No.2013AA103005-04)Changchun City science and technology development program(No.2014174)Changchun City science and technology support program(No.2014NK002)
文摘In this study, using Taxus cuspidata as a raw material, we obtained stable high-yielding cell lines by subculturing and quantified paclitaxel content using ultra- sonic extraction combined with TLC-UV spectrophotom- etry. In single factor and multiple factors tests to optimize design and study the effects of elicitors, precursors, and metabolic inhibitors on paclitaxel production by Taxus cuspidata cells, paclitaxel production reached 4.32 mg/L when 100 μmol/L methyl jasmonate, 20 mg/L salicylic acid, 400 mg/L phenylalanine and 2 mg/L gibberellin （GA3） were added to the culture medium of suspension cells. When adding metabolic adjustment factors on the 7th day of culture, extra- and intracellular paclitaxel production was the highest at 4.855 mg/L, paclitaxel release rate was 10.48 %, fresh mass and paclitaxel production of cell increased, respectively, by 6.08 and 11.57 %. By controlling the anabolism of paclitaxel, paclitaxel yield was significantly improved.
文摘The expression of a protein elicitor from Magnaporthe griesea and its biological function in activating resistance in rice （Oryza safiva L） were reported. The gene of elicitor was expressed in Escherichia colicells and produced a His6-fusion protein with 42 kD apparent molecular weight on SDS-PAGE. The purified protein could induce the resistance to blast disease, with the control efficiency of 46.47% and 36.41% at the 14^th day and the 21^st day after blast inoculation, respectively. After treatment with the expressed protein, the phenylalanine ammonia-lyase （PAL） and peroxidase （POD） activities were promoted in rice plants, meanwhile, the transcription levels of STKM, FAD, PBZ1 and PR1 genes were increased in rice plants. Moreover, after comparing the profile of total rice leaf proteins on two-dimensional electrophoresis gel, about 14 proteins were found to be increased in expression level after the expressed protein treatment. All the results indicated that the expressed protein could act as an elicitor to trigger the resistance in rice.
文摘Callus cultures of Origanum vulgare L. were established from leaf discus on Murashige and Skoog （MS） medium containing different levels of growth regulators, i.e., 2,4-Dichlorophenoxyacetic acid （2,4-D）, Naphthalene acetic acid （NAA）, Benzyl Adenine （BA） and Kinetin （Kn） and incubated under dark condition. Callus tissues were employed to study the influence of abiotic elicitors on the production of thymol. Constant weights of callus （300 mg） were cultured on accumulation medium treated separately with each one of elicitors used （50 g/L sucrose, 200 mg/L NaC1 and 50 or 100 mg/L proline）. The fresh and dry weights of callus were recorded after six weeks. The result indicated that maximum production of fresh and dry callus weight were 1,014 mg and 46.20 mg respectively achieved at 0.5 mg/L 2,4-D and 3 mg/L BA adding to the medium. Dry callus tissues were extracted with 70% methanol and analyzed by HPLC to determine the concentrations of thymol. The addition of abiotic elicitors to MS medium caused significant reduction in fresh weight of callus compared with control treatment. The concentration of thymol in the callus cultured on control treatment was 146.6 ppm. The data showed that 50 or 100 mg/L proline produced the highest yield of thymol 181.48 ppm and 174.58 ppm respectively, followed by sucrose 162.9 ppm, whereas the treatment with NaCI caused reduction in thymol concentration to percentage of 50.56% compared with the control.
基金supported by the National Key Research and Development Program of China(grant nos.2022YFF1001500 and 2023YFE0123400)the China Postdoctoral Science Foundation(grant no.2024T170421,G.S.)+2 种基金the Jiangsu Funding Program for Excellent Postdoctoral Talent(grant no.2023ZB236,G.S.)the Postdoctoral Fellowship Program of CPSF(grant no.GZC20231129,G.S.)the Key Research and Development Program of Guangdong Province(grant no.2022B0202080004).
文摘The recognition of oligosaccharide elicitors,which originate from both pathogens and hosts,by membrane-localized receptors is of fundamental importance for triggering host immunity and disease resistance.It is therefore a topic of utmost significance for agricultural and botanical research.This review provides a comprehensive analysis of our current understanding of the types of oligosaccharide elicitors.We explore their diverse immunological functions,aiming to uncover the underlying mechanisms.We then detail the known recognition receptors for these oligosaccharide elicitors and describe the immune signaling pathways in which they participate.We outline the counter-defense strategies used by pathogens in response to oligosaccharide-induced immunity,offering insight into the complex interactions between plants and pathogens.Finally,we discuss challenges and limitations in the field of oligosaccharidebased immunity and propose directions for future research.A holistic view of oligosaccharide elicitors can facilitate the development of more effective strategies for enhancing plant disease resistance by leveraging mechanisms of oligosaccharide-induced immunity,ultimately promoting more sustainable agricultural practices and a better understanding of plant-pathogen interactions.
基金supported by the National Natural Science Foundation of China(Grant No.30572331)the Natural Science Foundation of Zhejiang Province(Grant No.302785).
文摘Nitric oxide (NO) has emerged as a key signaling molecule in plant secondary metabolite biosynthesis recently. In order to investigate the molecular basis of NO signaling in elicitor-induced secondary metabolite biosynthesis of plant cells, we determined the contents of NO, salicylic acid (SA), jasmonic acid (JA), and puerarin in Pueraria thomsonii Benth. suspension cells treated with the elicitors prepared from cell walls of Penicillium citrinum. The results showed that the fungal elicitor induced NO burst, SA accumulation and puerarin production of P. thomsonii Benth. cells. The elicitor-induced SA accumulation and puerarin production was suppressed by nitric oxide specific scavenger cPITO, indicating that NO was essential for elicitor-induced SA and puerarin biosynthesis in P. thomsonii Benth. cells. In transgenic NahG P. thomsonii Benth. cells, the fungal elicitor also induced puerarin biosynthesis, NO burst, and JA accumulation, though the SA biosynthe-sis was impaired. The elicitor-induced JA accumulation in transgenic cells was blocked by cPITO, which suggested that JA acted downstream of NO and its biosynthesis was controlled by NO. External application of NO via its donor sodium nitroprusside (SNP) enhanced puerarin biosynthesis in trans-genic NahG P. thomsonii Benth. cells, and the NO-triggered puerarin biosynthesis was suppressed by JA inhibitors IBU and NDGA, which indicated that NO induced puerarin production through a JA-dependent signal pathway in the transgenic cells. Exogenous application of SA suppressed the elicitor-induced JA biosynthesis and reversed the inhibition of IBU and NDGA on elicitor-induced pu-erarin accumulation in transgenic cells, which indicated that SA inhibited JA biosynthesis in the cells and that SA might be used as a substitute for JA to mediate the elicitor- and NO-induced puerarin biosynthesis. It was, therefore, concluded that NO might mediate the elicitor-induced puerarin bio-synthesis through SA- and JA-dependent signal pathways in wildtype P. thomsonii Benth. cells and transgenic NahG cells respectively.
基金This work was supported by the Foundation of Guangzhou Science and Technology Key Project(201904020041)the National Natural Science Foundation of China(31770295)to J.-F.L.
文摘Plants can produce animal cytokine-like immune peptides,among which plant elicitor peptides(Peps)derive from the C termini of their precursors(PROPEPs).Recently,the functions of Peps have been expanded beyond plant immunity.However,a long-standing enigma is how PROPEPs are processed into Peps.Here,we report that the Ca2+-dependent type-ll metacaspases(MCs)constitute the proteolytic enzymes to mediate PROPEP processing in Arabidopsis.In protoplasts,co-expression of PROPEP1 with type-ll MCs,including MC4 to MC9,can promote the generation of processed Pep1.Destruction of the catalytic cysteine residue in MC4 or the conserved arginine residue preceding the Pep1 sequence blocks PROPEP1 cleavage,whereas the bacterial elicitor flg22 enhances the MC4-mediated PROPEP1 processing.MC4 cleaves PROPEP1 in vitro and also cleaves PROPEP2 to PROPEP8,but,surprisingly,not PROPEP6 in protoplasts.Domain swapping between PROPEP1 and PROPEP6 suggests a hidden role of the sequence context upstream of the Pep sequence for PROPEP processing.flg22-induced PROPEP1 processing and B otrytis cinerea resistance are severely impaired in the m c4/5/6/7 quadruple-mutant plants.Taken together,our study identifies the type-ll MCs as new players in Pep signaling,and lays the foundation for understanding the regulation of multifaceted functions of Peps in plant immunity and beyond.
文摘Hymexazol （3-Hydroxy-5-methylisoxazole） as the main ingredients of HI （elicitor） was used to screen salt-tolerant species from 122 salt-tolerant rice （Oryza sativa L.） cultivars under specific inducement. The results showed that the local species R6 is highly induce-sensitive. R6 showed salt tolerance during the whole growth period by using 1.0% NaCI solution after HI treatment. Cyclosporin A （CsA） and verapamil （VP） as P-glycoprotein （PGP） inhibitors and rifampin （RFP） as a PGP elicitor were used to treat R6. The morphological traits, structure of the root, physiological characteristics of leaf and root systems, the content of endog- enous hormones indole-3-acetic acid （IAA） and abscisic acid （ABA） etc. show that CsA, VP and RFP had remarkable effects on the rice＇s salt tolerance. Hymexazol inducement （HI） can improve the rice＇s salt tolerance greatly and make it more salt-resistant.
基金Project supported by the Beijing Natural Science Foundation(No.6021004)and the Ministry of Science and Technology(No.2001AA246014).
文摘The phytoalexin elicitor β-(1→3)-branched β-(1→6)-linked glucohexatose has been regie- and stereospeciflcally synthesized by coupling of the 3, 6-branched gluco-trisaccharide Schmidt reagent 10 with a mixture of multiol 3,6-branched gluco-trisac-charides 13 which consists of free 5,6'-OH trisaccharide, free 5,2' ,6'-OH trisaccharide, free 5,3' ,6'-OH trisaccharide and so on. The compounds 10 and 13 were prepared from 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, 2, 3, 4, 6-tetra-O-ben-zoyl-α-D-glucopyranosyl trichloroacetimidate, and 2,3,4,6-te-tra-O-acetyl-α-D-glucopyranosyl trichloroacetimidate through re-gio- and stereoselective manners.
基金supported by the National Natural Science Foundation of China(Grant No.39870050).
文摘Magnaporthe grisea special races 98-186-1G1 and 97-23-2D1 induce incompatible and compatible reactions respectively with rice Xiushui? The elicitor from the cell wall of M. grisea race 98-186-1G1, termed IE, strongly in-duced the HR response in suspension cultures of rice Xiushui? including increased PAL activity, transcription of pal , pr1, chi, cell death and the generation of NO. The elici-tor prepared from the cell wall of M. grisea race 97-23-2D1, named CE, was much less efficient at inducing such effects. The NOS enzyme inhibitors L-NAA and PBITU suppressed the production of NO induced by IE in Xiushui?rice. The increased PAL activity and transcription of pr1, pal, chi genes induced by IE were blocked by L-NAA, PBITU or CPTIO pretreatment. Direct treatment of rice cultures with the NO donor (SNP) also induced the transcription of pr1, pal and chi genes. These data implicated that NO acted as a signal mediating the HR induced by IE in rice and showed that NO, in combination with H2O2, is necessary for induc-tion of cell death by IE in rice suspension cells.
文摘Elicitor prepared from the cell walls of Peni-cillium citrinum induces multiple responses of Taxuschinensis cells, including nitric oxide (NO) generation, se-quentially followed by the activation of PAL and synthesis oftaxol. NO scavenger cPITO and nitric oxide synthase (NOS)inhibitor PBITU prevent the latter two reactions, all of whichare triggered in the absence of elicitor by NO donor sodiumnitroprusside (SNP). The elicitor-induced NO release ofTaxus chinensis suspension cells is strongly inhibited byPBITU. These results demonstrate a causal relationship be-tween NO generation and the latter two reactions of Taxus chinensis cells to the elicitor, and also indicate that NO, pro-duced via NOS in Taxus chinensis cells treated with fungalelicitor, might act as an essential signaling molecule for trig-gering the activation of PAL and synthesis of taxol.
基金supported in part by the National Natural Science Foundation of China(Grant No.30270865)the Key Program for Science and Technology of Education Ministry of China(Grant No.01098)..
文摘The protein elicitor PB90 secreted by Phytophthora boehmeriae is an efficient elicitor inducing the hypersensitive response and systemic acquired resistance in tobacco plants. Here, we observed cell death in suspension-cultured cells of Nicotiana tabacum BY-2 with PB90 treatment using Trypan blue staining method. And this cell death could be suppressed by cycloheximide, an inhibitor of proteins synthesis, which implies that PB90-induced cell death was an active cell death process requiring new protein synthesis. DAPI staining revealed that PB90 induce rapid chromatin condensation, margination, apoptotic bodies' formation and DNA laddering, further TUNEL assay also observed the specific breakage of 3′-OH ends. All of the above common morphological characteristics indicated that PB90 induced apoptosis in suspension cultures of tobacco, suggesting that hypersensitive response induced by PB90 is an apoptotic process.
