With validamycin A.（0.2 billion spores/ml） Paenibacillus polymyxa DN-1 3% AS as the test agent, the effects of different dosage and different application time on the control efficacy for＇ rich sheath blight were in...With validamycin A.（0.2 billion spores/ml） Paenibacillus polymyxa DN-1 3% AS as the test agent, the effects of different dosage and different application time on the control efficacy for＇ rich sheath blight were investigated. The results of two- year test showed that when the application amount was in the range of 45-90 g.a.i/ hm^2, the field efficacy of validamycin A-（0.2 billion spores/ml） P. polymyxa DN-1 3% AS in the initial infection stage of rich sheath blight （Le., the diseased plant rate was below 5%） reached 80.38%-89.06%, and that in the peak infection stage （i.e., the diseased plant rate was higher than 10%） reached only 41.12%-53.26%. The field efficacy of validamycin A.（0.2 billion spores/ml） P. polymyxa DN-1 3% AS at the early onset of rich sheath blight was significantly better than that at the onset, so that the application time of validamycin A .（0.2 billion spores/ml） P. polymyxa DN-1 3% AS should be appropriately brought forward in the prevention and control of rice sheath blight.展开更多
Fermentation experiments to produce validamycins from crude substrates by Streptomyces hygroscopicus were carried out in an external-loop airlift bioreactor (0.0115 m^3 ) with a low ratio of height to diameter of the ...Fermentation experiments to produce validamycins from crude substrates by Streptomyces hygroscopicus were carried out in an external-loop airlift bioreactor (0.0115 m^3 ) with a low ratio of height to diameter of the riser of 2.9 and a ratio of riser to downcomer diameter of 6.6. The influences of gas flow rate and liquid volume on fermentation of validamycins were investigated. Comparisons of validamycin fermentation were made among the external-loop airlift bioreactor, a mechanically stirred tank bioreactor (0.010m^3 ) and shaking flasks. Under the same operation conditions including fermentation medium composition, inoculum ratio and culture temperature, the fermentation time in the external-loop airlift bioreactor (45 h) was shorter than that in the shaking flasks (100 h) and the same as that in the mechanically stirred tank bioreactor. After a total fermentation time of 45 h under optimized operation conditions, average validamycin concentration obtained in the external-loop airlift bioreactor was close to 19630 μg·ml^-1 validamycin concentration in the mechanically stirred tank bioreactor. It was demonstrated that the external-loop airlift bioreactor could substitute for the mechanically stirred tank bioreactor in production of validamycins from crude substrates with dregs by Streptomyces hygroscopicus.展开更多
[Objective] The paper was to explore the effective agent against seedling blight of Atractylodes macrocephala. [Method] The control effects of 60% validamycin A SP against seeding blight of A. macrocephala were studie...[Objective] The paper was to explore the effective agent against seedling blight of Atractylodes macrocephala. [Method] The control effects of 60% validamycin A SP against seeding blight of A. macrocephala were studied in the field, and compared with that of control agent 20% bismerthiazol WP. [Result] At 14 d post the third spraying, the control effect of 60% validamycin A SP at the dose of 495-540 g/hm;was 76.9%,which was equivalent to that of control agent 20% bismerthiazol WP sprayed at the dose of 270 g/hm;（76.7%）. [Conclusion] 60% Validamycin A SP could be used as the ideal agent against seedling blight of A. macrocephala, with good prospects of application and popularization.展开更多
[Objective] The paper was to understand the control efficacy and the optimal dosage of 16% validamycin？thifluzamide SC on controlling Selerotium rolfsii in Dendrobium officinale Kimura et Migo. [Method] The contr...[Objective] The paper was to understand the control efficacy and the optimal dosage of 16% validamycin？thifluzamide SC on controlling Selerotium rolfsii in Dendrobium officinale Kimura et Migo. [Method] The control efficacy of 16% validamycin·thifluzamide SC against S.rolfsii was determined by spraying agents on the whole plant of D.officinale. The significance of differences was analyzed by Duncan＇s new multiple range test （DMRT）. [Result] The control efficacy of 16% validamycin.thifluzamide SC sprayed at the doses of 80-160 mg a.i./kg was 85.33% at 14 d post spraying, higher than that of control agent 4% validamycin AS sprayed at the dose of 80 mg a.i./kg （78.36%）, and equivalent to that of control agent 240 g/L thifluzamide SC sprayed at the dose of 120 mg a.i./kg （90.60%）. [Conclusion] 16% Validamycin·thifluzamide SC sprayed at the doses of 80-160 mg a.i./kg could effectively control the damage of S.rolfsii in D.officinale, and could be popularized in the production.展开更多
Validamycin,as a broadly applied antibiotic,has been used to control rice sheath blight disease.Furthermore,validamycin was considered as an insecticide to control agricultural pests.Insight into the mechanism of vali...Validamycin,as a broadly applied antibiotic,has been used to control rice sheath blight disease.Furthermore,validamycin was considered as an insecticide to control agricultural pests.Insight into the mechanism of validamycin’s action on insects can provide molecular targets for the control of agricultural pests.In this study,a toxicological test analysis revealed that Spodoptera litura larval growth and development was significantly inhibited and the pupation rate was significantly reduced with the increase of the concentration of validamycin.According to the NMR-based metabolomic analysis,a total of 15 metabolites involved in glycolysis and tricarboxylic acid cycle(TCA)pathways were identified.Additionally,trehalase activities,glucose and chitin contents were significantly downregulated,but the trehalose content was upregulated after exposure to validamycin.Reverse transcription quantitative PCR analysis revealed that the expression level of genes involved in glycolysis,TCA and chitin synthesis were upregulated after treating with validamycin.Further chitin staining also confirmed that chitin content was downregulated at 12 h after validamycin treatment.Our results indicated that validamycin worked via two different molecular mechanisms,one through inhibiting glycometabolism and the other by inhibiting chitin synthesis in S.litura.The information lays a theoretical foundation for further control of S.litura.展开更多
Validamycin has been widely used as a specific competitive inhibitor of tre-halase.In our previous research,validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri,resulting in ...Validamycin has been widely used as a specific competitive inhibitor of tre-halase.In our previous research,validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri,resulting in abnormal phenotypes.However,the mechanism of validamycin's action on D.citri remains unclear.Here,using a comparative transcriptome analysis,464 differentially expressed genes(DEGs)in D.citri were identified after validamycin treatment.A Gene Ontology enrichment analysis revealed that these DEGs were mainly involved in“small molecule process”,“structural molecule ac-tivity”and“transition metal ion binding”.DEGs involved in chitin metabolism,cuticle synthesis and insecticide detoxification were validated by reverse transcription quantitative polymerase chain reaction.The RNA interference of D.citri chitinase-like protein EN03 and D.citri cuticle protein 7 genes significantly affected D.citri molting.Moreover,the recombinant chitinase-like protein EN03 exhibited a chitin-binding property,and an antimicrobial activity against Bacillus subtilis.This study provides a first insight into the molecular changes in D.citri after exposure to validamycin and identifies two effective RNA interference targets for D.citri control.展开更多
Cultivation shift from 30℃ to 37℃ significantly enhanced validamycin (VAL) production. Analyzed by reverse-transcription PCR, the transcription of three val genes, valA, valK and valG, representing the three operons...Cultivation shift from 30℃ to 37℃ significantly enhanced validamycin (VAL) production. Analyzed by reverse-transcription PCR, the transcription of three val genes, valA, valK and valG, representing the three operons of the cluster was simultaneously increased at elevated temperature. Furthermore, the transcription of valP and valQ, a pair of two-component regulators in validamycin biosynthetic gene cluster, was also increased at 37℃. Inactivation of valP and valQ reduced validamycin production at 37℃ to the yield level of wild type strain at 30℃, and the val genes showed reduced expression in the mutant LL-8 at 37℃. These results revealed that the two-component regulator valP and valQ contribute to the elevated validamycin production.展开更多
基金Supported by National Agricultural Science and Technology Achievement Transformation Fund of China(2010GB2C300196)Modern Agricultural Production Development Fund(Rice Industry)Project of Anhui Academy of Agricultural SciencesIntegration and Demonstration of Chemical Fertilizer and Agrochemical Reduction and Efficiency Increasing Technology for Rice in Rice-wheat(rape)Rotation Areas in Anhui(2016YFD0200806)~~
文摘With validamycin A.（0.2 billion spores/ml） Paenibacillus polymyxa DN-1 3% AS as the test agent, the effects of different dosage and different application time on the control efficacy for＇ rich sheath blight were investigated. The results of two- year test showed that when the application amount was in the range of 45-90 g.a.i/ hm^2, the field efficacy of validamycin A-（0.2 billion spores/ml） P. polymyxa DN-1 3% AS in the initial infection stage of rich sheath blight （Le., the diseased plant rate was below 5%） reached 80.38%-89.06%, and that in the peak infection stage （i.e., the diseased plant rate was higher than 10%） reached only 41.12%-53.26%. The field efficacy of validamycin A.（0.2 billion spores/ml） P. polymyxa DN-1 3% AS at the early onset of rich sheath blight was significantly better than that at the onset, so that the application time of validamycin A .（0.2 billion spores/ml） P. polymyxa DN-1 3% AS should be appropriately brought forward in the prevention and control of rice sheath blight.
基金Supported by the Natural Science Foundation of Zhejiang Province (No. ZB0106)the National Natural Science Foundation of China (No. 20176055).
文摘Fermentation experiments to produce validamycins from crude substrates by Streptomyces hygroscopicus were carried out in an external-loop airlift bioreactor (0.0115 m^3 ) with a low ratio of height to diameter of the riser of 2.9 and a ratio of riser to downcomer diameter of 6.6. The influences of gas flow rate and liquid volume on fermentation of validamycins were investigated. Comparisons of validamycin fermentation were made among the external-loop airlift bioreactor, a mechanically stirred tank bioreactor (0.010m^3 ) and shaking flasks. Under the same operation conditions including fermentation medium composition, inoculum ratio and culture temperature, the fermentation time in the external-loop airlift bioreactor (45 h) was shorter than that in the shaking flasks (100 h) and the same as that in the mechanically stirred tank bioreactor. After a total fermentation time of 45 h under optimized operation conditions, average validamycin concentration obtained in the external-loop airlift bioreactor was close to 19630 μg·ml^-1 validamycin concentration in the mechanically stirred tank bioreactor. It was demonstrated that the external-loop airlift bioreactor could substitute for the mechanically stirred tank bioreactor in production of validamycins from crude substrates with dregs by Streptomyces hygroscopicus.
文摘[Objective] The paper was to explore the effective agent against seedling blight of Atractylodes macrocephala. [Method] The control effects of 60% validamycin A SP against seeding blight of A. macrocephala were studied in the field, and compared with that of control agent 20% bismerthiazol WP. [Result] At 14 d post the third spraying, the control effect of 60% validamycin A SP at the dose of 495-540 g/hm;was 76.9%,which was equivalent to that of control agent 20% bismerthiazol WP sprayed at the dose of 270 g/hm;（76.7%）. [Conclusion] 60% Validamycin A SP could be used as the ideal agent against seedling blight of A. macrocephala, with good prospects of application and popularization.
文摘[Objective] The paper was to understand the control efficacy and the optimal dosage of 16% validamycin？thifluzamide SC on controlling Selerotium rolfsii in Dendrobium officinale Kimura et Migo. [Method] The control efficacy of 16% validamycin·thifluzamide SC against S.rolfsii was determined by spraying agents on the whole plant of D.officinale. The significance of differences was analyzed by Duncan＇s new multiple range test （DMRT）. [Result] The control efficacy of 16% validamycin.thifluzamide SC sprayed at the doses of 80-160 mg a.i./kg was 85.33% at 14 d post spraying, higher than that of control agent 4% validamycin AS sprayed at the dose of 80 mg a.i./kg （78.36%）, and equivalent to that of control agent 240 g/L thifluzamide SC sprayed at the dose of 120 mg a.i./kg （90.60%）. [Conclusion] 16% Validamycin·thifluzamide SC sprayed at the doses of 80-160 mg a.i./kg could effectively control the damage of S.rolfsii in D.officinale, and could be popularized in the production.
基金The work was supported by the Natural Science Foundation of Jiangxi Province(20202BAB215004)the Major Science and technology R&D Program of Jiangxi Province(20194ABC28007)+1 种基金the Educational Commission of Jiangxi Province of China(GJJ180747 and GJJ190759)Jiangxi Agriculture System(JXARS-07).
文摘Validamycin,as a broadly applied antibiotic,has been used to control rice sheath blight disease.Furthermore,validamycin was considered as an insecticide to control agricultural pests.Insight into the mechanism of validamycin’s action on insects can provide molecular targets for the control of agricultural pests.In this study,a toxicological test analysis revealed that Spodoptera litura larval growth and development was significantly inhibited and the pupation rate was significantly reduced with the increase of the concentration of validamycin.According to the NMR-based metabolomic analysis,a total of 15 metabolites involved in glycolysis and tricarboxylic acid cycle(TCA)pathways were identified.Additionally,trehalase activities,glucose and chitin contents were significantly downregulated,but the trehalose content was upregulated after exposure to validamycin.Reverse transcription quantitative PCR analysis revealed that the expression level of genes involved in glycolysis,TCA and chitin synthesis were upregulated after treating with validamycin.Further chitin staining also confirmed that chitin content was downregulated at 12 h after validamycin treatment.Our results indicated that validamycin worked via two different molecular mechanisms,one through inhibiting glycometabolism and the other by inhibiting chitin synthesis in S.litura.The information lays a theoretical foundation for further control of S.litura.
基金supported by the Natural Science Foundation of Jiangxi Province(20202BAB215004)the National Natural Science Foundation of China(31960116)+5 种基金the Educational Commission of Jiangxi Province of China(GJJ180747)Key Research and Development Plan of Jiangxi Province(20192BBF60057,2017ZDD02005)Ministry of Science and Technology of China(2018YFD0201504)the earmarked fund for Jiangxi Agriculture Research System(JXARS-07)Gan-nan Normal University-level bidding project(20162B08)Graduate student innovation Fund Project(YC2019-S392).
文摘Validamycin has been widely used as a specific competitive inhibitor of tre-halase.In our previous research,validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri,resulting in abnormal phenotypes.However,the mechanism of validamycin's action on D.citri remains unclear.Here,using a comparative transcriptome analysis,464 differentially expressed genes(DEGs)in D.citri were identified after validamycin treatment.A Gene Ontology enrichment analysis revealed that these DEGs were mainly involved in“small molecule process”,“structural molecule ac-tivity”and“transition metal ion binding”.DEGs involved in chitin metabolism,cuticle synthesis and insecticide detoxification were validated by reverse transcription quantitative polymerase chain reaction.The RNA interference of D.citri chitinase-like protein EN03 and D.citri cuticle protein 7 genes significantly affected D.citri molting.Moreover,the recombinant chitinase-like protein EN03 exhibited a chitin-binding property,and an antimicrobial activity against Bacillus subtilis.This study provides a first insight into the molecular changes in D.citri after exposure to validamycin and identifies two effective RNA interference targets for D.citri control.
基金Supported by National Key Basic Research and Development Program of China (Grant No. 2003CB114205)National High Technology Research and Development Program of China (Grant No. 2006AA02Z185)+1 种基金the National Natural Science Foundation of China (Grant No. 30570019)the Shanghai Municipal Council of Science and Technology, and Shanghai Leading Academic Discipline Project B203
文摘Cultivation shift from 30℃ to 37℃ significantly enhanced validamycin (VAL) production. Analyzed by reverse-transcription PCR, the transcription of three val genes, valA, valK and valG, representing the three operons of the cluster was simultaneously increased at elevated temperature. Furthermore, the transcription of valP and valQ, a pair of two-component regulators in validamycin biosynthetic gene cluster, was also increased at 37℃. Inactivation of valP and valQ reduced validamycin production at 37℃ to the yield level of wild type strain at 30℃, and the val genes showed reduced expression in the mutant LL-8 at 37℃. These results revealed that the two-component regulator valP and valQ contribute to the elevated validamycin production.
