[ Objective ] The study aimed to explore the release conditions for the conidia of Botryosphaena berengeriana and understand the release dynamic of conidia. [Method] The systematical survey on the release conditions f...[ Objective ] The study aimed to explore the release conditions for the conidia of Botryosphaena berengeriana and understand the release dynamic of conidia. [Method] The systematical survey on the release conditions for the conidia of B. berengeriana were conducted in two growing seasons in 2008 and 2009, combined with the collection of meteorological data around conidia release period, the weather conditions causing large amount release of B. berengedana were analyzed. [ Result] During a growing season, the conidia of pathogen appeared several large release peaks. Under the suitable temperature, when the precipitation lasted for 4 h, the conidia of B. berengeriana began to release with large amount, the amount of conidia reached the peak after release and trended to be stable during 4 - 12 h, which significantly reduced after 24 h, tended to dis- appear after 36 h, and completely disappeared after 72 h. [Conclusion] The dominant factor affecting B. berengeriana conidia release in large a- mount was precipitation, while the lasting time of precipitation played a decisive role.展开更多
Tremellafuciformis is one of higher basidiomycetes. Its basidiospore can reproduce yeast-like conidia, which is also called the blastospore by budding. The yeast-like conidia of T. fuciformis is monokaryotic and easy ...Tremellafuciformis is one of higher basidiomycetes. Its basidiospore can reproduce yeast-like conidia, which is also called the blastospore by budding. The yeast-like conidia of T. fuciformis is monokaryotic and easy to culture by submerged fermentation similar to yeast. Thus, it is a good recipient cell for exogenous gene expression. In this study, the expression plasmid pAN7-1 （containing promoter gpd-An derived from Aspergillus nidulans and selectable marker gene hph conferring resistance to hygromycin B） and plasmid pLg-hph （containing promoter gpd-Le derived from Lentinula edodes and selectable marker gene hph） were transformed into the yeast-like conidia of T. fuciformis by PEG-mediated protoplast transformation, respectively. The primary putative transformants were selected by the sandwich screening method with the selective medium containing 50 μg mL^-1 hygromycin. The putative transformants were obtained from the primary putative transformants transferred on PDSA plates containing 100 μg mL^-1 hygromycin for second round selection. Experimental results showed that the optimal concentration of PEG 4000 for mediating protoplast transformation was 25%. PCR and Southern blotting confirmed that the selectable marker gene hph was integrated effectively into the genome of the yeast-like conidia of T. fuciformis with plasmid pLg-hph transformation. Its transformation efficiency was 110 transformants per μg DNA, and the hph gene was integrated into the genome of some yeast-like conidia with plasmid pAN7-1 transformation. However, its transformation efficiency was only 9 transformants per μg DNA. The presence of hph gene in the genome of transformants after 5 generations of sub- culturing on PDSB medium was confirmed by PCR, suggesting that the foreign gene hph was stable during subculture.展开更多
Fusarium is usually thought to cause soybean root rot, which results in a large quantity of annual yield loss in soybean production, by its secretions including Fusarium toxins and cell wall degrading enzymes, but not...Fusarium is usually thought to cause soybean root rot, which results in a large quantity of annual yield loss in soybean production, by its secretions including Fusarium toxins and cell wall degrading enzymes, but not by the conidia themselves that do not underlie any virulence so far. Here we report that the conidia of one Fusarium solani isolate are able to be virulent to soybean and make soybean seedlings wilted alone. We isolated them from the wilted plants in a soybean-production field and molecularly identified 17 Fusarium isolates through phylogenetic analysis. Of them, except for one isolate that showed diversity of virulence to different soybeans （virulent to one soybean whereas avirulent to another soybean）, the others were all virulent to the two tested soybeans： both conidia cultures and secretions could make soybean seedlings wilted at 5 days post infection, and their virulence had dosage effects that only conidia cultures of at least 5×10^6 conidia mL-1 could show virulence to soybean; however, the sole conidia of the F. solani isolate #4 also exhibited virulence to soybean and could make soybean seedlings wilted. Finally, we developed the specific cleaved amplified polymorphic sequences （CAPS） markers to easily differentiate Fusarium isolates. The isolate #4 in this work will likely be used to investigate the new mechanism of virulence of Fusarium to soybean.展开更多
The single spores were isolated from chlamydospores of Ustilaginoidea virens with three different maturities by PSA. The isolated single spores were cul- tured on different media at different temperatures under natura...The single spores were isolated from chlamydospores of Ustilaginoidea virens with three different maturities by PSA. The isolated single spores were cul- tured on different media at different temperatures under natural light for inducing conidia to explore the optimum isolation technique of single spore and optimum cul- ture condition of conidia. The results showed that the successful isolating rate of single spore from yellow rice false smut balls reached 90.00%. The sporulatina quantities of isolated single spores cultured on PSD and PDB media at 22 -29 ~C （variable temperature under natural light） or 28 ℃ （constant temperature under dark condition） for 12 d were up to 6.3× 107 and 1.1× 106 spore/mL, respectively. PSA was the most effective method to isolate single spores from yellow rice false smut balls of U. virens. The optimum conidia culture condition included PSD or PDB medium, 22 -29℃ or 28℃, natural light and vibration culture. Key words Ustilaginoidea virens; Single spore isolation; Conidia; Culture condition展开更多
[Objective] This study aimed to find methods suitable for the preservation and conidia production of Ustilaginoidea virens. [Method] Six different preservation methods were tested by checking at three month interval f...[Objective] This study aimed to find methods suitable for the preservation and conidia production of Ustilaginoidea virens. [Method] Six different preservation methods were tested by checking at three month interval for the viability and sporulation, and seven liquid media of different composition were tested by shaking cul- ture at 150 r/min. [Result] Among the six methods studied, the periodic transfer and paraffin oil overlay were suitable, and the fungus could survive more than 12 months. The conidia concentration went up to 7.25×10^7 conidia/ml after 9 d in the PSB liquid medium, indicating that PSB was the best medium for conidia production. [Conclusion] This study provides a theoretical basis for the preservation and conidia production of U. virens.展开更多
Background The efficacies of current treatments for invasive aspergillus （IA） are unsatisfactory and new therapeutic targets or regimens to treat IA are urgently needed. Previous studies have indicated that the abil...Background The efficacies of current treatments for invasive aspergillus （IA） are unsatisfactory and new therapeutic targets or regimens to treat IA are urgently needed. Previous studies have indicated that the ability of conidia to invade host cells is critical in IA development and fibronectin has a hand in the conidia adherence process. In the clinical setting, many patients who receive glucocorticoid for extended periods are susceptible to Aspergillus fumigatus （A. fumigatus） infection, for this reason we investigated the effect of glucocorticoid on conidia invasiveness by comparing the invasiveness of A. fumigatus conidia in the type II human alveolar cell line （A549） cultured with different concentrations of dexamethasone. We also explored the relationships between dexamethasone and fibronectin expression. Methods Following culture with anti-fibronectin antibodies and/or dexamethasone, type II human alveolar A549 cells were infected with conidia of A. fumigatus. After 4 hours, the extracellular free conidia were washed away and the remaining immobilized conidia were released using Triton-X 100 and quantified by counting the colony-forming units. The invasiveness of conidia was measured by calculating the invasion rate （%）. The transcription of the fibronectin gene in cells cultured with different concentrations of dexamethasone for 24 hours was tested by fluorogenic quantitative RT-PCR while the expression of fibronectinin cells cultured for 48 hours was tested by Western blotting and immunocytochemistry. Results A significant reduction in the invasiveness of conidia was seen in the cells cultured with anti-fibronectin antibody （（14.42±1.68）% vs. （19.17±2.53）%, P 〈0.05）, but no significant difference was observed in cells cultured with a combination of anti-fibronectin antibody and dexamethasone （6.37×10^-5 mol/L）. There was no correlation between the dexamethasone concentration and the invasiveness of conidia after dexamethasone pretreatment of cells for 4 hours. In contrast, after pretreated for 24 hours, the invasiveness of conidia in the presence of 6.37×10^-5 mol/L dexamethasone （（24.66±2.41）%） was higher than for the control （（19.17±2.53）%） and the 0.25×10^-5 mol/L group （（19.93±3.06）%）, and the invasiveness in the 1.27×10^-5 mol/L group （（22.47±2.46）%） was also higher than in the control, P 〈0.05. The relative transcripts of the fibronectin gene after exposure to 6.37× 10^-5 mol/L dexamethasone （9.19×10^-3±1.2×10^-3） was higher than for the control （4.61 ± 10^-3±1.54× 10^-3） and the 0.25× 10^-5 mol/L group （6.20× 10^-3±1.93× 10^-3）, and expression in the 1.27× 10^-5 mol/L group （7.94× 10^-3±2.24×10^3） was also higher than for the control, P 〈0.05. High concentrations of dexamethasone promoted fibronectin production after culture for 48 hours. Conclusions Dexamethasone can increase invasiveness of A. fumigatus conidia by promoting fibronectin expression. This may partially explain why patients who are given large doses of glucocorticoids for extended periods are more susceptible to A. fumigatus infection.展开更多
Trichophyton rubrum is a dominating superficial dermatophyte, whose conidial germination is corre- lated to pathopoiesis and a highly important developmental process. To investigate the changes of physiology, biochemi...Trichophyton rubrum is a dominating superficial dermatophyte, whose conidial germination is corre- lated to pathopoiesis and a highly important developmental process. To investigate the changes of physiology, biochemistry and cytology during the germination, we selected 3364 function identified ESTs from T. rubrum cDNA library to construct cDNA microarrays, and compared the gene expression levels of conidia and germinating phase. Data analysis indicated that 335 genes were up-regulated during the germination, which mainly encoded translated, modified proteins and structural proteins. The constituents of cell wall and cell membrane were synthetized abundantly, suggesting that they are the foundation of cell morphogenesis. The ingredients of the two-component signal transduction sys- tem were up-regulated, presuming that they were important for the conidial germination. Genes of various metabolic pathways were expressed prosperously, especially the genes that participated in glycolysis and oxidative phosphorylation were up-regulated on the whole, demonstrating that in the environment with sufficient oxygen and glucose, conidia obtained energy through aerobic respiration. This paper provides important clues which are helpful to understanding the changes in gene expres- sion, signal conduction and metabolism characteristics during T. rubrum conidial germination, and possess significant meaning to the study of other superficial dermatophytes.展开更多
[ Objective ] The study systematically studied the biological characteristics of ginseng Botrytis cinerea Pers. [ Method ] The pure pathogenic fungus was isolated from ginseng B. cinerea collected in the field by tiss...[ Objective ] The study systematically studied the biological characteristics of ginseng Botrytis cinerea Pers. [ Method ] The pure pathogenic fungus was isolated from ginseng B. cinerea collected in the field by tissue segregation and purification cultivation. Subsequently, using PDA medium plate culture method, the effect of various culture conditions on mycelium growth and sporulation of ginseng B. cinerea was detected. [ Result] The optimum temperature for mycelium growth and sporulation of B. cinerea was 25 ℃. The appropriate temperature for conidia germination ranged from 20 to 25 ℃. And the optimum pH value for mycelium growth and conidia germination was 6.0. The optimum carbon source was sucrose, followed by glucose and fructose. The optimum nitrogen source was peptone, fol- lowed by beef extract, yeast extract, alanine and ammonium nitrate. Among the media, the growth of mycelium cultured on PDA medium was the fastest with the production of gray mycelium and dense colonies. Lethal temperatures for sclerotia, mycelium and conidia were 60, 55 and 50 ℃, respectively. [ Conclusion] The study provided the scientific basis for the research on the incidence law of B. cinerea and its control.展开更多
The inhibitory effects of 10 fungicides on apple tree valsa canker were compared on dishes and twigs.The results showed that conidia germination and mycelial growth were inhibited by all fungicedes tested.The EC50 val...The inhibitory effects of 10 fungicides on apple tree valsa canker were compared on dishes and twigs.The results showed that conidia germination and mycelial growth were inhibited by all fungicedes tested.The EC50 value of Difenoconazole was 6.1×10-3 μg·mL-1,the lowest among tested fungicide in inhi-biting conidia germination.Tebuconazole and Imazalil also showed obvious inhibition effect.Thiophanate-methyl was the least efficient with the EC50 value 2.6×101 μg·mL-1.Difenoconazole also showed the highest activity for inhibiting mycelial growth with EC50 value of2.3×10-2 μg·mL-1.Tebuconazole was better than other fungicide.Thiophanate-methyl and Propineb were the least efficient with quite high EC50 value.Furthermore,the size of the lesion after inoculation on excised twigs also revealed that Difenoconazole was most efficient because it showed the smallest lesion of 394 mm2 compared with other tested fungicides.So Difenoconazole and Tebuconazole could be used to control apple tree valsa canker in field to subsititute forbided fungicides such as asomate.展开更多
In order to get a great quantity of spores of Botryosphaeria berengeriana f.sp.piricola,several methods to promote sporulation of the pathogen were compared.The results showed that the wounded young apple fruits withi...In order to get a great quantity of spores of Botryosphaeria berengeriana f.sp.piricola,several methods to promote sporulation of the pathogen were compared.The results showed that the wounded young apple fruits within 60-day old was inoculated with mycelia of B.berengeriana f.sp.piricola and induced under the 365 nm-UV-light;when the brown lesion was shown,the young apple began to form pycnidia on the lesion around the inoculation point after 3-5 days irradiation with UV-light and extruded plenty of conidia.This method induced great more conidia than that of irradiating wounded mycelia with UV-light.However,mature apple seldom produced conidia when induced with the same method.展开更多
基金Supported by State Apple Industry Technology System Project(nybcytx-08-04-01)~~
文摘[ Objective ] The study aimed to explore the release conditions for the conidia of Botryosphaena berengeriana and understand the release dynamic of conidia. [Method] The systematical survey on the release conditions for the conidia of B. berengeriana were conducted in two growing seasons in 2008 and 2009, combined with the collection of meteorological data around conidia release period, the weather conditions causing large amount release of B. berengedana were analyzed. [ Result] During a growing season, the conidia of pathogen appeared several large release peaks. Under the suitable temperature, when the precipitation lasted for 4 h, the conidia of B. berengeriana began to release with large amount, the amount of conidia reached the peak after release and trended to be stable during 4 - 12 h, which significantly reduced after 24 h, tended to dis- appear after 36 h, and completely disappeared after 72 h. [Conclusion] The dominant factor affecting B. berengeriana conidia release in large a- mount was precipitation, while the lasting time of precipitation played a decisive role.
基金funded by the National Hi-Tech Research and Development Program of China (863 Program,2006AA10Z301)the National Natural Science Foundation of China (30371000, 30671457)
文摘Tremellafuciformis is one of higher basidiomycetes. Its basidiospore can reproduce yeast-like conidia, which is also called the blastospore by budding. The yeast-like conidia of T. fuciformis is monokaryotic and easy to culture by submerged fermentation similar to yeast. Thus, it is a good recipient cell for exogenous gene expression. In this study, the expression plasmid pAN7-1 （containing promoter gpd-An derived from Aspergillus nidulans and selectable marker gene hph conferring resistance to hygromycin B） and plasmid pLg-hph （containing promoter gpd-Le derived from Lentinula edodes and selectable marker gene hph） were transformed into the yeast-like conidia of T. fuciformis by PEG-mediated protoplast transformation, respectively. The primary putative transformants were selected by the sandwich screening method with the selective medium containing 50 μg mL^-1 hygromycin. The putative transformants were obtained from the primary putative transformants transferred on PDSA plates containing 100 μg mL^-1 hygromycin for second round selection. Experimental results showed that the optimal concentration of PEG 4000 for mediating protoplast transformation was 25%. PCR and Southern blotting confirmed that the selectable marker gene hph was integrated effectively into the genome of the yeast-like conidia of T. fuciformis with plasmid pLg-hph transformation. Its transformation efficiency was 110 transformants per μg DNA, and the hph gene was integrated into the genome of some yeast-like conidia with plasmid pAN7-1 transformation. However, its transformation efficiency was only 9 transformants per μg DNA. The presence of hph gene in the genome of transformants after 5 generations of sub- culturing on PDSB medium was confirmed by PCR, suggesting that the foreign gene hph was stable during subculture.
基金financially supported by the Innovation Program and Youth Elite Program of Chinese Academy of Agricultural Sciences
文摘Fusarium is usually thought to cause soybean root rot, which results in a large quantity of annual yield loss in soybean production, by its secretions including Fusarium toxins and cell wall degrading enzymes, but not by the conidia themselves that do not underlie any virulence so far. Here we report that the conidia of one Fusarium solani isolate are able to be virulent to soybean and make soybean seedlings wilted alone. We isolated them from the wilted plants in a soybean-production field and molecularly identified 17 Fusarium isolates through phylogenetic analysis. Of them, except for one isolate that showed diversity of virulence to different soybeans （virulent to one soybean whereas avirulent to another soybean）, the others were all virulent to the two tested soybeans： both conidia cultures and secretions could make soybean seedlings wilted at 5 days post infection, and their virulence had dosage effects that only conidia cultures of at least 5×10^6 conidia mL-1 could show virulence to soybean; however, the sole conidia of the F. solani isolate #4 also exhibited virulence to soybean and could make soybean seedlings wilted. Finally, we developed the specific cleaved amplified polymorphic sequences （CAPS） markers to easily differentiate Fusarium isolates. The isolate #4 in this work will likely be used to investigate the new mechanism of virulence of Fusarium to soybean.
基金Science and Technology Project of Guizhou Province[QKH Major Project( 2012 ) 6012 ]Supported by Science and Technology Fund of Guizhou Province ( QKH J[2009]2103)+1 种基金Science and Technology Research Programof Guizhou Province ( QKH NY[2012]3031)Project of Guizhou Academy of Agricultural Sciences ( [2010]033 and QNKH[Major]07016)
文摘The single spores were isolated from chlamydospores of Ustilaginoidea virens with three different maturities by PSA. The isolated single spores were cul- tured on different media at different temperatures under natural light for inducing conidia to explore the optimum isolation technique of single spore and optimum cul- ture condition of conidia. The results showed that the successful isolating rate of single spore from yellow rice false smut balls reached 90.00%. The sporulatina quantities of isolated single spores cultured on PSD and PDB media at 22 -29 ~C （variable temperature under natural light） or 28 ℃ （constant temperature under dark condition） for 12 d were up to 6.3× 107 and 1.1× 106 spore/mL, respectively. PSA was the most effective method to isolate single spores from yellow rice false smut balls of U. virens. The optimum conidia culture condition included PSD or PDB medium, 22 -29℃ or 28℃, natural light and vibration culture. Key words Ustilaginoidea virens; Single spore isolation; Conidia; Culture condition
基金Supported by the Programs of Guizhou Academy of Agricultural Sciences in China [No. QianNongKeYuan(2010) 033 and No.QianNongKeHe 07016]the Programs of Science and Technology Department of Guizhou Province [No.QianKeHe J(2009) 2103,and No.QianKeHe NY(2012) 3031]Science and Technology Project of Guizhou Province [QKH Major Project(2012) 6012]~~
文摘[Objective] This study aimed to find methods suitable for the preservation and conidia production of Ustilaginoidea virens. [Method] Six different preservation methods were tested by checking at three month interval for the viability and sporulation, and seven liquid media of different composition were tested by shaking cul- ture at 150 r/min. [Result] Among the six methods studied, the periodic transfer and paraffin oil overlay were suitable, and the fungus could survive more than 12 months. The conidia concentration went up to 7.25×10^7 conidia/ml after 9 d in the PSB liquid medium, indicating that PSB was the best medium for conidia production. [Conclusion] This study provides a theoretical basis for the preservation and conidia production of U. virens.
文摘Background The efficacies of current treatments for invasive aspergillus （IA） are unsatisfactory and new therapeutic targets or regimens to treat IA are urgently needed. Previous studies have indicated that the ability of conidia to invade host cells is critical in IA development and fibronectin has a hand in the conidia adherence process. In the clinical setting, many patients who receive glucocorticoid for extended periods are susceptible to Aspergillus fumigatus （A. fumigatus） infection, for this reason we investigated the effect of glucocorticoid on conidia invasiveness by comparing the invasiveness of A. fumigatus conidia in the type II human alveolar cell line （A549） cultured with different concentrations of dexamethasone. We also explored the relationships between dexamethasone and fibronectin expression. Methods Following culture with anti-fibronectin antibodies and/or dexamethasone, type II human alveolar A549 cells were infected with conidia of A. fumigatus. After 4 hours, the extracellular free conidia were washed away and the remaining immobilized conidia were released using Triton-X 100 and quantified by counting the colony-forming units. The invasiveness of conidia was measured by calculating the invasion rate （%）. The transcription of the fibronectin gene in cells cultured with different concentrations of dexamethasone for 24 hours was tested by fluorogenic quantitative RT-PCR while the expression of fibronectinin cells cultured for 48 hours was tested by Western blotting and immunocytochemistry. Results A significant reduction in the invasiveness of conidia was seen in the cells cultured with anti-fibronectin antibody （（14.42±1.68）% vs. （19.17±2.53）%, P 〈0.05）, but no significant difference was observed in cells cultured with a combination of anti-fibronectin antibody and dexamethasone （6.37×10^-5 mol/L）. There was no correlation between the dexamethasone concentration and the invasiveness of conidia after dexamethasone pretreatment of cells for 4 hours. In contrast, after pretreated for 24 hours, the invasiveness of conidia in the presence of 6.37×10^-5 mol/L dexamethasone （（24.66±2.41）%） was higher than for the control （（19.17±2.53）%） and the 0.25×10^-5 mol/L group （（19.93±3.06）%）, and the invasiveness in the 1.27×10^-5 mol/L group （（22.47±2.46）%） was also higher than in the control, P 〈0.05. The relative transcripts of the fibronectin gene after exposure to 6.37× 10^-5 mol/L dexamethasone （9.19×10^-3±1.2×10^-3） was higher than for the control （4.61 ± 10^-3±1.54× 10^-3） and the 0.25× 10^-5 mol/L group （6.20× 10^-3±1.93× 10^-3）, and expression in the 1.27× 10^-5 mol/L group （7.94× 10^-3±2.24×10^3） was also higher than for the control, P 〈0.05. High concentrations of dexamethasone promoted fibronectin production after culture for 48 hours. Conclusions Dexamethasone can increase invasiveness of A. fumigatus conidia by promoting fibronectin expression. This may partially explain why patients who are given large doses of glucocorticoids for extended periods are more susceptible to A. fumigatus infection.
基金the National High Technology Research and Development Program of China (Grant No. 2001AA223021) National Key Technologies R&D Programme (Grant No. 2002BA711A14)
文摘Trichophyton rubrum is a dominating superficial dermatophyte, whose conidial germination is corre- lated to pathopoiesis and a highly important developmental process. To investigate the changes of physiology, biochemistry and cytology during the germination, we selected 3364 function identified ESTs from T. rubrum cDNA library to construct cDNA microarrays, and compared the gene expression levels of conidia and germinating phase. Data analysis indicated that 335 genes were up-regulated during the germination, which mainly encoded translated, modified proteins and structural proteins. The constituents of cell wall and cell membrane were synthetized abundantly, suggesting that they are the foundation of cell morphogenesis. The ingredients of the two-component signal transduction sys- tem were up-regulated, presuming that they were important for the conidial germination. Genes of various metabolic pathways were expressed prosperously, especially the genes that participated in glycolysis and oxidative phosphorylation were up-regulated on the whole, demonstrating that in the environment with sufficient oxygen and glucose, conidia obtained energy through aerobic respiration. This paper provides important clues which are helpful to understanding the changes in gene expres- sion, signal conduction and metabolism characteristics during T. rubrum conidial germination, and possess significant meaning to the study of other superficial dermatophytes.
基金Supported by State Foreign Experts Bureau Projects(SFEBPS2005#0023)Technology Development Plan Project in Yanbian University(200802)~~
文摘[ Objective ] The study systematically studied the biological characteristics of ginseng Botrytis cinerea Pers. [ Method ] The pure pathogenic fungus was isolated from ginseng B. cinerea collected in the field by tissue segregation and purification cultivation. Subsequently, using PDA medium plate culture method, the effect of various culture conditions on mycelium growth and sporulation of ginseng B. cinerea was detected. [ Result] The optimum temperature for mycelium growth and sporulation of B. cinerea was 25 ℃. The appropriate temperature for conidia germination ranged from 20 to 25 ℃. And the optimum pH value for mycelium growth and conidia germination was 6.0. The optimum carbon source was sucrose, followed by glucose and fructose. The optimum nitrogen source was peptone, fol- lowed by beef extract, yeast extract, alanine and ammonium nitrate. Among the media, the growth of mycelium cultured on PDA medium was the fastest with the production of gray mycelium and dense colonies. Lethal temperatures for sclerotia, mycelium and conidia were 60, 55 and 50 ℃, respectively. [ Conclusion] The study provided the scientific basis for the research on the incidence law of B. cinerea and its control.
文摘The inhibitory effects of 10 fungicides on apple tree valsa canker were compared on dishes and twigs.The results showed that conidia germination and mycelial growth were inhibited by all fungicedes tested.The EC50 value of Difenoconazole was 6.1×10-3 μg·mL-1,the lowest among tested fungicide in inhi-biting conidia germination.Tebuconazole and Imazalil also showed obvious inhibition effect.Thiophanate-methyl was the least efficient with the EC50 value 2.6×101 μg·mL-1.Difenoconazole also showed the highest activity for inhibiting mycelial growth with EC50 value of2.3×10-2 μg·mL-1.Tebuconazole was better than other fungicide.Thiophanate-methyl and Propineb were the least efficient with quite high EC50 value.Furthermore,the size of the lesion after inoculation on excised twigs also revealed that Difenoconazole was most efficient because it showed the smallest lesion of 394 mm2 compared with other tested fungicides.So Difenoconazole and Tebuconazole could be used to control apple tree valsa canker in field to subsititute forbided fungicides such as asomate.
文摘In order to get a great quantity of spores of Botryosphaeria berengeriana f.sp.piricola,several methods to promote sporulation of the pathogen were compared.The results showed that the wounded young apple fruits within 60-day old was inoculated with mycelia of B.berengeriana f.sp.piricola and induced under the 365 nm-UV-light;when the brown lesion was shown,the young apple began to form pycnidia on the lesion around the inoculation point after 3-5 days irradiation with UV-light and extruded plenty of conidia.This method induced great more conidia than that of irradiating wounded mycelia with UV-light.However,mature apple seldom produced conidia when induced with the same method.
