Objective: To isolate endophytic fungi from Elaeocarpus sylvestris(E. sylvestris) and to isolate antioxidant compounds from a potential source fungus.Methods: Endophytic fungi were isolated from fresh leaves and stems...Objective: To isolate endophytic fungi from Elaeocarpus sylvestris(E. sylvestris) and to isolate antioxidant compounds from a potential source fungus.Methods: Endophytic fungi were isolated from fresh leaves and stems of E. sylvestris and identified based on DNA analysis. 1,1-Diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activity was used to evaluate the antioxidant activity of the fungi. The potential antioxidant fungus was further studied to isolate antioxidant compounds. The isolated compounds were identified by melting point analysis, optical rotation, spectral analysis using a UV spectrophotometer, high resolution fast atom bombardment mass spectrometry, X-ray crystallography analysis,~1H nuclear magnetic resonance analysis and ^(13)C nuclear magnetic resonance analysis. The isolated compounds were evaluated with DPPH radical scavenging, reducing power, and b-carotene bleaching assays.Results: Seven endophytic fungi were successfully isolated from E. sylvestris and identified as Pestalotiopsis sp. EST 01, Pestalotiopsis sp. EST 02, Diaporthales sp. EST03, Meyerozyma sp. EST 04, Diaporthales sp. EST 05, Pestalotiopsis sp. ESL 01, and Pseudocercospora sp. ESL 02. Of the seven fungi, Pseudocercospora sp. ESL 02 had the highest antioxidant activity [IC50=(30.54 ± 0.88) mg/mL]. From that fungus, two compounds identified as terreic acid(1) and 6-methylsalicylic acid(2) were isolated with an IC50 of DPPH radical scavenging activity of(0.22 ± 0.02) mmol/L and(3.87 ± 0.27)mmol/L, respectively. The compounds also had good activities from the reducing power and b-carotene bleaching assays.Conclusions: The Pseudocercospora sp. ESL 02 fungus isolated from E. sylvestris looks promising as a novel source of terreic acid.展开更多
An investigation to assess the spatial structure and severity of Pseudocercospora leaf and fruit spot disease (PLFSD) on citrus trees in cocoa-based agroforests was carried out in three contrasting ecological zones in...An investigation to assess the spatial structure and severity of Pseudocercospora leaf and fruit spot disease (PLFSD) on citrus trees in cocoa-based agroforests was carried out in three contrasting ecological zones in southern Cameroon, viz: 1) the humid forest zone, 2) the degraded forest zone, and 3) the forest-savannah transition zone. Two main parameters were investigated viz: 1) the spatial structure of cocoa based agroforests, and 2) the disease severity. In total, the spatial structure of 19 cocoa-based agroforests was analysed using the Ripley K(r) function, meanwhile the collection of epidemiological data that consisted of noting the presence of PLFSD spots on leaves and fruits on 438 citrus trees was used to characterise the severity of the disease. Results showed that, the spatial structure of citrus trees in these agroforests investigated were regular in seven plots, random in nine, and aggregated in three. Aggregated plots presented a significantly higher mean of disease severity on leaves and fruits (28.55 and 30.37 respectively), as compared to randomised (20.91 and 16.32 respectively) and regular plots (16.28 and 14.97 respectively), at P-value < 0.05. These results suggest that the spatial structure of citrus trees in the cocoa-based agroforests studied influences the severity of PFLSD. Proper integrated control measures can therefore be initiated, leading to a considerable reduction of the use of manufactured inputs, and thereby, the cost of production of citrus fruits.展开更多
In the search for new alternatives to control tropical fungal pathogens,the ethanol extracts(EEs)from Acalypha gaumeri(Euphorbiaceae)roots showed antifungal properties against several tropical fungal phytopathogens.A....In the search for new alternatives to control tropical fungal pathogens,the ethanol extracts(EEs)from Acalypha gaumeri(Euphorbiaceae)roots showed antifungal properties against several tropical fungal phytopathogens.A.gaumeri is classified as endemic to the Yucatan Peninsula,Mexico,an area with distinct rainy,drought and northern seasons.The present study evaluated the antifungal activity of threewild populations of A.gaumeri collected quarterly in different seasons during one year against Alternaria chrysanthemi,Colletotrichumgloeosporioides,andPseudocercospora fijiensis and explored their ex-situ propagation.The highest activity was shown by the EE from the Tinum wild population during the rainy season against A.chrysanthemi,C.gloeosporioides,and P.fijiensis with MIC values of 500–1000μg/mL,followed by Yaxcaba populations during the rainy season and Kiuic and Tinum from November against A.chrysanthemi and P.fijiensis 1000 and 500μg/mL,respectively.The propagation of A.gaumeri was more effective throughmediumcuttings,showing 96%with 0.06%auxin indolbutyric acid,whereas only 51%of seeds germinated.The results indicated that seasonal changes and edaphic conditions in the three populations influence the antifungal efficacy of the extracts from A.gaumeri roots.This study enhances the knowledge of the biology and sustainable management of the A.gaumeri plant and advances the development of a biorational product to control tropical fungal diseases.展开更多
文摘Objective: To isolate endophytic fungi from Elaeocarpus sylvestris(E. sylvestris) and to isolate antioxidant compounds from a potential source fungus.Methods: Endophytic fungi were isolated from fresh leaves and stems of E. sylvestris and identified based on DNA analysis. 1,1-Diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activity was used to evaluate the antioxidant activity of the fungi. The potential antioxidant fungus was further studied to isolate antioxidant compounds. The isolated compounds were identified by melting point analysis, optical rotation, spectral analysis using a UV spectrophotometer, high resolution fast atom bombardment mass spectrometry, X-ray crystallography analysis,~1H nuclear magnetic resonance analysis and ^(13)C nuclear magnetic resonance analysis. The isolated compounds were evaluated with DPPH radical scavenging, reducing power, and b-carotene bleaching assays.Results: Seven endophytic fungi were successfully isolated from E. sylvestris and identified as Pestalotiopsis sp. EST 01, Pestalotiopsis sp. EST 02, Diaporthales sp. EST03, Meyerozyma sp. EST 04, Diaporthales sp. EST 05, Pestalotiopsis sp. ESL 01, and Pseudocercospora sp. ESL 02. Of the seven fungi, Pseudocercospora sp. ESL 02 had the highest antioxidant activity [IC50=(30.54 ± 0.88) mg/mL]. From that fungus, two compounds identified as terreic acid(1) and 6-methylsalicylic acid(2) were isolated with an IC50 of DPPH radical scavenging activity of(0.22 ± 0.02) mmol/L and(3.87 ± 0.27)mmol/L, respectively. The compounds also had good activities from the reducing power and b-carotene bleaching assays.Conclusions: The Pseudocercospora sp. ESL 02 fungus isolated from E. sylvestris looks promising as a novel source of terreic acid.
文摘An investigation to assess the spatial structure and severity of Pseudocercospora leaf and fruit spot disease (PLFSD) on citrus trees in cocoa-based agroforests was carried out in three contrasting ecological zones in southern Cameroon, viz: 1) the humid forest zone, 2) the degraded forest zone, and 3) the forest-savannah transition zone. Two main parameters were investigated viz: 1) the spatial structure of cocoa based agroforests, and 2) the disease severity. In total, the spatial structure of 19 cocoa-based agroforests was analysed using the Ripley K(r) function, meanwhile the collection of epidemiological data that consisted of noting the presence of PLFSD spots on leaves and fruits on 438 citrus trees was used to characterise the severity of the disease. Results showed that, the spatial structure of citrus trees in these agroforests investigated were regular in seven plots, random in nine, and aggregated in three. Aggregated plots presented a significantly higher mean of disease severity on leaves and fruits (28.55 and 30.37 respectively), as compared to randomised (20.91 and 16.32 respectively) and regular plots (16.28 and 14.97 respectively), at P-value < 0.05. These results suggest that the spatial structure of citrus trees in the cocoa-based agroforests studied influences the severity of PFLSD. Proper integrated control measures can therefore be initiated, leading to a considerable reduction of the use of manufactured inputs, and thereby, the cost of production of citrus fruits.
基金supported by Secihti project PDCPN-2015-266,Mexico.
文摘In the search for new alternatives to control tropical fungal pathogens,the ethanol extracts(EEs)from Acalypha gaumeri(Euphorbiaceae)roots showed antifungal properties against several tropical fungal phytopathogens.A.gaumeri is classified as endemic to the Yucatan Peninsula,Mexico,an area with distinct rainy,drought and northern seasons.The present study evaluated the antifungal activity of threewild populations of A.gaumeri collected quarterly in different seasons during one year against Alternaria chrysanthemi,Colletotrichumgloeosporioides,andPseudocercospora fijiensis and explored their ex-situ propagation.The highest activity was shown by the EE from the Tinum wild population during the rainy season against A.chrysanthemi,C.gloeosporioides,and P.fijiensis with MIC values of 500–1000μg/mL,followed by Yaxcaba populations during the rainy season and Kiuic and Tinum from November against A.chrysanthemi and P.fijiensis 1000 and 500μg/mL,respectively.The propagation of A.gaumeri was more effective throughmediumcuttings,showing 96%with 0.06%auxin indolbutyric acid,whereas only 51%of seeds germinated.The results indicated that seasonal changes and edaphic conditions in the three populations influence the antifungal efficacy of the extracts from A.gaumeri roots.This study enhances the knowledge of the biology and sustainable management of the A.gaumeri plant and advances the development of a biorational product to control tropical fungal diseases.
