The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by che...The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by chestnut blight caused by the Ascomycetous fungus <em>Cryphonectria parasitica</em>. Identification of compounds specific to species and backcross hybrids may help further refine disease resistance breeding and testing. Phenolic compounds produced by plants are significant to their defense mechanisms against fungal pathogens. Therefore, an analytical platform has been developed to estimate the total phenolic content in leaf tissues of the American chestnut, Chinese chestnut (<em>Castanea mollissima</em>), and their backcross breeding generations (B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>) using the Folin-Ciocalteu reagent assay with UV/Vis spectrophotometry which may be used to predict blight resistance. Adsorption (765 nm) results from leaf tissue extraction in methanol/water (95%:5% v/v) and pH 2, show that the variations among these four tree species are significant (ANOVA p = 2.3 × 10<sup>-7</sup>). The kinetics of phenolic compound solid-liquid extraction was elaborated using Peleg, second order, Elovich, and power law models. In addition, extensive analysis using headspace solid phase microextraction (SPME) gas chromatography and mass spectrometry was conducted to identify volatile organic compounds (VOCs) from the leaf of American chestnut, Chinese chestnut, and their backcross hybrids B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>. A total of 67 VOCs were identified among all chestnut types. Many of the metabolites associated with the Chinese chestnut have been reported to have antifungal properties, whereas the native and hybrid American chestnut metabolites have not. Most of the antifungal metabolites showed the strongest efficacy towards the Ascomycota phylum. A partial least squares discriminant analysis (PLS-DA) model (R<sup>2</sup>X = 0.884, R<sup>2</sup>Y = 0.917, Q<sup>2</sup> = 0.584) differentiated chestnut species and hybrids within the first five principal component (PCs).展开更多
An 11 year study was conducted to reevaluate the species of stipitate hydnums from the southern United States especially the Great Smoky Mountains and surrounding geography.The genera evaluated included Bankera herein...An 11 year study was conducted to reevaluate the species of stipitate hydnums from the southern United States especially the Great Smoky Mountains and surrounding geography.The genera evaluated included Bankera herein reduced to synonym with Phellodon,Hydnellum,Sarcodon,and Phellodon.Basidiomata of many stipitate hydnum species from this region were abundant but nitrogen depositions during the last 20 years have impacted their occurrences.Therefore it became critical to do a definitive study of these fungi using current taxonomic tools.Many species within Hydnellum and Phellodon have a indeterminate type growth often dependant on environmental conditions making discrimination between closely related species difficult without supportive molecular sequence data.Once sequence data(ITS)was obtained a phylogenetic analyzes were conducted and the sequences were compared to those in GenBank with particular attention to European data.A total of 41 distinct taxa were determined and many of those were confirmed based on morphological data.A specific new combination from Bankera fuligineoalbum to Phellodon fuligineoalbus is made herein.Futhermore,Phellodon brunneoolivaceus is described as new based on morphological and sequence data.展开更多
文摘The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by chestnut blight caused by the Ascomycetous fungus <em>Cryphonectria parasitica</em>. Identification of compounds specific to species and backcross hybrids may help further refine disease resistance breeding and testing. Phenolic compounds produced by plants are significant to their defense mechanisms against fungal pathogens. Therefore, an analytical platform has been developed to estimate the total phenolic content in leaf tissues of the American chestnut, Chinese chestnut (<em>Castanea mollissima</em>), and their backcross breeding generations (B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>) using the Folin-Ciocalteu reagent assay with UV/Vis spectrophotometry which may be used to predict blight resistance. Adsorption (765 nm) results from leaf tissue extraction in methanol/water (95%:5% v/v) and pH 2, show that the variations among these four tree species are significant (ANOVA p = 2.3 × 10<sup>-7</sup>). The kinetics of phenolic compound solid-liquid extraction was elaborated using Peleg, second order, Elovich, and power law models. In addition, extensive analysis using headspace solid phase microextraction (SPME) gas chromatography and mass spectrometry was conducted to identify volatile organic compounds (VOCs) from the leaf of American chestnut, Chinese chestnut, and their backcross hybrids B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>. A total of 67 VOCs were identified among all chestnut types. Many of the metabolites associated with the Chinese chestnut have been reported to have antifungal properties, whereas the native and hybrid American chestnut metabolites have not. Most of the antifungal metabolites showed the strongest efficacy towards the Ascomycota phylum. A partial least squares discriminant analysis (PLS-DA) model (R<sup>2</sup>X = 0.884, R<sup>2</sup>Y = 0.917, Q<sup>2</sup> = 0.584) differentiated chestnut species and hybrids within the first five principal component (PCs).
文摘An 11 year study was conducted to reevaluate the species of stipitate hydnums from the southern United States especially the Great Smoky Mountains and surrounding geography.The genera evaluated included Bankera herein reduced to synonym with Phellodon,Hydnellum,Sarcodon,and Phellodon.Basidiomata of many stipitate hydnum species from this region were abundant but nitrogen depositions during the last 20 years have impacted their occurrences.Therefore it became critical to do a definitive study of these fungi using current taxonomic tools.Many species within Hydnellum and Phellodon have a indeterminate type growth often dependant on environmental conditions making discrimination between closely related species difficult without supportive molecular sequence data.Once sequence data(ITS)was obtained a phylogenetic analyzes were conducted and the sequences were compared to those in GenBank with particular attention to European data.A total of 41 distinct taxa were determined and many of those were confirmed based on morphological data.A specific new combination from Bankera fuligineoalbum to Phellodon fuligineoalbus is made herein.Futhermore,Phellodon brunneoolivaceus is described as new based on morphological and sequence data.
