On Guam, the estimated lifespan of Casuarina equisetifolia subsp. equisetifolia is 35 to 90 years... more On Guam, the estimated lifespan of Casuarina equisetifolia subsp. equisetifolia is 35 to 90 years and trees may reach a height of 24 m and a diameter at breast height of 92 cm. The majority of its trees are monecious. In 2002, it was noticed that many trees were in a slow decline and when felled, droplets often formed on their fresh stumps. In 2009, this condition was coined ironwood tree decline (IWTD). The droplets which consisted of various mixtures of plant exudates and bacterial ooze were found to contain Ralstonia solanacearum and various wetwood bacteria. Reported in 2015 and confirmed in 2020, Guam’s R. solanacearum strains are of the phylotype 1 (Asia). Cross-sections of IWTD trees from Guam are very similar in appearance with those of bacterial wilt from China. In 2012, a project was initiated to diversify the gene pool and identify resistance of C. equisetifolia in Guam trees. Using the 1991-1993 international provenance trials of C. equisetifolia, 11 geographically paire...
Mmbaga, M. T., Kim M.-S., Mackasmiel, L. and Klopfenstein, N. B. 2015. Differentiation of Corynes... more Mmbaga, M. T., Kim M.-S., Mackasmiel, L. and Klopfenstein, N. B. 2015. Differentiation of Corynespora cassiicola and Cercospora sp. in leaf-spot diseases of Hydrangea macrophylla using a PCR-mediated method. Can. J. Plant Sci. 95: 711–717. Corynespora cassiicola and Cercospora sp. have been identified as the most prevalent and destructive leaf-spot pathogens of garden hydrangea [Hydrangea macrophylla (Thunberg) Seringe] in the southeastern USA, but they are often difficult to accurately detect and distinguish because they often occur together in a disease complex with other pathogenic leaf-spot fungi and produce very similar symptoms. This study was conducted to provide diagnostic PCR primers for detecting and distinguishing Corynespora cassiicola and Cercospora sp. among other leaf-spot pathogens of garden hydrangea. Two primer pairs showed specificity to Corynespora cassiicola and one primer pair showed specificity to Cercospora sp., and these primers did not amplify DNA from any ...
Puccinia psidii causes rust disease on many host species in the Myrtaceae [1]. First reported in ... more Puccinia psidii causes rust disease on many host species in the Myrtaceae [1]. First reported in 1884 on guava in Southern Brazil [2], the rust has since been detected on several myrtaceous in South America, Central America,
Emerging plant pathogens have been increasing exponentially over the last century. To address thi... more Emerging plant pathogens have been increasing exponentially over the last century. To address this issue, it is critical to determine whether these pathogens are native to ecosystems or have been recently introduced. Understanding the ecological and evolutionary processes fostering emergence can help to manage their spread and predict epidemics/epiphytotics. Using restriction site-associated DNA sequencing data, we studied genetic relationships, pathways of spread, and evolutionary history of Phellinus noxius, an emerging root-rotting fungus of unknown origin, in eastern Asia, Australia, and the Pacific Islands. We analyzed patterns of genetic variation using Bayesian inference, maximum likelihood phylogeny, populations splits and mixtures measuring correlations in allele frequencies and genetic drift, and finally applied coalescent based theory using Approximate Bayesian computation (ABC) with supervised machine learning. Population structure analyses revealed five genetic groups w...
Climate change and associated disturbances are expected to exacerbate forest root diseases becaus... more Climate change and associated disturbances are expected to exacerbate forest root diseases because of altered distributions of existing and emerging forest pathogens and predisposition of trees due to climatic maladaptation and other disturbances. Predictions of suitable climate space (potential geographic distribution) for forest pathogens and host trees under contemporary and future climate scenarios will guide the selection of appropriate management practices by forest managers to minimize adverse impacts of forest disease within forest ecosystems. A native pathogen (Armillaria solidipes) that causes Armillaria root disease of conifers in North America is used to demonstrate bioclimatic models (maps) that predict suitable climate space for both pathogen and a primary host (Pseudotsuga menziesii, Douglas-fir) under contemporary and future climate scenarios. Armillaria root disease caused by A. solidipes is a primary cause of lost productivity and reduced carbon sequestration in co...
Because Armillaria species display different ecological behaviors across diverse forest ecosystem... more Because Armillaria species display different ecological behaviors across diverse forest ecosystems, it is critical to identify Armillaria species accurately for any assessment of forest health. To further develop DNA-based identification methods, partial sequences of the translation elongation factor-1 alpha (EF-1α) gene were used to examine the phylogenetic relationship among 30 isolates representing the ten North American Armillaria species: A. solidipes (=A. ostoyae), A. gemina, A. calvescens, A. sinapina, A. mellea, A. gallica, A. nabsnona, North American Biological Species X, A. cepistipes, and A. tabescens. The phylogenetic relationship inferred using the Maximum Likelihood method revealed separation of all ten North American Armillaria species. Thus, our preliminary results indicate the EF-1α gene could serve as a potential diagnostic tool for distinguishing among currently recognized North American Biological Species of Armillaria.
Puccinia psidii (Basidiomycota, Uredinales) is a biotrophic rust fungus that was first reported i... more Puccinia psidii (Basidiomycota, Uredinales) is a biotrophic rust fungus that was first reported in Brazil from guava (Psidium guajava) in 1884 (Winter 1884) and later from nonnative eucalypt (Eucalyptus capitelata and Corymbia citriodora, syn. Eucalyptus citriodora; Joffily 1944). Considered to be of Neotropical origin, the rust has also been reported to infect diverse myrtaceous hosts elsewhere in South America, Central America, the Caribbean, Mexico, the United States (California, Florida, and Hawaii), Japan, Australia, China, and most recently South Africa and New Caledonia (Carnegie et al. 2010; Giblin 2013; Kawanishi et al. 2009; MacLachlan 1938; Marlatt and Kimbrough 1979; Mellano 2006; Perez et al. 2011; Roux et al. 2013; Uchida et al. 2006; Zambino and Nolan 2011; Zhuang and Wei 2011). Given the rate at which the pathogen is spreading and its wide host range, the objectives of this study are to determine how much genetic diversity exists within populations across the species...
... Southern, P. wallichiana, Natural host. Russia, Far East: Sikhote-Alin, Vladivostok, Bolschec... more ... Southern, P. wallichiana, Natural host. Russia, Far East: Sikhote-Alin, Vladivostok, Bolschechtsirsky, P. koraiensis, Rarely infected; natural host alternating with Ribes and Pedicularis. ... (1995) reported blister rust was rare on P. koraiensis in the Sikhote-Alin Reserve. ...
Armillaria mexicana (Agaricales, Physalacriaceae) is described as a new species based on morpholo... more Armillaria mexicana (Agaricales, Physalacriaceae) is described as a new species based on morphology, DNA sequence data, and phylogenetic analyses. It clearly differs from previously reported Armillaria species in North, Central, and South America. It is characterized by the absence of fibulae in the basidioma, abundant cheilocystidia, and ellipsoidal, hyaline basidiospores that are apparently smooth under light microscope, but slightly to moderately rugulose under scanning electron microscope. It is differentiated from other Armillaria species by macromorphological characters, including annulus structure, pileus and stipe coloration, and other structures. DNA sequence data (nuc rDNA internal transcribed spacers [ITS1-5.8S-ITS2 = ITS], 28S D-domain, 3' end of 28S intergenic spacer 1, and translation elongation factor 1-α [TEF1]) show that A. mexicana sequences are quite distinct from sequences of analogous Armillaria species in GenBank. In addition, sequences of ITS of the A. mex...
On Guam, the estimated lifespan of Casuarina equisetifolia subsp. equisetifolia is 35 to 90 years... more On Guam, the estimated lifespan of Casuarina equisetifolia subsp. equisetifolia is 35 to 90 years and trees may reach a height of 24 m and a diameter at breast height of 92 cm. The majority of its trees are monecious. In 2002, it was noticed that many trees were in a slow decline and when felled, droplets often formed on their fresh stumps. In 2009, this condition was coined ironwood tree decline (IWTD). The droplets which consisted of various mixtures of plant exudates and bacterial ooze were found to contain Ralstonia solanacearum and various wetwood bacteria. Reported in 2015 and confirmed in 2020, Guam’s R. solanacearum strains are of the phylotype 1 (Asia). Cross-sections of IWTD trees from Guam are very similar in appearance with those of bacterial wilt from China. In 2012, a project was initiated to diversify the gene pool and identify resistance of C. equisetifolia in Guam trees. Using the 1991-1993 international provenance trials of C. equisetifolia, 11 geographically paire...
Mmbaga, M. T., Kim M.-S., Mackasmiel, L. and Klopfenstein, N. B. 2015. Differentiation of Corynes... more Mmbaga, M. T., Kim M.-S., Mackasmiel, L. and Klopfenstein, N. B. 2015. Differentiation of Corynespora cassiicola and Cercospora sp. in leaf-spot diseases of Hydrangea macrophylla using a PCR-mediated method. Can. J. Plant Sci. 95: 711–717. Corynespora cassiicola and Cercospora sp. have been identified as the most prevalent and destructive leaf-spot pathogens of garden hydrangea [Hydrangea macrophylla (Thunberg) Seringe] in the southeastern USA, but they are often difficult to accurately detect and distinguish because they often occur together in a disease complex with other pathogenic leaf-spot fungi and produce very similar symptoms. This study was conducted to provide diagnostic PCR primers for detecting and distinguishing Corynespora cassiicola and Cercospora sp. among other leaf-spot pathogens of garden hydrangea. Two primer pairs showed specificity to Corynespora cassiicola and one primer pair showed specificity to Cercospora sp., and these primers did not amplify DNA from any ...
Puccinia psidii causes rust disease on many host species in the Myrtaceae [1]. First reported in ... more Puccinia psidii causes rust disease on many host species in the Myrtaceae [1]. First reported in 1884 on guava in Southern Brazil [2], the rust has since been detected on several myrtaceous in South America, Central America,
Emerging plant pathogens have been increasing exponentially over the last century. To address thi... more Emerging plant pathogens have been increasing exponentially over the last century. To address this issue, it is critical to determine whether these pathogens are native to ecosystems or have been recently introduced. Understanding the ecological and evolutionary processes fostering emergence can help to manage their spread and predict epidemics/epiphytotics. Using restriction site-associated DNA sequencing data, we studied genetic relationships, pathways of spread, and evolutionary history of Phellinus noxius, an emerging root-rotting fungus of unknown origin, in eastern Asia, Australia, and the Pacific Islands. We analyzed patterns of genetic variation using Bayesian inference, maximum likelihood phylogeny, populations splits and mixtures measuring correlations in allele frequencies and genetic drift, and finally applied coalescent based theory using Approximate Bayesian computation (ABC) with supervised machine learning. Population structure analyses revealed five genetic groups w...
Climate change and associated disturbances are expected to exacerbate forest root diseases becaus... more Climate change and associated disturbances are expected to exacerbate forest root diseases because of altered distributions of existing and emerging forest pathogens and predisposition of trees due to climatic maladaptation and other disturbances. Predictions of suitable climate space (potential geographic distribution) for forest pathogens and host trees under contemporary and future climate scenarios will guide the selection of appropriate management practices by forest managers to minimize adverse impacts of forest disease within forest ecosystems. A native pathogen (Armillaria solidipes) that causes Armillaria root disease of conifers in North America is used to demonstrate bioclimatic models (maps) that predict suitable climate space for both pathogen and a primary host (Pseudotsuga menziesii, Douglas-fir) under contemporary and future climate scenarios. Armillaria root disease caused by A. solidipes is a primary cause of lost productivity and reduced carbon sequestration in co...
Because Armillaria species display different ecological behaviors across diverse forest ecosystem... more Because Armillaria species display different ecological behaviors across diverse forest ecosystems, it is critical to identify Armillaria species accurately for any assessment of forest health. To further develop DNA-based identification methods, partial sequences of the translation elongation factor-1 alpha (EF-1α) gene were used to examine the phylogenetic relationship among 30 isolates representing the ten North American Armillaria species: A. solidipes (=A. ostoyae), A. gemina, A. calvescens, A. sinapina, A. mellea, A. gallica, A. nabsnona, North American Biological Species X, A. cepistipes, and A. tabescens. The phylogenetic relationship inferred using the Maximum Likelihood method revealed separation of all ten North American Armillaria species. Thus, our preliminary results indicate the EF-1α gene could serve as a potential diagnostic tool for distinguishing among currently recognized North American Biological Species of Armillaria.
Puccinia psidii (Basidiomycota, Uredinales) is a biotrophic rust fungus that was first reported i... more Puccinia psidii (Basidiomycota, Uredinales) is a biotrophic rust fungus that was first reported in Brazil from guava (Psidium guajava) in 1884 (Winter 1884) and later from nonnative eucalypt (Eucalyptus capitelata and Corymbia citriodora, syn. Eucalyptus citriodora; Joffily 1944). Considered to be of Neotropical origin, the rust has also been reported to infect diverse myrtaceous hosts elsewhere in South America, Central America, the Caribbean, Mexico, the United States (California, Florida, and Hawaii), Japan, Australia, China, and most recently South Africa and New Caledonia (Carnegie et al. 2010; Giblin 2013; Kawanishi et al. 2009; MacLachlan 1938; Marlatt and Kimbrough 1979; Mellano 2006; Perez et al. 2011; Roux et al. 2013; Uchida et al. 2006; Zambino and Nolan 2011; Zhuang and Wei 2011). Given the rate at which the pathogen is spreading and its wide host range, the objectives of this study are to determine how much genetic diversity exists within populations across the species...
... Southern, P. wallichiana, Natural host. Russia, Far East: Sikhote-Alin, Vladivostok, Bolschec... more ... Southern, P. wallichiana, Natural host. Russia, Far East: Sikhote-Alin, Vladivostok, Bolschechtsirsky, P. koraiensis, Rarely infected; natural host alternating with Ribes and Pedicularis. ... (1995) reported blister rust was rare on P. koraiensis in the Sikhote-Alin Reserve. ...
Armillaria mexicana (Agaricales, Physalacriaceae) is described as a new species based on morpholo... more Armillaria mexicana (Agaricales, Physalacriaceae) is described as a new species based on morphology, DNA sequence data, and phylogenetic analyses. It clearly differs from previously reported Armillaria species in North, Central, and South America. It is characterized by the absence of fibulae in the basidioma, abundant cheilocystidia, and ellipsoidal, hyaline basidiospores that are apparently smooth under light microscope, but slightly to moderately rugulose under scanning electron microscope. It is differentiated from other Armillaria species by macromorphological characters, including annulus structure, pileus and stipe coloration, and other structures. DNA sequence data (nuc rDNA internal transcribed spacers [ITS1-5.8S-ITS2 = ITS], 28S D-domain, 3' end of 28S intergenic spacer 1, and translation elongation factor 1-α [TEF1]) show that A. mexicana sequences are quite distinct from sequences of analogous Armillaria species in GenBank. In addition, sequences of ITS of the A. mex...
Uploads