The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Kerry Odonnell - One of the best experts on this subject based on the ideXlab platform.
-
phylogenetic diversity trichothecene potential and pathogenicity within Fusarium sambucinum species complex
PLOS ONE, 2021Co-Authors: Imane Laraba, Susan P Mccormick, Martha M Vaughan, David M Geiser, Kerry OdonnellAbstract:The Fusarium sambucinum species complex (FSAMSC) is one of the most taxonomically challenging groups of fusaria, comprising prominent mycotoxigenic plant pathogens and other species with various lifestyles. Among toxins produced by members of the FSAMSC, trichothecenes pose the most significant threat to public health. Herein a global collection of 171 strains, originating from diverse hosts or substrates, were selected to represent FSAMSC diversity. This strain collection was used to assess their species diversity, evaluate their potential to produce trichothecenes, and cause disease on wheat. Maximum likelihood and Bayesian analyses of a combined 3-gene dataset used to infer evolutionary relationships revealed that the 171 strains originally received as 48 species represent 74 genealogically exclusive phylogenetically distinct species distributed among six strongly supported clades: Brachygibbosum, Graminearum, Longipes, Novel, sambucinum, and Sporotrichioides. Most of the strains produced trichothecenes in vitro but varied in type, indicating that the six clades correspond to type A, type B, or both types of trichothecene-producing lineages. Furthermore, five strains representing two putative novel species within the sambucinum Clade produced two newly discovered type A trichothecenes, 15-keto NX-2 and 15-keto NX-3. Strains of the two putatively novel species together with members of the Graminearum Clade were aggressive toward wheat when tested for pathogenicity on heads of the susceptible cultivar Apogee. In planta, the Graminearum Clade strains produced nivalenol or deoxynivalenol and the aggressive sambucinum Clade strains synthesized NX-3 and 15-keto NX-3. Other strains within the Brachygibbosum, Longipes, Novel, sambucinum, and Sporotrichioides Clades were nonpathogenic or could infect the inoculated floret without spreading within the head. Moreover, most of these strains did not produce any toxin in the inoculated spikelets. These data highlight aggressiveness toward wheat appears to be influenced by the type of toxin produced and that it is not limited to members of the Graminearum Clade.
-
ribosomal dna internal transcribed spacers are highly divergent in the phytopathogenic ascomycete Fusarium sambucinum gibberella pulicaris
Current Genetics, 1992Co-Authors: Kerry OdonnellAbstract:Variation within the internal transcribed spacers (ITS1 and ITS2) and 5.8s ribosomal DNA gene of the heterothallic phytopathogenic filamentous fungus, Fusarium sambucinum (teleomorph=Gibberella pulicaris), was examined in 86 strains from diverse geographical locations by PCR amplification and direct sequencing in order to measure intraspecific divergence within the ITS region. Sequence analysis revealed three ITS types (A, B, C), within which divergence was extremely low (0–2.3%). Surprisingly, the level of intraspecific divergence observed between ITS types, A→B=14.3%, A→C=15%, and B→C=4.6%, is much greater than that reported for any other species. The degree to which transition/transversions and insertion/deletions make up the pattern of ITS sequence evolution both within and between types was analyzed. The sequences of the ITS types exhibit a C-T transition bias together with a GC insertion/deletion bias. In comparison, the genic flanking sequences, including the 5.8s rDNA gene and 5′ end of the 28s large nuclear rDNA, are highly conserved. By the criteria of mating and DNA-DNA hybridization, all the strains examined represent a single species. Discordance between the ITS sequence data and other molecular and genetic data on F. sambucinum is discussed.
Klausm Weltring - One of the best experts on this subject based on the ideXlab platform.
-
metabolism of the potato saponins α chaconine and α solanine by gibberella pilicaris
Phytochemistry, 1997Co-Authors: Klausm Weltring, Judith Wessels, Rudolf GeyerAbstract:Abstract Potato tubers accumulate varying amounts of several saponins preferentially in the peel. These compounds are toxic to living cells containing sterols in their plasma membrane and are therefore thought to be preformed chemical defence compounds. Two strains of the potato pathogen Gibberella pulicaris (Fusarium sambucinum) , R-6380 and R-7843, were analysed for their ability to metabolize the most predominant saponins found in tubers, α-chaconine and α-solanine. The first compound is degraded by both strains via removal of α-1,2- l -rhamnose leading to β 2 -chaconine. This product is converted to the aglycone, solanidine, which is further metabolized to unknown products. The release of α-1,2- l -rhamnose is also the first step in the break down of α-solanine by strain R-6380, followed by the removal of the β-1,3-bound glucose molecule leading to γ-solanine, which is not metabolized any further. Strain R-7843 is not able to metabolize α-solanine. Crude protein extracts of the culture fluid of both strains contained enzymes able to convert α-chaconine to β 2 -chaconine, but with no α-solanine metabolic activity. This result indicates that G. pulicaris excretes enzymes specific for different saponins.
-
detoxification of sesquiterpene phytoalexins bygibberella pulicaris Fusarium sambucinum and its importance for virulence on potato tubers
Journal of Industrial Microbiology & Biotechnology, 1992Co-Authors: Anne E Desjardins, Harold W Gardner, Klausm WeltringAbstract:Gibberella pulicaris (Fusarium sambucinum) is a major cause of dry-rot of stored potatoes (Solanum tuberosum) worldwide. The ability of field strains ofG. pulicaris to cause dry-rot is correlated with their ability to detoxify sesquiterpene phytoalexins produced by potato. All highly virulent field strains can detoxify the sesquiterpenes rishitin and lubimin. Meiotic recombinational analysis indicates that rishitin detoxification can be controlled at two or more loci. High virulence has been associated with one of these loci, designatedRiml. Detoxification of rishitin and lubimin comprises a complex pattern of reactions involving epoxidation, dehydrogenation, and cyclization. To date, seven lubimin metabolites and one rishitin metabolite have been characterized. Genes for rishitin and lubimin detoxification are being cloned fromG. pulicaris in order to more rigorously analyze the role and regulation of sesquiterpene metabolism in potato dry-rot. Our results indirectly support a role for sesquiterpene phytoalexins in resistance of potato tubers to dry-rot and may enhance research on alternative control strategies for this economically important potato disease.
Mohamed Hijri - One of the best experts on this subject based on the ideXlab platform.
-
The arbuscular mycorrhizal fungus, Glomus irregulare, controls the mycotoxin production of Fusarium sambucinum in the pathogenesis of potato.
FEMS microbiology letters, 2013Co-Authors: Youssef Ismail, Susan P Mccormick, Mohamed HijriAbstract:Trichothecenes are an important family of mycotoxins produced by several species of the genus Fusarium. These fungi cause serious disease on infected plants and postharvest storage of crops, and the toxins can cause health problems for humans and animals. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens, and most rely on chemicals, creating therefore subsequent problems of chemical resistance. We tested the impact of the symbiotic arbuscular mycorrhizal fungus Glomus irregulare on a trichothecene-producing strain of Fusarium sambucinum isolated from naturally infected potato plants. Using dual in vitro cultures, we showed that G. irregulare inhibited the growth of F. sambucinum and significantly reduced the production of the trichothecene 4, 15-diacetoxyscirpenol (DAS). Furthermore, using G. irregulare-colonized potato plants infected with F. sambucinum, we found that the G. irregulare treatment inhibited the production of DAS in roots and tubers. Thus, in addition to the known beneficial effect of mycorrhizal symbiosis on plant growth, we found that G. irregulare controlled the growth of a virulent fungal pathogen and reduced production of a mycotoxin. This previously undescribed, biological control of Fusarium mycotoxin production by G. irregulare has potential implications for improved potato crop production and food safety.
-
arbuscular mycorrhisation with glomus irregulare induces expression of potato pr homologues genes in response to infection by Fusarium sambucinum
Functional Plant Biology, 2012Co-Authors: Youssef Ismail, Mohamed HijriAbstract:Arbuscular mycorrhizal fungi (AMF) are symbiotic, root-inhabiting fungi colonising a wide range of vascular plant species. We previously showed that AMF modulate the expression of mycotoxin genes in Fusarium sambucinum. Here, we tested the hypothesis that AMF may induce defence responses in potato to protect against infection with F. sambucinum. We analysed the response of AMF-colonised potato plants to the pathogenic fungus F. sambucinum by monitoring the expression of defence-related genes ChtA3, gluB, CEVI16, OSM-8e and PR-1. In response to F. sambucinum infection, we found that the AMF treatment upregulated the expression of all defence genes except OSM-8e in potato roots at 72 and 120h post infection (hpi). However, we found variable transcriptional regulation with gluB and CEVI16 in shoots at both times 72 and 120hpi in AMF-colonisation and infected plants. Overall, differential regulation of defence-related genes in leaf tissues indicate that AMF are a systemic bio-inducer and their effect could extend into non-infected parts. Thus, AMF significantly suppressed disease severity of F. sambucinum on potato plants compared with those infected and non-mycorrhizal plants. Furthermore, the AMF treatment decreased the negative effects of F. sambucinum on biomass and potato tuber production.
-
a fungal symbiont of plant roots modulates mycotoxin gene expression in the pathogen Fusarium sambucinum
PLOS ONE, 2011Co-Authors: Youssef Ismail, Susan P Mccormick, Mohamed HijriAbstract:Fusarium trichothecenes are fungal toxins that cause disease on infected plants and, more importantly, health problems for humans and animals that consume infected fruits or vegetables. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens. In this study, we isolated and characterized sixteen Fusarium strains from naturally infected potato plants in the field. Pathogenicity tests were carried out in the greenhouse to evaluate the virulence of the strains on potato plants as well as their trichothecene production capacity, and the most aggressive strain was selected for further studies. This strain, identified as F. sambucinum, was used to determine if trichothecene gene expression was affected by the symbiotic Arbuscular mycorrhizal fungus (AMF) Glomus irregulare. AMF form symbioses with plant roots, in particular by improving their mineral nutrient uptake and protecting plants against soil-borne pathogens. We found that that G. irregulare significantly inhibits F. sambucinum growth. We also found, using RT-PCR assays to assess the relative expression of trichothecene genes, that in the presence of the AMF G. irregulare, F. sambucinum genes TRI5 and TRI6 were up-regulated, while TRI4, TRI13 and TRI101 were down-regulated. We conclude that AMF can modulate mycotoxin gene expression by a plant fungal pathogen. This previously undescribed effect may be an important mechanism for biological control and has fascinating implications for advancing our knowledge of plant-microbe interactions and controlling plant pathogens.
G Dal M Bello - One of the best experts on this subject based on the ideXlab platform.
-
first report of Fusarium sambucinum sensu stricto causing postharvest fruit rot of tomato in argentina
Plant Disease, 2016Co-Authors: Cecilia Alejandra Mourelos, Ismael Malbran, Gladys Albina Lori, G Dal M BelloAbstract:Fil: Mourelos, Cecilia Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biologicas. Centro de Investigaciones de Fitopatologia. Provincia de Buenos Aires. Gobernacion. Comision de Investigaciones Cientificas. Centro de Investigaciones de Fitopatologia; Argentina
Susan P Mccormick - One of the best experts on this subject based on the ideXlab platform.
-
phylogenetic diversity trichothecene potential and pathogenicity within Fusarium sambucinum species complex
PLOS ONE, 2021Co-Authors: Imane Laraba, Susan P Mccormick, Martha M Vaughan, David M Geiser, Kerry OdonnellAbstract:The Fusarium sambucinum species complex (FSAMSC) is one of the most taxonomically challenging groups of fusaria, comprising prominent mycotoxigenic plant pathogens and other species with various lifestyles. Among toxins produced by members of the FSAMSC, trichothecenes pose the most significant threat to public health. Herein a global collection of 171 strains, originating from diverse hosts or substrates, were selected to represent FSAMSC diversity. This strain collection was used to assess their species diversity, evaluate their potential to produce trichothecenes, and cause disease on wheat. Maximum likelihood and Bayesian analyses of a combined 3-gene dataset used to infer evolutionary relationships revealed that the 171 strains originally received as 48 species represent 74 genealogically exclusive phylogenetically distinct species distributed among six strongly supported clades: Brachygibbosum, Graminearum, Longipes, Novel, sambucinum, and Sporotrichioides. Most of the strains produced trichothecenes in vitro but varied in type, indicating that the six clades correspond to type A, type B, or both types of trichothecene-producing lineages. Furthermore, five strains representing two putative novel species within the sambucinum Clade produced two newly discovered type A trichothecenes, 15-keto NX-2 and 15-keto NX-3. Strains of the two putatively novel species together with members of the Graminearum Clade were aggressive toward wheat when tested for pathogenicity on heads of the susceptible cultivar Apogee. In planta, the Graminearum Clade strains produced nivalenol or deoxynivalenol and the aggressive sambucinum Clade strains synthesized NX-3 and 15-keto NX-3. Other strains within the Brachygibbosum, Longipes, Novel, sambucinum, and Sporotrichioides Clades were nonpathogenic or could infect the inoculated floret without spreading within the head. Moreover, most of these strains did not produce any toxin in the inoculated spikelets. These data highlight aggressiveness toward wheat appears to be influenced by the type of toxin produced and that it is not limited to members of the Graminearum Clade.
-
The arbuscular mycorrhizal fungus, Glomus irregulare, controls the mycotoxin production of Fusarium sambucinum in the pathogenesis of potato.
FEMS microbiology letters, 2013Co-Authors: Youssef Ismail, Susan P Mccormick, Mohamed HijriAbstract:Trichothecenes are an important family of mycotoxins produced by several species of the genus Fusarium. These fungi cause serious disease on infected plants and postharvest storage of crops, and the toxins can cause health problems for humans and animals. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens, and most rely on chemicals, creating therefore subsequent problems of chemical resistance. We tested the impact of the symbiotic arbuscular mycorrhizal fungus Glomus irregulare on a trichothecene-producing strain of Fusarium sambucinum isolated from naturally infected potato plants. Using dual in vitro cultures, we showed that G. irregulare inhibited the growth of F. sambucinum and significantly reduced the production of the trichothecene 4, 15-diacetoxyscirpenol (DAS). Furthermore, using G. irregulare-colonized potato plants infected with F. sambucinum, we found that the G. irregulare treatment inhibited the production of DAS in roots and tubers. Thus, in addition to the known beneficial effect of mycorrhizal symbiosis on plant growth, we found that G. irregulare controlled the growth of a virulent fungal pathogen and reduced production of a mycotoxin. This previously undescribed, biological control of Fusarium mycotoxin production by G. irregulare has potential implications for improved potato crop production and food safety.
-
a fungal symbiont of plant roots modulates mycotoxin gene expression in the pathogen Fusarium sambucinum
PLOS ONE, 2011Co-Authors: Youssef Ismail, Susan P Mccormick, Mohamed HijriAbstract:Fusarium trichothecenes are fungal toxins that cause disease on infected plants and, more importantly, health problems for humans and animals that consume infected fruits or vegetables. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens. In this study, we isolated and characterized sixteen Fusarium strains from naturally infected potato plants in the field. Pathogenicity tests were carried out in the greenhouse to evaluate the virulence of the strains on potato plants as well as their trichothecene production capacity, and the most aggressive strain was selected for further studies. This strain, identified as F. sambucinum, was used to determine if trichothecene gene expression was affected by the symbiotic Arbuscular mycorrhizal fungus (AMF) Glomus irregulare. AMF form symbioses with plant roots, in particular by improving their mineral nutrient uptake and protecting plants against soil-borne pathogens. We found that that G. irregulare significantly inhibits F. sambucinum growth. We also found, using RT-PCR assays to assess the relative expression of trichothecene genes, that in the presence of the AMF G. irregulare, F. sambucinum genes TRI5 and TRI6 were up-regulated, while TRI4, TRI13 and TRI101 were down-regulated. We conclude that AMF can modulate mycotoxin gene expression by a plant fungal pathogen. This previously undescribed effect may be an important mechanism for biological control and has fascinating implications for advancing our knowledge of plant-microbe interactions and controlling plant pathogens.
