title: Toxin distribution and sphingoid base imbalances in Fusarium verticillioides-infected and fumonisin B1-watered maize seedlings.
abstract: Fusarium verticillioides is a major maize pathogen and there are susceptible and resistant cultivars to this fungal infection. Recent studies suggest that its main mycotoxin fumonisin B1 (FB1) may be involved in phytopathogenicity, but the underlying mechanisms are mostly still unknown. This work was aimed at assessing whether FB1 disseminates inside the plants, as well as identifying possible correlations between the maize resistant/susceptible phenotype and the unbalances of the FB1-structurally-related sphingoid base sphinganine (Sa) and phytosphingosine (Pso) due to toxin accumulation. Resistant (RH) and susceptible hybrid (SH) maize seedlings grown from seeds inoculated with a FB1-producer F. verticillioides and from uninoculated ones irrigated with FB1 (20 ppm), were harvested at 7, 14 and 21 days after planting (dap), and the FB1, Sa and Pso levels were quantified in roots and aerial parts. The toxin was detected in roots and aerial parts for inoculated and FB1-irrigated plants of both hybrids. However, FB1 levels were overall higher in SH seedlings regardless of the treatment (infection or watering). Sa levels increased substantially in RH lines, peaking at 54-fold in infected roots at 14 dap. In contrast, the main change observed in SH seedlings was an increase of Pso in infected roots at 7 dap. Here, it was found that FB1 disseminates inside seedlings in the absence of FB1-producer fungal infections, perhaps indicating this might condition the fungus-plant interaction before the first contact. Furthermore, the results strongly suggest the existence of at least two ceramide synthase isoforms in maize with different substrate specificities, whose differential expression after FB1 exposure could be closely related to the susceptibility/resistance to F. verticillioides.
authors.affiliation: Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina.
authors.forename: Silvina L
authors.initials: SL
authors.lastname: Arias
authors.affiliation: Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina.
authors.forename: Verónica S
authors.initials: VS
authors.lastname: Mary
authors.affiliation: Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina.
authors.forename: Santiago N
authors.initials: SN
authors.lastname: Otaiza
authors.affiliation: Instituto de Ciencia y Tecnología de Alimentos Córdoba (ICYTAC, UNC-CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Wunderlin
authors.affiliation: Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina.
authors.forename: Héctor R
authors.initials: HR
authors.lastname: Rubinstein
authors.affiliation: Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina. Electronic address: mgtheumer@fcq.unc.edu.ar.
authors.forename: Martín G
authors.initials: MG
authors.lastname: Theumer
mesh_terms: D037341:Fumonisins / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology*; D005670:Fusarium / Q000737:chemistry*; D009183:Mycotoxins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D012639:Seeds / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives / Q000032:analysis; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000254:growth & development / Q000382:microbiology*
chemical_list: D037341:Fumonisins; D009183:Mycotoxins; D014867:Water; C056933:fumonisin B1; D013110:Sphingosine; C005682:safingol
keywords: Fumonisin B1; Fusarium verticillioides; Maize; Phytosphingosine; Poaceae; Resistant LT 622 MG and susceptible HX 31P77 maize hybrids; Sphinganine; Zea mays L.