Bacteria existing in pre-pollinated styles (silks) can defend the exposed male gamete fertilization channel of maize against an environmental Fusarium pathogen

In flowering plants, fertilization requires exposing maternal style channels to the external environment to capture pollen and transmit its resident sperm nuclei to eggs. This results in progeny seed. However, environmental fungal pathogens invade developing seeds through the style. We hypothesized that prior to environmental exposure, style tissue already possesses bacteria that can protect styles and seed from such pathogens. We further hypothesized that farmers have been inadvertently selecting immature styles over many generations to have such bacteria. We tested these hypotheses in maize, a wind-pollinated crop, which has unusually long styles (silks) that are invaded by the economically-important fungal pathogen Fusarium graminearum (Fg). Here, unpollinated silk-associated bacteria were cultured from a wild teosinte ancestor of maize and diverse maize landraces selected by indigenous farmers across the Americas, grown in a common Canadian field for one season. The bacteria were taxonomically classified using 16S rRNA sequencing. In total, 201 bacteria were cultured, spanning 29 genera, 63 species, and 62 unique OTUs, dominated by Pseudomonas, Pantoea and Microbacterium. These bacteria were tested for their ability to suppress Fg in vitro which identified 10 strains belonging to 6 species: Rouxiella badensis, Pantoea ananatis, Pantoea dispersa, Pseudomonas koreensis, Rahnella aquatilis, and Ewingella americana. Two anti-Fg strains were sprayed onto silks before/after Fg inoculation, resulting in ≤90% reductions in disease (Gibberella ear rot) and 70-100% reductions in associated mycotoxins (deoxynivalenol and zearalenone) in progeny seeds. These strains also protected progeny seeds post-harvest. Confocal fluorescent imaging showed that one silk bacterium (Rouxiella AS112) colonized susceptible entry points of Fg on living silks including stigmatic trichomes, wounds, and epidermal surfaces where they formed thick biofilms. Post-infection, AS112 was associated with masses of dead Fg hyphae. These results suggest that the maize style (silk) is endowed with potent bacteria from the mother plant to protect itself and progeny from Fusarium. The evidence suggests this trait may have been selected by specific indigenous peoples, though this interpretation requires further study

Root hair-endophyte stacking (RHESt) in an ancient Afro-Indian crop creates an unusual physico-chemical barrier to trap pathogen(s)

WKM was supported by generous scholarships from the Government of Egypt and the University of Guelph (International Graduate Student Scholarships, 2012, 2014). This research was supported by grants to MNR by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), Grain Farmers of Ontario (GFO), Natural Sciences and Engineering Research Council of Canada (NSERC) and the CIFSRF program funded by the International Development Research Centre (IDRC, Ottawa) and Canadian Department of Global Affairs.The objectives of this study were to isolate bacterial endophytes from finger millet, assay for anti-Fusarium activity and characterize the underlying cellular, molecular and biochemical mechanisms. We report an unusual symbiosis between the host and a root-inhabiting bacterial endophyte

Manejo de un aborto frustro en paciente con útero doble más tabique vaginal longitudinal

Paciente de 32 años que de manera incidental se descubre un útero didelfo, a la especuloscopía presentaba un tabique vaginal longitudinal total; en la ecografía vaginal se evidencio dos cavidades endouterinas separadas, dos canales cervicales y la presencia de embrión inactivo de seis semanas en cavidad izquierda; tras el diagnóstico de aborto frustro se le realiza una aspiración manual endouterina (AMEU) con guía ecográfica, no se logra acceder a cavidad uterina izquierda, siendo fallido este proceso en varias oportunidades; se re examina el canal vaginal y  se encuentra un orificio vaginal anterior superior lateral izquierdo, con entrada de un pulpejo de dedo, en el cual se ingresa y evidencia cuello cervical izquierdo; este orificio fue ampliado en su abertura luego del cual se introdujo la cánula de aspiración previamente curvada, para que con ayuda ecográfica se proceda a realizar el aspirado el cual fue exitoso. Las malformaciones müllerianas tienen un sin número de variedades, es la experiencia del médico lo que determina resolviendo el cas

Effect of Prothioconazole Application Timing on <i>Fusarium</i> Mycotoxin Content in Maize Grain

In 2010 and 2011, studies to determine the optimal timing of prothioconazole application (200 g a.i./ha) for reducing <i>Fusarium</i> mycotoxin accumulation in grain were conducted in controlled replicated experiments under small-plot mist-irrigated experiments and in field-scale experiments using two hybrids susceptible to <i>F. gramineaerum</i> infection. A significant decrease in total deoxynivalenol (DON) [DON + 15-acetyl-DON + DON 3-glucoside + 3-acetyl-DON] and zearalenone concentrations was observed when fungicide was sprayed at VT (tasseling) and R1 (silking; <i>P</i> < 0.01) followed by applications at V18 (18th leaf) and R2 (blister; <i>P</i> < 0.05) stages, corresponding to silk completely emerged and fully elongated and to silk emergence and browning, respectively. No reduction in <i>Fusarium graminearum</i> toxins was found after silk senescence (R3 or milk) stage. Moniliformin, fumonisins, beauvericin, enniatins, HT-2 and T-2 toxins were also found in small quantities, and no reduction was observed after treatment (<i>P</i> > 0.05). Mean reduction (±s.d.) of 59 ± 20% and 57 ± 38% of total DON and zearalenone was observed at full silk elongation, respectively

Mycotoxin Co-Occurrence in Michigan Harvested Maize Grain

Mycotoxins are secondary metabolites produced by fungi that, depending on the type and exposure levels, can be a threat to human and animal health. When multiple mycotoxins occur together, their risk effects on human and animal health can be additive or synergistic. Little information is known about the specific types of mycotoxins or their co-occurrence in the state of Michigan and the Great Lakes region of the United States. To understand the types, incidences, severities, and frequency of co-occurrence of mycotoxins in maize grain (Zea mays L.), samples were collected from across Michigan over two years and analyzed for 20 different mycotoxins. Every sample was contaminated with at least four and six mycotoxins in 2017 and 2018, respectively. Incidence and severity of each mycotoxin varied by year and across locations. Correlations were found between mycotoxins, particularly mycotoxins produced by Fusarium spp. Environmental differences at each location played a role in which mycotoxins were present and at what levels. Overall, data from this study demonstrated that mycotoxin co-occurrence occurs at high levels in Michigan, especially with mycotoxins produced by Fusarium spp., such as deoxynivalenol

Occurrence of Penicillium verrucosum, ochratoxin A, ochratoxin B and citrinin in on-farm stored winter wheat from the Canadian Great Lakes Region

The occurrence of P. verrucosum and ochratoxin A (OTA) were surveyed for 3 and 4 years, respectively. A total of 250 samples was collected from an average of 30 farms during the 2011, 2012, 2013 and 2014 winter seasons. Most storage bins surveyed were typically 11 m high round bins made of corrugated, galvanized steel, with flat-bottoms and conical roofs. Samples of clumped grain contained the most P. verrucosum (p<0.05, n = 10) followed by samples taken from the first load (n = 24, mean = 147±87 CFU/g) and last load (n = 17, mean = 101±77 CFU/g). Five grain samples (2.2%) tested positive for OTA, citrinin and OTB at concentrations of 14.7±7.9, 4.9±1.9 and 1.2±0.7 ng/g, with only three samples exceeding 5 ng/g. Grain samples positive for OTA were related to moisture resulting from either condensation or migrating moist warm air in the bin or areas where precipitation including snow entered the bin. Bins containing grain and clumps contaminated with OTA were studied in detail. A number of statistically-significant risk factors for OTA contamination were identified. These included 1) grain clumps accumulated around or directly under manhole openings, 2) debris and residue of old grain or grain clumps collected from the bin walls or left on storage floor and augers and 3) grain clumps accumulated around side doors. Even when grain enters storage below the 14.5% threshold of moisture, condensation and moisture migration occurs in hotspots in modern corrugated steel storage bins. Hot spots of OTA contamination were most often in areas affected by moisture migration due to inadequate aeration and exposure to moisture from precipitation or condensation. Further, we found that the nature of the condensation affects the nature and distribution of small and isolated areas with high incidence of toxin contamination and/or P. verrucosum prevalence in the grain bins examined

Neonicotinoid insecticide residues in subsurface drainage and open ditch water around maize fields in southwestern Ontario.

Neonicotinoids are widely used class of insecticides. Most are seed treatments and during planting active ingredient may be abraded and lost in fugitive dust. Much of this active ingredient contaminates surface waters, exposing aquatic organism to potential ill effects. This study examines concentrations of neonicotinoids appearing in tile drains and open ditches around commercial maize fields around planting time where neonicotinoid seed treatments had been used. This sample set represents surface water leaving the point of origin, for which data are sparse. Clothianidin was found more often than thiamethoxam and at higher concentrations; at a median concentration of 0.35 ng/mL in tile drain water and almost twice that (0.68 ng/mL) in ditches into which the tiles are draining after applications of 19 g/ha on seed. This concentration reveals a 40 to 50 fold dilution for neonicotinoid residues between the points where they leave the field in which they were applied and when they are found in nearby streams in a similar ecosystem. Our data support that for a no-observed-effect concentration of 0.3 ng/mL for thiamethoxam there would be between a 1.6 and 100-fold margin of safety to mayflies in most streams if fugitive dust on pneumatic planters were properly mitigated

Occurrence of <i>Penicillium verrucosum</i>, ochratoxin A, ochratoxin B and citrinin in on-farm stored winter wheat from the Canadian Great Lakes Region

<div><p>The occurrence of <i>P</i>. <i>verrucosum</i> and ochratoxin A (OTA) were surveyed for 3 and 4 years, respectively. A total of 250 samples was collected from an average of 30 farms during the 2011, 2012, 2013 and 2014 winter seasons. Most storage bins surveyed were typically 11 m high round bins made of corrugated, galvanized steel, with flat-bottoms and conical roofs. Samples of clumped grain contained the most <i>P</i>. <i>verrucosum</i> (<i>p</i><0.05, n = 10) followed by samples taken from the first load (n = 24, mean = 147±87 CFU/g) and last load (n = 17, mean = 101±77 CFU/g). Five grain samples (2.2%) tested positive for OTA, citrinin and OTB at concentrations of 14.7±7.9, 4.9±1.9 and 1.2±0.7 ng/g, with only three samples exceeding 5 ng/g. Grain samples positive for OTA were related to moisture resulting from either condensation or migrating moist warm air in the bin or areas where precipitation including snow entered the bin. Bins containing grain and clumps contaminated with OTA were studied in detail. A number of statistically-significant risk factors for OTA contamination were identified. These included 1) grain clumps accumulated around or directly under manhole openings, 2) debris and residue of old grain or grain clumps collected from the bin walls or left on storage floor and augers and 3) grain clumps accumulated around side doors. Even when grain enters storage below the 14.5% threshold of moisture, condensation and moisture migration occurs in hotspots in modern corrugated steel storage bins. Hot spots of OTA contamination were most often in areas affected by moisture migration due to inadequate aeration and exposure to moisture from precipitation or condensation. Further, we found that the nature of the condensation affects the nature and distribution of small and isolated areas with high incidence of toxin contamination and/or <i>P</i>. <i>verrucosum</i> prevalence in the grain bins examined.</p></div

Winter wheat production and fluctuation of on-farm grain stocks held in Ontario, Canada from July 1997 to December 2012.

<p>Data acquired from Statistics Canada from 1997–2012. Source: Annual Field Crop Reporting Series, Stock of principal field crops.</p

Analysis of variance for reduced model of the distribution of <i>P</i>. <i>verrucosum</i> inoculum found in grain and grain clumps (CFU/g) collected in winter 2011–2013 from on-farm storage bins located in Ontario, Canada.

<p>Analysis of variance for reduced model of the distribution of <i>P</i>. <i>verrucosum</i> inoculum found in grain and grain clumps (CFU/g) collected in winter 2011–2013 from on-farm storage bins located in Ontario, Canada.</p