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Maple syrup, made by boiling the sap of Acer saccharum, is an important agriculture commodity in eastern Canada and New England. Although the collection season is relatively short, a rich progression in the sensory qualities of maple syrup can occur throughout the season. A risk associated with maple syrup production at the end of a season is the development of off-flavors that result in syrup with little to no commercial value. Maple syrup producers in Canada and the USA call this 'buddy syrup'. In this study, sugar maple (Acer saccharum) sap was collected in sequential samples through the harvest season from stands across Ontario. Metabolomics analysis of the sap samples was performed by high-resolution mass spectrometry. This revealed an evolution of the chemical composition, mainly occurring 30 days prior to leaf emergence. The major chemical constituent of maple syrup, sucrose, decreased sharply in late season sap, driven by microbial activity. The alditol mannitol increased in late season sap to concentrations ≥2 mg/mL and is likely an indicator of the start of photosynthesis. Amino acids, notably methionine and asparagine were present in higher amounts in late season sap. Non-targeted analysis revealed a series of related compounds that contained quaternary ammonium moieties including choline, hercynine, trigonelline, glycine betaine and carnitine increased in late season sap. These classes of compounds could act as methyl donors during the heating/evaporation of sap into syrup, affecting taste. Based on descriptions of the nature of buddy syrup and an extensive literature on flavors in foods, the amino acids methionine and asparagine were found as likely precursors to the compounds responsible for buddy syrup. [ABSTRACT FROM AUTHOR]

Background: Microorganisms, including Bacillus species are used to help control plant pathogens, thereby reducing reliance on synthetic pesticides in agriculture. Bacillus velezensis strain 1B-23 has been shown to reduce symptoms of bacterial disease caused by Clavibacter michiganensis subsp. michiganensis in greenhouse-grown tomatoes, with in vitro studies implicating the lipopeptide surfactin as a key antimicrobial. While surfactin is known to be effective against many bacterial pathogens, it is inhibitory to a smaller proportion of fungi which nonetheless cause the majority of crop diseases. In addition, knowledge of optimal conditions for surfactin production in B. velezensis is lacking., Results: Here, B. velezensis 1B-23 was shown to inhibit in vitro growth of 10 fungal strains including Candida albicans, Cochliobolus carbonum, Cryptococcus neoformans, Cylindrocarpon destructans Fusarium oxysporum, Fusarium solani, Monilinia fructicola, and Rhizoctonia solani, as well as two strains of C. michiganensis michiganensis. Three of the fungal strains (C. carbonum, C. neoformans, and M. fructicola) and the bacterial strains were also inhibited by purified surfactin (surfactin C, or [Leu7] surfactin C15) from B. velezensis 1B-23. Optimal surfactin production occurred in vitro at a relatively low temperature (16 °C) and a slightly acidic pH of 6.0. In addition to surfactin, B. velenzensis also produced macrolactins, cyclic dipeptides and minor amounts of iturins which could be responsible for the bioactivity against fungal strains which were not inhibited by purified surfactin C., Conclusions: Our study indicates that B. velezensis 1B-23 has potential as a biocontrol agent against both bacterial and fungal pathogens, and may be particularly useful in slightly acidic soils of cooler climates.

Background: With the high demand for diesel across the world, environmental decontamination from its improper usage, storage and accidental spills becomes necessary. One highly environmentally friendly and cost-effective decontamination method is to utilize diesel-degrading microbes as a means for bioremediation. Here, we present a newly isolated and identified strain of Acinetobacter calcoaceticus ('CA16') as a candidate for the bioremediation of diesel-contaminated areas., Results: Acinetobacter calcoaceticus CA16 was able to survive and grow in minimal medium with diesel as the only source of carbon. We determined through metabolomics that A. calcoaceticus CA16 appears to be efficient at diesel degradation. Specifically, CA16 is able to degrade 82 to 92% of aliphatic alkane hydrocarbons (C n H n + 2 ; where n = 12-18) in 28 days. Several diesel-degrading genes (such as alkM and xcpR) that are present in other microbes were also found to be activated in CA16., Conclusions: The results presented here suggest that Acinetobacter strain CA16 has good potential in the bioremediation of diesel-polluted environments.

Several Aspergillus species produce ochratoxin A (OTA) and/or fumonisins on wine and table grapes. The relevant species and their mycotoxins have been investigated in a number of wine-producing regions around the world; however, similar data have not been reported for Canadian vineyards. A multiyear survey of black Aspergilli in Niagara, ON, vineyards was conducted to determine the diversity of species present and to assess the risk of OTA and fumonisin contamination of wine grapes from this region. From 2012 to 2014, 253 black Aspergilli were isolated from soil samples and the fruits of 10 varieties of grapes. The isolates were identified by DNA sequencing: Aspergillus welwitschiae (43%), Aspergillus uvarum (32%), Aspergillus brasiliensis (11%), Aspergillus tubingensis (9%), and Aspergillus niger (4%). Aspergillus carbonarius, the primary OTA producer on grapes in other parts of the world, was isolated only once, and this is the first report for it in Canada. All 10 A. niger strains produced fumonisins, but, in contrast, only 26% of the 109 A. welwitschiae isolates were producers, and no strains of either species produced OTA. Grape samples were analyzed for OTA and fumonisins from sites where strains with mycotoxigenic potential were isolated. Fumonisin B2 (FB2) was detected in 7 of 22 (32%) of these grape samples in the 1-15 ppb range, but no OTA was detected. Additionally, the recently reported nonaminated fumonisins were detected in 3 of 22 grape samples. These results suggest that fumonisin-producing Aspergilli can occur in Ontario vineyards but, at present, the risk of contamination of grapes appears low. The risk of OTA contamination in Niagara wine is also low because of the low prevalence of A. carbonarius.