One of the main problems in the production of cacao in Ecuador is the disease caused by the fungus Moniliophthora roreri (frosty pod rot) which affects the pods. Here, we evaluate the genetic diversity of this fungus in Ecuador, and its sensitivity to the fungicide azoxystrobin. We evaluated 76 monosporic cultures from the Amazon and the Pacific coast regions. In vitro sensitivity assays tested several doses of the fungicide azoxystrobin to determine the percent of growth inhibition and the IC50. Concentrations of 1 to 0.1 µg mL−1 inhibited the growth of at least 91% of the isolates. Three isolates were the less sensitive (IC50 = 0.0220–0.0364 µg mL−1), two from Guayas (Pacific coast) and one from Sucumbíos (Amazon) provinces. However, M. roreri is highly sensitive, and it could be used in integrated management of the disease. Genetic analyses were carried out by amplifying microsatellite markers (SSR). All the genetic diversity statistics show a higher diversity in the Amazon compared to samples of the coast region; however, the molecular variance was low (FST = 0.11). Discriminant analysis clearly distinguishes three clusters concurrent with the provinces (Sucumbíos, Orellana and El Oro) and a group with the rest of the provinces. Minimum spanning networks shows, unexpectedly, that M. roreri from the coast were derived from at least three independent introductions from the Amazon. Findings are discussed in light of previous Pan-American genetic studies and available historical reports.
Biosurfactants (BS) are amphiphilic molecules that align at the interface reducing the surface tension. BS production is developed as an alternative to synthetic surfactants because they are biodegradable, with low toxicity and high specificity. BS are versatile, and this research proposes using a biosurfactant crude extract (BCE) as part of cleaning products. This paper reported the BCE production from Bacillus subtilis DS03 using a medium with molasses. The BCE product was characterized by different physical and chemical tests under a wide pH range, high temperatures, and emulsifying properties showing successful results. The water surface tension of 72 mN/m was reduced to 34 mN/m with BCE, achieving a critical micelle concentration at 24.66 ppm. BCE was also applied to polystyrene surface as pre-treatment to avoid microbial biofilm development, showing inhibition in more than 90% of Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes above 2000 ppm BCE. The test continued using BCE as post-treatment to remove biofilms, reporting a significant reduction of 50.10% Escherichia coli, 55.77% Staphylococcus aureus, and 59.44% Listeria monocytogenes in a concentration higher than 250 ppm BCE. Finally, a comparison experiment was performed between sodium lauryl ether sulfate (SLES) and BCE (included in commercial formulation), reporting an efficient reduction with the mixtures. The results suggested that BCE is a promising ingredient for cleaning formulations with applications in industrial food applications.
Frosty pod rot (FPR) of cacao is caused by Moniliophthora roreri (MR). Effective management must include chemical or biological control, in addition to agronomic tactics. Flutolanil has been effective in controlling FPR. The objective of this research was to determine the response to flutolanil of MR isolates from the Amazon and Coast regions of Ecuador. Percentage of mycelial growth inhibition (PGI), and medium inhibitory concentration (IC50) against three concentrations of the fungicide were determined. One µg mL-1 of flutolanil in the culture medium inhibited completely the growth of the 76 MR isolates. At 0.1 μg mL-1, 74/76 were inhibited between 70-97 % compared to the control. Conversely, at the lower concentrations (0.01-0.001 μg mL-1) the results of inhibition were only of 22 % and 47 %, respectively. Four groups were identified: one included the most sensitive (66/76) to different degrees, and three groups representing 10 isolates that were stimulated at low concentrations of flutolanil. IC50 values were low, indicating very high sensitivity in the MR population. IC50max were 0.1342 and 0.1457 in two isolates from the Coast and the Amazon regions, respectively. Isolates from the Coast were significantly less sensitive to flutolanil than those from the Amazon ( IC50 = 0.046 ± 0.03 and IC50 = 0.030 ± 0.02, respectively), however, the differences were minimal. There were no significant differences when comparing the provinces. The most stimulated isolates were found in the provinces of Orellana and Los Ríos. It is concluded that flutolanil seems effective against the causal agent of FPR in Ecuador, both Coast and Amazon regions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.