Examinando por Autor "Caro Castro, Junior"

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Rhizospheric actinomycetes from organic crops of native potato (Solanum tuberosum): isolation, phenotypic characterization, molecular identification, and impact on biocontrol of Phytophthora infestans (Mont.) de Bary
(Universidad Nacional de Trujillo, 2020-05-31) Chumpitaz Bermejo, Astrid; Caro Castro, Junior; Cruz Hilacondo, Wilbert Eddy; León Quispe, Jorge
Potato (Solanum tuberosum L.) is the fourth most consumed food crop in the world, whose production in Peru is diminished due to phytosanitary problems and high costs of chemical fertilizers. In the present work, 32 actinomycetes isolated from the rhizosphere of organic native potato crops collected in the town of Cabana, Lucanas, Ayacucho, were characterized phenotypically and evaluated for their in vitro antagonistic capacity against Oomycete phytopathogen Phytophthora infestans. The characterization tests showed that 97% of the actinomycetes were able to assimilate glucose, sucrose, and mannitol; as well as producing extracellular enzymes like amylases (100%) and cellulases (50%). Furthermore, the growth in laboratory culture was better in the range of pH 5.5-8.5 and temperature 28-30 °C. From the tests of antagonism in oat agar (71.9%) and rye agar (31.2%), three strains were selected according to the native potato variety were selected as CAB10-J2 (Ccompis), CAB9-CA4 (Cuchipa-akan) and CAB5-F5 (Futis) with pathogen inhibition rates of 80.05, 77.47 and 37.5% respectively. The strains were identified by molecular tests as members of the genus Streptomyces and owners of polyketide synthase (PKS) genes. It is concluded that the rhizospheric actinomycetes of potato are producers of bioactive compounds capable of remarkably inhibiting the pathogen Phytophthora infestans, being able to be considered candidates in biological control programs of the "potato blight".
Use of yeasts for the biological control of toxigenic Aspergillus sp. associated with Zea mays L.
(Wiley, 2026-03-09) Sánchez Purihuamán, Marilín; Córdova Rojas, L.M.; Caro Castro, Junior; Barturen Quispe, Ada; Vásquez Llanos, Segundo; Robles Castillo, Heber; Carreño Farfán, Carmen
Zea mays "maize" is one of the most important staple foods for both humans and animals, but it is highly susceptible to pathogens such as toxigenic Aspergillus flavus. Yeasts, however, have the potential to control the growth and activity of toxigenic fungi, representing a viable and economical alternative for biocontrol. This study is aimed at evaluating the efficiency of yeasts in controlling toxigenic A. flavus associated with maize grains. To achieve this, toxigenic A. flavus and yeast isolates were obtained and identified, then coinoculated in vitro to assess their effect on mycelial growth inhibition and total aflatoxin production through yeast-derived volatile organic compounds (VOCs). We found that 147 of the isolated yeasts, when coinoculated with A. flavus, reduced mycelial growth up to 89%. VOCs from five yeast strains of the genera Saccharomyces and Meyerozyma inhibited colony growth up to 86% and induced changes at both the macro- and micromorphological levels in toxigenic A. flavus. Additionally, VOCs from four yeast strains reduced total aflatoxin levels up to 98%. In conclusion, one yeast strain, identified as Meyerozyma caribbica, effectively inhibited both mycelial growth and toxin production in toxigenic Aspergillus sp., demonstrating its potential as a biocontrol agent to reduce fungal contamination in maize grains.