Author: Irma Leticia Medina Baizabal
The development of plant-derived products to control Bemisia tabaci Genn. (Hemiptera: Aleyrodidae) is an urgent need for production of horticultural crops. Plant extracts and essential oils of several species of the genus Eugenia (Myrtaceae) have shown insecticidal activity. In southern Mexico, leaf extracts from Eugenia winzerlingii showed nematicidal effect but its insecticidal properties have not been explored. Therefore, the objective of this study was to evaluate the insecticidal effect of aqueous and organic extracts from E. winzerlingii leaves on B. tabaci egg, nymph and adult stages, and else to explore its nursery propagation. Then, extracts of this species were obtained by maceration with different polarity solvents. Bioassays were carried out on Capsicum chinense leaves. Mortality assays showed that aqueous and total crude ethanol (TCE) extracts necrosed the eggs (LC50 = 0.21% w/v and 4.68 mg/mL, respectively), whereas hexane, ethyl acetate (ETA), residual ethanol and TCE extracts affected the nymphs (LC50 = 0.25 - 4.85 mg/mL). In adults, oviposition inhibition by free choice assay indicated that TCE and ETA extracts had major activity (EC50 = 14.62 and 27.86 µg/cm2 , respectively). On other hand, the sexual and vegetative propagation of E. winzerlingii showed that this species can be easily cultivated by seeds. In conclusion, extracts of E. winzerlingii leaves are highly effective in controlling B. tabaci. TCE extract, in particular, was toxic to three stages of B. tabaci. This plant could be a potential alternative to develop a novel botanical insecticide to manage this destructive pest.
BIOASSAYS EUGENIA WINZERLINGII OVIPOSITION INHIBITION PLANT PROPAGATION BEMISIA TABACI BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA MOLECULAR BIOLOGÍA MOLECULAR DE PLANTAS BIOLOGÍA MOLECULAR DE PLANTAS
MARTIN PABLO ANTONIO MORENO PEREZ MARIA MARCELA GAMBOA ANGULO GABRIELA PATRICIA HEREDIA ABARCA BLONDY BEATRIZ CANTO CANCHE CECILIA MONICA RODRIGUEZ GARCIA Irma Leticia Medina Baizabal LETICIA PERAZA ECHEVERRIA (2016)
Nowadays, it is highly necessary to find more and safer agrochemicals. In this sense, micromycetes are an important source of natural products which could be used to control plant diseases. Therefore with the aims to contribute in this searching of natural products with antimicrobial applications, a total of 49 fungal strains were isolated from the Yucatan Peninsula. These fungi were cultured in fermented rice, their respective organic extracts macerated in ethyl acetate (EAE) and methanol (ME) were obtained and tested against five fungal pathogens of agricultural importance. These included Alternaria chrysanthemi, Colletotrichum gloeosporioides, Mycosphaerella fijiensis, and the bacteria Erwinia carotovora and Xanthomonas campestris using microdilution assays. The 69% of fungal extracts showed antifungal or antibacterial (2000 and 200 µg/mL, respectively) against at least one of the tested target. Strains Penicillium sp. OSE-61, Fusarium sp. OH2-30, Hypocrea lixii OSN-37 and Rhizoctonia solani OSE-73 showed activity against at least three of the five study pathogens. The most active EAE were partitioned, and its low (A), medium (B) polarity and precipitated (C) were obtained and assessed. The fraction A from Fusarium KS-15 displayed the lowest Minimum Inhibitory Concentration (MIC ≤25 µg/mL) and bactericide effect on X. campestris; fraction B of Penicillium sp. OSE-61 was relatively greater than the previous on A. chrysanthemi (MIC ≤500 µg/mL). Last fraction also exhibited good inhibitory effect on C. gloeosporioides. Finally, fraction B of H. lixii OSN-37 displayed promissory antifungal effect on C. gloeosporioides y M. fijiensis (MIC=1000 µg/mL). This research contributes to enrich the limited knowledge on the biological activity of native anamorphic fungi of the sinkholes of Yucatan and its potential use in biotechnological applications in agriculture.
Martín Antonio Pablo Moreno Pérez MARIA MARCELA GAMBOA ANGULO GABRIELA PATRICIA HEREDIA ABARCA Blondy Beatriz Canto Canché MIGUEL ENRIQUE ROSADO VALLADO Irma Leticia Medina Baizabal RAUL TAPIA TUSSELL (2014)
In the search for natural alternatives to control fungal diseases, antagonistic fungi are valuable sources to find new models. In the present study, a total of 41 tropical micromycetes were isolated from plant debris submerged in sinkholes of the Yucatán Península. All strains were tested in antagonist assays against four phytopathogenic fungi (Colletotrichum gloeosporioides, Corynespora cassiicola, Curvularia sp. and Fusarium sp.). Results of the antagonistic assays showed mycelial growth inhibition (MCI ≥50 %) by 17 isolates (41 %) against at least one of the targets tested. The highest inhibition was exhibited by the Hypocrea lixii OSN-37 (MCI=61-77%) and Rhizoctonia solani OSE-73 (MCI=55-64%) strains against all targets while Pestalotiopsis mangiferae OH-02 (51-59%) caused inhibition on three of four pathogen strains. These three strains were cultured in fermented rice to obtain their ethyl acetate and methanol extracts which were tested against C. gloeosporioides using the microdilution assay. Results showed H. lixii OSN-37 and R. solani OSE-73 to be producers of antifungal metabolites as one of their modes of action. In conclusion, three promising antagonistic native strains were isolated from plant debris submerged in the Yucatán sinkholes, representing a valuable contribution to the development of ecofriendly alternatives to control fungal diseases in agriculture crops of the tropical regions.
MARIA MANUELA DE JESUS REYES ESTEBANEZ ELIZABETH DE LOS ANGELES HERRERA PARRA JARIO CRISTOBAL ALEJO GABRIELA PATRICIA HEREDIA ABARCA BLONDY BEATRIZ CANTO CANCHE Irma Leticia Medina Baizabal MARIA MARCELA GAMBOA ANGULO (2011)
Forty seven fungal strains were isolated from plant debris in the tropical regions of Mexico, where fifteen of them were identified to species and twenty two to genus level. All isolates were grown in fermented rice and their EtOAc extracts screened against ten targets, four bacteria (Bacillus subtilis, Erwinia carotovora, Staphylococcus aureus and Xanthomonas campestris), the yeast Candida albicans, three phytopathogenic fungi (Alternaria tagetica, Colletotrichum gloeosporioides and Fusarium oxysporum), the Oomycete Pythium aphanidermatum and the nematode Meloidogyne incognita. Antimicrobial activity was detected in 18 isolates against at least one of the target strains tested. Seven of these isolates with broad spectrum activity, which were defatted and their minimum inhibitory concentrations (MICs) were determined by microdilution assay. The greatest antagonistic action was produced by Cylindrium elongatum with broad spectrum activity while Corynespora cassiicola and Memnoniella sp. MR33 showed moderate antimicrobial properties. On other hand, in vitro nematotoxic activity was clearly detected only in Selenosporella sp. GH26 with 91 (LD 50) and 147 µg/ml (LD 90). This is the first report on the isolation and biological evaluation of anamorphic fungi from some Mexican tropical regions, demonstrating their potential as a source of biologically active natural metabolites for use in future applications in agriculture or pharmacy. Antimicrobial and nematicidal screening of anamorphic fungi isolated from plant debris of tropical areas in Mexico
ANA LILIA RUIZ JIMENEZ AZUCENA GONZALEZ-COLOMA MARIA FE ANDRES ESAU RUIZ SANCHEZ GABRIELA PATRICIA HEREDIA ABARCA SERGIO RUBEN PERAZA SANCHEZ Irma Leticia Medina Baizabal MARIA MANUELA DE JESUS REYES ESTEBANEZ Blondy Beatriz Canto Canché MARIA MARCELA GAMBOA ANGULO (2017)
Fungal metabolites are promising alternatives for the development of biorational pesticides. In this sense, microfungi from tropical regions are valuable sources of natural compounds for pest management. With the aim of broadening the search for new eco-friendly products to manage plant pests, this study was carried out to evaluate the biological activity of 23 tropical fungal extracts on three species of phytophagous insects and a plant parasitic nematode. In addition, the active principles of the most effective extract were identified. The insect deterrent activity of fungal extracts was evaluated on the settling of aphids Myzus persicae and Rhopalosiphum padi, and on the feeding of lepidoptera larva Spodoptera littoralis; the nematostatic activity was evaluated on the mobility of Meloidogyne javanica. Active metabolites from Gliomastix masseei were identified by GC-MS techniques and by comparison with commercial standards. Results showed seven extracts with strong effect on the settling of M. persicae and R. padi (settling inhibition >80%). The calculated median of effective concentration (EC50) values ranged from 8 to 38μg/cm2 for the extracts of Clonostachys rosea and G. masseei, respectively. Bioassay-guided separation of the ethyl acetate extract of G. masseei revealed the presence of fatty acids and their derivatives, where methyl 9-octadecenoate was the most active compound with EC50 values of 16μg and 35μg/cm2 for M. persicae and R. padi, respectively. Extracts of C. rosea and G. masseei could be a promising option in the control of pest aphids in agriculture.
MARIA DEL ROCIO DE FATIMA ALEJOS GONZALEZ ROCIO DE LOURDES BORGES ARGAEZ Fabiola Escalante Erosa MARIA MARCELA GAMBOA ANGULO Irma Leticia Medina Baizabal YASMIN DEL CARMEN OJEDA UC FILOGONIO MAY PAT MATILDE PEREZ RODRIGUEZ SERGIO RUBEN PERAZA SANCHEZ NORMA EDISELA SALAZAR AGUILAR Luis Manuel Peña-Rodríguez (1996)
Desde sus inicios el hombre ha aprendido a conocer y clasificar las plantas de acuerdo a sus propios usos e intereses. Por un lado ha reconocido aquellas plantas que le sirven como alimento y, por otro, las plantas que puede utilizar con fines medicinales, tóxicos, insecticidas y de construcción. 1,2. La medicina tradicional, basada en el uso de plantas, nunca ha desaparecido por completo y en las zonas rurales remotas o entre minorías étnicas de la sociedad industrial moderna, persiste corno complemento del hombre pobre o como alternativa de la asistencia médica inexistente.