Marco Antonio Tucuch-Pérez

This research objective was to characterize Euphorbia antisyphilitica, Helianthus annuus and Thymus vulgaris extracts, and to determine their antifungal activity against Macrophomina phaseolina. Additionally, the capacity of filtrates from a Bacillus subtilis (FBS) strain against the same pathogen was evaluated. Phytochemical characterization was performedusing HPLC-MS, while the antifungal activity of the extracts was determined through poisoned medium assays at concentrations ranging from 1 to 80 %. From these results, the inhibitory concentrations at 50 % and 90 % (IC50 and IC90) were obtained. Subsequently, the Detached Leaf Assay (DLA) was used to evaluate the antifungal activity of the extracts and FBS IC90 through the Area Under the Disease Progress Curve (AUDPC). Phenolic compounds from various chemical families were identified. Regarding the antifungal activity, 100 % inhibition was observed using H. annuus and T. vulgarisat a concentration of 20 %. In the DLA assay, FBS and the T. vulgaris and H. annuus extracts were highly effective, limiting the growth of M. phaseolina to 7.14 %, 12.57 %, and 13.86 %, respectively. The results demonstrate that plant extracts and FBS effectively control M. phaseolina.

La marchitez causada por Fusarium oxysporum es una de las principales enfermedades que afectan la producción de chile. En este estudio se evaluó la actividad antifúngica de extractos metanólicos de hojas de Agave striata y tallos de Fouquieria splendens del Desierto Chihuahuense sobre F. oxysporum bajo condiciones in vitro e in vivo en invernadero. La identificación del hongo se realizó mediante claves taxonómicas y análisis molecular. La actividad antifúngica de los extractos se determinó por la técnica de microdilución, con dosis de 3.9 a 2 000 mg∙L-1, con el fin de establecer las concentraciones inhibitorias al 50 y 90 %. Asimismo, se analizó el daño celular inducido en F. oxysporum y se evaluó la efectividad antifúngica de los extractos en condiciones in vivo. Los resultados in vitro evidenciaron que A. striata y F. splendens inhibieron el 100 % del crecimiento del hongo a concentraciones de1 000 y 250 mg∙L-1, respectivamente. Ambos extractos indujeron vacuolización y desorganización citoplasmática en las estructuras del hongo. En condiciones in vivo, el extracto de F. splendens controló totalmente la enfermedad, mientras que A. striata redujosignificativamente su severidad. Los resultados confirman el potencial de estos extractos como agentes de biocontrol sobre F. oxyporum en el cultivo de chile.

Los herbicidas químicos para control de malezas, representa un problema en la actualidad, ya que su uso indiscriminado causa la aparición de poblaciones resistente de malezas, además de afectar el medio ambiente y la salud humana. Por lo que los metabolitos secundarios de microrganismos (MSMs) y los extractos vegetales (EVs) en formulaciones micro-nano encapsulados (NPs) surgen como una posible alternativa al uso de herbicidas de síntesis química, razón por la cual dilucidar su mecanismo de acción es necesario para entender los cambios bioquímicos que estos inducen en las plantas, para poder desarrollar estrategias de control de malezas. El objetivo de la investigación fue determinar la actividad de las enzimas antioxidantes fenilalanina amonio liasa (PAL), peroxidasa (POD) y super oxido dismutasa (SOD) en plantas de Sorghum bicolor, tratadas con metabolitos secundarios de Alternaria sp. (MSAs) y un extracto vegetal de Solanum rostratum (EVSR) solos y formulados en NPs a base de los biopolímeros alginato y quitosan. El estudio se realizó durante el mes de junio del año 2024, para esto se utilizaron plantas de S. bicolor y se determinó la actividad de las enzimas durante 0, 3, 6, 12, 24 y 48 h. Se pudo observar que los NPs cargados con el EVSR y los MSAs fueron los que indujeron mayor actividad enzimática a distintos tiempos, alcanzando 0.36 y 0.34 U mol-1 respectivamente en el caso de PAL, 4.7 y 4.3 U mol-1 con la enzima POD, y 7.3 y 6.5 U mol-1 con SOD. Se concluye que los MSAs y el EVSR formulados en NPS tiene potencial como agentes que pueden modificar los procesos bioquímicos en plantas.

Se realizó un análisis microbiológico en cacahuates salados comercializados a granel y de marcas comerciales en el sur de Saltillo, Coahuila, México, con el objetivo de detectar la presencia de microorganismos de importancia sanitaria, utilizando las metodologías descritas por las Normas NOM-112-SSA1-1994, NOM-210-SSA1-2014 (Apendice H), NOM-114-SSA1-1994 para determinar coliformes totales (CT), Escherichia coli (E. coli) y Salmonella spp., se emplearon claves taxonómicas para identificación de hongos. Dando como resultado la presencia de CT, E. coli y Salmonella spp. en muestras a granel, CT y Salmonella spp. en productos empaquetados. Aspergillus flavus, A. niger, Fusarium spp. y Penicillium spp. en muestras a granel y mediante la prueba presuntiva de aflatoxinas (AF) en agar coco, se detectó fluorescencia azul bajo luz UV en una muestra a granel. Estos resultados resaltan la necesidad de aplicar estrictos estándares de higiene y control de calidad durante la producción, manipulación y venta de los cacahuetes salados.

Tomato crop is among the more important worldwide due to its high production and consumption. However, tomatoes are affected by plant-parasitic nematode Meloidogyne spp., which reduce their yield and quality. To manage this issue, synthetic nematicides are commonly used. However, the use of synthetic nematicides impacts the soil microbiome and alters its structure affecting soil porosity and having effects on organic matter. In contrast, plant oils and extracts have emerged as alternative methods for controlling Meloidogyne spp. The objective of this research was to characterize the oils of Thymus vulgaris and Allium sativum, along with an ethanolic extract of Yucca schidigera, and to evaluate their nematicidal activity when incorporated into a formulation against Meloidogyne spp. under greenhouse conditions. Phytochemical characterization was performed using qualitative techniques and measurements of antioxidant capacity (AC) and total polyphenol content (TPC). The experiment was conducted on tomato plants of the Rio Grande variety, with the following treatments: ATY formulation (A. sativum + T. vulgaris + Y. schidigera) at 8.0 L ha-1, ATY formulation at 12.0 L ha-1, chemical control (a.i. cadusafos, C10H23O2PS2) at 10.0 L ha-1, positive control (inoculated), and negative control (non-inoculated). Phytochemicals with nematicidal properties, such as alkaloids, flavonoids, terpenes, saponins, and tannins, were detected. The ATY formulation (A. sativum + T. vulgaris + Y. schidigera) at doses of 8.0 and 12.0 L ha-1 reduced the number of galls up to 97.29% and juvenile populations (J2) of Meloidogyne spp. up to 98.5%, and improved the plants' physiological development.

Weeds decrease yield in crops through competition for water, nutrients, and light. Due to the circumstances mentioned above and the challenge of the emergence of herbicide-resistant weeds, developing sustainable alternatives becomes imperative. Plant extracts formulated into nano- and micro-encapsulates (NPs) emerge as a viable option for weed management. The objectives of this study were to identify phytochemical compounds within the ethanolic extracts of Carya illinoinensis, Ruta graveolens, and Solanum rostratum; determine their pre-emergence herbicidal activity on the indicator plants Sorghum bicolor and Phaseolus vulgaris; produce and characterize NPs with plant extracts; and assess their phytotoxicity under greenhouse conditions. The extracts were provided by Greencorp Biorganiks de México. Phytochemicals were identified through colorimetric assays and HPLC-MS, while pre-emergence tests were conducted in vitro, assessing concentrations of 12.5, 25, and 50% for each extract. NPs were synthesized using the ionotropic pre-gelation method, with size, zeta potential, and encapsulation efficiency (EE) being characterized. Finally, post-emergence tests were carried out in a greenhouse with seedlings. Compounds belonging to the hydroxycinnamic acid, flavonol, methoxyflavonol, hydroxybenzoic acid, methoxyflavone, tyrosol, stilbene, and lignan families were identified in all extracts. The pre-emergence herbicidal activity was observed for all extracts, with germination percentages ranging from 0 to 41% in both indicator plants. NPs exhibited sizes between 290 and 345 nm, zeta potentials ranging from −30 to −35 mV, and EE up to 94%. Finally, enhanced herbicidal activity was observed with plant extract NPs, with the species S. bicolor being more susceptible. NPs containing plant extracts are a viable option for bioherbicide production; however, continued research is necessary to refine formulations and enhance efficacy.

El cancro bacteriano es una de las enfermedades del tomate (Solanum lycopersicum), la cual es causada por la bacteria Clavibacter michiganensis subsp. michiganensis (Cmm). En el presente trabajo se realizó la identificación de Cmm mediante PCR de punto final utilizando los primers CMM5F y CMM6R. Se evaluó la efectividad de los extractos metanólicos de Agave striata y Fouquieria splendens sobre Cmm in vitro e invernadero, así también se obtuvo información acerca de la composición de fitoquímicos presentes en las plantas. El ensayo in vitro se realizó mediante la técnica de microdilución en placa desde los 3.9 mg/L a 1000 mg/L, se determinó la Ci50 y Ci90 de cada extracto . En el experimento en invernadero se evaluó el efecto de los extractos y un producto orgánico “Biobacter” contra Cmm, se calculó la incidencia, severidad y parámetros morfométricos. Los resultados in vitro indicaron que los extractos de F. splendens y A. striata presentan inhibición sobre el fitopatógeno, sin embargo, el extracto de F. splendens mostro control a menores concentraciones que con A striata. El ensayo en invernadero demostró que la incidencia, severidad y parámetros morfométricos fue menor con el extracto de F. splendens, así después con el producto Biobacter.

Plant extracts (PEs) and essential oils (EOs) contain phytochemical compounds (PCs). Nevertheless, PCs can be degraded when applied on field. The use of nano-encapsulates (NEs) and micro-encapsulates (MEs) arise as an alternative to the application of botanical products. However, NEs and MEs with PCs in plant disease control have not been explored enough. This review discusses the use of PCs for plant disease control and the benefits obtained from formulations with NEs and MEs; furthermore, it discusses methods to produce NEs and MEs.

This chapter will cover topics about the microbial antagonists Trichoderma spp. and Bacillus spp. from the perspective of use as potential biological control agents on plant diseases. Results obtained in the laboratory about from their isolation, microbial strain collections for both genera, taxonomic identification, antifungal activity in in vitro tests, obtained evaluation of the antifungal effect of secondary metabolites from microbial antagonists will be shown. Besides, results obtained from bioassays in the greenhouse and field are used as biopesticides in the control of diseases in fruit trees and vegetables and their effects on the promotion of plant growth and increased crop yield.

Introduction: In several regions of the world, Fusarium oxysporum causes losses on tomato crops; for control it, chemical fungicides are used. Nevertheless, these fungicides causing environmental and resistance problems; therefore, ecological alternatives as plant extracts have been developed. Due to the aim of this work, identify phytochemicals present in ethanolic and aqueous extracts from Agave lechuguilla qualitatively, Carya illinoinensis, Jatropha dioica, Larrea tridentata, and Lippia graveolens and determine their antifungal activity against F. oxysporum.Method: The plants collected from the northeast of Mexico; crudes and concentrated plant extracts obtained; the inhibition percentage and inhibitory concentration to 50 % (IC50) of F. oxysporum for each plant extract were determinate trough microdilution in the plate methodResults: The essential phytochemicals were flavonoids, saponins, tannins, and quinones. The antifungal activity showed at 1000 mg/L inhibition around 40 to 60% by aqueous crude extracts from leaves of L. graveolens and concentrated aqueous extracts from the stem of L. graveolens, respectively. The ethanolic extracts presented 100 % of inhibition for crude extracts of husk from C. illinoinensis; in leaves and stem from L. graveolens the inhibition started from 250 mg/L; for resuspended extracts, the inhibition started from 125 mg/L with L. graveolens stem and leaves; and finally in roots of A. lechuguilla and leaves from L. graveolens the inhibition started from to 250 and 500 mg/L respectively. The best IC50 was of 8.02 mg/L from the ethanolic resuspended extract of L. graveolens stem.Conclusion: The ethanolic plant extracts from L. graveolens, A. lechuguilla, and C. illinoinensis, showed 100 % of inhibiting activity against the development of F. oxysporum, representing an alternative for control of F. oxysporum.