Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Evaluation of the contribution of maize germ peroxidases to resistance to the storage pest prostephanus truncatus(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-07) Cervantes Macedo, Elizabeth; García Lara, Silverio; emipsanchez; School of Engineering and Sciences; Campus Monterrey; González Rodríguez, América TzitzikiMaize is a globally important crop used for food, feed, and bioethanol production. However, during storage, it faces serious threats from biotic factors, such as insect pests, particularly Prostephanus truncatus, which can cause severe grain damage and losses of up to 80%, depending on the region and conditions. These infestations also affect grain quality, nutritional value, and marketability. Maize kernels exhibit various resistance mechanisms involving structural, genetic, and biochemical traits, including proteins like peroxidases. Recent studies have linked peroxidase activity to insect resistance, with activity detected in kernel tissues, including the aleurone layer, pedicel, and germ. Although peroxidase activity is mainly concentrated in the germ, little is known about the specific peroxidases involved and their role during insect interactions, creating a gap in our understanding of this defense mechanism. This research aims to analyze the role of germ peroxidases in resistance to P. truncatus in mature maize kernels and germs. Susceptibility of maize kernels and germ tissues to P. truncatus was evaluated and compared with soluble protein concentration and peroxidase activity in the germ. Additionally, a proteomic approach was employed to identify candidate peroxidases and other proteins potentially involved in resistance mechanisms. Results revealed a significant negative correlation between susceptibility traits in maize kernels and peroxidase activity in the germ, as well as a similar correlation between these traits and soluble protein concentration. These findings suggest that peroxidase activity and soluble protein accumulation in the germ likely play an important role in kernel resistance. Despite previous reports of some genotypes exhibiting low germ damage after insect interaction, all germ samples in this study showed relatively high levels of damage, regardless of genotype. Therefore, germ tissue does not exhibit any antixenosis effect. Further research is recommended to evaluate protein candidates in the germ and kernel contributing to resistance during storage.
- Tocopherol contribution to the resistance against storage pest Prostephanus truncatus in maize(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024-12-02) Aguirre Espinoza, Carlos; García Lara, Silverio; emimmayorquin; Mora Vásquez, Soledad; School of Engineering and Sciences; Campus Monterrey; Gonzalez Rodriguez, America TzitzikiProstephanus truncatus infestation can cause losses as high as 80% on stored maize. Sources of resistance against this pest are related to the antioxidant capacity of the pericarp and aleurone layer structures, mainly due to phenolic acids content and their derivatives. Nonetheless, there is not enough information about the germ structure or the liposoluble antioxidants, such as tocopherols. To determine the contribution of tocopherols and liposoluble antioxidant capacity to the resistance against P. truncatus, thirteen genotypes of maize were tested in two confined bioassays (n=3). The first was to assess the susceptibility of each genotype. The second was with the enriched structure of the germ to gather information on damage and development of P. truncatus on this structure. Seven susceptibility parameters were recorded 7 and 60 days after infestation, and ten genotypes were selected based on a Susceptibility Selection Index, with five recognized as resistant and five as susceptible. HPLC-FLD was used to determine the content of tocopherols (δT, γT, and αT), and an ORAC assay was performed to measure the lipophilic antioxidant capacity among the ten genotypes selected. All Population 84 genotypes exhibited less damage by P. truncatus and were categorized as resistant. Three Population 84 genotypes were selected: P84C0Y (SI = 0.17), P84C4W (SI = 0.27; highest tocopherol content, 39.58 mg/kg; high L-AC, 429.04 μmol TE/g), and P84C4Y (SI = 0.51). Two selected genotypes previously recognized as susceptible were classified as resistant: Pink Creole (SI = 0.39; high tocopherol content 39.40 mg/kg; highest L-AC, 488.30 μmol TE/g) and Don Goyo (SI = 0.55). The most susceptible genotype was Red Creole (SI = 3.56; lowest L-AC, 205.48 μmol TE/g), the remaining 4 susceptible varieties selected were Peru2 (SI = 1.23), NAYA29B (SI = 1.07), Panchito (SI = 1.00; lowest tocopherol content, 11.21 mg/kg; low L-AC, 250.4 μmol TE/g), and Pozolero (SI = 0.97). Additionally, a strong correlation (p > 0.01) demonstrated that a short-length bioassay (7 days) can be comparable to a full-length bioassay (60 days). Both can measure a genotype susceptibility to P. truncatus based on weight loss, but only a full-length bioassay can provide information on adult emergence.