Genetic Diversity of Mexican Avocado in Nuevo Leon, Mexico | InTechOpen, Published on: 2015-04-15. Authors: Adriana Gutiérrez-Díez, Enrique Ignacio Sánchez-González, Jorge Ariel Torres-Castillo, et

This study evaluates the impact of biotic elicitors and hormone regimes on the in vitro establishment, shoot multiplication, and organogenesis of Solanum tuberosum L. cv. Fianna under controlled laboratory conditions. Explants derived from pre-treated tubers were cultured on Murashige and Skoog (MS) medium supplemented with vitamins and varying concentrations of growth regulators or elicitors. Aseptic establishment achieved a high success rate (~95%) using a 6% sodium hypochlorite disinfection protocol. Multiplication was significantly enhanced with a combination of 0.2 mg L⁻¹ naphthaleneacetic acid (NAA) and 0.5–1.0 mg L⁻¹ benzylaminopurine (BAP), producing the greatest number and length of shoots and roots. Direct organogenesis was stimulated by bio-elicitors Activane^®, Micobiol^®, and Stemicol^® in (MS) basal medium at mid-level concentrations (0.5 g or mL L⁻¹), improving shoot number, elongation, and root development. Activane^®, Micobiol^®, and Stemicol^® are commercial elicitors that stimulate plant defense pathways and morphogenesis through salicylic acid, microbial, and jasmonic acid signaling mechanisms, respectively. Indirect organogenesis showed significantly higher callus proliferation in Stemicol^® and Micobiol^® treatments compared to the control medium, resulting in the highest fresh weight, diameter, and friability of callus. The results demonstrate the potential of biotic elicitors as alternatives or enhancers to traditional plant growth regulators in potato tissue culture, supporting more efficient and cost-effective micropropagation strategies.

Plants protect themselves, after pathogen attack, through the passive and active defense mechanisms. The treatment of plants with various agents, including cell wall fragments, plant extracts, and synthetic chemicals, can induce resistance to subsequent pathogen attack both locally and systemically. In view of the capability of phytochemicals compounds found in fruits and vegetables with different proven health benefits to consumers, there are different strategies to enhance the concentration of these compounds, among which the use of elicitors. Elicitation has been used to trigger different defense responses in plants, which lead to different mechanisms, such as activation of enzymes related with secondary metabolism. In this study we investigated the effects of elicitors (Activane®, Micobiol®, Stemicol® in doses of 1.8 g L⁻¹, 3 m L⁻¹ and 2.5 g·L⁻¹) on the activity of two enzymes (polyphenoloxydase and peroxidase) in leaves as well as on the bioactive content (DPPH scavenging activity, total phenol and total flavonoid content) in fruits of Solanum lycopersicumL. The elicitors studied affected the production of enzyme and antioxidant activities in tomato, though showed a variable influence on the production of total phenolic and flavonoid content in tomato fruits. In general, the elicitors are able to increase polyphenoloxydase activity in leaves and phytochemical properties in fruits, with a significant negative correlation between the DPPH scavenging activity, total phenolic and flavonoids. These findings provide positive directions for the possible use of these elicitors in tomato (‘Bola’ and ‘Saladette’) production in greenhouse. Highlights - Elicitors increase the enzymatic activity of PPO in tomato leaves. - The production of total phenolic contents and flavonoids depends on type of elicitors. - No effects on the peroxidase content of the tomato leaves. - The antioxidant capacity of the aqueous fruits extract showed a significant difference (P = 0.05) between the treatments in the Saladette variety. - Positive relationship between total phenolic contents and flavonoids.

Potato is an essential crop worldwide, and optimizing micropropagation techniques is important for enhancing germplasm conservation and large-scale production. This study focuses on the in vitro propagation of two potato varieties, Agata and Fianna, emphasizing optimizing sterilization protocols, shoot induction, rooting, and microtuber production. Apical buds from healthy, disease-free plants were selected as explants. These buds were surface-sterilized using 70% ethanol and sodium hypochlorite (NaOCl) with Tween-20. The explants were excised from tuber sprouts and cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of plant growth regulators, including benzylaminopurine (BAP) at 0.10–0.40 mg/L, gibberellic acid (GA3) at 0.20–1.00 mg/L, and naphthalene acetic acid (NAA) at 0.01 and 0.04 mg/L to promote root development. The study also explored the effects of these hormonal treatments on shoot induction, proliferation, and rooting. Significant differences were observed between the two varieties regarding oxidation, contamination, and aseptic conditions, with Fianna demonstrating better resistance to oxidation and contamination than Agata. Shoot multiplication was most efficient with BAP concentrations of 0.40 mg/L for Fianna and 0.30 mg/L for Agata. Root induction was maximized with higher sucrose concentrations (110 g/L) and GA3 (1.00 mg/L) for Agata, while moderate concentrations of these compounds produced optimal results for Fianna. Microtuber formation was most successful with moderate sucrose (80–100 g/L) and GA3 (0.25–0.75 mg/L) concentrations. This study provides valuable insights into optimizing tissue culture practices for potato propagation, enhancing both microtuber production and the overall efficiency of potato production systems.

La resistencia a los antibióticos por parte de las bacterias está provocando gran impacto negativo en la salud humana y en la producción animal. Actualmente, Staphylococcus aureus es considerada dentro de los seis principales grupos bacterianos con mayores reportes de aparición de resistencia a nivel mundial. Por otro lado, durante décadas las plantas de uso medicinal han sido fuente importante de compuestos bactericidas; sin embargo, también se ha empezado a documentar otras moléculas con otros mecanismos antimicrobianos, como es la inhibición de la percepción de quórum (anti-percepción de quórum (APQ)). En la medicina tradicional mexicana las hojas de aguacate mexicano (Persea americana var drymifolia) han sido empleadas para tratar diversos padecimientos que involucran infecciones bacterianas, por lo que es factible contenga compuestos que posean efectos antioxidantes, bactericidas y APQ, que ayuden a combatir las infecciones de cepas resistentes. De tal manera, que el objetivo de esta investigación fue determinar el efecto de los polifenoles totales de las hojas de Persea americana var. drymifolia y su actividad APQ sobre cepas de S. aureus resistentes a meticilina (MRSA). Métodos: Se obtuvieron los polifenoles presentes en las hojas de 18 cultivares de aguacate mexicano mediante extracción asistida por ultrasonido y fueron purificados en una columna de amberlita. Estos polifenoles fueron analizados funcionalmente y evaluados contra cepas de S. aureus MRSA para determinar su efecto APQ sobre el sistema denominado Agr.Resultados: Los polifenoles extraídos de las hojas de aguacate de raza mexicana exhiben una fuerte actividad bactericida. De los 18 cultivares probados, la variedad María Elena fue la que presentó el mayor efecto, exhibiendo una CMI de 116 μg∙mL-1 y un CMB de 133 μg∙mL-1 contra la cepa de MRSA μ3. Sin embargo, también logran inhibir los niveles de expresión del operón agr (P2 y P3) con respecto al gen constitutivo de rDNA 16S. De igual manera, los polifenoles mostraron una buena actividad antioxidante, además de que se logró identificar la presencia de flavonoides y saponinas.Discusión y Conclusión: Los polifenoles extraídos de las hojas de aguacate mexicano, exhiben principalmente actividad bactericida, pero también inhiben la expresión de genes asociados a la percepción de quórum de cepas de S. aureus MRSA. De igual manera, presentan una buena actividad antioxidante, lo que en conjunto puede ayudar a contrarrestar las infecciones con cepas resistentes de manera más eficiente. Por lo tanto, las hojas de aguacate mexicano son una fuente importante de metabolitos antioxidantes, bactericidas y APQ.