Controlled Production of Carnosic Acid and Carnosol in Cell Suspensions of Lepechinia meyenii Treated with Different Elicitors and Biosynthetic Precursors.

Lepechinia meyenii is a medicinal plant specialized in the biosynthesis of different types of antioxidants including the diterpenes carnosic (CA) acid and carnosol (CS). Herein we present the results of plant tissue culture approaches performed in this medicinal plant with particular emphasis on the generation and evaluation of a cell suspension system for CA and CS production. The effect of sucrose concentration, temperature, pH, and UV-light exposure was explored. In addition, diverse concentrations of microbial elicitors (salicylic acid, pyocyanin, Glucanex, and chitin), simulators of abiotic elicitors (polyethylene glycol and NaCl), and biosynthetic precursors (mevalonolactone, geranylgeraniol, and miltiradiene/abietatriene) were evaluated on batch cultures for 20 days. Miltiradiene/abietatriene obtainment was achieved through a metabolic engineering approach using a recombinant strain of Saccharomyces cerevisiae. Our results suggested that the maximum accumulation (Accmax ) of CA and CS was mainly conferred to stimuli associated with oxidative stress such as UV-light exposure (Accmax , 6.2 mg L-1 ) polyethylene glycol (Accmax , 6.5 mg L-1 ) NaCl (Accmax , 5.9 mg L-1 ) which simulated drought and saline stress, respectively. Nevertheless the bacterial elicitor pyocyanin was also effective to increase the production of both diterpenes (Accmax , 6.4 mg L-1 ). Outstandingly, the incorporation of upstream biosynthetic precursors such as geranylgeraniol and miltiradiene/abietatriene, generated the best results with Accmax of 8.6 and 16.7 mg L-1 , respectively. Optimized batch cultures containing 100 mg L-1 geranylgeraniol, 50 mg L-1 miltiradiene/abietatriene (95 : 5 %) and 5 g L-1 polyethylene glycol treated with 6 min UV light pulse during 30 days resulted in Accmax of 26.7 mg L-1 for CA and 17.3 mg L-1 for CS on days 18-24. This strategy allowed to increase seven folds the amounts of CA and CS in comparison with batch cultures without elicitation (Accmax , 4.3 mg L-1 ).

Essential Oil of Lepidium virginicum: Protective Activity on Anthracnose Disease and Preservation Effect on the Nutraceutical Content of Tamarillo Fruit (Solanum betaceum).

The essential oil from the annual plant Lepidium virginicum L. was chemically characterized in three consecutive years (2018-2020). The essential oils were evaluated in vitro and in situ on the causal agent of anthracnose in tamarillo fruits (Solanum betaceum). The main volatile constituents were phenylacetonitrile (>60 %), linalool (>10 %), limonene (>7 %) and α-terpineol (>5 %). The essential oil (MIC, 19-30 µg mL-1 ), phenylacetonitrile (MIC, 45 µg mL-1 ) and α-terpineol (MIC, 73 µg mL-1 ) caused a significant inhibition in the conidial viability from a wild strain of Colletotrichum acutatum, which was isolated and identified as a causal agent of anthracnose. The inoculation of conidia from C. acutatum in non-symptomatic tamarillo fruits, followed by the in situ treatment with different concentrations of the essential oil (>30 µg mL-1 ), phenylacetonitrile and α-terpineol, significantly (p<0.01) avoided the degradation of anthocyanins (delphinidin 3-O-rutinoside, cyanidin 3-O-rutinoside and pelargonidin 3-O-rutinoside) and carotenoids (ß-cryptoxanthin and ß-carotene) as well as retarded yellowing and necrosis triggered by anthracnose at least for 10 days. Our results suggest the potential use of the essential oil from L. virginicum as a natural component to preserve the nutraceutical content of tamarillo fruits against C. acutatum infection.

Distribución potencial de dos subespecies de Montanoa tomentosa (Asteracerae) en México / Potential distribution of two subspecies of Montanoa tomentosa (Asteracerae) in Mexico

Introducción: la Montanoa tomentosa es un recurso fitogenético con propiedades medicinales utilizado en México. A pesar de su relevancia botánica, la información específica de las distribuciones de taxones infraespecíficos y la los factores que influyen en su desarrollo aún son limitados. Objetivo: Informar el potencial geográfico distribución y las variables ambientales asociadas a nichos ecológicos de dos subespecies de M. tomentosa (M. tomentosa subsp. Tomentosa y M. tomentosa subsp. Xanthiifolia) en territorio mexicano. Métodos: A Se creó una base de datos de registros de herbario, se realizó una búsqueda sistemática in situ de ambas subespecies desde Octubre de 2015 a marzo de 2016, durante la temporada de floración y fructificación. Posteriormente, recorridos exploratorios (Guanajuato, Querétaro, Hidalgo, Ciudad de México, Estado de México, Puebla, Oaxaca y Chiapas). Un total de 181 Se muestrearon y georreferenciaron individuos, generando nuevos registros para la actualización de la base de datos. Tres hábitat modelos de idoneidad (complejo M. tomentosa, M. tomentosa subsp. tomentosa y M. tomentosa subsp. xanthiifolia) se generaron utilizando el software MaxEnt. Este software estima la probabilidad de distribución de especies. utilizando datos georreferenciados y características ambientales como predictores, mediante el logaritmo de entropía máxima y el método bayesiano. Resultados: De 22 variables ambientales utilizadas como predictores, cinco (estacionalidad de temperatura, isotermalidad, temperatura máxima del mes más cálido, precipitación del más cálido trimestre y precipitación del trimestre más húmedo) contribuyeron con el 70,2% de la contribución porcentual total. los El modelo mostró una distribución potencial de 77 688 km2, aproximadamente el 4% del territorio de la República Mexicana. Ambos La subespecie creció entre 500 y 2 500 m. Se asociaron a vegetación xerófila y heliófila, a veces también estaban ubicadas en la periferia o incrustadas en aberturas de bosques templados y subhúmedos. No estuvieron presentes regiones secas del norte del país. Conclusiones: estacionalidad de la temperatura, isotermalidad y la temperatura máxima del mes más cálido determinan la distribución de la especie. Precipitación del cuarto más cálido y la precipitación del cuarto más húmedo define el hábitat entre M. tomentosa subsp. tomentosa y M. tomentosa subsp. xanthiifolia. Estos hallazgos aclaran las preferencias ecológicas y la delimitación los taxones infraespecíficos de M. tomentosa.

Introduction: Montanoa tomentosa is a phytogenetic resource with medicinal properties used in Mexico. Despite its botanic relevance, the specific information of infraespecific taxa distributions and the environmental factors that influence their development is still limited. Objective: To report the potential geographic distribution and the environmental variables associated to ecological niches of two subspecies of M. tomentosa (M. tomentosa subsp. tomentosa and M. tomentosa subsp. xanthiifolia) in the Mexican territory. Methods: A database of herbarium records was created, an in situ systematic search of both subspecies was carried out from October 2015 to March 2016, during the flowering-fruiting season. After that, exploratory tours (Guanajuato, Querétaro, Hidalgo, Mexico City, State of Mexico, Puebla, Oaxaca and Chiapas) were realized. A total of 181 individuals were sampled and georeferenced, generating new records for the database upgrading. Three habitat suitability models (M. tomentosa complex, M. tomentosa subsp. tomentosa and M. tomentosa subsp. xanthiifolia) were generated using the MaxEnt software. These software estimates the probability of species distribution using geo-referenced data and environmental characteristics as predictors, through the maximum entropy logarithm and the Bayesian method. Results: From 22 environmental variables used as predictors, five (seasonality of temperature, isothermality, maximum temperature of the warmest month, precipitation of the warmest trimester and precipitation of the wettest trimester) contributed 70.2 % of the total percentage contribution. The model showed a potential distribution of 77 688 km2, approximately 4 % of the Mexican Republic territory. Both subspecies grew between 500 and 2 500 m. They were associated to xerophilous and heliophiles vegetation, sometimes they were located in the periphery or embed in openings of temperate and sub-humid forests too. They were not present dry regions from the North of the country. Conclusions: Temperature seasonality, isothermality and maximum temperature of the warmest month determine the distribution of the species. Precipitation of the warmest quarter and precipitation of wettest quarter defines the habitat between M. tomentosa subsp. tomentosa and M. tomentosa subsp. xanthiifolia. These findings clarify the ecological preferences and delimitation the infraspecific taxa of M. tomentosa.