Araceli Rodríguez-Sahagún

Effect of light quality and culture medium on somatic embryogenesis of Agave tequilana Weber var. Azul

Somatic embryogenesis in Agave tequilana Weber var. Azul was affected by the interaction between the light regimes applied during the induction phase and the expression phase. When embryogenic calli was exposed to white or red light during the expression phase, an average of two germinated embryos per explant was obtained regardless of the light treatment used for callus induction. Conversely, the highest number of germinated embryos, an average of 18 per explant, was obtained when applying either white or red light during the induction phase and then wide-spectrum light during the expression phase. Culture medium had also a great influence in this process, with embryo germination being reduced by up to 70%, depending on the light treatment, when using Schenk and Hildebrandt (SH) medium instead of Murashige and Skoog (MS) medium.

Biotechnological Production of Plant Secondary Metabolites

Description: Modern techniques have been developed to overcome problems associated with the extraction of natural products from plants. These techniques include production of secondary metabolites by biotechnological methods such as plant tissue culture and microbial biotransformation of natural substances. Such methods have led to an increased yield of secondary metabolite amount, the discovery of new biochemical derivatives and agricultural development. For instance, use of these techniques in agricultural area have led to some beneficial traits such as formation of new varieties of known plant species, better crop quality, higher yield, better nutritive properties, more resistant species to insects and pests. Microbial biotransformation is beneficial in plant secondary metabolite production and derivatization (chemical modification of any compound made by a microorganism) and is chiefly applicable to several varieties of terpenes and steroids. This E-book demonstrates recent developments in this field. It will be of particular interest to the professionals in pharmaceutical and biotechnological industries, as well as natural product chemists, medicinal chemists, plant biochemists, and molecular biologists.

Modulation of antioxidant defense system after long term arsenic exposure in Zantedeschia aethiopica and Anemopsis californica

Zantedeschia aethiopica (calla lily) and Anemopsis californica (yerba mansa) are plant species capable of accumulating arsenic (As) and therefore proposed as phytoremediation for removal of As from drinking water. The effects of a continuous 6 month As exposure (34±11 μg/L) from local contaminated groundwater on the antioxidant response of Z. aethiopica and A. californica were evaluated in leaves and stems of the plants bimonthly in a subsurface flow constructed wetland. As increased the activities of the antioxidant enzymes ascorbate peroxidase, glutathione reductase and catalase where higher levels were observed in Z. aethiopica than A. californica. No significant differences were detected on lipid peroxidation levels or antioxidant capacity evaluated by ORAC and DPPH assays or total phenol contents in any part of the plant, although in general the leaves of both plants showed the best antioxidant defense against the metal. In conclusion, Z. aethiopica and A. californica were able to cope to As through induction of a more sensitive enzymatic antioxidant response mechanism.

Efficient protocols for in vitro axillary bud proliferation and somatic embryogenesis of the medicinal plant Anemopsis californica

Anemopsis californica, commonly known as yerba mansa, is an important medicinal plant that has traditionally been used to treat a variety of digestive, respiratory and skin ailments, and has been reported to possess anticancer properties. The increase in demand for this medicinal plant puts wild populations at risk due to over-harvesting; therefore, the development of alternatives such as in vitro propagation may help reduce this pressure on natural plant resources. The aim of this work was to develop protocols for the in vitro propagation of A. californica through axillary bud proliferation and somatic embryogenesis. Shoot bud multiplication was achieved using nodal explants from axenic seedlings, reaching the highest multiplication rate (on average 15 shoots per explant) when the culture medium was supplemented with 4 mg/L kinetin. Propagated shoots produced roots in medium containing 1 mg/L indole-3-butyric acid. Best induction of somatic embryogenesis (on average 19.75 embryos per explant) was obtained from leaf explants cultured on medium supplemented with 4 mg/L naphthalene acetic acid. These protocols may be used either for the commercial mass propagation of the species, studies on the production of secondary metabolites or as a basis for the development of genetic improvement strategies.

In vitro clonal propagation and regeneration of the commercially important plant Mexican oregano (Lippia graveolens)

Lippia graveolens (Verbenaceae family), commonly known asMexican oregano, is an important plant widely used as both a condiment and raw material for extraction of essential oil, having multiple applications in food, pharmaceutical, and cosmetic industries (Sánchez et al. 2007; Martínez-Rocha et al. 2008). The species is an evergreen, woody shrub, native to the southern part of the USA,Mexico, and Central America (Fig. 1a). Three closely related species belonging to the genus Lippia are customarily known as Mexican oregano: L. graveolens H.B.K., Lippia berlandieri Schauer, and Lippia palmeri; though the two former species have been reported as synonyms by several authors (Avila-Sosa et al. 2010). Mexico produces about 6,500 t of dry oregano leaves annually. The industry is primarily export oriented with up to 90% of total production being traded abroad, making this country the main exporter of Mexican oregano in the world (Villavicencio-Gutiérrez et al. 2010). The average biomass yield of this crop can vary between 1 and 4 t per hectare per year, with a typical recovery of 2 kg of essential oil per metric ton, which corresponds to an average yield of 30 kg of essential oil per hectare. Since sun drying destroys the essential oil, leaves must be shade dried and the extracted oil then stored in dark flasks to protect it from light (CONAFOR 2011). Mexican oregano offers great potential for further development in terms of economic profit, since the chemical composition of the essential oil is considered superior to that obtained from Mediterranean oregano (Origanum vulgare) produced mainly in Greece and Turkey. Moreover, the proportion of essential oil contained in L. graveolens (∼2%) is higher compared to O. vulgare subsp. hirtum and O. vulgare subsp. gracite (∼1.5% in both cases; Silva-Vázquez et al. 2008). Mexican oregano is harvested mainly from natural populations and the harvest period coincides with the flowering time, which consequently alters fruit and seed development. This fact, in conjunction with deficient crop management practices, has led to critical reductions in population size and density. Additionally, it has been reported that only about 11% of flowers produce fruit, and each fruit usually contains only one seed (Ocampo-Velázquez et al. 2009). The commercial value of this nontimber forest resource increased significantly upon recognition of its medicinal properties due to the antioxidant, antimicrobial, and cytotoxic activities attributed to carvacrol, thymol, caffeic acid, flavonoids, apigenol derivatives, luteolol, kaempferol, sesquiterpenes, and p-cimene which is present in the oil (Hernández et al. 2009). Specifically, antioxidant activity has been demonstrated in leaf extracts through inhibition of linoleic acid oxidation (Avila-Sosa et al. 2010). Extracts O. A. Castellanos-Hernández (*) :G. J. Acevedo-Hernández : F. Zurita :M. Gutiérrez-Lomelí :C. L. Del Toro-Sánchez : A. Rodríguez-Sahagún Centro Universitario de la Ciénega, Universidad de Guadalajara, Av. Universidad 1115, Col. Lindavista, 47820 Ocotlán, Jalisco, Mexico e-mail: ocnoscr@gmail.com

Optimization of DNA isolation and PCR protocol for analysis and evaluation of genetic diversity of the medicinal plant, Anemopsis californica using RAPD

Anemopsis californica is a perennial herbaceous plant that has been utilized as a medicinal plant for the treatment of various diseases. The present work was carried out with the objective of optimizing a method of extraction of the genomic DNA of A. californica and a PCR protocol and later to evaluate the existing genetic diversity among the genotypes deriving from different origins. For DNA extraction, we tested four procedures: with the CTA B-2 protocol, we obtained the highest yield (61.5±2.2 μg DNA/g of leaf tissues) and the best quality (A260/280 1.83±0.022). To estimate genetic variability, we utilized the randomly amplified polymorphism DNA (RAPD) technique, employing 20 oligonucleotides, of which only 18 generated reproducible banding patterns, producing 123 polymorphic bands generated, thus obtaining a polymorphism rate of 93.93% among the genotypes analyzed. The Jaccard similarity coefficient generated a variation ranging from 0.325-0.921, indicating a high level of genetic variation among the studied genotypes. An Unweighted pair-group method with arithmetic mean (UPGMA) group analysis indicated six distinct groups. The present optimized method for DNA isolation and RAPD protocol may serve as an efficient tool for further molecular studies.

Genetic Transformation of Forest Trees

Forests are complex ecosystems capable of providing a wide range of economic, social and environmental benefits. They help to regulate the water cycle, stabilize soils and moderate the climate of the Earth by absorbing and storing carbon dioxide. In addition to these environmental services, forests provide habitat to numerous species and are an important source of food, medicines and wood for humankind. In many countries, forests contribute importantly to their economic and social development through employment, the production and trade of forest products, and the protection and hosting of sites and landscapes of high cultural, spiritual or recreational value. As a result of the increase in human population and economic activities, larger volumes of forest products, particularly wood, were required, and the natural processes were insufficient to restore the damage imposed on the forests. At present, the total forest area in the world is estimated to be nearly 4,000 million hectares, which cover about 30 percent of the global land area. Although the forest cover is still extensive, the problem of deforestation continues at an alarming rate: according to the Food and Agriculture Organization of the United Nations (FAO), in the 15 years from 1990 to 2005 the world lost 3 percent of its total forest area, representing an average decline of about 0.2 percent per year (FAO, 2007). Deforestation results from a combination of factors, including, among others, increased global demand for forest products, land-use change (e.g. conversion of forest into agriculture land) and the expansion of urban areas. A reduction in forest area can also happen through natural disasters, but deforestation is by far the most important cause of forest loss (FAO, 2007). Deforestation rates differ considerably from region to region, and figure 1 presents estimate data that illustrate the extent of losses and gains of forest land area around the world in the last two decades. It is interesting to note that deforestation is preponderant in developing countries in Latin America (with the notable exception of Cuba), Africa and Southeast Asia. The primary causes of this is the land-use change to agriculture and the production of fuelwood and charcoal through processes that are inefficient and lead to over-exploitation. Between years 2000 and 2010, however, net loss of forest area in the world decreased slightly, which is probably an indicator of the natural expansion of forests primarily due to efforts made to ensure the conservation of