Effectiveness of Bacillus subtilis ANT01 and Rhizobium sp. 11B on the control of fusarium wilt in pineapple (Ananas comosus).

Pineapple (Ananas comosus) is commonly infected by Fusarium oxysporum, causal agent of the fusarium wilt disease. Conventionally, growers use synthetic fungicides to control the disease, which lead to environmental pollution, hazardous effects on non-target organisms and risks on human health. The aim of this work was to assess the effectiveness of Bacillus subtilis ANT01 and Rhizobium sp. 11B to control fusarium wilt on pineapple plants. Four treatments derived from a complete factorial design were tested under field conditions. Treatments composed of B. subtilis ANT01 and the combination B. subtilis ANT01-Rhizobium sp. 11B decreased disease severity by 94.4% and 86.1%, respectively. On the other hand, the treatment prepared with Rhizobium sp. 11B alone showed a reduction of 75.0%. Size of leaves and nutritional condition (SPAD units) of the biocontrol agents-treated plants showed no statistical differences. Moreover, B. subtilis ANT01 decreased by 46% the initial soil population of F. oxysporum, while Rhizobium sp. 11B, B. subtilis ANT01 plus Rhizobium sp. 11B and control, showed a population reduction of 12.5%, 24.2% and 23.0%, respectively. These results make evident the potential of B. subtilis ANT01 as biocontrol agent of the pathogen under field conditions.

Production of cytotoxic compounds in dedifferentiated cells of Jatropha curcas L. (Euphorbiaceae).

This study addresses the in vitro culture as an alternative to obtain compounds with cytotoxic activity from the medicinal plant Jatropha curcas (Euphorbiaceae). We determined the presence of cytotoxic compounds in both whole plants and dedifferentiated cells. We evaluated the effect of auxin, cytokinins and light on callus induction in cotyledon explants. We found that the most effective combination to induce callus was the auxin 2,4-D (5 mM) with the cytokinin 6-BAP (2.5 mM), on Murashige-Skoog medium in darkness. We compared the callogenic potential among accessions from different geographic origins, finding that ARR-251107-MFG7 is most prone to form callus. The roots of J. curcas grown in field produced a compound chromatographically similar to the cytotoxic diterpene jatrophone. The profile of compounds extracted from the dedifferentiated cells was similar to that of the whole plant, including a relatively abundant stilbene-like compound. This study contributes to the future establishment of protocols to produce anti-cancer compounds from J. curcas cultivated in vitro.

Alcaloides y polifenoles del cacao, mecanismos que regulan su biosíntesis y sus implicaciones en el sabor y aroma / Cacao alkaloids and polyphenols: Mechanisms that regulate their biosynthesis and its implications on the taste and aroma

El sabor y aroma de los granos de cacao (Theobroma cacao L.) fueron las principales razones que promovieron su domesticación y uso alimentario por los pueblos precolombinos de Mesoamérica. Incluso hoy día, la calidad sensorial determina la clasificación entre cacaos finos y a granel. Muchos compuestos químicos de las almendras son responsables de la calidad sensorial, pero sobresalen los polifenoles y los alcaloides, compuestos que de manera directa inciden en el sabor y palatabilidad de las almendras y de manera indirecta sobre los precursores de aroma. Los alcaloides están asociados con el amargor. Su concentración está relacionada con la variedad y se modifica con el procesamiento. Los polifenoles son responsables, junto con otras moléculas de la astringencia (poco deseable en chocolates), pero también de propiedades antioxidantes deseables por los consumidores. En esta revisión se abordan aspectos de la biosíntesis de estas importantes moléculas en las almendras de cacao, de las implicaciones en el sabor y aroma, así como los cambios que ocurren durante el procesamiento de las mismas(AU)

The flavor and aroma of cacao (Theobroma cacao) beans were the main reasons that promoted its domestication and food-use by pre-Columbian peoples of Mesoamerica. Polyphenols and alkaloids are compounds that directly affect the flavor of the cocoa beans and indirectly on the flavor precursors. The alkaloids are associated with bitterness; its concentration is related to the cultivar and its modifying through the processing. Polyphenols molecules are responsible together with other molecules of the astringency (not desirable in chocolate), but also are responsible for antioxidant properties, very desirable by consumers. This review focuses on aspects of the biosynthesis of these important molecules in cocoa beans as well as implications in taste and flavor. The changes of these molecules that occur during processing are also approached(AU)

Reproductive biology of the biofuel plant Jatropha curcas in its center of origin.

In this work, we studied the main characteristics of flowering, reproductive system and diversity of pollinators for the biofuel plant Jatropha curcas (L.) in a site of tropical southeastern Mexico, within its center of origin. The plants were monoecious with inflorescences of unisexual flowers. The male flowers produced from 3062-5016 pollen grains (266-647 per anther). The plants produced fruits with both geitonogamy and xenogamy, although insect pollination significantly increased the number and quality of fruits. A high diversity of flower visiting insects (36 species) was found, of which nine were classified as efficient pollinators. The native stingless bees Scaptotrigona mexicana (Guérin-Meneville) and Trigona (Tetragonisca) angustula (Latreille) were the most frequent visitors and their presence coincided with the hours when the stigma was receptive. It is noteworthy that the female flowers open before the male flowers, favoring xenogamy, which may explain the high genetic variability reported in J. curcas for this region of the world.

Cacao alkaloids and polyphenols: Mechanisms that regulate their biosynthesis and its im- plications on the taste and aroma.

The flavor and aroma of cacao (Theobroma cacao) beans were the main reasons that promoted its domestication and food-use by pre-Columbian peoples of Mesoamerica. Polyphenols and alkaloids are compounds that directly affect the flavor of the cocoa beans and indirectly on the flavor precursors. The alkaloids are associated with bitterness; its concentration is related to the cultivar and its modifying through the processing. Polyphenols molecules are responsible together with other molecules of the astringency (not desirable in chocolate), but also are responsible for antioxidant properties, very desirable by consumers. This review focuses on aspects of the biosynthesis of these important molecules in cocoa beans as well as implications in taste and flavor. The changes of these molecules that occur during processing are also approached.