Establecimiento de las bases biotecnológicas y ecológicas en la mejora genética de Vanilla planifolia Jacqs. (Orchidaceae)

Vanilla planifolia Jacks is a genetic resource of socio-economic importance to the State of Veracruz, México. However, in recent years, this culture is facing a serious problem due to the fall of its fruits. To contribute to the conservation, improvement and management of V. planifolia, it has been developed a network project for the strengthening of academic bodies sponsored by the Secretariat of public education. This paper presents some of the progress made in this context

Incremento de embriones somáticos de Cacao (Theobroma cacao L.) en sistema de inmersión automatico

Abstract: Cacao is a tropical tree native to America. Its fruit is used in the elaboration of chocolate and its derivatives. The propagation of cacao is done through sexual means or seeds; additionally, it propagates through the use of cuttings and grafting. Currently, somatic embryogenesis is also employed for the clonal propagation of cacao, which can be repeated several times and contributes to the increase in the formation of somatic embryos. Therefore, the use of a temporary immersion system can increase the production of secondary somatic embryos. Given the aforementioned, the objective was to evaluate the Rita® temporary immersion system in the performance of secondary somatic embryos from 30 to 180 days in two cultivation cycles. The results showed that somatic embryos were generated in cotyledon explants and in full somatic embryos. A second cycle was obtained from the secondary somatic embryogenesis where 150 somatic embryos were obtained per Rita® recipient with an average of 15 embryos per explant. The temporary immersion system favored the production of somatic embryos, its synchronization, and decreased the oxidation of the tissue.Resumen: El cacao es un árbol tropical originario de América, su fruto se usa en la elaboración del chocolate y sus derivados. La propagación del cacao se realiza por la vía sexual o semillas, adicionalmente se propaga por enraizamiento de estacas e injertos. En la actualidad también se emplea la embriogénesis somática para la propagación clonal del cacao, la cual puede repetirse varias veces, lo que contribuye al incremento en la formación de embriones somáticos; por lo que el uso de un sistema de inmersión automático, puede incrementar la producción de embriones somáticos secundarios. Por lo anterior, el objetivo fue evaluar el sistema de inmersión automático Rita® en el rendimiento de embriones somáticos secundarios de los 30 a los 180 d en dos ciclos de cultivo. Los resultados muestran que se generaron embriones somáticos en los explantes de fragmento de cotiledón y en embriones somáticos completos. Se obtuvo un segundo ciclo de la embriogénesis somática secundaria, en el que se obtuvieron 150 embriones somáticos por recipiente Rita® con promedio de 15 embriones por explante. El sistema de inmersión automático favoreció la producción de embriones somáticos, su sincronización y disminuyó la oxidación del tejido

Control of carotenoid gene expression in Bixa orellana L. leaves treated with norflurazon

Bixa orellana (annatto or lipstick tree) is a perennial tropical plant that stores and produces considerable quantities of the apocarotenoid bixin, a culturally and economically important pigment used worldwide. However, the mechanisms underlying the gene regulation and pigment accumulation of bixin and carotenoids in annatto remain unknown. Bixin is present in the different tissues of the plant, although this pigment is primarily accumulated in the seed coat. Thus, the leaves are useful organs for understanding carotenoid and bixin production, thereby facilitating the study of this pigment, which would otherwise be difficult in ligneous adult plants. To study the regulation of bixin synthesis and to determine which genes are important regulatory molecules at the transcription level, the herbicide norflurazon (NF) was used to block carotenoid synthesis and bixin concentrations in B. orellana leaves. The genes activated in the early stages of the carotenoid pathway are involved in lycopene production (dxs, psy and pds), and those induced in the later stages of the carotenoid pathway, such as β and ε-lycopene cyclases and boccd1, were differentially expressed compared with the control. The expression of some genes was more susceptible to certain concentrations of NF, potentially reflecting the roles of these genes in carotenoid synthesis in B. orellana. These results suggest that apocarotenoids, such as bixin, are synthesized using alternative precursors through the actions of genes that have not yet been identified