Induction of somatic embryogenesis and plant regeneration in the tropical timber tree Spanish red cedar [Cedrela odorata L. (Meliaceae)]

Abstract

Spanish red cedar (Cedrela odorata L.) is a tropical timber tree native to the Americas from southern Mexico to northern Argentina. Commercial plantations are scarce and, consequently, natural populations are overexploited. Traditional propagation practices for the establishment of large-scale plantations have had limited success in this species due to the relative scarcity of seeds, its broad genetic diversity and the lack of domesticated varieties. In vitro clonal propagation provides an effective method to overcome this situation and increase the yield of commercial plantations through the rapid multiplication of elite materials. Somatic embryogenesis (SE) is one of the most promising strategies for tree propagation due to the possibility of producing artificial seeds, the ability to store and rapidly mobilize germplasm and the opportunity for genetic manipulation. We report here the induction of indirect SE in C. odorata from calli derived from immature zygotic embryos after 12 weeks of culture. Macroscopic, histological, and scanning electron microscopic analyses of the calli revealed the presence of embryogenic cell clusters that formed cotyledonary embryos with clear bipolar structures and no vascular connections with the mother tissue. Different media preparations containing combinations of diverse auxins and cytokinins are known to have different effects on the type and frequency of embryogenic structures. Embryo conversion was achieved using an MS-based medium [Murashige T, Skoog F (1962) Physiol Plant 15:473-497, 1962 supplemented with abscisic acid, and transfer to soil was successful at a rate of 75%. The method described here provides a basis for optimizing the clonal propagation and genetic manipulation of this valuable species.

Somatic embryogenesis and plant regeneration from leaf and petiole explants of Campanula punctata Lam. var. rubriflora Makino

“…2). The role of GA 3 on the germination of SE has been reported in many plants (Cangahuala-Inocente et al 2007;Peña-Ramírez et al 2011;Siddiqui et al 2011).The highest frequency of germination (94%) was achieved when globular embryos were cultured on MS medium supplemented with 0.3% AC and 1.0 mg L -1 GA 3 (Fig. 2).…”

Short Communication Characterization of chloroplast region rrn16-rrn23S from the tropical timber tree Cedrela odorata L. and de novo construction of a transplastomic expression vector suitable for Meliaceae trees and other economically important crops

“…Specifically, for C. odorata, this second bottleneck is significant. Although a reproducible protocol for repetitive somatic embryogenesis has been already reported for C. odorata (Peña-Ramírez et al, 2010), as a recalcitrant woody species, the regeneration rate remains low compared to herbaceous model plants, such as tobacco or carrot. Therefore, it is relevant to use homologous sequences flanking expression cassettes for plastidic transformation.…”

Inducción de callos embriogénicos y formación de proembriones somáticos en Pterogyne nitens Tull "tipa colorada"

“…Los callos friables considerados embriogénicos, mostraron una superficie desorganizada pero con cierto grado de compactación entre las cé-lulas (figura 5 A). La presencia de células isodiamétri-cas en estos callos, concuerda con las observaciones realizadas por Peña Ramírez et al (2011), para callo embriogénico en Cedrela odorata. Mientras que los callos no embriogénicos se caracterizaron por presentar células alargadas, sin uniones entre ellas, con una desorganización total del tejido (figura 5 B).…”

“…Samaj et al (2003), describe en maíz una estructura globular a la que denomina 'pre-embryogenic units', rodeada por grandes células parenquimáticas las cuales podrían estar actuando como "células nodrizas". Al igual que lo reportado para Cedrela odorata L. (Peña Ramírez et al, 2011), las masas celulares presentaron diferentes grados de organización, con múltiples zonas meristemáticas, incluyendo proembriones con presencia de protodermis, y estructuras embrionarias globulares. Se observaron los estadios globulares y acorazonado, sin embargo no se registró sincronía durante el proceso inductivo desarrollado (figura 7).…”

“…Avilés et al (2009) utilizando técnicas de cultivo de tejidos vegetales logra la inducción y desarrollo de yemas axilares, con bajo porcentaje de enraizamiento. La embriogénesis somática (ES) se considera para las especies forestales, como la vía de regeneración más adecuada ya que ofrece la posibilidad de una alta tasa de producción de propágulos, criopreservación de callos embriogénicos, rejuvenilización, producción de semilla sintética y la utilización de cultivos embriogé-nicos en transformación genética (Peña-Ramírez et al, 2011). Se basa en el principio de la formación de un embrión a partir de células somáticas diferentes a un gameto o al producto de la unión de gametos.…”