作者：Peña L, Pérez RM, Cervera M, Juárez JA, Navarro L.
摘要：Background and Aims: Genetic transformation of plants relies on two independent but concurrent processes: integration of foreign DNA into plant cells and regeneration of whole plants from these transformed cells. Cell competence for regeneration and for transformation does not always fall into the same cell type/developmental stage, and this is one of the main causes of the so-called recalcitrance for transformation of certain plant species. In this study, a detailed examination of the ?rst steps of morphogenesis from citrus explants after co-cultivation with Agrobacterium tumefaciens was performed, and an investigation into which cells and tissues are competent for regeneration and transformation was carried out. Moreover, the role of phytohormones in the co-cultivation medium as possible enhancers of gene transfer was also studied.
Methods : A highly responsive citrus genotype and well-established culture conditions were used to perform a histological analysis of morphogenesis and cell competence for transformation after co-cultivation of citrus epicotyl segments with A. tumefaciens. In addition, the role of phytohormones as transformation enhancers was investigated by ?ow cytometry.
Key Results: It is demonstrated that cells competent for transformation are located in the newly formed callus growing from the cambial ring. Conditions conducive to further development of this callus, such as treatment of explants in a medium rich in auxins, resulted in a more pronounced formation of cambial callus and a slower shoot regeneration process, both in Agrobacterium-inoculated and non-inoculated explants. Furthermore, cocultivation in a medium rich in auxins caused a signi?cant increase in the rate of actively dividing cells in S-phase, the stage in which cells are more prone to integrate foreign DNA.
Conclusions: Use of proper co-cultivation medium and conditions led to a higher number of stably transformed cells and to an increase in the ?nal number of regenerated transgenic plants.
关键词：Agrobacterium tumefaciens, callus, cambium, cell cycle, citrange (Citrus sinensi
文献注录：Peña L, Pérez RM, Cervera M, Juárez JA, Navarro L.. Early Events in Agrobacterium-mediated Genetic Transformation of Citrus explants [J]. Annals of Botany. 2004, 01: 67-74.
报/刊名：《Annals of Botany》，发表于2004 / 第 01 期。
文献类型： [J]
页码：第 67-74 页 / 共8 页