This first report of cellular and molecular changes after repetitive somatic embryogenesis in conifers shows that each cycle enhanced the structure and singularization of EMs through modulation of growth regulator pathways, thereby improving the line´s embryogenic status.
Douglas-fir (Pseudotsuga menziesii (Mirb) Franco) is a native conifer from the Pacific North-West of the US and Canada, and is one of the most important timber species used in the world. Douglas-fir is highly productive in a range of climatic conditions and has valuable wood properties (quality) as well as a strong tolerance to diseases and insects. In Europe, Douglas-fir is a major species for reforestation with increasing demand for its wood. Adaptation of new varieties to climate change and associated stresses is one challenging question for ongoing breeding programs.
Lelu-Walter M.-A., Gautier F., Eliášová K., Sanchez L., Teyssier C., Lomenech A.-M., Le Metté C., Hargreaves C., Trontin J.-F., Reeves C.
Embryogenic cultures of Douglas-fir were induced from immature zygotic embryos. They proliferate as embryonal masses, however, in some lines of Douglas-fir, non-embryogenic cell (NECs) clusters interspersed with early somatic embryos (SEs) were observed. In order to evaluate the differences between lines we wanted to quantify the proportion of the SEs and NECs in the embryonal mass. For estimation of this proportion (volume density) we used stereological point-counting method based on counting points of the test grid falling in the tissue under study.
