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Research article - Peer-reviewed, 2018

Identification of molecular processes that differ among Scots pine somatic embryogenic cell lines leading to the development of normal or abnormal cotyledonary embryos

Merino, Irene; Abrahamsson, Malin; Larsson, Emma; von Arnold, Sara

Abstract

Several coniferous species can today be propagated through somatic embryogenesis, but for species belonging to the Pinus genus, there are still problems related to the small number of genotypes from which embryogenic cultures can be established and the low yield of high-quality cotyledonary embryos. In order to pinpoint molecular processes that might be disturbed during somatic embryogenesis in Scots pine, we have analyzed the expression pattern of selected transcripts during development of somatic embryos in a normal and an abnormal cell line of Scots pine. The selected transcripts have been previously shown to be differentially expressed during early zygotic embryogenesis in Scots pine (Merino et al. 2016). Based on the transcripts that accumulated differentially between the two cell lines, we conclude that the apical-basal polarization in early somatic embryos and the transition from the morphogenic phase to the maturation phase are disturbed in the abnormal cell line. A comparison between transcript accumulation during somatic and zygotic embryogenesis highlighted problems with the continuous embryo degeneration processes in embryogenic cultures of Scots pine. Transcripts that were highly abundant during the cleavage process in zygotic embryos showed different accumulation patterns during somatic embryogenesis in Scots pine compared to those in Norway spruce. Furthermore, altering the expression of these transcripts in embryogenic cultures of Norway spruce resulted in a changed proliferation pattern of the embryos so that they became more similar to proliferating somatic embryos of Scots pine. Taken together, our results provide a deeper understanding of the deviations in abnormal cell lines and indicate that embryogenic cultures of Scots pine are proliferating by a cleavage-like process.

Keywords

Cleavage polyembryony; Conifers; Molecular regulation; Pinus sylvestris

Published in

Tree Genetics and Genomes
2018, Volume: 14, number: 2, article number: 34
Publisher: SPRINGER HEIDELBERG