Embryology in conifers

Arnold, Sara von; Clapham, David; Abrahamsson, Malin

doi:10.1016/bs.abr.2018.11.005

Cited by 16 publications

(21 citation statements)

References 68 publications

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“…Somatic embryogenesis in conifers is a multistage process that comprises the following steps: initiation of embryogenic cultures from explants, proliferation or multiplication of embryogenic masses (EMs), development and maturation of cotyledonary somatic embryos from EMs, germination and plantlet acclimatization ( Figure 1 ) (for a complete review, see [ 16 , 20 , 26 , 29 ]).…”

Section: In Vitro Plant Regeneration In Conifersmentioning

confidence: 99%

“…Somatic embryogenesis is mainly achieved from mature zygotic embryos in species with simple polyembryony and from immature zygotic embryos (enclosed within the megagametophyte) in species having cleavage polyembryony [ 20 ]. However, the initiation of embryogenic cultures from mature vegetative explants in conifers is still much more challenging.…”

Section: In Vitro Plant Regeneration In Conifersmentioning

confidence: 99%

“…Somatic embryos complete their differentiation and undergo maturation when they are cultured in a medium with higher concentration of gelling agent and carbohydrate, and with osmotic agents such as polyethylene glycol. All these factors reduce the water availability for embryos, promoting the growth arrest, the accumulation of storage reserves and the acquisition of desiccation tolerance [ 20 ]. The addition of abscisic acid also improves somatic embryo maturation, an essential process for proper germination of conifers embryos.…”

Section: In Vitro Plant Regeneration In Conifersmentioning

confidence: 99%

“…Altogether, these studies allowed the identification of genes that play key roles during SE or DNO in conifers, which were related with processes such as the regulation of the endogenous content and distribution of different PGRs, stress responses, stem cell regulation or cell wall remodeling (for a complete review, see [ 16 , 17 , 18 , 19 , 20 ]). Among them, it was reported the relevance in these processes of WOX and KNOX gene families that belong to the homeobox gene superfamily.…”

Section: Introductionmentioning

confidence: 99%

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In Vitro Plant Regeneration in Conifers: The Role of WOX and KNOX Gene Families

Bueno

Cuesta

Centeno

et al. 2021

Genes

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Conifers are a group of woody plants with an enormous economic and ecological importance. Breeding programs are necessary to select superior varieties for planting, but they have many limitations due to the biological characteristics of conifers. Somatic embryogenesis (SE) and de novo organogenesis (DNO) from in vitro cultured tissues are two ways of plant mass propagation that help to overcome this problem. Although both processes are difficult to achieve in conifers, they offer advantages like a great efficiency, the possibilities to cryopreserve the embryogenic lines, and the ability of multiplying adult trees (the main bottleneck in conifer cloning) through DNO. Moreover, SE and DNO represent appropriate experimental systems to study the molecular bases of developmental processes in conifers such as embryogenesis and shoot apical meristem (SAM) establishment. Some of the key genes regulating these processes belong to the WOX and KNOX homeobox gene families, whose function has been widely described in Arabidopsis thaliana. The sequences and roles of these genes in conifers are similar to those found in angiosperms, but some particularities exist, like the presence of WOXX, a gene that putatively participates in the establishment of SAM in somatic embryos and plantlets of Pinus pinaster.

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Section: In Vitro Plant Regeneration In Conifersmentioning

confidence: 99%

Section: In Vitro Plant Regeneration In Conifersmentioning

confidence: 99%

Section: In Vitro Plant Regeneration In Conifersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

In Vitro Plant Regeneration in Conifers: The Role of WOX and KNOX Gene Families

Bueno

Cuesta

Centeno

et al. 2021

Genes

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“…The same kinds of questions apply to other stages of embryo development, where distinct features are evident in the two plant groups. In fact, in addition to the occurrence of cleavage polyembryony, a common phenomenon in gymnosperms during early embryogeny, the differentiation of multiple cotyledons, instead of only two cotyledons, around the shoot apical meristem (SAM) during late embryogeny, is also a highly distinctive characteristic that confers radial symmetry to the embryo instead of the bilateral symmetry observed in angiosperms [ 14 ]. Furthermore, it is also important to focus on the events that occur prior to embryo development, during the induction of SE, where a somatic cell changes its fate in order to become an embryo.…”

Section: Introductionmentioning

confidence: 99%

Small Non-Coding RNAs at the Crossroads of Regulatory Pathways Controlling Somatic Embryogenesis in Seed Plants

Alves

Cordeiro

Correia

et al. 2021

Plants

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Small non-coding RNAs (sncRNAs) are molecules with important regulatory functions during development and environmental responses across all groups of terrestrial plants. In seed plants, the development of a mature embryo from the zygote follows a synchronized cell division sequence, and growth and differentiation events regulated by highly regulated gene expression. However, given the distinct features of the initial stages of embryogenesis in gymnosperms and angiosperms, it is relevant to investigate to what extent such differences emerge from differential regulation mediated by sncRNAs. Within these, the microRNAs (miRNAs) are the best characterized class, and while many miRNAs are conserved and significantly represented across angiosperms and other seed plants during embryogenesis, some miRNA families are specific to some plant lineages. Being a model to study zygotic embryogenesis and a relevant biotechnological tool, we systematized the current knowledge on the presence and characterization of miRNAs in somatic embryogenesis (SE) of seed plants, pinpointing the miRNAs that have been reported to be associated with SE in angiosperm and gymnosperm species. We start by conducting an overview of sncRNA expression profiles in the embryonic tissues of seed plants. We then highlight the miRNAs described as being involved in the different stages of the SE process, from its induction to the full maturation of the somatic embryos, adding references to zygotic embryogenesis when relevant, as a contribution towards a better understanding of miRNA-mediated regulation of SE.

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