About this Research Topic
Embryogenesis is a developmental program initiated with the formation of a zygote and ending in a mature embryo, able to germinate and to develop into a sporophyte. Common to all embryophytes, with development protected by maternal tissues, the zygote is not the only cell able to originate from an embryo. The observation that cells other than the zygote can from an embryo and are also totipotent has profound implications not only in an evolutionary perspective, but also in terms of fundamental and applied science. Non-zygotic embryogenesis is a widespread developmental pathway occurring naturally in many plant species and following different strategies. Embryos arising from the nucellus in citrus species, or by apospory or diplospory in other taxa, have been often reported. Moreover, in well-defined experimental conditions, differentiated cells can be stimulated to produce somatic embryos following treatments by auxins, or by exposing them to different types of stresses, a process usually known as somatic embryogenesis. Even haploid cells, like the microspores are able to embark into an embryogenic pathway – pollen embryogenesis.
The ability of plant cells, other than the zygote, to change into an embryo has paved the way to analyze embryo formation, development and germination in well-defined experimental conditions not permitted when the embryo develops inside the mother plant, surrounded by different tissues, only in particular periods of the year and, in a vast number of species, in a limited number. Furthermore, non-zygotic embryogenesis, in particular somatic embryogenesis, offers the possibility to clone selected genotypes, to produce synthetic seeds and to obtain genetically modified plants through classical methods of genetic transformation or through gene editing. In species with long life cycles, as trees, embryogenic tissues and somatic embryos can be cryopreserved until field tests can prove the quality of the cloned genotypes. Equally relevant is the opportunity to obtain haploid plants from pollen and to use inbred lines in breeding programs.
This Research Topic is dedicated to the most recent advances on zygotic and non-zygotic embryogenesis, both from a practical and a fundamental perspective. Original research, review and mini review manuscripts around biotechnological applications of non-zygotic embryogenesis, such as cloning, haploid production, plant genetic transformation and cryopreservation, among others, are welcomed. Manuscripts dealing with the more recent advances on fundamental research on plant embryogenesis such as functional genomics, transcriptomics, and proteomics analysis are also encouraged to be submitted, as are those concerning the role of epigenetics on embryo formation and development.
i) New somatic embryogenesis methods in intractable species will not be considered for review in this Research Topic.
ii) Descriptive collection of transcripts, proteins or metabolites, including comparative sets as a result of different conditions or treatments, unless accompanied by physiologically relevant functional characterization of differentially expressed/accumulating candidate transcripts, metabolites or proteins, will not be considered for review, unless they are expanded and provide insight into the biological system or process being studied.
Keywords: Cloning, embryo development, plant embryogenesis, totipotency
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.