Biochemical markers associated with carbohydrate metabolism during the zygotic and somatic embryogenesis of Araucaria angustifolia (Bertol.) Kuntze

Author(s)

Bruno Viana Navarro

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2018-08-17

Examining board members

Eny Iochevet Segal Floh; Claudete Santa Catarina; Igor Cesarino; Carlos Alberto Labate; Marie Anne van Sluys

• Advisor: Eny Iochevet Segal Floh; Marcos Silveira Buckeridge

Abstract

Araucaria angustifolia is a native conifer species of Brazil, that with economic, social and ecological importance. Due to its intense exploitation, the species cover only 2% of its original forest area. In this system, somatic embryogenesis may be integrated into breeding and conservation programs. Beside this, the similarity between zygotic and somatic embryogenesis have been used to develop studies based on system biology, in order to optimize the in vitro somatic embryo development, as well as to generate a better understanding of molecular, biochemical and physiological events that modulate the embryogenesis. Carbohydrates metabolism is a central route that plays an important role during plant growth and development. In addition to its essential role as a substrate in carbon and energy metabolism, sugars also play important roles as signal molecules. For A. angustifolia, transcriptome and proteome databases identified carbohydrates metabolism as an important pathway in the modulation of embryogenic process. Thus, the main objective of this work was to study the carbohydrates metabolism during three zygotic embryogenesis stages (globular, cotyledonal and mature) and in proliferation and maturation phases of embryogenic cell lines with contrasting embryogenic potential (responsive and blocked). To achieve this purpose, the profiles of non-structural carbohydrates and cell wall monosaccharides were generated, as well as the identification and characterization of the main genes and proteins involved in carbohydrate-mediated responses, cell-to-cell communication homeostasis and modulation of sucrose, starch, raffinose and cell wall metabolism. Additionally, a metabolome database was generated and integrated with A. angustifolia transcriptome and proteome through co-expression networks in a system biology approach. The carbohydrate-mediated responses that occur during A. angustifolia somatic embryogenesis resembled those occurring in the early stages of zygotic embryogenesis, where the main responses that affect the targeting of the tissue differentiation of the seed occur. Beside this, sucrose and starch accumulation during embryo development were modulated by sugar sensing and signaling responses, highlighting this process as an important trait that directs the responsiveness of embryogenic cell lines. Associated to this, the selectivity mediated by plasmodesmata communication and vesicular transport in the responsive cell line, appeared as an important control of cell types differentiation and development. Even though the complete mechanism of A. angustifolia somatic embryogenesis has not been completely elucidated, our analyses about the metabolic changes (metabolome) during zygotic and somatic embryogenesis indicate that the regulatory networks involved in growth and development are highly inter-connected at the metabolite, protein and transcript levels, showing high correlations between targets involved in carbohydrate metabolism. The results obtained provide relevant and inedited information about the carbohydrates metabolism in A. angustifolia zygotic and somatic embryogenesis, as well as provide news subsidies for optimization of in vitro conditions for somatic embryos development. (AU)

• FAPESP's process: 14/26888-0 - Biochemical markers associated with carbohydrate metabolism during Araucaria angustifolia zygotic and somatic embryogenesis
• Grantee: Bruno Viana Navarro
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)