Caracterização das transições de fases em maracujazeiro (Passiflora spp.)

Author(s)

Helena Augusto Gioppato

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2022-07-07

Examining board members

Marcelo Carnier Dornelas; Sarah Caroline Ribeiro Souza; Samantha Koehler; Diego Ismael Rocha; Clarisse Palma da Silva

• Advisor: Marcelo Carnier Dornelas

Abstract

Since their origin, terrestrial plants have developed different strategies that have allowed them to adapt to the different environmental conditions in which they are inserted. And shoot meristems are crucial for their evolutionary success, as they are responsible for two very important processes: the control of the plasticity of plant morphogenesis and the control of phase changes. As they age, plants undergo two major phase transitions, the first from juvenile to adult vegetative phase and then, the second, to the reproductive phase. These transitions occur in response to environmental and endogenous signals accompanied by changes in plant morphology, physiology, and also in their gene regulatory networks. Seven main and interconnected pathways are considered responsible for controlling the phase transitions of the plant: the photoperiod, the autonomous, the vernalization, the temperature, the gibberellins, the age and the sugar pathways. Some of them are also related to the control of plant architecture, and the sugar pathway seems to be the main part of these two processes. In the aim to better understand and characterize the mechanisms of developmental phase transitions in a species other than the usual model plant Arabidopsis thaliana, a new possible model plant was selected: Passiflora edulis, a perennial species that have specific traits characterizing each phase and a reference genome for the genus. Using this species, several analyses using different approaches were performed and their respective results are presented in three themed chapters. The first is a review of the current knowledge of phase transitions and plant architecture control. In it, it was possible to establish a relationship between phase transitions and plant architecture, opening space for future work that explores this relationship. The second is concerned with in silico analyses of shoot apexes in all three different phases, which demonstrated that the aging process of P. edulis plants resembles a decreasing gradient of gene expression. Finally, in the third and final chapter, we seek to empirically deepen the understanding of this process in a perennial species. For this purpose, the chapter was divided into two approaches: morphoanatomical and molecular. These analyzes endorsed the group's previous results regarding the development of passion fruit and also provided empirical evidence of what was observed in the in silico analyzes carried out earlier and presented in Chapter II, providing material for the continuity of the work. In addition, these findings raised important points that should be considered for future studies on the subject (AU)

• FAPESP's process: 18/25242-0 - Characterization and analysis of differential expression pattern of genes involved in the phase transition in passion fruit (Passiflora spp.)
• Grantee: Helena Augusto Gioppato
• Support Opportunities: Scholarships in Brazil - Doctorate