Flower development in Passionfruit: a transcriptomic approach to corona ontogenesis

Author(s)

Mariana Bombardi da Silva

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2022-02-15

Examining board members

Marcelo Carnier Dornelas; Sara Adrián López de Andrade; Melina Cristina Mancini

• Advisor: Marcelo Carnier Dornelas

Abstract

The passion fruit or yellow passion fruit (Passiflora edulis var. flavicarpa) belongs to the genus Passiflora, which consists of about 600 species. The floral diversity present among species of this genus is the product of several adaptations to the wide variety of pollinators. The presence of one or multiple series of corona filaments, usually pigmented, is of fundamental importance in the interaction with pollinators - helping as a landing platform and as a visual signaling structure. The diversity of pigmentation observed in Passiflora species can be explained by the combination of different anthocyanin molecules accumulated in cells of the corona filaments, resulting in a wide spectrum of flower colors. However, despite its importance, the molecular mechanisms that act in phases related to the development of the corona have not been yet elucidated. The literature presents different hypotheses about its origin, such as stamens or petals modifications, or that it is a sui generis organ, developed to promote a special adaptation in the flower associated with pollination. Our hypothesis is that conserved molecular mechanisms involved in meristematic activities may play an important role in the origin of the corona. Using transcriptomic and gene structure analysis techniques in Passiflora edulis, the present work identified more than 30,000 transcripts whose expression differs between different stages of corona development. Among them, 14 were identified as possible genes related to meristematic activity - including a representative of the WUSCHEL gene - corroborating the hypothesis that the corona is a sui generis organ developed from a set of meristematic cells. In addition, 17 transcripts appear to be related to the anthocyanin biosynthesis pathway, a pigment responsible for coloring the corona filaments and essential for pollination to occur, consolidating the hypothesis that alterations in key genes of the anthocyanin biosynthesis pathway are responsible for the pigmentation process of the corona filaments. Structural analysis of genes of interest were carried out through the genome of Passiflora organensis, providing a characterization of these genes and opening the possibility of better understanding their functions within plants of the genus Passiflora (AU)

• FAPESP's process: 18/24742-0 - Flower development in passionfruit: a transciptomic approach to corona ontogenesis
• Grantee: Mariana Bombardi da Silva
• Support Opportunities: Scholarships in Brazil - Master