Genetic and anatomical studies of self-incompatibility in selected genotypes of the sweet passion fruit (Passiflora alata)

• Grant number: 20/11143-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2020
• End date: October 31, 2021
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Principal Investigator: Maria Lúcia Carneiro Vieira
• Grantee: Carolina Albuquerque Massena Ribeiro
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The sweet passion fruit (Passiflora alata) is a tropical species whose fruits are very much appreciated for in natura consumption. Our research group has been directing its efforts aiming at expanding the cultivation of P. alata in the São Paulo State, and for this purpose successive evaluations were performed that resulted in the selection of superior genotypes for yield and fruit quality. However, sweet passion fruit possess self-incompatibility (SI). Therefore, individuals are unable to self-pollinate; similarly, related individuals are frequently unable to cross, and this is a setback to fruiting, and for the development of inbred lines and cultivars. In this scenario, this project intends to determine the relations of compatibility among six previously selected genotypes within a full-sib family. It also aims to characterize the morphological responses in both types of crossings, compatible and incompatible. For that, a full diallel crossing system, including the parents, will be performed in order to define the compatibility relationships existing among them. Moreover, histochemical studies for the detection of callose, polysaccharides, phenolic and protein compounds, previously described as involved in SI, will be conducted, as well as the production of reactive species of oxygen (H2O2) will be verified. In addition, Scanning Electron Microscopy analysis will be performed to visualize the pollen and stigma surfaces in compatible and incompatible crosses. Finally, the S locus will be prospected in a genomic library of Passiflora edulis (the sour passion fruit), already available, with the aim of identifying the SRK and SLG genes, known to be involved in the mechanism of self-incompatibility. Bearing all this in mind, the goal is to generate important information about the SI response in P. alata, and establishing the potential of the selected genotypes for commercial use.