Molecular attributes of tropical tree Avicennia schaueriana involved in low temperature tolerance

• Grant number: 19/21100-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): September 01, 2020
• Effective date (End): July 31, 2023
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Principal Investigator: Anete Pereira de Souza
• Grantee: Yohans Alves de Moura
• Host Institution: Centro de Biologia Molecular e Engenharia Genética (CBMEG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Angiosperms appeared in the lower Cretaceous, probably in warm habitats, and they spread to very varied habitats, assuming different ways of life. Even with some ability to resist under low temperatures, species productivity, richness and density, particularly of woody angiosperms, remain limited in regions where temperatures values reaches close to 0°C or below. Although the physiological mechanisms involved in cold resistance of these species are well known, molecular mechanisms have been little explored in these organisms. Most of this knowledge still focuses on model organisms such as the herbaceous Arabidopsis thaliana, or on cultivars such as tomatoes, cassava and grapes. To advance knowledge of molecular mechanisms involved with cold resistance in woody angiosperms, we intend to conduct a gene expression experiment with Avicennia schaueriana (Black Mangrove), a typically tropical specie abundant on the Atlantic coast of the South American continent, whose distribution is probably limited by low temperatures. In this experiment we used seeds from non-sibling individuals collected from contrasting ecotypes (from equatorial and subtropical regions) and cultivated for seven months under homogeneous conditions. The seedlings were exposed at -4°C for one night, in which leaf material was collected in a time series (0, 15 and 180 minutes) for RNA extraction. In this proposal, we intend to use the RNA obtained for the construction of large-scale sequencing libraries (RNA-Seq) in Illumina platform, in order to analyze gene co-expression networks throughout the treatment and the differential gene expression between contrasting ecotypes. These statistical approaches will allow us to identify cold resistance candidate genes in this species. Functional enrichment analyzes will be conducted using gene sets with alteration in expression between ecotypes and throughout the time series to characterize the overall patterns. The results will be discussed in the light of the literature regarding cold resistance, encompassing plants with different ways of life (such as tree and herbaceous) and different taxa (such as angiosperms and gymnosperms), found in different geographical areas (such as tropical and temperate). This study will contribute to the construction of knowledge about angiosperms evolutionary biology and their irradiation to cold environments, and will also bring valuable information to the programs of genetic improvement in tropical trees for the conservation of the species in question. (AU)