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| Author(s): |
Natália Moraes Silva
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2015-03-17 |
| Examining board members: |
Marcelo Carnier Dornelas;
Claudia Regina Baptista Haddad;
Adriana Pinheiro Martinelli
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| Advisor: | Marcelo Carnier Dornelas |
| Abstract | |
The TCP transcription factor family is plant-specific. Genes of this family are characterized by the TCP domain, responsible for the interaction with DNA, and are divided in two classes (Class I and Class II) with antagonist activity in the control of cell proliferation. TCP20 is a class I gene, and act as a complex with TCP8 and TCP9 in controlling cell cycle and plant growth. The main goal of this work was to characterize the phenotype of single and double mutants of these genes during reproductive development and to determine the expression pattern of TCP20 during flower development in Arabdopsis thaliana. Using RT-PCR it was possible to detect transcription of TCP8, TCP9 and TCP20 in roots, leaves, inflorescences, flowers and fruits of A. thaliana. Spatial and temporal analysis of expression, using in situ hybridization, showed a concentration of TCP20 transcripts in floral meristems and in floral organ primordia. The expression became more apical in sepals and petals later in development and in fertile organs it accumulated in pollen, ovules and in the stigmatic papillae. In situ hybridization experiments were also performed with TCP8 and TCP9 genes. These genes showed expression patterns very similar to those of TCP20, and were down-regulated at the end of the maturation process. TCP8 expression accumulated in some cells and was absent in other close cells from the same tissue region, indicating a `salt-and-pepper¿ expression pattern, especially at the beginning of floral organ development. Geometric morphometry analysis indicated some variations in the phenotype of mutant flowers, which were mainly modifications on the radial axis and at the apical portions of sepals, petals and pistil. Linear morphometry analysis pointed out that tcp9tcp20 double mutant sepals were statistically smaller than those of the wild type (p<0.05). The gynoecium of single mutants had smaller ovaries than those of the wild type (p<0.05). The analysis of the epidermic cells showed no modifications in the area of these cells among mutant individuals. The analysis of giant cells in sepals showed that the mean giant cell areas of mutated plants were statistically equal to the wild type. However analysis of total area coverage showed that tcp8 single mutant and tcp8tcp20 double mutant had a smaller area covered by giant cells, indicating a role of these genes in endorreduplication processes. Together, these results indicate that these genes act in complexes controlling processes responsible for flower organ formation and development, through the control of the cycles of cell division and endoreduplication (AU) | |
| FAPESP's process: | 12/23376-3 - Characterization of the role of TCP20 gene during Arabidopsis reproductive development |
| Grantee: | Natália Moraes Silva |
| Support Opportunities: | Scholarships in Brazil - Master |