Plant & Animal Genomes XIV Conference Plant & Animal Genomes XIV ConferenceJanuary 14-18, 2006
Town & Country Convention Center
San Diego, CA
Alessandra Souza , Marco Takita , Helvecio Coletta-Filho , Maria Luisa Targon , Marcelo Reis , Carolina Rodrigues , Eduardo Carlos , Alexandre Amaral , Mariangela Cristofani , Juliana Teixeira , Daniel Rosa , Magnolia Campos , Antonio Oliveira , Regina Costa de Oliveira , Luiz Nunes , Julio Ferraz , Carlos Fischer , Marcos Machado
1. Centro APTA Citros Sylvio Moreira/ IAC, CEP 13490-970 CP 04
2. IAC-Centro de Recursos Geneticos Vegetais, Campinas/SP
3. Embrapa Recursos Geneticos e Biotecnologia
4. Escola Superior de Agricultura Luiz de Queiroz. Dept. de Genetica e Fitopatologia
5. Universidade Federal de Lavras. Laboratorio Central de Biologia Molecular
6. Universidade Estadual Sudoeste da Bahia Campus Vitoria da Conquista. Depto de Ciencias Naturais.
7. Universidade de Mogi das Cruzes - Nucleo Integrado de Biotecnologia.
8. Departamento de Estatistica, Matematica Aplicada e Computacao (DEMAC) - UNESP/Rio Claro.
The citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is responsible for annual losses of about $100 million to the citrus agro-industry in Brazil. Citrus reticulata is considered tolerant to CVC since no development of symptoms is observed. However, it is possible to detect the bacteria for at least 30 but not 60 days after inoculation. For this reason this specie was included in a citrus breeding program aiming resistance to CVC. In order to better understand the responses of citrus plants to the infection of X. fastidiosa, we constructed three EST libraries from Citrus reticulata representing different conditions. Two of those were prepared from plants inoculated with X. fastidiosa, 30 and 60 days after inoculation. The other library was done with RNAs isolated from non-inoculated plants. We have sequenced a total of more than 21,000 ESTs from plants under these conditions. Through an in silico differential display, 270 genes were found to be significantly differentially expressed (2E<0,05). Genes associated with resistance, oxidative stress and sinalization were detected in the 30 days library. At 60 days, phytoalexins were over-expressed. In the presence of Xylella, an increase in chloroplast function and PR-proteins was observed both time points. The same pattern was observed for P450 that among others functions is involved with antimicrobial compounds synthesis. Our study suggest that the defense response of Citrus reticulata against X. fastidiosa could be one component of a multifactor anti-pathogen response. This study opens new possibilities in understanding this resistance mechanism.
Support: CNPq/MCT, Fapesp