P0809 Role of a CC-NBS-LRR-like in the Perception/Colonization of Arabidopsis thaliana by Xylella fastidiosa

Juarez Pires Tomaz , Centro APTA Citros 'Sylvio Moreira' - IAC, Cordeirópolis, Brazil
Raquel Caserta , Centro Apta Citros Sylvio Moreira
Willian Eduardo Lino Pereira , Centro Apta Citros Sylvio Moreira
Michel Vincentz , LAGEP-CBMEG -State University of Campinas -UNICAMP, Campinas, Sao Paulo, Brazil
Alessandra Alves de Souza , Centro de Citricultura Sylvio Moreira, IAC, Cordeiropolis, SP, Brazil
Xylella fastidiosa is a pathogen bacterium that causes Citrus Variegated Clorosis (CVC) disease in Citrus sinensis (Sweet orange). Due to the economic importance of C. sinensis to Brazil agribusiness, an extensive program for sequencing ESTs for different tissues in response to biotic and abiotic stresses was performed. A database (CitEST) was set in which a total of 38,781 C. sinensis unigenes were assembled. Expression analysis revealed that some of these unigenes could be involved in mandarin (C. reticulata) resistance to X. fastidiosa, being one of them a CC-NBS-LRR-like. To study the function of this gene, we used Arabidopsis thaliana as plant model. Therefore we challenged a CC-NBS-LRR (homologue to mandarin CC-NBS-LRR-like) A. thaliana mutant and WT plants with X. fastidiosa. Bacteria were detected mainly in mutant plants, which showed smaller size compared with WT infected with X. fastidiosa, 10 weeks after inoculation. Besides, we also analyzed the expression of other six genes probably involved in C. reticulata resistance to X. fastidiosa to verify if these genes could be implicated in CC-NBS-LRR-dependent response pathways. The results of this transcription analysis revealed that MOA2.2, a gene encoding a protein with aldolase glycolate oxidase activity, was induced in WT plants infected with X. fastidiosa, but not in mutant plants, while the expression of the other 5 genes did not change. These results suggest that X. fastidiosa is somehow perceived by the CC-NBS-LRR, possibly activating the expression of MOA2.2 in A. thaliana.

Financial Support: FAPESP, CNPq/INCT Citros.