Tobacco transcriptome análisis in response to Xanthomonas axonopodis pv. citri.

DAURELIO, L.D; PETROCELLI, S; OTTADO, J.; ORELLANO, E.G.

Rosario

Congreso; XLII Reunión Anual de SAIB (Sociedad Argentina de Investigación en Bioquímica y Biología Molecular); 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Citrus canker is an endemic disease caused by Xanthomonas axonopodis pv. citri (Xac) which produces serious economic losses. There are not resistant citrus cultivars to citrus canker but the bacteria is able to induce hypersensitive response (HR) in non-host plants. In this context, we have studied the tobacco-Xac interaction to identify plant genes that modify their expression in the response to Xac. We used the cDNA-AFLP technique to analyze changes in transcript levels at 2, 8 and 24 hs postinoculation (hpi). We used forty primers combinations (which represent 20 % of the whole tobacco transcriptome) and obtained about 2000 transcript derived fragment (TDFs). Differential expression was observed in 316 TDFs (2.8 %): 178 TDFs (1.6 %) were up-regulated, 56 at 2 hpi (0.5 %), 101 at 8 hpi (0.9 %) and 21 at 24 hpi (0.2 %); 138 TDFs (1.2 %) were downregulated, 25 at 2 hpi (0.2 %), 76 at 8 hpi (0.7 %) and 37 at 24 hpi (0.3 %). Our results indicate that the main variations at the transcriptional level in tobacco-Xac interaction occurs at 8 hpi, with a similar number of genes up and down-regulated. In addition a significant percentage of genes are up-regulated at 2 hpi. Analyses of TDFs sequences may reveal insights about tobacco defense genes in HR response.