Chloroplast redox status modulates genome-wide plant responses during plant-microbe interaction

Down-regulation of reactive oxygen species build-up in chloroplasts by expression of a plastid-targeted flavodoxin (Fld) delayed localized cell death in tobacco leaves inoculated with the non-host bacterium Xanthomonas campestris pv. vesicatoria (Xcv), while other defensive responses were unaffected. To better understand these effects we compared the transcriptomic alterations caused by Xcv inoculation on leaves of Fld-expressing tobacco plants and their wild-type siblings. Gene expression in tobacco leaves was measured at 19 hours after infiltration with a suspension of 10^8 CFU/ml of Xanthomonas campestris pv. vesicatoria. Control conditions were carried out infiltrating with mock solution (10 mM MgCl2). The analysed tobacco lines were the trangenic line pfld4-2, which expresses flavodoxin in their chloroplasts, and their wild type siblings. Two pooled biological replicates were used for each treatment and line.