Transcriptome profiling of two olive cultivars in response to Xylella fastidiosa infection

Olive Quick Decline Syndrome (OQDS) is a destructive disease of olive (Olea europaea) described in Apulia (Italy), to which the CoDiRO strain of Xylella fastidiosa subsp. pauca (Xfp) is associated. Differently from the severely affected cv. Ogliarola salentina, Xfp-infected plants of the cv. Leccino develop reduced symptoms, which are compatible with olive production. Comparison of the transcriptomes of the two olive cultivars, infected or not by Xfp, was performed to ascertain whether a tolerant condition of cv. Leccino exists, which could be exploited for lessening the economic impact of the disease on the local olive industry. 659 and 447 genes were differentially regulated in Xfp infected cvs Leccino and Ogliarola salentina, respectively, whereas expression of 512 genes was altered between the two infected cultivars. The study indicated that plants of both cultivars perceive the presence of Xfp, mainly involving cell wall-associated proteins. The tolerant response of cv. Leccino, which is missing in cv. Ogliarola salentina, consists on the up-regulation of genes encoding receptor-like kinases and receptor-like proteins. Likely, the active response of the cv. Leccino is responsible for a lower pathogen concentration, suggesting that it may harbor genetic constituents and/or regulatory elements which counteract Xfp infection. These findings suggest that cv. Leccino is endowed with an intrinsic tolerance to Xfp, which makes it eligible for further studies